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  • NetApp erroring with: STATUS_NOLOGON_WORKSTATION_TRUST_ACCOUNT

    - by Sobrique
    Since a sitewide upgrade to Windows 7 on desktop, I've started having a problem with virus checking. Specifically - when doing a rename operation on a (filer hosted) CIFS share. The virus checker seems to be triggering a set of messages on the filer: [filerB: auth.trace.authenticateUser.loginTraceIP:info]: AUTH: Login attempt by user server-wk8-r2$ of domain MYDOMAIN from client machine 10.1.1.20 (server-wk8-r2). [filerB: auth.dc.trace.DCConnection.statusMsg:info]: AUTH: TraceDC- attempting authentication with domain controller \\MYDC. [filerB: auth.trace.authenticateUser.loginRejected:info]: AUTH: Login attempt by user rejected by the domain controller with error 0xc0000199: STATUS_NOLOGON_WORKSTATION_TRUST_ACCOUNT. [filerB: auth.trace.authenticateUser.loginTraceMsg:info]: AUTH: Delaying the response by 5 seconds due to continuous failed login attempts by user server-wk8-r2$ of domain MYDOMAIN from client machine 10.1.1.20. This seems to specifically trigger on a rename so what we think is going on is the virus checker is seeing a 'new' file, and trying to do an on-access scan. The virus checker - previously running as LocalSystem and thus sending null as it's authentication request is now looking rather like a DOS attack, and causing the filer to temporarily black list. This 5s lock out each 'access attempt' is a minor nuisance most of the time, and really quite significant for some operations - e.g. large file transfers, where every file takes 5s Having done some digging, this seems to be related to NLTM authentication: Symptoms Error message: System error 1808 has occurred. The account used is a computer account. Use your global user account or local user account to access this server. A packet trace of the failure will show the error as: STATUS_NOLOGON_WORKSTATION_TRUST_ACCOUNT (0xC0000199) Cause Microsoft has changed the functionality of how a Local System account identifies itself during NTLM authentication. This only impacts NTLM authentication. It does not impact Kerberos Authentication. Solution On the host, please set the following group policy entry and reboot the host. Network Security: Allow Local System to use computer identity for NTLM: Disabled Defining this group policy makes Windows Server 2008 R2 and Windows 7 function like Windows Server 2008 SP1. So we've now got a couple of workaround which aren't particularly nice - one is to change this security option. One is to disable virus checking, or otherwise exempt part of the infrastructure. And here's where I come to my request for assistance from ServerFault - what is the best way forwards? I lack Windows experience to be sure of what I'm seeing. I'm not entirely sure why NTLM is part of this picture in the first place - I thought we were using Kerberos authentication. I'm not sure how to start diagnosing or troubleshooting this. (We are going cross domain - workstation machine accounts are in a separate AD and DNS domain to my filer. Normal user authentication works fine however.) And failing that, can anyone suggest other lines of enquiry? I'd like to avoid a site wide security option change, or if I do go that way I'll need to be able to supply detailed reasoning. Likewise - disabling virus checking works as a short term workaround, and applying exclusions may help... but I'd rather not, and don't think that solves the underlying problem. EDIT: Filers in AD ldap have SPNs for: nfs/host.fully.qualified.domain nfs/host HOST/host.fully.qualified.domain HOST/host (Sorry, have to obfuscate those). Could it be that without a 'cifs/host.fully.qualified.domain' it's not going to work? (or some other SPN? ) Edit: As part of the searching I've been doing I've found: http://itwanderer.wordpress.com/2011/04/14/tread-lightly-kerberos-encryption-types/ Which suggests that several encryption types were disabled by default in Win7/2008R2. This might be pertinent, as we've definitely had a similar problem with Keberized NFSv4. There is a hidden option which may help some future Keberos users: options nfs.rpcsec.trace on (This hasn't given me anything yet though, so may just be NFS specific). Edit: Further digging has me tracking it back to cross domain authentication. It looks like my Windows 7 workstation (in one domain) is not getting Kerberos tickets for the other domain, in which my NetApp filer is CIFS joined. I've done this separately against a standalone server (Win2003 and Win2008) and didn't get Kerberos tickets for those either. Which means I think Kerberos might be broken, but I've no idea how to troubleshoot further. Edit: A further update: It looks like this may be down Kerberos tickets not being issued cross domain. This then triggers NTLM fallback, which then runs into this problem (since Windows 7). First port of call will be to investigate the Kerberos side of things, but in neither case do we have anything pointing at the Filer being the root cause. As such - as the storage engineer - it's out of my hands. However, if anyone can point me in the direction of troubleshooting Kerberos spanning two Windows AD domains (Kerberos Realms) then that would be appreciated. Options we're going to be considering for resolution: Amend policy option on all workstations via GPO (as above). Talking to AV vendor about the rename triggering scanning. Talking to AV vendor regarding running AV as service account. investigating Kerberos authentication (why it's not working, whether it should be).

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  • Trying get dynamic content hole-punched through Magento's Full Page Cache

    - by rlflow
    I am using Magento Enterprise 1.10.1.1 and need to get some dynamic content on our product pages. I am inserting the current time in a block to quickly see if it is working, but can't seem to get through full page cache. I have tried a variety of implementations found here: http://tweetorials.tumblr.com/post/10160075026/ee-full-page-cache-hole-punching http://oggettoweb.com/blog/customizations-compatible-magento-full-page-cache/ http://magentophp.blogspot.com/2011/02/magento-enterprise-full-page-caching.html (http://www.exploremagento.com/magento/simple-custom-module.php - custom module) Any solutions, thoughts, comments, advice is welcome. here is my code: app/code/local/Fido/Example/etc/config.xml <?xml version="1.0"?> <config> <modules> <Fido_Example> <version>0.1.0</version> </Fido_Example> </modules> <global> <blocks> <fido_example> <class>Fido_Example_Block</class> </fido_example> </blocks> </global> </config> app/code/local/Fido/Example/etc/cache.xml <?xml version="1.0" encoding="UTF-8"?> <config> <placeholders> <fido_example> <block>fido_example/view</block> <name>example</name> <placeholder>CACHE_TEST</placeholder> <container>Fido_Example_Model_Container_Cachetest</container> <cache_lifetime>86400</cache_lifetime> </fido_example> </placeholders> </config> app/code/local/Fido/Example/Block/View.php <?php /** * Example View block * * @codepool Local * @category Fido * @package Fido_Example * @module Example */ class Fido_Example_Block_View extends Mage_Core_Block_Template { private $message; private $att; protected function createMessage($msg) { $this->message = $msg; } public function receiveMessage() { if($this->message != '') { return $this->message; } else { $this->createMessage('Hello World'); return $this->message; } } protected function _toHtml() { $html = parent::_toHtml(); if($this->att = $this->getMyCustom() && $this->getMyCustom() != '') { $html .= '<br />'.$this->att; } else { $now = date('m-d-Y h:i:s A'); $html .= $now; $html .= '<br />' ; } return $html; } } app/code/local/Fido/Example/Model/Container/Cachetest.php <?php class Fido_Example_Model_Container_Cachetest extends Enterprise_PageCache_Model_Container_Abstract { protected function _getCacheId() { return 'HOMEPAGE_PRODUCTS' . md5($this->_placeholder->getAttribute('cache_id') . $this->_getIdentifier()); } protected function _renderBlock() { $blockClass = $this->_placeholder->getAttribute('block'); $template = $this->_placeholder->getAttribute('template'); $block = new $blockClass; $block->setTemplate($template); return $block->toHtml(); } protected function _saveCache($data, $id, $tags = array(), $lifetime = null) { return false; } } app/design/frontend/enterprise/[mytheme]/template/example/view.phtml <?php /** * Fido view template * * @see Fido_Example_Block_View * */ ?> <div> <?php echo $this->receiveMessage(); ?> </span> </div> snippet from app/design/frontend/enterprise/[mytheme]/layout/catalog.xml <reference name="content"> <block type="catalog/product_view" name="product.info" template="catalog/product/view.phtml"> <block type="fido_example/view" name="product.info.example" as="example" template="example/view.phtml" />

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  • Migrate Spring JPA DAO unit testing to google app engine

    - by twingocerise
    I'm trying to put together a simple environment where I can get Spring, Maven, JPA, Google App Engine and DAO unit testing working happily all together. The goal is to be able to run a simple DAO unit test creating an entity and then load it again with a simple find to check it's been created properly - all of this from my maven build. My dao is making use of the JPA entity manager (query(), persist(), etc.) I've got it working no problem with hsqldb and a datasource, etc. but I'm struggling to get it working with appengine. My questions are: 1) I'm using an entity manager, injecting my persistence unit as followed. Is it OK? Is there any need for a datasource or something special? I thought not but correct me if I'm wrong. applicationContext.xml <bean id='entityManagerFactory' class='org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean'> <property name="persistenceUnitName" value="transactions-optional" /> </bean> Persistence.xml <persistence-unit name="transactions-optional"> <provider>org.datanucleus.store.appengine.jpa.DatastorePersistenceProvider</provider> <properties> <property name="datanucleus.NontransactionalRead" value="true"/> <property name="datanucleus.NontransactionalWrite" value="true"/> <property name="datanucleus.ConnectionURL" value="appengine"/> </properties> </persistence-unit> 2) what are the dependencies I need to add to my pom file to be able to run the unit test making use of the entityManager? What about versions ? I found loads of things about appengine-api-labs/stubs/testing but none them got it working i.e. I'm getting jdo dependency missing while I'm using JPA... I also get loads of conflicts when I try to add some jars (datanucleus and stuff). So far I'm trying appengine-api-1.0-sdk v1.7.0 - ASM-all v3.3 - datanucleus core/api-jpa/enhancer v3.1.0 - datanucleus-appengine v2.0.1.1 and all the gae testing jars v1.7.0 3) Is there anything I need to add to my surefire plugin (test runner) to make sure it picks up all the dependencies? I'm getting an exhausting ClassNotFound on DatastorePersistenceProvider while it is in my classpath (I checked the jars and the mvn dependency:tree) I had a look at this but it doesn't seem to be working at all: http://www.vertigrated.com/blog/2011/02/working-maven-3-google-app-engine-plugin-with-gwt-support/ 4) Do I need to use any sot of localhelper to test my DAOs? Ideally I'd want to test my dao layer "as is" with the entity manager... what's your opinion ? Has anyone managed to run a unit test using JPA on google app engine ? 5) Do I need to set up any sort of gae.home somewhere in my pom file? Would anyone make use of it (a plugin or something) ? 6) Is the gwt-maven plugin any helpful if I don't use gwt - I'm writing a simple webservice making use of appengine, not a GWT app... Any help would be much appreciated as I've been struggling for 2 days now... Cheers, V.

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  • not able to style a ul inside a nav tag

    - by user1831677
    I am trying to make a nav menu for my website and have been using http://www.onextrapixel.com/2011/06/03/how-to-create-a-horizontal-dropdown-menu-with-html-css-and-jquery/ as a guide. It has worked fine but as soon as I try to add ( id="coolMenu" ) to the nav tag it stops working. I took it away from the ul tag and added it to the nav tag and it no longer works. It does not display anything at all. What am in doing wrong? Thanks. html code below: <nav id="coolMenu"> <ul> <li><a href="#">Lorem</a></li> <li><a href="#">Mauricii</a></li> <li> <a href="#">Periher</a> <ul class="noJS"> <li><a href="#">Hellenico</a></li> <li><a href="#">Genere</a></li> <li><a href="#">Indulgentia</a></li> </ul> </li> <li><a href="#">Tyrio</a></li> <li><a href="#">Quicumque</a></li> </ul> </nav> css below: /* Structure ------------------------------------------*/ #coolMenu, #coolMenu ul { list-style: none; } #coolMenu { float: left; } #coolMenu > li { float: left; } #coolMenu li a { display: block; height: 2em; line-height: 2em; padding: 0 1.5em; text-decoration: none; } #coolMenu ul { position: absolute; display: none; z-index: 999; } #coolMenu ul li a { width: 80px; } #coolMenu li:hover ul.noJS { display: block; } /* Main menu ------------------------------------------*/ #coolMenu { font-family: Arial; font-size: 12px; background: #2f8be8; } #coolMenu > li > a { color: #fff; font-weight: bold; } #coolMenu > li:hover > a { background: #f09d28; color: #000; } /* Submenu ------------------------------------------*/ #coolMenu ul { background: #f09d28; } #coolMenu ul li a { color: #000; } #coolMenu ul li:hover a { background: #ffc97c; }

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  • unpack dependency and repack classes using maven?

    - by u123
    I am trying to unpack a maven artifact A and repack it into a new jar file in the maven project B. Unpacking class files from artifact A into: <my.classes.folder>${project.build.directory}/staging</my.classes.folder> works fine using this: <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-dependency-plugin</artifactId> <executions> <execution> <id>unpack</id> <phase>generate-resources</phase> <goals> <goal>unpack</goal> </goals> <configuration> <artifactItems> <artifactItem> <groupId>com.test</groupId> <artifactId>mvn-sample</artifactId> <version>1.0.0-SNAPSHOT</version> <type>jar</type> <overWrite>true</overWrite> <outputDirectory>${my.classes.folder}</outputDirectory> <includes>**/*.class,**/*.xml</includes> </artifactItem> </artifactItems> </configuration> </execution> </executions> </plugin> In the same pom I now want to generate an additional jar containing the classes just unpacked: <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-jar-plugin</artifactId> <version>2.4</version> <executions> <execution> <phase>package</phase> <goals> <goal>jar</goal> </goals> <configuration> <classesdirectory>${my.classes.folder}</classesdirectory> <classifier>sample</classifier> </configuration> </execution> </executions> </plugin> A new jar is created but it does not contain the classes from the: ${my.classes.folder} its simply a copy of the default project jar. Any ideas? I have tried to follow this guide: http://jkrishnaraotech.blogspot.dk/2011/06/unpack-remove-some-classes-and-repack.html but its not working.

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  • Android onClickListener options and help on creating a non-static array adapter

    - by CoderInTraining
    I am trying to make an application that gets data dynamically and displays it in a listView. Here is my code that I have with static data. There are a couple of things I want to try and do and can't figure out how. MainActivity.java package text.example.project; import java.util.ArrayList; import java.util.Arrays; import java.util.Collections; import android.app.ListActivity; import android.os.Bundle; import android.view.View; import android.widget.AdapterView; import android.widget.AdapterView.OnItemClickListener; import android.widget.ArrayAdapter; import android.widget.ListView; import android.widget.TextView; import android.widget.Toast; public class MainActivity extends ListActivity { //declarations private boolean isItem; private ArrayAdapter<String> item1Adapter; private ArrayAdapter<String> item2Adapter; private ArrayAdapter<String> item3Adapter; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); Collections.sort(ITEM1); Collections.sort(ITEM2); Collections.sort(ITEM3); item1Adapter = new ArrayAdapter<String>(this, R.layout.list_item, ITEM1); item2Adapter = new ArrayAdapter<String>(this, R.layout.list_item, ITEM2); item3Adapter = new ArrayAdapter<String>(this, R.layout.list_item, ITEM3); setListAdapter(item1Adapter); isItem = true; ListView lv = getListView(); lv.setTextFilterEnabled(true); lv.setOnItemClickListener(new OnItemClickListener() { @Override public void onItemClick(AdapterView<?> parent, View view, int position, long id) { // When clicked, show a toast with the TextView text if (isItem) { //ITEM1.add("another\n\t" + Calendar.getInstance().getTime()); Collections.sort(ITEM1); item2Adapter.notifyDataSetChanged(); setListAdapter(item2Adapter); isItem = false; } else { item1Adapter.notifyDataSetChanged(); setListAdapter(item1Adapter); isItem = true; } Toast.makeText(getApplicationContext(), ((TextView) view).getText(), Toast.LENGTH_SHORT).show(); } }); } // need to turn dynamic static ArrayList<String> ITEM1 = new ArrayList<String> (Arrays.asList( "ITEM1-1", "ITEM1-2" )); static ArrayList<String> ITEM2 = new ArrayList<String> (Arrays.asList( "ITEM2-1", "ITEM2-2" )); static ArrayList<String> ITEM3 = new ArrayList<String> (Arrays.asList("ITEM3-1", "ITEM3-2")); } list_item.xml <?xml version="1.0" encoding="utf-8"?> <TextView xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" android:padding="10dp" android:textSize="16sp" > </TextView> What I want to do is first pull from a dynamic source. I need to do what is almost exactly like this tutorial... http://androiddevelopement.blogspot.in/2011/06/android-xml-parsing-tutorial-using.html ... however, I can't get the tutorial to work... I also would like to know how I can make the list item clicks so that if I click on "ITEM1-1" it goes to the menu "ITEM2-1" and "ITEM2-2". and if "ITEM1-2" is clicked, then it goes to the menu with "ITEM3-1" and "ITEM3-2"... I am totally a noob at this whole android development thing. So any suggestions would be great!

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  • Productivity Tips

    - by Brian T. Jackett
    A few months ago during my first end of year review at Microsoft I was doing an assessment of my year.  One of my personal goals to come out of this reflection was to improve my personal productivity.  While I hear many people say “I wish I had more hours in the day so that I could get more done” I feel like that is the wrong approach.  There is an inherent assumption that you are being productive with your time that you already have and thus more time would allow you to be as productive given more time.    Instead of wishing I could add more hours to the day I’ve begun adopting a number of processes or behavior changes in my personal life to make better use of my time with the goal of improving productivity.  The areas of focus are as follows: Focus Processes Tools Personal health Email Note: A number of these topics have spawned from reading Scott Hanselman’s blog posts on productivity, reading of David Allen’s book Getting Things Done, and discussions with friends and coworkers who had great insights into this topic.   Focus Pre-reading / viewing: Overcome your work addiction Millennials paralyzed by choice Its Not What You Read Its What You Ignore (Scott Hanselman video)    I highly recommend Scott Hanselman’s video above and this post before continuing with this article.  It is well worth the 40+ mins price of admission for the video and couple minutes for article.  One key takeaway for me was listing out my activities in an average week and realizing which ones held little or no value to me.  We all have a finite amount of time to work each day.  Do you know how much time and effort you spend on various aspects of your life (family, friends, religion, work, personal happiness, etc.)?  Do your actions and commitments reflect your priorities?    The biggest time consumers with little value for me were time spent on social media services (Twitter and Facebook), playing an MMO video game, and watching TV.  I still check up on Facebook, Twitter, Microsoft internal chat forums, and other services to keep contact with others but I’ve reduced that time significantly.  As for TV I’ve cut the cord and no longer subscribe to cable TV.  Instead I use Netflix, RedBox, and over the air channels but again with reduced time consumption.  With the time I’ve freed up I’m back to working out 2-3 times a week and reading 4 nights a week (both of which I had been neglecting previously).  I’ll mention a few tools for helping measure your time in the Tools section.   Processes    Do not multi-task.  I’ll say it again.  Do not multi-task.  There is no such thing as multi tasking.  The human brain is optimized to work on one thing at a time.  When you are “multi-tasking” you are really doing 2 or more things at less than 100%, usually by a wide margin.  I take pride in my work and when I’m doing something less than 100% the results typically degrade rapidly.    Now there are some ways of bending the rules of physics for this one.  There is the notion of getting a double amount of work done in the same timeframe.  Some examples would be listening to podcasts / watching a movie while working out, using a treadmill as your work desk, or reading while in the bathroom.    Personally I’ve found good results in combining one task that does not require focus (making dinner, playing certain video games, working out) and one task that does (watching a movie, listening to podcasts).  I believe this is related to me being a visual and kinesthetic (using my hands or actually doing it) learner.  I’m terrible with auditory learning.  My fiance and I joke that sometimes we talk and talk to each other but never really hear each other.   Goals / Tasks    Goals can give us direction in life and a sense of accomplishment when we complete them.  Goals can also overwhelm us and give us a sense of failure when we don’t complete them.  I propose that you shift your perspective and not dwell on all of the things that you haven’t gotten done, but focus instead on regularly setting measureable goals that are within reason of accomplishing.    At the end of each time frame have a retrospective to review your progress.  Do not feel guilty about what you did not accomplish.  Feel proud of what you did accomplish and readjust your goals for the next time frame to more attainable goals.  Here is a sample schedule I’ve seen proposed by some.  I have not consistently set goals for each timeframe, but I do typically set 3 small goals a day (this blog post is #2 for today). Each day set 3 small goals Each week set 3 medium goals Each month set 1 large goal Each year set 2 very large goals   Tools    Tools are an extension of our human body.  They help us extend beyond what we can physically and mentally do.  Below are some tools I use almost daily or have found useful as of late. Disclaimer: I am not getting endorsed to promote any of these products.  I just happen to like them and find them useful. Instapaper – Save internet links for reading later.  There are many tools like this but I’ve found this to be a great one.  There is even a “read it later” JavaScript button you can add to your browser so when you navigate to a site it will then add this to your list. Stacks for Instapaper – A Windows Phone 7 app for reading my Instapaper articles on the go.  It does require a subscription to Instapaper (nominal $3 every three months) but is easily worth the cost.  Alternatively you can set up your Kindle to sync with Instapaper easily but I haven’t done so. SlapDash Podcast – Apps for Windows Phone and  Windows 8 (possibly other platforms) to sync podcast viewing / listening across multiple devices.  Now that I have my Surface RT device (which I love) this is making my consumption easier to manage. Feed Reader – Simple Windows 8 app for quickly catching up on my RSS feeds.  I used to have hundreds of unread items all the time.  Now I’m down to 20-50 regularly and it is much easier and faster to consume on my Surface RT.  There is also a free version (which I use) and I can’t see much different between the free and paid versions currently. Rescue Time – Have you ever wondered how much time you’ve spent on websites vs. email vs. “doing work”?  This service tracks your computer actions and then lets you report on them.  This can help you quantitatively identify areas where your actions are not in line with your priorities. PowerShell – Windows automation tool.  It is now built into every client and server OS.  This tool has saved me days (and I mean the full 24 hrs worth) of time and effort in the past year alone.  If you haven’t started learning PowerShell and you administrating any Windows OS or server product you need to start today. Various blogging tools – I wrote a post a couple years ago called How I Blog about my blogging process and tools used.  Almost all of it still applies today.   Personal Health    Some of these may be common sense or debatable, but I’ve found them to help prioritize my daily activities. Get plenty of sleep on a regular basis.  Sacrificing sleep too many nights a week negatively impacts your cognition, attitude, and overall health. Exercise at least three days.  Exercise could be lifting weights, taking the stairs up multiple flights of stairs, walking for 20 mins, or a number of other "non-traditional” activities.  I find that regular exercise helps with sleep and improves my overall attitude. Eat a well balanced diet.  Too much sugar, caffeine, junk food, etc. are not good for your body.  This is not a matter of losing weight but taking care of your body and helping you perform at your peak potential.   Email    Email can be one of the biggest time consumers (i.e. waster) if you aren’t careful. Time box your email usage.  Set a meeting invite for yourself if necessary to limit how much time you spend checking email. Use rules to prioritize your email.  Email from external customers, my manager, or include me directly on the To line go into my inbox.  Everything else goes a level down and I have 30+ rules to further sort it, mostly distribution lists. Use keyboard shortcuts (when available).  I use Outlook for my primary email and am constantly hitting Alt + S to send, Ctrl + 1 for my inbox, Ctrl + 2 for my calendar, Space / Tab / Shift + Tab to mark items as read, and a number of other useful commands.  Learn them and you’ll see your speed getting through emails increase. Keep emails short.  No one Few people like reading through long emails.  The first line should state exactly why you are sending the email followed by a 3-4 lines to support it.  Anything longer might be better suited as a phone call or in person discussion.   Conclusion    In this post I walked through various tips and tricks I’ve found for improving personal productivity.  It is a mix of re-focusing on the things that matter, using tools to assist in your efforts, and cutting out actions that are not aligned with your priorities.  I originally had a whole section on keyboard shortcuts, but with my recent purchase of the Surface RT I’m finding that touch gestures have replaced numerous keyboard commands that I used to need.  I see a big future in touch enabled devices.  Hopefully some of these tips help you out.  If you have any tools, tips, or ideas you would like to share feel free to add in the comments section.         -Frog Out   Links Scott Hanselman Productivity posts http://www.hanselman.com/blog/CategoryView.aspx?category=Productivity Overcome your work addiction http://blogs.hbr.org/hbsfaculty/2012/05/overcome-your-work-addiction.html?awid=5512355740280659420-3271   Millennials paralyzed by choice http://priyaparker.com/blog/millennials-paralyzed-by-choice   Its Not What You Read Its What You Ignore (video) http://www.hanselman.com/blog/ItsNotWhatYouReadItsWhatYouIgnoreVideoOfScottHanselmansPersonalProductivityTips.aspx   Cutting the cord – Jeff Blankenburg http://www.jeffblankenburg.com/2011/04/06/cutting-the-cord/   Building a sitting standing desk – Eric Harlan http://www.ericharlan.com/Everything_Else/building-a-sitting-standing-desk-a229.html   Instapaper http://www.instapaper.com/u   Stacks for Instapaper http://www.stacksforinstapaper.com/   Slapdash Podcast Windows Phone -  http://www.windowsphone.com/en-us/store/app/slapdash-podcasts/90e8b121-080b-e011-9264-00237de2db9e Windows 8 - http://apps.microsoft.com/webpdp/en-us/app/slapdash-podcasts/0c62e66a-f2e4-4403-af88-3430a821741e/m/ROW   Feed Reader http://apps.microsoft.com/webpdp/en-us/app/feed-reader/d03199c9-8e08-469a-bda1-7963099840cc/m/ROW   Rescue Time http://www.rescuetime.com/   PowerShell Script Center http://technet.microsoft.com/en-us/scriptcenter/bb410849.aspx

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  • Exam 70-480 Study Material: Programming in HTML5 with JavaScript and CSS3

    - by Stacy Vicknair
    Here’s a list of sources of information for the different elements that comprise the 70-480 exam: General Resources http://www.w3schools.com (As pointed out in David Pallmann’s blog some of this content is unverified, but it is a decent source of information. For more about when it isn’t decent, see http://www.w3fools.com ) http://www.bloggedbychris.com/2012/09/19/microsoft-exam-70-480-study-guide/ (A guy who did a lot of what I did already, sadly I found this halfway through finishing my resources list. This list is expertly put together so I would recommend checking it out.) http://davidpallmann.blogspot.com/2012/08/microsoft-certification-exam-70-480.html http://pluralsight.com/training/Courses (Yes, this isn’t free, but if you look at the course listing there is an entire section on HTML5, CSS3 and Javascript. You can always try the trial!)   Some of the links I put below will overlap with the other resources above, but I tried to find explanations that looked beneficial to me on links outside those already mentioned.   Test Breakdown Implement and Manipulate Document Structures and Objects (24%) Create the document structure. o This objective may include but is not limited to: structure the UI by using semantic markup, including for search engines and screen readers (Section, Article, Nav, Header, Footer, and Aside); create a layout container in HTML http://www.w3schools.com/html/html5_new_elements.asp   Write code that interacts with UI controls. o This objective may include but is not limited to: programmatically add and modify HTML elements; implement media controls; implement HTML5 canvas and SVG graphics http://www.w3schools.com/html/html5_canvas.asp http://www.w3schools.com/html/html5_svg.asp   Apply styling to HTML elements programmatically. o This objective may include but is not limited to: change the location of an element; apply a transform; show and hide elements   Implement HTML5 APIs. o This objective may include but is not limited to: implement storage APIs, AppCache API, and Geolocation API http://www.w3schools.com/html/html5_geolocation.asp http://www.w3schools.com/html/html5_webstorage.asp http://www.w3schools.com/html/html5_app_cache.asp   Establish the scope of objects and variables. o This objective may include but is not limited to: define the lifetime of variables; keep objects out of the global namespace; use the “this” keyword to reference an object that fired an event; scope variables locally and globally http://robertnyman.com/2008/10/09/explaining-javascript-scope-and-closures/ http://www.quirksmode.org/js/this.html   Create and implement objects and methods. o This objective may include but is not limited to: implement native objects; create custom objects and custom properties for native objects using prototypes and functions; inherit from an object; implement native methods and create custom methods http://www.javascriptkit.com/javatutors/object.shtml http://www.crockford.com/javascript/inheritance.html http://stackoverflow.com/questions/1635116/javascript-class-method-vs-class-prototype-method http://www.javascriptkit.com/javatutors/proto.shtml     Implement Program Flow (25%) Implement program flow. o This objective may include but is not limited to: iterate across collections and array items; manage program decisions by using switch statements, if/then, and operators; evaluate expressions http://www.javascriptkit.com/jsref/looping.shtml http://www.javascriptkit.com/javatutors/varshort.shtml http://www.javascriptkit.com/javatutors/switch.shtml   Raise and handle an event. o This objective may include but is not limited to: handle common events exposed by DOM (OnBlur, OnFocus, OnClick); declare and handle bubbled events; handle an event by using an anonymous function http://dev.w3.org/2006/webapi/DOM-Level-3-Events/html/DOM3-Events.html http://javascript.info/tutorial/bubbling-and-capturing   Implement exception handling. o This objective may include but is not limited to: set and respond to error codes; throw an exception; request for null checks; implement try-catch-finally blocks http://www.javascriptkit.com/javatutors/trycatch.shtml   Implement a callback. o This objective may include but is not limited to: receive messages from the HTML5 WebSocket API; use jQuery to make an AJAX call; wire up an event; implement a callback by using anonymous functions; handle the “this” pointer http://www.w3.org/TR/2011/WD-websockets-20110419/ http://www.html5rocks.com/en/tutorials/websockets/basics/ http://api.jquery.com/jQuery.ajax/   Create a web worker process. o This objective may include but is not limited to: start and stop a web worker; pass data to a web worker; configure timeouts and intervals on the web worker; register an event listener for the web worker; limitations of a web worker https://developer.mozilla.org/en-US/docs/DOM/Using_web_workers http://www.html5rocks.com/en/tutorials/workers/basics/   Access and Secure Data (26%) Validate user input by using HTML5 elements. o This objective may include but is not limited to: choose the appropriate controls based on requirements; implement HTML input types and content attributes (for example, required) to collect user input http://diveintohtml5.info/forms.html   Validate user input by using JavaScript. o This objective may include but is not limited to: evaluate a regular expression to validate the input format; validate that you are getting the right kind of data type by using built-in functions; prevent code injection http://www.regular-expressions.info/javascript.html http://msdn.microsoft.com/en-us/library/66ztdbe6(v=vs.94).aspx https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Operators/typeof http://blog.stackoverflow.com/2008/06/safe-html-and-xss/ http://stackoverflow.com/questions/942011/how-to-prevent-javascript-injection-attacks-within-user-generated-html   Consume data. o This objective may include but is not limited to: consume JSON and XML data; retrieve data by using web services; load data or get data from other sources by using XMLHTTPRequest http://www.erichynds.com/jquery/working-with-xml-jquery-and-javascript/ http://www.webdevstuff.com/86/javascript-xmlhttprequest-object.html http://www.json.org/ http://stackoverflow.com/questions/4935632/how-to-parse-json-in-javascript   Serialize, deserialize, and transmit data. o This objective may include but is not limited to: binary data; text data (JSON, XML); implement the jQuery serialize method; Form.Submit; parse data; send data by using XMLHTTPRequest; sanitize input by using URI/form encoding http://api.jquery.com/serialize/ http://www.javascript-coder.com/javascript-form/javascript-form-submit.phtml http://stackoverflow.com/questions/327685/is-there-a-way-to-read-binary-data-into-javascript https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/encodeURI     Use CSS3 in Applications (25%) Style HTML text properties. o This objective may include but is not limited to: apply styles to text appearance (color, bold, italics); apply styles to text font (WOFF and @font-face, size); apply styles to text alignment, spacing, and indentation; apply styles to text hyphenation; apply styles for a text drop shadow http://www.w3schools.com/css/css_text.asp http://www.w3schools.com/css/css_font.asp http://nicewebtype.com/notes/2009/10/30/how-to-use-css-font-face/ http://webdesign.about.com/od/beginningcss/p/aacss5text.htm http://www.w3.org/TR/css3-text/ http://www.css3.info/preview/box-shadow/   Style HTML box properties. o This objective may include but is not limited to: apply styles to alter appearance attributes (size, border and rounding border corners, outline, padding, margin); apply styles to alter graphic effects (transparency, opacity, background image, gradients, shadow, clipping); apply styles to establish and change an element’s position (static, relative, absolute, fixed) http://net.tutsplus.com/tutorials/html-css-techniques/10-css3-properties-you-need-to-be-familiar-with/ http://www.w3schools.com/css/css_image_transparency.asp http://www.w3schools.com/cssref/pr_background-image.asp http://ie.microsoft.com/testdrive/graphics/cssgradientbackgroundmaker/default.html http://www.w3.org/TR/CSS21/visufx.html http://www.barelyfitz.com/screencast/html-training/css/positioning/ http://davidwalsh.name/css-fixed-position   Create a flexible content layout. o This objective may include but is not limited to: implement a layout using a flexible box model; implement a layout using multi-column; implement a layout using position floating and exclusions; implement a layout using grid alignment; implement a layout using regions, grouping, and nesting http://www.html5rocks.com/en/tutorials/flexbox/quick/ http://www.css3.info/preview/multi-column-layout/ http://msdn.microsoft.com/en-us/library/ie/hh673558(v=vs.85).aspx http://dev.w3.org/csswg/css3-grid-layout/ http://dev.w3.org/csswg/css3-regions/   Create an animated and adaptive UI. o This objective may include but is not limited to: animate objects by applying CSS transitions; apply 3-D and 2-D transformations; adjust UI based on media queries (device adaptations for output formats, displays, and representations); hide or disable controls http://www.bloggedbychris.com/2012/09/19/microsoft-exam-70-480-study-guide/   Find elements by using CSS selectors and jQuery. o This objective may include but is not limited to: choose the correct selector to reference an element; define element, style, and attribute selectors; find elements by using pseudo-elements and pseudo-classes (for example, :before, :first-line, :first-letter, :target, :lang, :checked, :first-child) http://www.bloggedbychris.com/2012/09/19/microsoft-exam-70-480-study-guide/   Structure a CSS file by using CSS selectors. o This objective may include but is not limited to: reference elements correctly; implement inheritance; override inheritance by using !important; style an element based on pseudo-elements and pseudo-classes (for example, :before, :first-line, :first-letter, :target, :lang, :checked, :first-child) http://www.bloggedbychris.com/2012/09/19/microsoft-exam-70-480-study-guide/   Technorati Tags: 70-480,CSS3,HTML5,HTML,CSS,JavaScript,Certification

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  • Building Simple Workflows in Oozie

    - by dan.mcclary
    Introduction More often than not, data doesn't come packaged exactly as we'd like it for analysis. Transformation, match-merge operations, and a host of data munging tasks are usually needed before we can extract insights from our Big Data sources. Few people find data munging exciting, but it has to be done. Once we've suffered that boredom, we should take steps to automate the process. We want codify our work into repeatable units and create workflows which we can leverage over and over again without having to write new code. In this article, we'll look at how to use Oozie to create a workflow for the parallel machine learning task I described on Cloudera's site. Hive Actions: Prepping for Pig In my parallel machine learning article, I use data from the National Climatic Data Center to build weather models on a state-by-state basis. NCDC makes the data freely available as gzipped files of day-over-day observations stretching from the 1930s to today. In reading that post, one might get the impression that the data came in a handy, ready-to-model files with convenient delimiters. The truth of it is that I need to perform some parsing and projection on the dataset before it can be modeled. If I get more observations, I'll want to retrain and test those models, which will require more parsing and projection. This is a good opportunity to start building up a workflow with Oozie. I store the data from the NCDC in HDFS and create an external Hive table partitioned by year. This gives me flexibility of Hive's query language when I want it, but let's me put the dataset in a directory of my choosing in case I want to treat the same data with Pig or MapReduce code. CREATE EXTERNAL TABLE IF NOT EXISTS historic_weather(column 1, column2) PARTITIONED BY (yr string) STORED AS ... LOCATION '/user/oracle/weather/historic'; As new weather data comes in from NCDC, I'll need to add partitions to my table. That's an action I should put in the workflow. Similarly, the weather data requires parsing in order to be useful as a set of columns. Because of their long history, the weather data is broken up into fields of specific byte lengths: x bytes for the station ID, y bytes for the dew point, and so on. The delimiting is consistent from year to year, so writing SerDe or a parser for transformation is simple. Once that's done, I want to select columns on which to train, classify certain features, and place the training data in an HDFS directory for my Pig script to access. ALTER TABLE historic_weather ADD IF NOT EXISTS PARTITION (yr='2010') LOCATION '/user/oracle/weather/historic/yr=2011'; INSERT OVERWRITE DIRECTORY '/user/oracle/weather/cleaned_history' SELECT w.stn, w.wban, w.weather_year, w.weather_month, w.weather_day, w.temp, w.dewp, w.weather FROM ( FROM historic_weather SELECT TRANSFORM(...) USING '/path/to/hive/filters/ncdc_parser.py' as stn, wban, weather_year, weather_month, weather_day, temp, dewp, weather ) w; Since I'm going to prepare training directories with at least the same frequency that I add partitions, I should also add that to my workflow. Oozie is going to invoke these Hive actions using what's somewhat obviously referred to as a Hive action. Hive actions amount to Oozie running a script file containing our query language statements, so we can place them in a file called weather_train.hql. Starting Our Workflow Oozie offers two types of jobs: workflows and coordinator jobs. Workflows are straightforward: they define a set of actions to perform as a sequence or directed acyclic graph. Coordinator jobs can take all the same actions of Workflow jobs, but they can be automatically started either periodically or when new data arrives in a specified location. To keep things simple we'll make a workflow job; coordinator jobs simply require another XML file for scheduling. The bare minimum for workflow XML defines a name, a starting point, and an end point: <workflow-app name="WeatherMan" xmlns="uri:oozie:workflow:0.1"> <start to="ParseNCDCData"/> <end name="end"/> </workflow-app> To this we need to add an action, and within that we'll specify the hive parameters Also, keep in mind that actions require <ok> and <error> tags to direct the next action on success or failure. <action name="ParseNCDCData"> <hive xmlns="uri:oozie:hive-action:0.2"> <job-tracker>localhost:8021</job-tracker> <name-node>localhost:8020</name-node> <configuration> <property> <name>oozie.hive.defaults</name> <value>/user/oracle/weather_ooze/hive-default.xml</value> </property> </configuration> <script>ncdc_parse.hql</script> </hive> <ok to="WeatherMan"/> <error to="end"/> </action> There are a couple of things to note here: I have to give the FQDN (or IP) and port of my JobTracker and NameNode. I have to include a hive-default.xml file. I have to include a script file. The hive-default.xml and script file must be stored in HDFS That last point is particularly important. Oozie doesn't make assumptions about where a given workflow is being run. You might submit workflows against different clusters, or have different hive-defaults.xml on different clusters (e.g. MySQL or Postgres-backed metastores). A quick way to ensure that all the assets end up in the right place in HDFS is just to make a working directory locally, build your workflow.xml in it, and copy the assets you'll need to it as you add actions to workflow.xml. At this point, our local directory should contain: workflow.xml hive-defaults.xml (make sure this file contains your metastore connection data) ncdc_parse.hql Adding Pig to the Ooze Adding our Pig script as an action is slightly simpler from an XML standpoint. All we do is add an action to workflow.xml as follows: <action name="WeatherMan"> <pig> <job-tracker>localhost:8021</job-tracker> <name-node>localhost:8020</name-node> <script>weather_train.pig</script> </pig> <ok to="end"/> <error to="end"/> </action> Once we've done this, we'll copy weather_train.pig to our working directory. However, there's a bit of a "gotcha" here. My pig script registers the Weka Jar and a chunk of jython. If those aren't also in HDFS, our action will fail from the outset -- but where do we put them? The Jython script goes into the working directory at the same level as the pig script, because pig attempts to load Jython files in the directory from which the script executes. However, that's not where our Weka jar goes. While Oozie doesn't assume much, it does make an assumption about the Pig classpath. Anything under working_directory/lib gets automatically added to the Pig classpath and no longer requires a REGISTER statement in the script. Anything that uses a REGISTER statement cannot be in the working_directory/lib directory. Instead, it needs to be in a different HDFS directory and attached to the pig action with an <archive> tag. Yes, that's as confusing as you think it is. You can get the exact rules for adding Jars to the distributed cache from Oozie's Pig Cookbook. Making the Workflow Work We've got a workflow defined and have collected all the components we'll need to run. But we can't run anything yet, because we still have to define some properties about the job and submit it to Oozie. We need to start with the job properties, as this is essentially the "request" we'll submit to the Oozie server. In the same working directory, we'll make a file called job.properties as follows: nameNode=hdfs://localhost:8020 jobTracker=localhost:8021 queueName=default weatherRoot=weather_ooze mapreduce.jobtracker.kerberos.principal=foo dfs.namenode.kerberos.principal=foo oozie.libpath=${nameNode}/user/oozie/share/lib oozie.wf.application.path=${nameNode}/user/${user.name}/${weatherRoot} outputDir=weather-ooze While some of the pieces of the properties file are familiar (e.g., JobTracker address), others take a bit of explaining. The first is weatherRoot: this is essentially an environment variable for the script (as are jobTracker and queueName). We're simply using them to simplify the directives for the Oozie job. The oozie.libpath pieces is extremely important. This is a directory in HDFS which holds Oozie's shared libraries: a collection of Jars necessary for invoking Hive, Pig, and other actions. It's a good idea to make sure this has been installed and copied up to HDFS. The last two lines are straightforward: run the application defined by workflow.xml at the application path listed and write the output to the output directory. We're finally ready to submit our job! After all that work we only need to do a few more things: Validate our workflow.xml Copy our working directory to HDFS Submit our job to the Oozie server Run our workflow Let's do them in order. First validate the workflow: oozie validate workflow.xml Next, copy the working directory up to HDFS: hadoop fs -put working_dir /user/oracle/working_dir Now we submit the job to the Oozie server. We need to ensure that we've got the correct URL for the Oozie server, and we need to specify our job.properties file as an argument. oozie job -oozie http://url.to.oozie.server:port_number/ -config /path/to/working_dir/job.properties -submit We've submitted the job, but we don't see any activity on the JobTracker? All I got was this funny bit of output: 14-20120525161321-oozie-oracle This is because submitting a job to Oozie creates an entry for the job and places it in PREP status. What we got back, in essence, is a ticket for our workflow to ride the Oozie train. We're responsible for redeeming our ticket and running the job. oozie -oozie http://url.to.oozie.server:port_number/ -start 14-20120525161321-oozie-oracle Of course, if we really want to run the job from the outset, we can change the "-submit" argument above to "-run." This will prep and run the workflow immediately. Takeaway So, there you have it: the somewhat laborious process of building an Oozie workflow. It's a bit tedious the first time out, but it does present a pair of real benefits to those of us who spend a great deal of time data munging. First, when new data arrives that requires the same processing, we already have the workflow defined and ready to run. Second, as we build up a set of useful action definitions over time, creating new workflows becomes quicker and quicker.

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  • Solving Big Problems with Oracle R Enterprise, Part I

    - by dbayard
    Abstract: This blog post will show how we used Oracle R Enterprise to tackle a customer’s big calculation problem across a big data set. Overview: Databases are great for managing large amounts of data in a central place with rigorous enterprise-level controls.  R is great for doing advanced computations.  Sometimes you need to do advanced computations on large amounts of data, subject to rigorous enterprise-level concerns.  This blog post shows how Oracle R Enterprise enables R plus the Oracle Database enabled us to do some pretty sophisticated calculations across 1 million accounts (each with many detailed records) in minutes. The problem: A financial services customer of mine has a need to calculate the historical internal rate of return (IRR) for its customers’ portfolios.  This information is needed for customer statements and the online web application.  In the past, they had solved this with a home-grown application that pulled trade and account data out of their data warehouse and ran the calculations.  But this home-grown application was not able to do this fast enough, plus it was a challenge for them to write and maintain the code that did the IRR calculation. IRR – a problem that R is good at solving: Internal Rate of Return is an interesting calculation in that in most real-world scenarios it is impractical to calculate exactly.  Rather, IRR is a calculation where approximation techniques need to be used.  In this blog post, we will discuss calculating the “money weighted rate of return” but in the actual customer proof of concept we used R to calculate both money weighted rate of returns and time weighted rate of returns.  You can learn more about the money weighted rate of returns here: http://www.wikinvest.com/wiki/Money-weighted_return First Steps- Calculating IRR in R We will start with calculating the IRR in standalone/desktop R.  In our second post, we will show how to take this desktop R function, deploy it to an Oracle Database, and make it work at real-world scale.  The first step we did was to get some sample data.  For a historical IRR calculation, you have a balances and cash flows.  In our case, the customer provided us with several accounts worth of sample data in Microsoft Excel.      The above figure shows part of the spreadsheet of sample data.  The data provides balances and cash flows for a sample account (BMV=beginning market value. FLOW=cash flow in/out of account. EMV=ending market value). Once we had the sample spreadsheet, the next step we did was to read the Excel data into R.  This is something that R does well.  R offers multiple ways to work with spreadsheet data.  For instance, one could save the spreadsheet as a .csv file.  In our case, the customer provided a spreadsheet file containing multiple sheets where each sheet provided data for a different sample account.  To handle this easily, we took advantage of the RODBC package which allowed us to read the Excel data sheet-by-sheet without having to create individual .csv files.  We wrote ourselves a little helper function called getsheet() around the RODBC package.  Then we loaded all of the sample accounts into a data.frame called SimpleMWRRData. Writing the IRR function At this point, it was time to write the money weighted rate of return (MWRR) function itself.  The definition of MWRR is easily found on the internet or if you are old school you can look in an investment performance text book.  In the customer proof, we based our calculations off the ones defined in the The Handbook of Investment Performance: A User’s Guide by David Spaulding since this is the reference book used by the customer.  (One of the nice things we found during the course of this proof-of-concept is that by using R to write our IRR functions we could easily incorporate the specific variations and business rules of the customer into the calculation.) The key thing with calculating IRR is the need to solve a complex equation with a numerical approximation technique.  For IRR, you need to find the value of the rate of return (r) that sets the Net Present Value of all the flows in and out of the account to zero.  With R, we solve this by defining our NPV function: where bmv is the beginning market value, cf is a vector of cash flows, t is a vector of time (relative to the beginning), emv is the ending market value, and tend is the ending time. Since solving for r is a one-dimensional optimization problem, we decided to take advantage of R’s optimize method (http://stat.ethz.ch/R-manual/R-patched/library/stats/html/optimize.html). The optimize method can be used to find a minimum or maximum; to find the value of r where our npv function is closest to zero, we wrapped our npv function inside the abs function and asked optimize to find the minimum.  Here is an example of using optimize: where low and high are scalars that indicate the range to search for an answer.   To test this out, we need to set values for bmv, cf, t, emv, tend, low, and high.  We will set low and high to some reasonable defaults. For example, this account had a negative 2.2% money weighted rate of return. Enhancing and Packaging the IRR function With numerical approximation methods like optimize, sometimes you will not be able to find an answer with your initial set of inputs.  To account for this, our approach was to first try to find an answer for r within a narrow range, then if we did not find an answer, try calling optimize() again with a broader range.  See the R help page on optimize()  for more details about the search range and its algorithm. At this point, we can now write a simplified version of our MWRR function.  (Our real-world version is  more sophisticated in that it calculates rate of returns for 5 different time periods [since inception, last quarter, year-to-date, last year, year before last year] in a single invocation.  In our actual customer proof, we also defined time-weighted rate of return calculations.  The beauty of R is that it was very easy to add these enhancements and additional calculations to our IRR package.)To simplify code deployment, we then created a new package of our IRR functions and sample data.  For this blog post, we only need to include our SimpleMWRR function and our SimpleMWRRData sample data.  We created the shell of the package by calling: To turn this package skeleton into something usable, at a minimum you need to edit the SimpleMWRR.Rd and SimpleMWRRData.Rd files in the \man subdirectory.  In those files, you need to at least provide a value for the “title” section. Once that is done, you can change directory to the IRR directory and type at the command-line: The myIRR package for this blog post (which has both SimpleMWRR source and SimpleMWRRData sample data) is downloadable from here: myIRR package Testing the myIRR package Here is an example of testing our IRR function once it was converted to an installable package: Calculating IRR for All the Accounts So far, we have shown how to calculate IRR for a single account.  The real-world issue is how do you calculate IRR for all of the accounts?This is the kind of situation where we can leverage the “Split-Apply-Combine” approach (see http://www.cscs.umich.edu/~crshalizi/weblog/815.html).  Given that our sample data can fit in memory, one easy approach is to use R’s “by” function.  (Other approaches to Split-Apply-Combine such as plyr can also be used.  See http://4dpiecharts.com/2011/12/16/a-quick-primer-on-split-apply-combine-problems/). Here is an example showing the use of “by” to calculate the money weighted rate of return for each account in our sample data set.  Recap and Next Steps At this point, you’ve seen the power of R being used to calculate IRR.  There were several good things: R could easily work with the spreadsheets of sample data we were given R’s optimize() function provided a nice way to solve for IRR- it was both fast and allowed us to avoid having to code our own iterative approximation algorithm R was a convenient language to express the customer-specific variations, business-rules, and exceptions that often occur in real-world calculations- these could be easily added to our IRR functions The Split-Apply-Combine technique can be used to perform calculations of IRR for multiple accounts at once. However, there are several challenges yet to be conquered at this point in our story: The actual data that needs to be used lives in a database, not in a spreadsheet The actual data is much, much bigger- too big to fit into the normal R memory space and too big to want to move across the network The overall process needs to run fast- much faster than a single processor The actual data needs to be kept secured- another reason to not want to move it from the database and across the network And the process of calculating the IRR needs to be integrated together with other database ETL activities, so that IRR’s can be calculated as part of the data warehouse refresh processes In our next blog post in this series, we will show you how Oracle R Enterprise solved these challenges.

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  • Oracle HRMS API – Create Employee

    - by PRajkumar
    API - hr_employee_api.create_employee Example --    -- Create Employee  -- ------------------------- DECLARE    lc_employee_number                       PER_ALL_PEOPLE_F.EMPLOYEE_NUMBER%TYPE    := 'PRAJ_01';  ln_person_id                                      PER_ALL_PEOPLE_F.PERSON_ID%TYPE;  ln_assignment_id                             PER_ALL_ASSIGNMENTS_F.ASSIGNMENT_ID%TYPE;  ln_object_ver_number                     PER_ALL_ASSIGNMENTS_F.OBJECT_VERSION_NUMBER%TYPE;  ln_asg_ovn                                          NUMBER;    ld_per_effective_start_date             PER_ALL_PEOPLE_F.EFFECTIVE_START_DATE%TYPE;  ld_per_effective_end_date              PER_ALL_PEOPLE_F.EFFECTIVE_END_DATE%TYPE;  lc_full_name                                        PER_ALL_PEOPLE_F.FULL_NAME%TYPE;  ln_per_comment_id                          PER_ALL_PEOPLE_F.COMMENT_ID%TYPE;  ln_assignment_sequence                 PER_ALL_ASSIGNMENTS_F.ASSIGNMENT_SEQUENCE%TYPE;  lc_assignment_number                    PER_ALL_ASSIGNMENTS_F.ASSIGNMENT_NUMBER%TYPE;    lb_name_combination_warning   BOOLEAN;  lb_assign_payroll_warning           BOOLEAN;  lb_orig_hire_warning                       BOOLEAN;   BEGIN            hr_employee_api.create_employee            (   -- Input data elements                 -- ------------------------------                p_hire_date                                         => TO_DATE('08-JUN-2011'),                p_business_group_id                      => fnd_profile.value_specific('PER_BUSINESS_GROUP_ID'),                p_last_name                                       => 'TEST',                p_first_name                                       => 'PRAJKUMAR',                p_middle_names                              => NULL,                p_sex                                                     => 'M',                p_national_identifier                       => '183-09-6723',                p_date_of_birth                                 => TO_DATE('03-DEC-1988'),                p_known_as                                       => 'PRAJ',                 -- Output data elements                 -- --------------------------------                p_employee_number                         => lc_employee_number,                p_person_id                                         => ln_person_id,                p_assignment_id                                => ln_assignment_id,                p_per_object_version_number       => ln_object_ver_number,                p_asg_object_version_number       => ln_asg_ovn,                p_per_effective_start_date               => ld_per_effective_start_date,                p_per_effective_end_date                => ld_per_effective_end_date,                p_full_name                                         => lc_full_name,                p_per_comment_id                            => ln_per_comment_id,                p_assignment_sequence                  => ln_assignment_sequence,                p_assignment_number                     => lc_assignment_number,                p_name_combination_warning    => lb_name_combination_warning,                p_assign_payroll_warning            => lb_assign_payroll_warning,                p_orig_hire_warning                        => lb_orig_hire_warning          );       COMMIT;   EXCEPTION       WHEN OTHERS THEN                     ROLLBACK;                     dbms_output.put_line(SQLERRM); END; / SHOW ERR;  

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  • Loosely coupled .NET Cache Provider using Dependency Injection

    - by Rhames
    I have recently been reading the excellent book “Dependency Injection in .NET”, written by Mark Seemann. I do not generally buy software development related books, as I never seem to have the time to read them, but I have found the time to read Mark’s book, and it was time well spent I think. Reading the ideas around Dependency Injection made me realise that the Cache Provider code I wrote about earlier (see http://geekswithblogs.net/Rhames/archive/2011/01/10/using-the-asp.net-cache-to-cache-data-in-a-model.aspx) could be refactored to use Dependency Injection, which should produce cleaner code. The goals are to: Separate the cache provider implementation (using the ASP.NET data cache) from the consumers (loose coupling). This will also mean that the dependency on System.Web for the cache provider does not ripple down into the layers where it is being consumed (such as the domain layer). Provide a decorator pattern to allow a consumer of the cache provider to be implemented separately from the base consumer (i.e. if we have a base repository, we can decorate this with a caching version). Although I used the term repository, in reality the cache consumer could be just about anything. Use constructor injection to provide the Dependency Injection, with a suitable DI container (I use Castle Windsor). The sample code for this post is available on github, https://github.com/RobinHames/CacheProvider.git ICacheProvider In the sample code, the key interface is ICacheProvider, which is in the domain layer. 1: using System; 2: using System.Collections.Generic; 3:   4: namespace CacheDiSample.Domain 5: { 6: public interface ICacheProvider<T> 7: { 8: T Fetch(string key, Func<T> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry); 9: IEnumerable<T> Fetch(string key, Func<IEnumerable<T>> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry); 10: } 11: }   This interface contains two methods to retrieve data from the cache, either as a single instance or as an IEnumerable. the second paramerter is of type Func<T>. This is the method used to retrieve data if nothing is found in the cache. The ASP.NET implementation of the ICacheProvider interface needs to live in a project that has a reference to system.web, typically this will be the root UI project, or it could be a separate project. The key thing is that the domain or data access layers do not need system.web references adding to them. In my sample MVC application, the CacheProvider is implemented in the UI project, in a folder called “CacheProviders”: 1: using System; 2: using System.Collections.Generic; 3: using System.Linq; 4: using System.Web; 5: using System.Web.Caching; 6: using CacheDiSample.Domain; 7:   8: namespace CacheDiSample.CacheProvider 9: { 10: public class CacheProvider<T> : ICacheProvider<T> 11: { 12: public T Fetch(string key, Func<T> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry) 13: { 14: return FetchAndCache<T>(key, retrieveData, absoluteExpiry, relativeExpiry); 15: } 16:   17: public IEnumerable<T> Fetch(string key, Func<IEnumerable<T>> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry) 18: { 19: return FetchAndCache<IEnumerable<T>>(key, retrieveData, absoluteExpiry, relativeExpiry); 20: } 21:   22: #region Helper Methods 23:   24: private U FetchAndCache<U>(string key, Func<U> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry) 25: { 26: U value; 27: if (!TryGetValue<U>(key, out value)) 28: { 29: value = retrieveData(); 30: if (!absoluteExpiry.HasValue) 31: absoluteExpiry = Cache.NoAbsoluteExpiration; 32:   33: if (!relativeExpiry.HasValue) 34: relativeExpiry = Cache.NoSlidingExpiration; 35:   36: HttpContext.Current.Cache.Insert(key, value, null, absoluteExpiry.Value, relativeExpiry.Value); 37: } 38: return value; 39: } 40:   41: private bool TryGetValue<U>(string key, out U value) 42: { 43: object cachedValue = HttpContext.Current.Cache.Get(key); 44: if (cachedValue == null) 45: { 46: value = default(U); 47: return false; 48: } 49: else 50: { 51: try 52: { 53: value = (U)cachedValue; 54: return true; 55: } 56: catch 57: { 58: value = default(U); 59: return false; 60: } 61: } 62: } 63:   64: #endregion 65:   66: } 67: }   The FetchAndCache helper method checks if the specified cache key exists, if it does not, the Func<U> retrieveData method is called, and the results are added to the cache. Using Castle Windsor to register the cache provider In the MVC UI project (my application root), Castle Windsor is used to register the CacheProvider implementation, using a Windsor Installer: 1: using Castle.MicroKernel.Registration; 2: using Castle.MicroKernel.SubSystems.Configuration; 3: using Castle.Windsor; 4:   5: using CacheDiSample.Domain; 6: using CacheDiSample.CacheProvider; 7:   8: namespace CacheDiSample.WindsorInstallers 9: { 10: public class CacheInstaller : IWindsorInstaller 11: { 12: public void Install(IWindsorContainer container, IConfigurationStore store) 13: { 14: container.Register( 15: Component.For(typeof(ICacheProvider<>)) 16: .ImplementedBy(typeof(CacheProvider<>)) 17: .LifestyleTransient()); 18: } 19: } 20: }   Note that the cache provider is registered as a open generic type. Consuming a Repository I have an existing couple of repository interfaces defined in my domain layer: IRepository.cs 1: using System; 2: using System.Collections.Generic; 3:   4: using CacheDiSample.Domain.Model; 5:   6: namespace CacheDiSample.Domain.Repositories 7: { 8: public interface IRepository<T> 9: where T : EntityBase 10: { 11: T GetById(int id); 12: IList<T> GetAll(); 13: } 14: }   IBlogRepository.cs 1: using System; 2: using CacheDiSample.Domain.Model; 3:   4: namespace CacheDiSample.Domain.Repositories 5: { 6: public interface IBlogRepository : IRepository<Blog> 7: { 8: Blog GetByName(string name); 9: } 10: }   These two repositories are implemented in the DataAccess layer, using Entity Framework to retrieve data (this is not important though). One important point is that in the BaseRepository implementation of IRepository, the methods are virtual. This will allow the decorator to override them. The BlogRepository is registered in a RepositoriesInstaller, again in the MVC UI project. 1: using Castle.MicroKernel.Registration; 2: using Castle.MicroKernel.SubSystems.Configuration; 3: using Castle.Windsor; 4:   5: using CacheDiSample.Domain.CacheDecorators; 6: using CacheDiSample.Domain.Repositories; 7: using CacheDiSample.DataAccess; 8:   9: namespace CacheDiSample.WindsorInstallers 10: { 11: public class RepositoriesInstaller : IWindsorInstaller 12: { 13: public void Install(IWindsorContainer container, IConfigurationStore store) 14: { 15: container.Register(Component.For<IBlogRepository>() 16: .ImplementedBy<BlogRepository>() 17: .LifestyleTransient() 18: .DependsOn(new 19: { 20: nameOrConnectionString = "BloggingContext" 21: })); 22: } 23: } 24: }   Now I can inject a dependency on the IBlogRepository into a consumer, such as a controller in my sample code: 1: using System; 2: using System.Collections.Generic; 3: using System.Linq; 4: using System.Web; 5: using System.Web.Mvc; 6:   7: using CacheDiSample.Domain.Repositories; 8: using CacheDiSample.Domain.Model; 9:   10: namespace CacheDiSample.Controllers 11: { 12: public class HomeController : Controller 13: { 14: private readonly IBlogRepository blogRepository; 15:   16: public HomeController(IBlogRepository blogRepository) 17: { 18: if (blogRepository == null) 19: throw new ArgumentNullException("blogRepository"); 20:   21: this.blogRepository = blogRepository; 22: } 23:   24: public ActionResult Index() 25: { 26: ViewBag.Message = "Welcome to ASP.NET MVC!"; 27:   28: var blogs = blogRepository.GetAll(); 29:   30: return View(new Models.HomeModel { Blogs = blogs }); 31: } 32:   33: public ActionResult About() 34: { 35: return View(); 36: } 37: } 38: }   Consuming the Cache Provider via a Decorator I used a Decorator pattern to consume the cache provider, this means my repositories follow the open/closed principle, as they do not require any modifications to implement the caching. It also means that my controllers do not have any knowledge of the caching taking place, as the DI container will simply inject the decorator instead of the root implementation of the repository. The first step is to implement a BlogRepository decorator, with the caching logic in it. Note that this can reside in the domain layer, as it does not require any knowledge of the data access methods. BlogRepositoryWithCaching.cs 1: using System; 2: using System.Collections.Generic; 3: using System.Linq; 4: using System.Text; 5:   6: using CacheDiSample.Domain.Model; 7: using CacheDiSample.Domain; 8: using CacheDiSample.Domain.Repositories; 9:   10: namespace CacheDiSample.Domain.CacheDecorators 11: { 12: public class BlogRepositoryWithCaching : IBlogRepository 13: { 14: // The generic cache provider, injected by DI 15: private ICacheProvider<Blog> cacheProvider; 16: // The decorated blog repository, injected by DI 17: private IBlogRepository parentBlogRepository; 18:   19: public BlogRepositoryWithCaching(IBlogRepository parentBlogRepository, ICacheProvider<Blog> cacheProvider) 20: { 21: if (parentBlogRepository == null) 22: throw new ArgumentNullException("parentBlogRepository"); 23:   24: this.parentBlogRepository = parentBlogRepository; 25:   26: if (cacheProvider == null) 27: throw new ArgumentNullException("cacheProvider"); 28:   29: this.cacheProvider = cacheProvider; 30: } 31:   32: public Blog GetByName(string name) 33: { 34: string key = string.Format("CacheDiSample.DataAccess.GetByName.{0}", name); 35: // hard code 5 minute expiry! 36: TimeSpan relativeCacheExpiry = new TimeSpan(0, 5, 0); 37: return cacheProvider.Fetch(key, () => 38: { 39: return parentBlogRepository.GetByName(name); 40: }, 41: null, relativeCacheExpiry); 42: } 43:   44: public Blog GetById(int id) 45: { 46: string key = string.Format("CacheDiSample.DataAccess.GetById.{0}", id); 47:   48: // hard code 5 minute expiry! 49: TimeSpan relativeCacheExpiry = new TimeSpan(0, 5, 0); 50: return cacheProvider.Fetch(key, () => 51: { 52: return parentBlogRepository.GetById(id); 53: }, 54: null, relativeCacheExpiry); 55: } 56:   57: public IList<Blog> GetAll() 58: { 59: string key = string.Format("CacheDiSample.DataAccess.GetAll"); 60:   61: // hard code 5 minute expiry! 62: TimeSpan relativeCacheExpiry = new TimeSpan(0, 5, 0); 63: return cacheProvider.Fetch(key, () => 64: { 65: return parentBlogRepository.GetAll(); 66: }, 67: null, relativeCacheExpiry) 68: .ToList(); 69: } 70: } 71: }   The key things in this caching repository are: I inject into the repository the ICacheProvider<Blog> implementation, via the constructor. This will make the cache provider functionality available to the repository. I inject the parent IBlogRepository implementation (which has the actual data access code), via the constructor. This will allow the methods implemented in the parent to be called if nothing is found in the cache. I override each of the methods implemented in the repository, including those implemented in the generic BaseRepository. Each override of these methods follows the same pattern. It makes a call to the CacheProvider.Fetch method, and passes in the parentBlogRepository implementation of the method as the retrieval method, to be used if nothing is present in the cache. Configuring the Caching Repository in the DI Container The final piece of the jigsaw is to tell Castle Windsor to use the BlogRepositoryWithCaching implementation of IBlogRepository, but to inject the actual Data Access implementation into this decorator. This is easily achieved by modifying the RepositoriesInstaller to use Windsor’s implicit decorator wiring: 1: using Castle.MicroKernel.Registration; 2: using Castle.MicroKernel.SubSystems.Configuration; 3: using Castle.Windsor; 4:   5: using CacheDiSample.Domain.CacheDecorators; 6: using CacheDiSample.Domain.Repositories; 7: using CacheDiSample.DataAccess; 8:   9: namespace CacheDiSample.WindsorInstallers 10: { 11: public class RepositoriesInstaller : IWindsorInstaller 12: { 13: public void Install(IWindsorContainer container, IConfigurationStore store) 14: { 15:   16: // Use Castle Windsor implicit wiring for the block repository decorator 17: // Register the outermost decorator first 18: container.Register(Component.For<IBlogRepository>() 19: .ImplementedBy<BlogRepositoryWithCaching>() 20: .LifestyleTransient()); 21: // Next register the IBlogRepository inmplementation to inject into the outer decorator 22: container.Register(Component.For<IBlogRepository>() 23: .ImplementedBy<BlogRepository>() 24: .LifestyleTransient() 25: .DependsOn(new 26: { 27: nameOrConnectionString = "BloggingContext" 28: })); 29: } 30: } 31: }   This is all that is needed. Now if the consumer of the repository makes a call to the repositories method, it will be routed via the caching mechanism. You can test this by stepping through the code, and seeing that the DataAccess.BlogRepository code is only called if there is no data in the cache, or this has expired. The next step is to add the SQL Cache Dependency support into this pattern, this will be a future post.

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  • Core Animation bad access on device

    - by user1595102
    I'm trying to do a frame by frame animation with CAlayers. I'm doing this with this tutorial http://mysterycoconut.com/blog/2011/01/cag1/ but everything works with disable ARC, when I'm try to rewrite code with ARC, it's works on simulator perfectly but on device I got a bad access memory. Layer Class interface #import <Foundation/Foundation.h> #import <QuartzCore/QuartzCore.h> @interface MCSpriteLayer : CALayer { unsigned int sampleIndex; } // SampleIndex needs to be > 0 @property (readwrite, nonatomic) unsigned int sampleIndex; // For use with sample rects set by the delegate + (id)layerWithImage:(CGImageRef)img; - (id)initWithImage:(CGImageRef)img; // If all samples are the same size + (id)layerWithImage:(CGImageRef)img sampleSize:(CGSize)size; - (id)initWithImage:(CGImageRef)img sampleSize:(CGSize)size; // Use this method instead of sprite.sampleIndex to obtain the index currently displayed on screen - (unsigned int)currentSampleIndex; @end Layer Class implementation @implementation MCSpriteLayer @synthesize sampleIndex; - (id)initWithImage:(CGImageRef)img; { self = [super init]; if (self != nil) { self.contents = (__bridge id)img; sampleIndex = 1; } return self; } + (id)layerWithImage:(CGImageRef)img; { MCSpriteLayer *layer = [(MCSpriteLayer*)[self alloc] initWithImage:img]; return layer ; } - (id)initWithImage:(CGImageRef)img sampleSize:(CGSize)size; { self = [self initWithImage:img]; if (self != nil) { CGSize sampleSizeNormalized = CGSizeMake(size.width/CGImageGetWidth(img), size.height/CGImageGetHeight(img)); self.bounds = CGRectMake( 0, 0, size.width, size.height ); self.contentsRect = CGRectMake( 0, 0, sampleSizeNormalized.width, sampleSizeNormalized.height ); } return self; } + (id)layerWithImage:(CGImageRef)img sampleSize:(CGSize)size; { MCSpriteLayer *layer = [[self alloc] initWithImage:img sampleSize:size]; return layer; } + (BOOL)needsDisplayForKey:(NSString *)key; { return [key isEqualToString:@"sampleIndex"]; } // contentsRect or bounds changes are not animated + (id < CAAction >)defaultActionForKey:(NSString *)aKey; { if ([aKey isEqualToString:@"contentsRect"] || [aKey isEqualToString:@"bounds"]) return (id < CAAction >)[NSNull null]; return [super defaultActionForKey:aKey]; } - (unsigned int)currentSampleIndex; { return ((MCSpriteLayer*)[self presentationLayer]).sampleIndex; } // Implement displayLayer: on the delegate to override how sample rectangles are calculated; remember to use currentSampleIndex, ignore sampleIndex == 0, and set the layer's bounds - (void)display; { if ([self.delegate respondsToSelector:@selector(displayLayer:)]) { [self.delegate displayLayer:self]; return; } unsigned int currentSampleIndex = [self currentSampleIndex]; if (!currentSampleIndex) return; CGSize sampleSize = self.contentsRect.size; self.contentsRect = CGRectMake( ((currentSampleIndex - 1) % (int)(1/sampleSize.width)) * sampleSize.width, ((currentSampleIndex - 1) / (int)(1/sampleSize.width)) * sampleSize.height, sampleSize.width, sampleSize.height ); } @end I create the layer on viewDidAppear and start animate by clicking on button, but after init I got a bad access error -(void)viewDidAppear:(BOOL)animated { [super viewDidAppear:animated]; NSString *path = [[NSBundle mainBundle] pathForResource:@"mama_default.png" ofType:nil]; CGImageRef richterImg = [UIImage imageWithContentsOfFile:path].CGImage; CGSize fixedSize = animacja.frame.size; NSLog(@"wid: %f, heigh: %f", animacja.frame.size.width, animacja.frame.size.height); NSLog(@"%f", animacja.frame.size.width); richter = [MCSpriteLayer layerWithImage:richterImg sampleSize:fixedSize]; animacja.hidden = 1; richter.position = animacja.center; [self.view.layer addSublayer:richter]; } -(IBAction)animacja:(id)sender { if ([richter animationForKey:@"sampleIndex"]) {NSLog(@"jest"); } if (! [richter animationForKey:@"sampleIndex"]) { CABasicAnimation *anim = [CABasicAnimation animationWithKeyPath:@"sampleIndex"]; anim.fromValue = [NSNumber numberWithInt:0]; anim.toValue = [NSNumber numberWithInt:22]; anim.duration = 4; anim.repeatCount = 1; [richter addAnimation:anim forKey:@"sampleIndex"]; } } Have you got any idea how to fix it? Thanks a lot.

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  • Inconsistent results in R with RNetCDF - why?

    - by sarcozona
    I am having trouble extracting data from NetCDF data files using RNetCDF. The data files each have 3 dimensions (longitude, latitude, and a date) and 3 variables (latitude, longitude, and a climate variable). There are four datasets, each with a different climate variable. Here is some of the output from print.nc(p8m.tmax) for clarity. The other datasets are identical except for the specific climate variable. dimensions: month = UNLIMITED ; // (1368 currently) lat = 3105 ; lon = 7025 ; variables: float lat(lat) ; lat:long_name = "latitude" ; lat:standard_name = "latitude" ; lat:units = "degrees_north" ; float lon(lon) ; lon:long_name = "longitude" ; lon:standard_name = "longitude" ; lon:units = "degrees_east" ; short tmax(lon, lat, month) ; tmax:missing_value = -9999 ; tmax:_FillValue = -9999 ; tmax:units = "degree_celsius" ; tmax:scale_factor = 0.01 ; tmax:valid_min = -5000 ; tmax:valid_max = 6000 ; I am getting behavior I don't understand when I use the var.get.nc function from the RNetCDF package. For example, when I attempt to extract 82 values beginning at stval from the maximum temperature data (p8m.tmax <- open.nc(tmaxdataset.nc)) with > var.get.nc(p8m.tmax,'tmax', start=c(lon_val, lat_val, stval),count=c(1,1,82)) (where lon_val and lat_val specify the location in the dataset of the coordinates I'm interested in and stval is stval is set to which(time_vec==200201), which in this case equaled 1285.) I get Error: Invalid argument But after successfully extracting 80 and 81 values > var.get.nc(p8m.tmax,'tmax', start=c(lon_val, lat_val, stval),count=c(1,1,80)) > var.get.nc(p8m.tmax,'tmax', start=c(lon_val, lat_val, stval),count=c(1,1,81)) the command with 82 works: > var.get.nc(p8m.tmax,'tmax', start=c(lon_val, lat_val, stval),count=c(1,1,82)) [1] 444 866 1063 ... [output snipped] The same problem occurs in the identically structured tmin file, but at 36 instead of 82: > var.get.nc(p8m.tmin,'tmin', start=c(lon_val, lat_val, stval),count=c(1,1,36)) produces Error: Invalid argument But after repeating with counts of 30, 31, etc > var.get.nc(p8m.tmin,'tmin', start=c(lon_val, lat_val, stval), count=c(1,1,36)) works. These examples make it seem like the function is failing at the last count, but that actually isn't the case. In the first example, var.get.nc gave Error: Invalid argument after I asked for 84 values. I then narrowed the failure down to the 82nd count by varying the starting point in the dataset and asking for only 1 value at a time. The particular number the problem occurs at also varies. I can close and reopen the dataset and have the problem occur at a different location. In the particular examples above, lon_val and lat_val are 1595 and 1751, respectively, identifying the location in the dataset along the lat and lon dimensions for the latitude and longitude I'm interested in. The 1595th latitude and 1751th longitude are not the problem, however. The problem occurs with all other latitude and longitudes I've tried. Varying the starting location in the dataset along the climate variable dimension (stval) and/or specifying it different (as a number in the command instead of the object stval) also does not fix the problem. This problem doesn't always occur. I can run identical code three times in a row (clearing all objects in between runs) and get a different outcome each time. The first run may choke on the 7th entry I'm trying to get, the second might work fine, and the third run might choke on the 83rd entry. I'm absolutely baffled by such inconsistent behavior. The open.nc function has also started to fail with the same Error: Invalid argument. Like the var.get.nc problems, it also occurs inconsistently. Does anyone know what causes the initial failure to extract the variable? And how I might prevent it? Could have to do with the size of the data files (~60GB each) and/or the fact that I'm accessing them through networked drives? This was also asked here: https://stat.ethz.ch/pipermail/r-help/2011-June/281233.html > sessionInfo() R version 2.13.0 (2011-04-13) Platform: i386-pc-mingw32/i386 (32-bit) locale: [1] LC_COLLATE=English_United States.1252 LC_CTYPE=English_United States.1252 [3] LC_MONETARY=English_United States.1252 LC_NUMERIC=C [5] LC_TIME=English_United States.1252 attached base packages: [1] stats graphics grDevices utils datasets methods base other attached packages: [1] reshape_0.8.4 plyr_1.5.2 RNetCDF_1.5.2-2 loaded via a namespace (and not attached): [1] tools_2.13.0

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  • Java update/install via group policy

    - by Maximus
    I trying to deploy the latest Java RE version via GP, Java 7 update 9. I want to update computers that are currently running an older version of Java, a mixture of 7.6 and 7.7, some computers are running versions as old as 6.31. Some are running a mixture of both. I would also like this GP to install Java if it's not installed. Previously I used push out Java updates to users machines as Java didn't remove the old version. So when it was done the user would restart their browser or pc to start using the latest version. Not the best way to manage it as it leaves the old version installed but it worked. I've created group policies before for printer deployment, log on drive mapping scripts, but never software deployment. I've extracted the Java MSI and created a transform file to suppress reboot etc using orca. As described on this site http://ivan.dretvic.com/2011/06/how-to-package-and-deploy-java-jre-1-6-0_26-via-group-policy/. I have also tried saving the edited MSI directly and that didn't work either. But it just won't deploy. I have tried to enable logging as suggested on this site http://openofficetechnology.com/node/32, GPO logging via UserEnvDebugLevel, Software deployment logging via AppmgmtDebugLevel and MSI logging, but there is no log C:\Windows\Debug\UserMode\userenv.log being created. The windows event viewer has the following errors: Error 24/10/2012 11:44:04 AM - "Failed to apply changes to software installation settings. Software changes could not be applied. A previous log entry with details should exist. The error was : %%1612" Information 24/10/2012 11:44:04 AM - "The removal of the assignment of application Java 7 Update 9 - FB Java Transform from policy JavaDeploy succeeded." Error 24/10/2012 11:44:04 AM - "The install of application Java 7 Update 9 - FB Java Transform from policy JavaDeploy failed. The error was : %%1612" There is a log created for MSI logging and it's as below. It says the source is invalid but it exists on the share and the PC that I'm testing has permissions and I've included the recommendation here Group Policy installation failed error 1274 to enable "Always wait for the network at computer startup and logon" === Verbose logging started: 24/10/2012 11:43:59 Build type: SHIP UNICODE 5.00.7601.00 Calling process: C:\Windows\system32\svchost.exe === MSI (c) (9C:EC) [11:43:59:898]: Resetting cached policy values MSI (c) (9C:EC) [11:43:59:898]: Machine policy value 'Debug' is 3 MSI (c) (9C:EC) [11:43:59:898]: ******* RunEngine: ******* Product: {26a24ae4-039d-4ca4-87b4-2f83217009ff} ******* Action: ******* CommandLine: ********** MSI (c) (9C:EC) [11:43:59:898]: Client-side and UI is none or basic: Running entire install on the server. MSI (c) (9C:EC) [11:43:59:898]: Grabbed execution mutex. MSI (c) (9C:EC) [11:44:03:431]: Cloaking enabled. MSI (c) (9C:EC) [11:44:03:431]: Attempting to enable all disabled privileges before calling Install on Server MSI (c) (9C:EC) [11:44:03:439]: Incrementing counter to disable shutdown. Counter after increment: 0 MSI (s) (2C:70) [11:44:03:574]: Running installation inside multi-package transaction {26a24ae4-039d-4ca4-87b4-2f83217009ff} MSI (s) (2C:70) [11:44:03:574]: Grabbed execution mutex. MSI (s) (2C:7C) [11:44:03:607]: Resetting cached policy values MSI (s) (2C:7C) [11:44:03:607]: Machine policy value 'Debug' is 3 MSI (s) (2C:7C) [11:44:03:607]: ******* RunEngine: ******* Product: {26a24ae4-039d-4ca4-87b4-2f83217009ff} ******* Action: ******* CommandLine: ********** MSI (s) (2C:7C) [11:44:03:607]: Machine policy value 'DisableUserInstalls' is 0 MSI (s) (2C:7C) [11:44:03:623]: User policy value 'SearchOrder' is 'nmu' MSI (s) (2C:7C) [11:44:03:624]: User policy value 'DisableMedia' is 0 MSI (s) (2C:7C) [11:44:03:624]: Machine policy value 'AllowLockdownMedia' is 0 MSI (s) (2C:7C) [11:44:03:624]: SOURCEMGMT: Media enabled only if package is safe. MSI (s) (2C:7C) [11:44:03:624]: SOURCEMGMT: Looking for sourcelist for product {26a24ae4-039d-4ca4-87b4-2f83217009ff} MSI (s) (2C:7C) [11:44:03:624]: SOURCEMGMT: Adding {26a24ae4-039d-4ca4-87b4-2f83217009ff}; to potential sourcelist list (pcode;disk;relpath). MSI (s) (2C:7C) [11:44:03:624]: SOURCEMGMT: Now checking product {26a24ae4-039d-4ca4-87b4-2f83217009ff} MSI (s) (2C:7C) [11:44:03:624]: SOURCEMGMT: Media is enabled for product. MSI (s) (2C:7C) [11:44:03:624]: SOURCEMGMT: Attempting to use LastUsedSource from source list. MSI (s) (2C:7C) [11:44:03:624]: SOURCEMGMT: Processing net source list. MSI (s) (2C:7C) [11:44:03:624]: SOURCEMGMT: Trying source \\server\share\deployment\Java\stable\x32\. MSI (s) (2C:7C) [11:44:03:650]: Note: 1: 2303 2: 5 3: \\server\share\ MSI (s) (2C:7C) [11:44:03:650]: Note: 1: 1325 2: deployment MSI (s) (2C:7C) [11:44:03:650]: ConnectToSource: CreatePath/CreateFilePath failed with: -2147483648 1325 -2147483648 MSI (s) (2C:7C) [11:44:03:650]: ConnectToSource (con't): CreatePath/CreateFilePath failed with: -2147483648 -2147483648 MSI (s) (2C:7C) [11:44:03:650]: SOURCEMGMT: net source '\\server\share\deployment\Java\stable\x32\' is invalid. MSI (s) (2C:7C) [11:44:03:650]: Note: 1: 1706 2: -2147483647 3: jre1.7.0_09.msi MSI (s) (2C:7C) [11:44:03:650]: SOURCEMGMT: Processing media source list. MSI (s) (2C:7C) [11:44:04:668]: Note: 1: 2203 2: 3: -2147287037 MSI (s) (2C:7C) [11:44:04:668]: SOURCEMGMT: Source is invalid due to missing/inaccessible package. MSI (s) (2C:7C) [11:44:04:668]: Note: 1: 1706 2: -2147483647 3: jre1.7.0_09.msi MSI (s) (2C:7C) [11:44:04:668]: SOURCEMGMT: Processing URL source list. MSI (s) (2C:7C) [11:44:04:668]: Note: 1: 1402 2: UNKNOWN\URL 3: 2 MSI (s) (2C:7C) [11:44:04:668]: Note: 1: 1706 2: -2147483647 3: jre1.7.0_09.msi MSI (s) (2C:7C) [11:44:04:668]: Note: 1: 1706 2: 3: jre1.7.0_09.msi MSI (s) (2C:7C) [11:44:04:668]: SOURCEMGMT: Failed to resolve source MSI (s) (2C:7C) [11:44:04:668]: MainEngineThread is returning 1612 MSI (s) (2C:70) [11:44:04:670]: User policy value 'DisableRollback' is 0 MSI (s) (2C:70) [11:44:04:670]: Machine policy value 'DisableRollback' is 0 MSI (s) (2C:70) [11:44:04:670]: Incrementing counter to disable shutdown. Counter after increment: 0 MSI (s) (2C:70) [11:44:04:670]: Note: 1: 1402 2: HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Installer\Rollback\Scripts 3: 2 MSI (s) (2C:70) [11:44:04:671]: Note: 1: 1402 2: HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Installer\Rollback\Scripts 3: 2 MSI (s) (2C:70) [11:44:04:671]: Note: 1: 1402 2: HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Installer\InProgress 3: 2 MSI (s) (2C:70) [11:44:04:671]: Note: 1: 1402 2: HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Installer\InProgress 3: 2 MSI (s) (2C:70) [11:44:04:671]: Decrementing counter to disable shutdown. If counter >= 0, shutdown will be denied. Counter after decrement: -1 MSI (s) (2C:70) [11:44:04:671]: Restoring environment variables MSI (c) (9C:EC) [11:44:04:675]: Decrementing counter to disable shutdown. If counter >= 0, shutdown will be denied. Counter after decrement: -1 MSI (c) (9C:EC) [11:44:04:675]: MainEngineThread is returning 1612 === Verbose logging stopped: 24/10/2012 11:44:04 === I'm not sure what my next approach should be. Any help would be much appreciated. Thanks.

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  • Another "Windows 7 entry missing from Grub2" Question

    - by 4x10
    Like many before me had the following problem that after installing Ubuntu (with windows 7 already installed), the grub boot loader wouldnt show windows 7 as a boot option, though i can boot fine if I use the "Choose Boot Device" options on the x220. The difference is that I try using UEFI only so many answers didn't really fit my problem, though i tried several stuffs: after running boot repair it destroyed the ubuntu boot loader custom entry in /etc/grub.d/40_custom for windows which doesnt show up many update-grub and reboots trying windows repair recovery thing while being there i also did bootrec.exe /FixBoot and update-grub and reboot again and finaly because it was so much fun, i installed linux all over again, while formatting and deleting everything linux related before that. Now that i think of it, Ubuntu also didn't notice Windows being there during the Setup and it still doesnt according to the Boot Info from Boot Repair. Boot Info Script 0.61-git-patched [23 April 2012] ============================= Boot Info Summary: =============================== => No boot loader is installed in the MBR of /dev/sda. sda1: __________________________________________________________________________ File system: vfat Boot sector type: Windows 7: FAT32 Boot sector info: No errors found in the Boot Parameter Block. Operating System: Boot files: /efi/Boot/bootx64.efi /efi/ubuntu/grubx64.efi sda2: __________________________________________________________________________ File system: Boot sector type: - Boot sector info: Mounting failed: mount: unknown filesystem type '' sda3: __________________________________________________________________________ File system: ntfs Boot sector type: Windows Vista/7: NTFS Boot sector info: No errors found in the Boot Parameter Block. Operating System: Windows 7 Boot files: /Windows/System32/winload.exe sda4: __________________________________________________________________________ File system: ext4 Boot sector type: - Boot sector info: Operating System: Ubuntu precise (development branch) Boot files: /boot/grub/grub.cfg /etc/fstab sda5: __________________________________________________________________________ File system: ext4 Boot sector type: - Boot sector info: Operating System: Boot files: sda6: __________________________________________________________________________ File system: swap Boot sector type: - Boot sector info: ============================ Drive/Partition Info: ============================= Drive: sda _____________________________________________________________________ Disk /dev/sda: 320.1 GB, 320072933376 bytes 255 heads, 63 sectors/track, 38913 cylinders, total 625142448 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes Partition Boot Start Sector End Sector # of Sectors Id System /dev/sda1 1 625,142,447 625,142,447 ee GPT GUID Partition Table detected. Partition Start Sector End Sector # of Sectors System /dev/sda1 2,048 206,847 204,800 EFI System partition /dev/sda2 206,848 468,991 262,144 Microsoft Reserved Partition (Windows) /dev/sda3 468,992 170,338,303 169,869,312 Data partition (Windows/Linux) /dev/sda4 170,338,304 330,338,304 160,000,001 Data partition (Windows/Linux) /dev/sda5 330,338,305 617,141,039 286,802,735 Data partition (Windows/Linux) /dev/sda6 617,141,040 625,141,040 8,000,001 Swap partition (Linux) "blkid" output: ________________________________________________________________ Device UUID TYPE LABEL /dev/sda1 885C-ED1B vfat /dev/sda3 EE06CC0506CBCCB1 ntfs /dev/sda4 604dd3b2-64ca-4200-b8fb-820e8d0ca899 ext4 /dev/sda5 d62515fd-8120-4a74-b17b-0bdf244124a3 ext4 /dev/sda6 7078b649-fb2a-4c59-bd03-fd31ef440d37 swap ================================ Mount points: ================================= Device Mount_Point Type Options /dev/sda1 /boot/efi vfat (rw) /dev/sda4 / ext4 (rw,errors=remount-ro) /dev/sda5 /home ext4 (rw) =========================== sda4/boot/grub/grub.cfg: =========================== -------------------------------------------------------------------------------- # # DO NOT EDIT THIS FILE # # It is automatically generated by grub-mkconfig using templates # from /etc/grub.d and settings from /etc/default/grub # ### BEGIN /etc/grub.d/00_header ### if [ -s $prefix/grubenv ]; then set have_grubenv=true load_env fi set default="0" if [ "${prev_saved_entry}" ]; then set saved_entry="${prev_saved_entry}" save_env saved_entry set prev_saved_entry= save_env prev_saved_entry set boot_once=true fi function savedefault { if [ -z "${boot_once}" ]; then saved_entry="${chosen}" save_env saved_entry fi } function recordfail { set recordfail=1 if [ -n "${have_grubenv}" ]; then if [ -z "${boot_once}" ]; then save_env recordfail; fi; fi } function load_video { insmod efi_gop insmod efi_uga insmod video_bochs insmod video_cirrus } insmod part_gpt insmod ext2 set root='(hd0,gpt4)' search --no-floppy --fs-uuid --set=root 604dd3b2-64ca-4200-b8fb-820e8d0ca899 if loadfont /usr/share/grub/unicode.pf2 ; then set gfxmode=auto load_video insmod gfxterm insmod part_gpt insmod ext2 set root='(hd0,gpt4)' search --no-floppy --fs-uuid --set=root 604dd3b2-64ca-4200-b8fb-820e8d0ca899 set locale_dir=($root)/boot/grub/locale set lang=en_US insmod gettext fi terminal_output gfxterm if [ "${recordfail}" = 1 ]; then set timeout=-1 else set timeout=10 fi ### END /etc/grub.d/00_header ### ### BEGIN /etc/grub.d/05_debian_theme ### set menu_color_normal=white/black set menu_color_highlight=black/light-gray if background_color 44,0,30; then clear fi ### END /etc/grub.d/05_debian_theme ### ### BEGIN /etc/grub.d/10_linux ### function gfxmode { set gfxpayload="$1" if [ "$1" = "keep" ]; then set vt_handoff=vt.handoff=7 else set vt_handoff= fi } if [ ${recordfail} != 1 ]; then if [ -e ${prefix}/gfxblacklist.txt ]; then if hwmatch ${prefix}/gfxblacklist.txt 3; then if [ ${match} = 0 ]; then set linux_gfx_mode=keep else set linux_gfx_mode=text fi else set linux_gfx_mode=text fi else set linux_gfx_mode=keep fi else set linux_gfx_mode=text fi export linux_gfx_mode if [ "$linux_gfx_mode" != "text" ]; then load_video; fi menuentry 'Ubuntu, with Linux 3.2.0-20-generic' --class ubuntu --class gnu-linux --class gnu --class os { recordfail gfxmode $linux_gfx_mode insmod gzio insmod part_gpt insmod ext2 set root='(hd0,gpt4)' search --no-floppy --fs-uuid --set=root 604dd3b2-64ca-4200-b8fb-820e8d0ca899 linux /boot/vmlinuz-3.2.0-20-generic root=UUID=604dd3b2-64ca-4200-b8fb-820e8d0ca899 ro quiet splash $vt_handoff initrd /boot/initrd.img-3.2.0-20-generic } menuentry 'Ubuntu, with Linux 3.2.0-20-generic (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os { recordfail insmod gzio insmod part_gpt insmod ext2 set root='(hd0,gpt4)' search --no-floppy --fs-uuid --set=root 604dd3b2-64ca-4200-b8fb-820e8d0ca899 echo 'Loading Linux 3.2.0-20-generic ...' linux /boot/vmlinuz-3.2.0-20-generic root=UUID=604dd3b2-64ca-4200-b8fb-820e8d0ca899 ro recovery nomodeset echo 'Loading initial ramdisk ...' initrd /boot/initrd.img-3.2.0-20-generic } ### END /etc/grub.d/10_linux ### ### BEGIN /etc/grub.d/20_linux_xen ### ### END /etc/grub.d/20_linux_xen ### ### BEGIN /etc/grub.d/20_memtest86+ ### menuentry "Memory test (memtest86+)" { insmod part_gpt insmod ext2 set root='(hd0,gpt4)' search --no-floppy --fs-uuid --set=root 604dd3b2-64ca-4200-b8fb-820e8d0ca899 linux16 /boot/memtest86+.bin } menuentry "Memory test (memtest86+, serial console 115200)" { insmod part_gpt insmod ext2 set root='(hd0,gpt4)' search --no-floppy --fs-uuid --set=root 604dd3b2-64ca-4200-b8fb-820e8d0ca899 linux16 /boot/memtest86+.bin console=ttyS0,115200n8 } ### END /etc/grub.d/20_memtest86+ ### ### BEGIN /etc/grub.d/30_os-prober ### ### END /etc/grub.d/30_os-prober ### ### BEGIN /etc/grub.d/40_custom ### # This file provides an easy way to add custom menu entries. Simply type the # menu entries you want to add after this comment. Be careful not to change # the 'exec tail' line above. ### END /etc/grub.d/40_custom ### ### BEGIN /etc/grub.d/41_custom ### if [ -f $prefix/custom.cfg ]; then source $prefix/custom.cfg; fi ### END /etc/grub.d/41_custom ### -------------------------------------------------------------------------------- =============================== sda4/etc/fstab: ================================ -------------------------------------------------------------------------------- # /etc/fstab: static file system information. # # Use 'blkid' to print the universally unique identifier for a # device; this may be used with UUID= as a more robust way to name devices # that works even if disks are added and removed. See fstab(5). # # <file system> <mount point> <type> <options> <dump> <pass> proc /proc proc nodev,noexec,nosuid 0 0 # / was on /dev/sda4 during installation UUID=604dd3b2-64ca-4200-b8fb-820e8d0ca899 / ext4 errors=remount-ro 0 1 # /boot/efi was on /dev/sda1 during installation UUID=885C-ED1B /boot/efi vfat defaults 0 1 # /home was on /dev/sda5 during installation UUID=d62515fd-8120-4a74-b17b-0bdf244124a3 /home ext4 defaults 0 2 # swap was on /dev/sda6 during installation UUID=7078b649-fb2a-4c59-bd03-fd31ef440d37 none swap sw 0 0 -------------------------------------------------------------------------------- =================== sda4: Location of files loaded by Grub: ==================== GiB - GB File Fragment(s) 129.422874451 = 138.966753280 boot/grub/grub.cfg 1 83.059570312 = 89.184534528 boot/initrd.img-3.2.0-20-generic 2 101.393131256 = 108.870045696 boot/vmlinuz-3.2.0-20-generic 1 83.059570312 = 89.184534528 initrd.img 2 101.393131256 = 108.870045696 vmlinuz 1 ADDITIONAL INFORMATION : =================== log of boot-repair 2012-04-25__23h40 =================== boot-repair version : 3.18-0ppa3~precise boot-sav version : 3.18-0ppa4~precise glade2script version : 0.3.2.1-0ppa7~precise internet: connected python-software-properties version : 0.82.7 0 upgraded, 0 newly installed, 1 reinstalled, 0 to remove and 591 not upgraded. dpkg-preconfigure: unable to re-open stdin: No such file or directory boot-repair is executed in installed-session (Ubuntu precise (development branch) , precise , Ubuntu , x86_64) WARNING: GPT (GUID Partition Table) detected on '/dev/sda'! The util fdisk doesn't support GPT. Use GNU Parted. =================== OSPROBER: /dev/sda4:The OS now in use - Ubuntu precise (development branch) CurrentSession:linux =================== BLKID: /dev/sda3: UUID="EE06CC0506CBCCB1" TYPE="ntfs" /dev/sda1: UUID="885C-ED1B" TYPE="vfat" /dev/sda4: UUID="604dd3b2-64ca-4200-b8fb-820e8d0ca899" TYPE="ext4" /dev/sda5: UUID="d62515fd-8120-4a74-b17b-0bdf244124a3" TYPE="ext4" /dev/sda6: UUID="7078b649-fb2a-4c59-bd03-fd31ef440d37" TYPE="swap" 1 disks with OS, 1 OS : 1 Linux, 0 MacOS, 0 Windows, 0 unknown type OS. WARNING: GPT (GUID Partition Table) detected on '/dev/sda'! The util sfdisk doesn't support GPT. Use GNU Parted. =================== /etc/default/grub : # If you change this file, run 'update-grub' afterwards to update # /boot/grub/grub.cfg. # For full documentation of the options in this file, see: # info -f grub -n 'Simple configuration' GRUB_DEFAULT=0 #GRUB_HIDDEN_TIMEOUT=0 #GRUB_HIDDEN_TIMEOUT_QUIET=true GRUB_TIMEOUT=10 GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian` GRUB_CMDLINE_LINUX_DEFAULT="quiet splash" GRUB_CMDLINE_LINUX="" # Uncomment to enable BadRAM filtering, modify to suit your needs # This works with Linux (no patch required) and with any kernel that obtains # the memory map information from GRUB (GNU Mach, kernel of FreeBSD ...) #GRUB_BADRAM="0x01234567,0xfefefefe,0x89abcdef,0xefefefef" # Uncomment to disable graphical terminal (grub-pc only) #GRUB_TERMINAL=console # The resolution used on graphical terminal # note that you can use only modes which your graphic card supports via VBE # you can see them in real GRUB with the command `vbeinfo' #GRUB_GFXMODE=640x480 # Uncomment if you don't want GRUB to pass "root=UUID=xxx" parameter to Linux #GRUB_DISABLE_LINUX_UUID=true # Uncomment to disable generation of recovery mode menu entries #GRUB_DISABLE_RECOVERY="true" # Uncomment to get a beep at grub start #GRUB_INIT_TUNE="480 440 1" EFI_OF_PART[1] (, ) =================== dmesg | grep EFI : [ 0.000000] EFI v2.00 by Lenovo [ 0.000000] Kernel-defined memdesc doesn't match the one from EFI! [ 0.000000] EFI: mem00: type=3, attr=0xf, range=[0x0000000000000000-0x0000000000001000) (0MB) [ 0.000000] EFI: mem01: type=7, attr=0xf, range=[0x0000000000001000-0x000000000004e000) (0MB) [ 0.000000] EFI: mem02: type=3, attr=0xf, range=[0x000000000004e000-0x0000000000058000) (0MB) [ 0.000000] EFI: mem03: type=10, attr=0xf, range=[0x0000000000058000-0x0000000000059000) (0MB) [ 0.000000] EFI: mem04: type=7, attr=0xf, range=[0x0000000000059000-0x000000000005e000) (0MB) [ 0.000000] EFI: mem05: type=4, attr=0xf, range=[0x000000000005e000-0x000000000005f000) (0MB) [ 0.000000] EFI: mem06: type=3, attr=0xf, range=[0x000000000005f000-0x00000000000a0000) (0MB) [ 0.000000] EFI: mem07: type=2, attr=0xf, range=[0x0000000000100000-0x00000000005b9000) (4MB) [ 0.000000] EFI: mem08: type=7, attr=0xf, range=[0x00000000005b9000-0x0000000020000000) (506MB) [ 0.000000] EFI: mem09: type=0, attr=0xf, range=[0x0000000020000000-0x0000000020200000) (2MB) [ 0.000000] EFI: mem10: type=7, attr=0xf, range=[0x0000000020200000-0x00000000364e4000) (354MB) [ 0.000000] EFI: mem11: type=2, attr=0xf, range=[0x00000000364e4000-0x000000003726a000) (13MB) [ 0.000000] EFI: mem12: type=7, attr=0xf, range=[0x000000003726a000-0x0000000040000000) (141MB) [ 0.000000] EFI: mem13: type=0, attr=0xf, range=[0x0000000040000000-0x0000000040200000) (2MB) [ 0.000000] EFI: mem14: type=7, attr=0xf, range=[0x0000000040200000-0x000000009df35000) (1501MB) [ 0.000000] EFI: mem15: type=2, attr=0xf, range=[0x000000009df35000-0x00000000d39a0000) (858MB) [ 0.000000] EFI: mem16: type=4, attr=0xf, range=[0x00000000d39a0000-0x00000000d39c0000) (0MB) [ 0.000000] EFI: mem17: type=7, attr=0xf, range=[0x00000000d39c0000-0x00000000d5df5000) (36MB) [ 0.000000] EFI: mem18: type=4, attr=0xf, range=[0x00000000d5df5000-0x00000000d6990000) (11MB) [ 0.000000] EFI: mem19: type=7, attr=0xf, range=[0x00000000d6990000-0x00000000d6b82000) (1MB) [ 0.000000] EFI: mem20: type=1, attr=0xf, range=[0x00000000d6b82000-0x00000000d6b9f000) (0MB) [ 0.000000] EFI: mem21: type=7, attr=0xf, range=[0x00000000d6b9f000-0x00000000d77b0000) (12MB) [ 0.000000] EFI: mem22: type=4, attr=0xf, range=[0x00000000d77b0000-0x00000000d780a000) (0MB) [ 0.000000] EFI: mem23: type=7, attr=0xf, range=[0x00000000d780a000-0x00000000d7826000) (0MB) [ 0.000000] EFI: mem24: type=4, attr=0xf, range=[0x00000000d7826000-0x00000000d7868000) (0MB) [ 0.000000] EFI: mem25: type=7, attr=0xf, range=[0x00000000d7868000-0x00000000d7869000) (0MB) [ 0.000000] EFI: mem26: type=4, attr=0xf, range=[0x00000000d7869000-0x00000000d786a000) (0MB) [ 0.000000] EFI: mem27: type=7, attr=0xf, range=[0x00000000d786a000-0x00000000d786b000) (0MB) [ 0.000000] EFI: mem28: type=4, attr=0xf, range=[0x00000000d786b000-0x00000000d786c000) (0MB) [ 0.000000] EFI: mem29: type=7, attr=0xf, range=[0x00000000d786c000-0x00000000d786d000) (0MB) [ 0.000000] EFI: mem30: type=4, attr=0xf, range=[0x00000000d786d000-0x00000000d825f000) (9MB) [ 0.000000] EFI: mem31: type=7, attr=0xf, range=[0x00000000d825f000-0x00000000d8261000) (0MB) [ 0.000000] EFI: mem32: type=4, attr=0xf, range=[0x00000000d8261000-0x00000000d82f7000) (0MB) [ 0.000000] EFI: mem33: type=7, attr=0xf, range=[0x00000000d82f7000-0x00000000d82f8000) (0MB) [ 0.000000] EFI: mem34: type=4, attr=0xf, range=[0x00000000d82f8000-0x00000000d8705000) (4MB) [ 0.000000] EFI: mem35: type=7, attr=0xf, range=[0x00000000d8705000-0x00000000d8706000) (0MB) [ 0.000000] EFI: mem36: type=4, attr=0xf, range=[0x00000000d8706000-0x00000000d8761000) (0MB) [ 0.000000] EFI: mem37: type=7, attr=0xf, range=[0x00000000d8761000-0x00000000d8768000) (0MB) [ 0.000000] EFI: mem38: type=4, attr=0xf, range=[0x00000000d8768000-0x00000000d9b9f000) (20MB) [ 0.000000] EFI: mem39: type=7, attr=0xf, range=[0x00000000d9b9f000-0x00000000d9e4c000) (2MB) [ 0.000000] EFI: mem40: type=2, attr=0xf, range=[0x00000000d9e4c000-0x00000000d9e52000) (0MB) [ 0.000000] EFI: mem41: type=3, attr=0xf, range=[0x00000000d9e52000-0x00000000da59f000) (7MB) [ 0.000000] EFI: mem42: type=5, attr=0x800000000000000f, range=[0x00000000da59f000-0x00000000da6c3000) (1MB) [ 0.000000] EFI: mem43: type=5, attr=0x800000000000000f, range=[0x00000000da6c3000-0x00000000da79f000) (0MB) [ 0.000000] EFI: mem44: type=6, attr=0x800000000000000f, range=[0x00000000da79f000-0x00000000da8b1000) (1MB) [ 0.000000] EFI: mem45: type=6, attr=0x800000000000000f, range=[0x00000000da8b1000-0x00000000da99f000) (0MB) [ 0.000000] EFI: mem46: type=0, attr=0xf, range=[0x00000000da99f000-0x00000000daa22000) (0MB) [ 0.000000] EFI: mem47: type=0, attr=0xf, range=[0x00000000daa22000-0x00000000daa9b000) (0MB) [ 0.000000] EFI: mem48: type=0, attr=0xf, range=[0x00000000daa9b000-0x00000000daa9c000) (0MB) [ 0.000000] EFI: mem49: type=0, attr=0xf, range=[0x00000000daa9c000-0x00000000daa9f000) (0MB) [ 0.000000] EFI: mem50: type=10, attr=0xf, range=[0x00000000daa9f000-0x00000000daadd000) (0MB) [ 0.000000] EFI: mem51: type=10, attr=0xf, range=[0x00000000daadd000-0x00000000dab9f000) (0MB) [ 0.000000] EFI: mem52: type=9, attr=0xf, range=[0x00000000dab9f000-0x00000000dabdc000) (0MB) [ 0.000000] EFI: mem53: type=9, attr=0xf, range=[0x00000000dabdc000-0x00000000dabff000) (0MB) [ 0.000000] EFI: mem54: type=4, attr=0xf, range=[0x00000000dabff000-0x00000000dac00000) (0MB) [ 0.000000] EFI: mem55: type=7, attr=0xf, range=[0x0000000100000000-0x000000021e600000) (4582MB) [ 0.000000] EFI: mem56: type=11, attr=0x8000000000000001, range=[0x00000000f80f8000-0x00000000f80f9000) (0MB) [ 0.000000] EFI: mem57: type=11, attr=0x8000000000000001, range=[0x00000000fed1c000-0x00000000fed20000) (0MB) [ 0.000000] ACPI: UEFI 00000000dabde000 0003E (v01 LENOVO TP-8D 00001280 PTL 00000002) [ 0.000000] ACPI: UEFI 00000000dabdd000 00042 (v01 PTL COMBUF 00000001 PTL 00000001) [ 0.000000] ACPI: UEFI 00000000dabdc000 00292 (v01 LENOVO TP-8D 00001280 PTL 00000002) [ 0.795807] fb0: EFI VGA frame buffer device [ 1.057243] EFI Variables Facility v0.08 2004-May-17 [ 9.122104] fb: conflicting fb hw usage inteldrmfb vs EFI VGA - removing generic driver ReadEFI: /dev/sda , N 128 , 0 , , PRStart 1024 , PRSize 128 WARNING: GPT (GUID Partition Table) detected on '/dev/sda'! The util fdisk doesn't support GPT. Use GNU Parted. =================== PARTITIONS & DISKS: sda4 : sda, not-sepboot, grubenv-ok grub2, grub-efi, update-grub, 64, with-boot, is-os, gpt-but-not-EFI, fstab-has-bad-efi, no-nt, no-winload, no-recov-nor-hid, no-bmgr, no-grldr, no-b-bcd, apt-get, grub-install, . sda3 : sda, maybesepboot, no-grubenv nogrub, no-docgrub, no-update-grub, 32, no-boot, no-os, gpt-but-not-EFI, part-has-no-fstab, no-nt, haswinload, no-recov-nor-hid, no-bmgr, no-grldr, no-b-bcd, nopakmgr, nogrubinstall, /mnt/boot-sav/sda3. sda1 : sda, maybesepboot, no-grubenv nogrub, no-docgrub, no-update-grub, 32, no-boot, no-os, is-correct-EFI, part-has-no-fstab, no-nt, no-winload, no-recov-nor-hid, no-bmgr, no-grldr, no-b-bcd, nopakmgr, nogrubinstall, /boot/efi. sda5 : sda, maybesepboot, no-grubenv nogrub, no-docgrub, no-update-grub, 32, no-boot, no-os, gpt-but-not-EFI, part-has-no-fstab, no-nt, no-winload, no-recov-nor-hid, no-bmgr, no-grldr, no-b-bcd, nopakmgr, nogrubinstall, /home. sda : GPT-BIS, GPT, no-BIOS_boot, has-correctEFI, 2048 sectors * 512 bytes =================== PARTED: Model: ATA HITACHI HTS72323 (scsi) Disk /dev/sda: 320GB Sector size (logical/physical): 512B/512B Partition Table: gpt Number Start End Size File system Name Flags 1 1049kB 106MB 105MB fat32 EFI system partition boot 2 106MB 240MB 134MB Microsoft reserved partition msftres 3 240MB 87.2GB 87.0GB ntfs Basic data partition 4 87.2GB 169GB 81.9GB ext4 5 169GB 316GB 147GB ext4 6 316GB 320GB 4096MB linux-swap(v1) =================== MOUNT: /dev/sda4 on / type ext4 (rw,errors=remount-ro) proc on /proc type proc (rw,noexec,nosuid,nodev) sysfs on /sys type sysfs (rw,noexec,nosuid,nodev) none on /sys/fs/fuse/connections type fusectl (rw) none on /sys/kernel/debug type debugfs (rw) none on /sys/kernel/security type securityfs (rw) udev on /dev type devtmpfs (rw,mode=0755) devpts on /dev/pts type devpts (rw,noexec,nosuid,gid=5,mode=0620) tmpfs on /run type tmpfs (rw,noexec,nosuid,size=10%,mode=0755) none on /run/lock type tmpfs (rw,noexec,nosuid,nodev,size=5242880) none on /run/shm type tmpfs (rw,nosuid,nodev) /dev/sda1 on /boot/efi type vfat (rw) /dev/sda5 on /home type ext4 (rw) gvfs-fuse-daemon on /home/vierlex/.gvfs type fuse.gvfs-fuse-daemon (rw,nosuid,nodev,user=vierlex) /dev/sda3 on /mnt/boot-sav/sda3 type fuseblk (rw,nosuid,nodev,allow_other,blksize=4096) /sys/block/sda: alignment_offset bdi capability dev device discard_alignment events events_async events_poll_msecs ext_range holders inflight power queue range removable ro sda1 sda2 sda3 sda4 sda5 sda6 size slaves stat subsystem trace uevent /dev: agpgart autofs block bsg btrfs-control bus char console core cpu cpu_dma_latency disk dri ecryptfs fb0 fd full fuse hpet input kmsg log mapper mcelog mei mem net network_latency network_throughput null oldmem port ppp psaux ptmx pts random rfkill rtc rtc0 sda sda1 sda2 sda3 sda4 sda5 sda6 sg0 shm snapshot snd stderr stdin stdout tpm0 uinput urandom usbmon0 usbmon1 usbmon2 v4l vga_arbiter video0 watchdog zero /dev/mapper: control /boot/efi: EFI /boot/efi/EFI: Boot Microsoft ubuntu /boot/efi/efi: Boot Microsoft ubuntu /boot/efi/efi/Boot: bootx64.efi /boot/efi/efi/ubuntu: grubx64.efi WARNING: GPT (GUID Partition Table) detected on '/dev/sda'! The util fdisk doesn't support GPT. Use GNU Parted. =================== DF: Filesystem Type Size Used Avail Use% Mounted on /dev/sda4 ext4 77G 4.1G 69G 6% / udev devtmpfs 3.9G 12K 3.9G 1% /dev tmpfs tmpfs 1.6G 864K 1.6G 1% /run none tmpfs 5.0M 0 5.0M 0% /run/lock none tmpfs 3.9G 152K 3.9G 1% /run/shm /dev/sda1 vfat 96M 18M 79M 19% /boot/efi /dev/sda5 ext4 137G 2.2G 128G 2% /home /dev/sda3 fuseblk 81G 30G 52G 37% /mnt/boot-sav/sda3 =================== FDISK: Disk /dev/sda: 320.1 GB, 320072933376 bytes 255 heads, 63 sectors/track, 38913 cylinders, total 625142448 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0xf34fe538 Device Boot Start End Blocks Id System /dev/sda1 1 625142447 312571223+ ee GPT =================== Before mainwindow FSCK no PASTEBIN yes WUBI no WINBOOT yes recommendedrepair, purge, QTY_OF_PART_FOR_REINSTAL 1 no-kernel-purge UNHIDEBOOT_ACTION yes (10s), noflag () PART_TO_REINSTALL_GRUB sda4, FORCE_GRUB no (sda) REMOVABLEDISK no USE_SEPARATEBOOTPART no (sda3) grub2 () UNCOMMENT_GFXMODE no ATA ADD_KERNEL_OPTION no (acpi=off) MBR_TO_RESTORE ( ) EFI detected. Please check the options. =================== Actions FSCK no PASTEBIN yes WUBI no WINBOOT no bootinfo, nombraction, QTY_OF_PART_FOR_REINSTAL 1 no-kernel-purge UNHIDEBOOT_ACTION no (10s), noflag () PART_TO_REINSTALL_GRUB sda4, FORCE_GRUB no (sda) REMOVABLEDISK no USE_SEPARATEBOOTPART no (sda3) grub2 () UNCOMMENT_GFXMODE no ATA ADD_KERNEL_OPTION no (acpi=off) MBR_TO_RESTORE ( ) No change has been performed on your computer. See you soon! internet: connected Thanks for your time and attention. EDIT: additional Info Request =No boot loader is installed in the MBR of /dev/sda. But maybe this is how it is supposed to work? yea this is ok. boot stuff seems to be on a seperate partition, in my case sda1. I'm very new to this UEFI thing too. missing files like bootmgr i don't really have a clue :D but yea, maybe thats how it suppose to be? Instead and whats not shown in the log for some reason: There is additional microsoft bootfiles on sda1 under /efi/microsoft/ [much stuff] I remember also doing some kind of hack to make a UEFI windows 7 usb stick. http://jake.io/b/2011/installing-windows-7-with-uefi-boot-on-an-x220-from-usb/ In short: creating and placing bootx64.efi on the stick so it can be booted in UEFI mode. boot order i decide that in my BIOS. i read somwhere that the thinkpad x220 (essential part of the serial number: 4921 http://www.lenovo.com/shop/americas/content/user_guides/x220_x220i_x220tablet_x220itablet_ug_en.pdf) doesnt really have UEFI interface or something, still, these 2 options are listed with all the other usual devices you can give a boot priority to. Right now it looks like this: Boot Priority Order 1. ubuntu 2. Windows Boot Manager 3. USB FDD 4. USB HDD 5. ATA HDD0 HITACHI [random string]

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  • A Taxonomy of Numerical Methods v1

    - by JoshReuben
    Numerical Analysis – When, What, (but not how) Once you understand the Math & know C++, Numerical Methods are basically blocks of iterative & conditional math code. I found the real trick was seeing the forest for the trees – knowing which method to use for which situation. Its pretty easy to get lost in the details – so I’ve tried to organize these methods in a way that I can quickly look this up. I’ve included links to detailed explanations and to C++ code examples. I’ve tried to classify Numerical methods in the following broad categories: Solving Systems of Linear Equations Solving Non-Linear Equations Iteratively Interpolation Curve Fitting Optimization Numerical Differentiation & Integration Solving ODEs Boundary Problems Solving EigenValue problems Enjoy – I did ! Solving Systems of Linear Equations Overview Solve sets of algebraic equations with x unknowns The set is commonly in matrix form Gauss-Jordan Elimination http://en.wikipedia.org/wiki/Gauss%E2%80%93Jordan_elimination C++: http://www.codekeep.net/snippets/623f1923-e03c-4636-8c92-c9dc7aa0d3c0.aspx Produces solution of the equations & the coefficient matrix Efficient, stable 2 steps: · Forward Elimination – matrix decomposition: reduce set to triangular form (0s below the diagonal) or row echelon form. If degenerate, then there is no solution · Backward Elimination –write the original matrix as the product of ints inverse matrix & its reduced row-echelon matrix à reduce set to row canonical form & use back-substitution to find the solution to the set Elementary ops for matrix decomposition: · Row multiplication · Row switching · Add multiples of rows to other rows Use pivoting to ensure rows are ordered for achieving triangular form LU Decomposition http://en.wikipedia.org/wiki/LU_decomposition C++: http://ganeshtiwaridotcomdotnp.blogspot.co.il/2009/12/c-c-code-lu-decomposition-for-solving.html Represent the matrix as a product of lower & upper triangular matrices A modified version of GJ Elimination Advantage – can easily apply forward & backward elimination to solve triangular matrices Techniques: · Doolittle Method – sets the L matrix diagonal to unity · Crout Method - sets the U matrix diagonal to unity Note: both the L & U matrices share the same unity diagonal & can be stored compactly in the same matrix Gauss-Seidel Iteration http://en.wikipedia.org/wiki/Gauss%E2%80%93Seidel_method C++: http://www.nr.com/forum/showthread.php?t=722 Transform the linear set of equations into a single equation & then use numerical integration (as integration formulas have Sums, it is implemented iteratively). an optimization of Gauss-Jacobi: 1.5 times faster, requires 0.25 iterations to achieve the same tolerance Solving Non-Linear Equations Iteratively find roots of polynomials – there may be 0, 1 or n solutions for an n order polynomial use iterative techniques Iterative methods · used when there are no known analytical techniques · Requires set functions to be continuous & differentiable · Requires an initial seed value – choice is critical to convergence à conduct multiple runs with different starting points & then select best result · Systematic - iterate until diminishing returns, tolerance or max iteration conditions are met · bracketing techniques will always yield convergent solutions, non-bracketing methods may fail to converge Incremental method if a nonlinear function has opposite signs at 2 ends of a small interval x1 & x2, then there is likely to be a solution in their interval – solutions are detected by evaluating a function over interval steps, for a change in sign, adjusting the step size dynamically. Limitations – can miss closely spaced solutions in large intervals, cannot detect degenerate (coinciding) solutions, limited to functions that cross the x-axis, gives false positives for singularities Fixed point method http://en.wikipedia.org/wiki/Fixed-point_iteration C++: http://books.google.co.il/books?id=weYj75E_t6MC&pg=PA79&lpg=PA79&dq=fixed+point+method++c%2B%2B&source=bl&ots=LQ-5P_taoC&sig=lENUUIYBK53tZtTwNfHLy5PEWDk&hl=en&sa=X&ei=wezDUPW1J5DptQaMsIHQCw&redir_esc=y#v=onepage&q=fixed%20point%20method%20%20c%2B%2B&f=false Algebraically rearrange a solution to isolate a variable then apply incremental method Bisection method http://en.wikipedia.org/wiki/Bisection_method C++: http://numericalcomputing.wordpress.com/category/algorithms/ Bracketed - Select an initial interval, keep bisecting it ad midpoint into sub-intervals and then apply incremental method on smaller & smaller intervals – zoom in Adv: unaffected by function gradient à reliable Disadv: slow convergence False Position Method http://en.wikipedia.org/wiki/False_position_method C++: http://www.dreamincode.net/forums/topic/126100-bisection-and-false-position-methods/ Bracketed - Select an initial interval , & use the relative value of function at interval end points to select next sub-intervals (estimate how far between the end points the solution might be & subdivide based on this) Newton-Raphson method http://en.wikipedia.org/wiki/Newton's_method C++: http://www-users.cselabs.umn.edu/classes/Summer-2012/csci1113/index.php?page=./newt3 Also known as Newton's method Convenient, efficient Not bracketed – only a single initial guess is required to start iteration – requires an analytical expression for the first derivative of the function as input. Evaluates the function & its derivative at each step. Can be extended to the Newton MutiRoot method for solving multiple roots Can be easily applied to an of n-coupled set of non-linear equations – conduct a Taylor Series expansion of a function, dropping terms of order n, rewrite as a Jacobian matrix of PDs & convert to simultaneous linear equations !!! Secant Method http://en.wikipedia.org/wiki/Secant_method C++: http://forum.vcoderz.com/showthread.php?p=205230 Unlike N-R, can estimate first derivative from an initial interval (does not require root to be bracketed) instead of inputting it Since derivative is approximated, may converge slower. Is fast in practice as it does not have to evaluate the derivative at each step. Similar implementation to False Positive method Birge-Vieta Method http://mat.iitm.ac.in/home/sryedida/public_html/caimna/transcendental/polynomial%20methods/bv%20method.html C++: http://books.google.co.il/books?id=cL1boM2uyQwC&pg=SA3-PA51&lpg=SA3-PA51&dq=Birge-Vieta+Method+c%2B%2B&source=bl&ots=QZmnDTK3rC&sig=BPNcHHbpR_DKVoZXrLi4nVXD-gg&hl=en&sa=X&ei=R-_DUK2iNIjzsgbE5ID4Dg&redir_esc=y#v=onepage&q=Birge-Vieta%20Method%20c%2B%2B&f=false combines Horner's method of polynomial evaluation (transforming into lesser degree polynomials that are more computationally efficient to process) with Newton-Raphson to provide a computational speed-up Interpolation Overview Construct new data points for as close as possible fit within range of a discrete set of known points (that were obtained via sampling, experimentation) Use Taylor Series Expansion of a function f(x) around a specific value for x Linear Interpolation http://en.wikipedia.org/wiki/Linear_interpolation C++: http://www.hamaluik.com/?p=289 Straight line between 2 points à concatenate interpolants between each pair of data points Bilinear Interpolation http://en.wikipedia.org/wiki/Bilinear_interpolation C++: http://supercomputingblog.com/graphics/coding-bilinear-interpolation/2/ Extension of the linear function for interpolating functions of 2 variables – perform linear interpolation first in 1 direction, then in another. Used in image processing – e.g. texture mapping filter. Uses 4 vertices to interpolate a value within a unit cell. Lagrange Interpolation http://en.wikipedia.org/wiki/Lagrange_polynomial C++: http://www.codecogs.com/code/maths/approximation/interpolation/lagrange.php For polynomials Requires recomputation for all terms for each distinct x value – can only be applied for small number of nodes Numerically unstable Barycentric Interpolation http://epubs.siam.org/doi/pdf/10.1137/S0036144502417715 C++: http://www.gamedev.net/topic/621445-barycentric-coordinates-c-code-check/ Rearrange the terms in the equation of the Legrange interpolation by defining weight functions that are independent of the interpolated value of x Newton Divided Difference Interpolation http://en.wikipedia.org/wiki/Newton_polynomial C++: http://jee-appy.blogspot.co.il/2011/12/newton-divided-difference-interpolation.html Hermite Divided Differences: Interpolation polynomial approximation for a given set of data points in the NR form - divided differences are used to approximately calculate the various differences. For a given set of 3 data points , fit a quadratic interpolant through the data Bracketed functions allow Newton divided differences to be calculated recursively Difference table Cubic Spline Interpolation http://en.wikipedia.org/wiki/Spline_interpolation C++: https://www.marcusbannerman.co.uk/index.php/home/latestarticles/42-articles/96-cubic-spline-class.html Spline is a piecewise polynomial Provides smoothness – for interpolations with significantly varying data Use weighted coefficients to bend the function to be smooth & its 1st & 2nd derivatives are continuous through the edge points in the interval Curve Fitting A generalization of interpolating whereby given data points may contain noise à the curve does not necessarily pass through all the points Least Squares Fit http://en.wikipedia.org/wiki/Least_squares C++: http://www.ccas.ru/mmes/educat/lab04k/02/least-squares.c Residual – difference between observed value & expected value Model function is often chosen as a linear combination of the specified functions Determines: A) The model instance in which the sum of squared residuals has the least value B) param values for which model best fits data Straight Line Fit Linear correlation between independent variable and dependent variable Linear Regression http://en.wikipedia.org/wiki/Linear_regression C++: http://www.oocities.org/david_swaim/cpp/linregc.htm Special case of statistically exact extrapolation Leverage least squares Given a basis function, the sum of the residuals is determined and the corresponding gradient equation is expressed as a set of normal linear equations in matrix form that can be solved (e.g. using LU Decomposition) Can be weighted - Drop the assumption that all errors have the same significance –-> confidence of accuracy is different for each data point. Fit the function closer to points with higher weights Polynomial Fit - use a polynomial basis function Moving Average http://en.wikipedia.org/wiki/Moving_average C++: http://www.codeproject.com/Articles/17860/A-Simple-Moving-Average-Algorithm Used for smoothing (cancel fluctuations to highlight longer-term trends & cycles), time series data analysis, signal processing filters Replace each data point with average of neighbors. Can be simple (SMA), weighted (WMA), exponential (EMA). Lags behind latest data points – extra weight can be given to more recent data points. Weights can decrease arithmetically or exponentially according to distance from point. Parameters: smoothing factor, period, weight basis Optimization Overview Given function with multiple variables, find Min (or max by minimizing –f(x)) Iterative approach Efficient, but not necessarily reliable Conditions: noisy data, constraints, non-linear models Detection via sign of first derivative - Derivative of saddle points will be 0 Local minima Bisection method Similar method for finding a root for a non-linear equation Start with an interval that contains a minimum Golden Search method http://en.wikipedia.org/wiki/Golden_section_search C++: http://www.codecogs.com/code/maths/optimization/golden.php Bisect intervals according to golden ratio 0.618.. Achieves reduction by evaluating a single function instead of 2 Newton-Raphson Method Brent method http://en.wikipedia.org/wiki/Brent's_method C++: http://people.sc.fsu.edu/~jburkardt/cpp_src/brent/brent.cpp Based on quadratic or parabolic interpolation – if the function is smooth & parabolic near to the minimum, then a parabola fitted through any 3 points should approximate the minima – fails when the 3 points are collinear , in which case the denominator is 0 Simplex Method http://en.wikipedia.org/wiki/Simplex_algorithm C++: http://www.codeguru.com/cpp/article.php/c17505/Simplex-Optimization-Algorithm-and-Implemetation-in-C-Programming.htm Find the global minima of any multi-variable function Direct search – no derivatives required At each step it maintains a non-degenerative simplex – a convex hull of n+1 vertices. Obtains the minimum for a function with n variables by evaluating the function at n-1 points, iteratively replacing the point of worst result with the point of best result, shrinking the multidimensional simplex around the best point. Point replacement involves expanding & contracting the simplex near the worst value point to determine a better replacement point Oscillation can be avoided by choosing the 2nd worst result Restart if it gets stuck Parameters: contraction & expansion factors Simulated Annealing http://en.wikipedia.org/wiki/Simulated_annealing C++: http://code.google.com/p/cppsimulatedannealing/ Analogy to heating & cooling metal to strengthen its structure Stochastic method – apply random permutation search for global minima - Avoid entrapment in local minima via hill climbing Heating schedule - Annealing schedule params: temperature, iterations at each temp, temperature delta Cooling schedule – can be linear, step-wise or exponential Differential Evolution http://en.wikipedia.org/wiki/Differential_evolution C++: http://www.amichel.com/de/doc/html/ More advanced stochastic methods analogous to biological processes: Genetic algorithms, evolution strategies Parallel direct search method against multiple discrete or continuous variables Initial population of variable vectors chosen randomly – if weighted difference vector of 2 vectors yields a lower objective function value then it replaces the comparison vector Many params: #parents, #variables, step size, crossover constant etc Convergence is slow – many more function evaluations than simulated annealing Numerical Differentiation Overview 2 approaches to finite difference methods: · A) approximate function via polynomial interpolation then differentiate · B) Taylor series approximation – additionally provides error estimate Finite Difference methods http://en.wikipedia.org/wiki/Finite_difference_method C++: http://www.wpi.edu/Pubs/ETD/Available/etd-051807-164436/unrestricted/EAMPADU.pdf Find differences between high order derivative values - Approximate differential equations by finite differences at evenly spaced data points Based on forward & backward Taylor series expansion of f(x) about x plus or minus multiples of delta h. Forward / backward difference - the sums of the series contains even derivatives and the difference of the series contains odd derivatives – coupled equations that can be solved. Provide an approximation of the derivative within a O(h^2) accuracy There is also central difference & extended central difference which has a O(h^4) accuracy Richardson Extrapolation http://en.wikipedia.org/wiki/Richardson_extrapolation C++: http://mathscoding.blogspot.co.il/2012/02/introduction-richardson-extrapolation.html A sequence acceleration method applied to finite differences Fast convergence, high accuracy O(h^4) Derivatives via Interpolation Cannot apply Finite Difference method to discrete data points at uneven intervals – so need to approximate the derivative of f(x) using the derivative of the interpolant via 3 point Lagrange Interpolation Note: the higher the order of the derivative, the lower the approximation precision Numerical Integration Estimate finite & infinite integrals of functions More accurate procedure than numerical differentiation Use when it is not possible to obtain an integral of a function analytically or when the function is not given, only the data points are Newton Cotes Methods http://en.wikipedia.org/wiki/Newton%E2%80%93Cotes_formulas C++: http://www.siafoo.net/snippet/324 For equally spaced data points Computationally easy – based on local interpolation of n rectangular strip areas that is piecewise fitted to a polynomial to get the sum total area Evaluate the integrand at n+1 evenly spaced points – approximate definite integral by Sum Weights are derived from Lagrange Basis polynomials Leverage Trapezoidal Rule for default 2nd formulas, Simpson 1/3 Rule for substituting 3 point formulas, Simpson 3/8 Rule for 4 point formulas. For 4 point formulas use Bodes Rule. Higher orders obtain more accurate results Trapezoidal Rule uses simple area, Simpsons Rule replaces the integrand f(x) with a quadratic polynomial p(x) that uses the same values as f(x) for its end points, but adds a midpoint Romberg Integration http://en.wikipedia.org/wiki/Romberg's_method C++: http://code.google.com/p/romberg-integration/downloads/detail?name=romberg.cpp&can=2&q= Combines trapezoidal rule with Richardson Extrapolation Evaluates the integrand at equally spaced points The integrand must have continuous derivatives Each R(n,m) extrapolation uses a higher order integrand polynomial replacement rule (zeroth starts with trapezoidal) à a lower triangular matrix set of equation coefficients where the bottom right term has the most accurate approximation. The process continues until the difference between 2 successive diagonal terms becomes sufficiently small. Gaussian Quadrature http://en.wikipedia.org/wiki/Gaussian_quadrature C++: http://www.alglib.net/integration/gaussianquadratures.php Data points are chosen to yield best possible accuracy – requires fewer evaluations Ability to handle singularities, functions that are difficult to evaluate The integrand can include a weighting function determined by a set of orthogonal polynomials. Points & weights are selected so that the integrand yields the exact integral if f(x) is a polynomial of degree <= 2n+1 Techniques (basically different weighting functions): · Gauss-Legendre Integration w(x)=1 · Gauss-Laguerre Integration w(x)=e^-x · Gauss-Hermite Integration w(x)=e^-x^2 · Gauss-Chebyshev Integration w(x)= 1 / Sqrt(1-x^2) Solving ODEs Use when high order differential equations cannot be solved analytically Evaluated under boundary conditions RK for systems – a high order differential equation can always be transformed into a coupled first order system of equations Euler method http://en.wikipedia.org/wiki/Euler_method C++: http://rosettacode.org/wiki/Euler_method First order Runge–Kutta method. Simple recursive method – given an initial value, calculate derivative deltas. Unstable & not very accurate (O(h) error) – not used in practice A first-order method - the local error (truncation error per step) is proportional to the square of the step size, and the global error (error at a given time) is proportional to the step size In evolving solution between data points xn & xn+1, only evaluates derivatives at beginning of interval xn à asymmetric at boundaries Higher order Runge Kutta http://en.wikipedia.org/wiki/Runge%E2%80%93Kutta_methods C++: http://www.dreamincode.net/code/snippet1441.htm 2nd & 4th order RK - Introduces parameterized midpoints for more symmetric solutions à accuracy at higher computational cost Adaptive RK – RK-Fehlberg – estimate the truncation at each integration step & automatically adjust the step size to keep error within prescribed limits. At each step 2 approximations are compared – if in disagreement to a specific accuracy, the step size is reduced Boundary Value Problems Where solution of differential equations are located at 2 different values of the independent variable x à more difficult, because cannot just start at point of initial value – there may not be enough starting conditions available at the end points to produce a unique solution An n-order equation will require n boundary conditions – need to determine the missing n-1 conditions which cause the given conditions at the other boundary to be satisfied Shooting Method http://en.wikipedia.org/wiki/Shooting_method C++: http://ganeshtiwaridotcomdotnp.blogspot.co.il/2009/12/c-c-code-shooting-method-for-solving.html Iteratively guess the missing values for one end & integrate, then inspect the discrepancy with the boundary values of the other end to adjust the estimate Given the starting boundary values u1 & u2 which contain the root u, solve u given the false position method (solving the differential equation as an initial value problem via 4th order RK), then use u to solve the differential equations. Finite Difference Method For linear & non-linear systems Higher order derivatives require more computational steps – some combinations for boundary conditions may not work though Improve the accuracy by increasing the number of mesh points Solving EigenValue Problems An eigenvalue can substitute a matrix when doing matrix multiplication à convert matrix multiplication into a polynomial EigenValue For a given set of equations in matrix form, determine what are the solution eigenvalue & eigenvectors Similar Matrices - have same eigenvalues. Use orthogonal similarity transforms to reduce a matrix to diagonal form from which eigenvalue(s) & eigenvectors can be computed iteratively Jacobi method http://en.wikipedia.org/wiki/Jacobi_method C++: http://people.sc.fsu.edu/~jburkardt/classes/acs2_2008/openmp/jacobi/jacobi.html Robust but Computationally intense – use for small matrices < 10x10 Power Iteration http://en.wikipedia.org/wiki/Power_iteration For any given real symmetric matrix, generate the largest single eigenvalue & its eigenvectors Simplest method – does not compute matrix decomposition à suitable for large, sparse matrices Inverse Iteration Variation of power iteration method – generates the smallest eigenvalue from the inverse matrix Rayleigh Method http://en.wikipedia.org/wiki/Rayleigh's_method_of_dimensional_analysis Variation of power iteration method Rayleigh Quotient Method Variation of inverse iteration method Matrix Tri-diagonalization Method Use householder algorithm to reduce an NxN symmetric matrix to a tridiagonal real symmetric matrix vua N-2 orthogonal transforms     Whats Next Outside of Numerical Methods there are lots of different types of algorithms that I’ve learned over the decades: Data Mining – (I covered this briefly in a previous post: http://geekswithblogs.net/JoshReuben/archive/2007/12/31/ssas-dm-algorithms.aspx ) Search & Sort Routing Problem Solving Logical Theorem Proving Planning Probabilistic Reasoning Machine Learning Solvers (eg MIP) Bioinformatics (Sequence Alignment, Protein Folding) Quant Finance (I read Wilmott’s books – interesting) Sooner or later, I’ll cover the above topics as well.

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  • Security Issues with Single Page Apps

    - by Stephen.Walther
    Last week, I was asked to do a code review of a Single Page App built using the ASP.NET Web API, Durandal, and Knockout (good stuff!). In particular, I was asked to investigate whether there any special security issues associated with building a Single Page App which are not present in the case of a traditional server-side ASP.NET application. In this blog entry, I discuss two areas in which you need to exercise extra caution when building a Single Page App. I discuss how Single Page Apps are extra vulnerable to both Cross-Site Scripting (XSS) attacks and Cross-Site Request Forgery (CSRF) attacks. This goal of this blog post is NOT to persuade you to avoid writing Single Page Apps. I’m a big fan of Single Page Apps. Instead, the goal is to ensure that you are fully aware of some of the security issues related to Single Page Apps and ensure that you know how to guard against them. Cross-Site Scripting (XSS) Attacks According to WhiteHat Security, over 65% of public websites are open to XSS attacks. That’s bad. By taking advantage of XSS holes in a website, a hacker can steal your credit cards, passwords, or bank account information. Any website that redisplays untrusted information is open to XSS attacks. Let me give you a simple example. Imagine that you want to display the name of the current user on a page. To do this, you create the following server-side ASP.NET page located at http://MajorBank.com/SomePage.aspx: <%@Page Language="C#" %> <html> <head> <title>Some Page</title> </head> <body> Welcome <%= Request["username"] %> </body> </html> Nothing fancy here. Notice that the page displays the current username by using Request[“username”]. Using Request[“username”] displays the username regardless of whether the username is present in a cookie, a form field, or a query string variable. Unfortunately, by using Request[“username”] to redisplay untrusted information, you have now opened your website to XSS attacks. Here’s how. Imagine that an evil hacker creates the following link on another website (hackers.com): <a href="/SomePage.aspx?username=<script src=Evil.js></script>">Visit MajorBank</a> Notice that the link includes a query string variable named username and the value of the username variable is an HTML <SCRIPT> tag which points to a JavaScript file named Evil.js. When anyone clicks on the link, the <SCRIPT> tag will be injected into SomePage.aspx and the Evil.js script will be loaded and executed. What can a hacker do in the Evil.js script? Anything the hacker wants. For example, the hacker could display a popup dialog on the MajorBank.com site which asks the user to enter their password. The script could then post the password back to hackers.com and now the evil hacker has your secret password. ASP.NET Web Forms and ASP.NET MVC have two automatic safeguards against this type of attack: Request Validation and Automatic HTML Encoding. Protecting Coming In (Request Validation) In a server-side ASP.NET app, you are protected against the XSS attack described above by a feature named Request Validation. If you attempt to submit “potentially dangerous” content — such as a JavaScript <SCRIPT> tag — in a form field or query string variable then you get an exception. Unfortunately, Request Validation only applies to server-side apps. Request Validation does not help in the case of a Single Page App. In particular, the ASP.NET Web API does not pay attention to Request Validation. You can post any content you want – including <SCRIPT> tags – to an ASP.NET Web API action. For example, the following HTML page contains a form. When you submit the form, the form data is submitted to an ASP.NET Web API controller on the server using an Ajax request: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title></title> </head> <body> <form data-bind="submit:submit"> <div> <label> User Name: <input data-bind="value:user.userName" /> </label> </div> <div> <label> Email: <input data-bind="value:user.email" /> </label> </div> <div> <input type="submit" value="Submit" /> </div> </form> <script src="Scripts/jquery-1.7.1.js"></script> <script src="Scripts/knockout-2.1.0.js"></script> <script> var viewModel = { user: { userName: ko.observable(), email: ko.observable() }, submit: function () { $.post("/api/users", ko.toJS(this.user)); } }; ko.applyBindings(viewModel); </script> </body> </html> The form above is using Knockout to bind the form fields to a view model. When you submit the form, the view model is submitted to an ASP.NET Web API action on the server. Here’s the server-side ASP.NET Web API controller and model class: public class UsersController : ApiController { public HttpResponseMessage Post(UserViewModel user) { var userName = user.UserName; return Request.CreateResponse(HttpStatusCode.OK); } } public class UserViewModel { public string UserName { get; set; } public string Email { get; set; } } If you submit the HTML form, you don’t get an error. The “potentially dangerous” content is passed to the server without any exception being thrown. In the screenshot below, you can see that I was able to post a username form field with the value “<script>alert(‘boo’)</script”. So what this means is that you do not get automatic Request Validation in the case of a Single Page App. You need to be extra careful in a Single Page App about ensuring that you do not display untrusted content because you don’t have the Request Validation safety net which you have in a traditional server-side ASP.NET app. Protecting Going Out (Automatic HTML Encoding) Server-side ASP.NET also protects you from XSS attacks when you render content. By default, all content rendered by the razor view engine is HTML encoded. For example, the following razor view displays the text “<b>Hello!</b>” instead of the text “Hello!” in bold: @{ var message = "<b>Hello!</b>"; } @message   If you don’t want to render content as HTML encoded in razor then you need to take the extra step of using the @Html.Raw() helper. In a Web Form page, if you use <%: %> instead of <%= %> then you get automatic HTML Encoding: <%@ Page Language="C#" %> <% var message = "<b>Hello!</b>"; %> <%: message %> This automatic HTML Encoding will prevent many types of XSS attacks. It prevents <script> tags from being rendered and only allows &lt;script&gt; tags to be rendered which are useless for executing JavaScript. (This automatic HTML encoding does not protect you from all forms of XSS attacks. For example, you can assign the value “javascript:alert(‘evil’)” to the Hyperlink control’s NavigateUrl property and execute the JavaScript). The situation with Knockout is more complicated. If you use the Knockout TEXT binding then you get HTML encoded content. On the other hand, if you use the HTML binding then you do not: <!-- This JavaScript DOES NOT execute --> <div data-bind="text:someProp"></div> <!-- This Javacript DOES execute --> <div data-bind="html:someProp"></div> <script src="Scripts/jquery-1.7.1.js"></script> <script src="Scripts/knockout-2.1.0.js"></script> <script> var viewModel = { someProp : "<script>alert('Evil!')<" + "/script>" }; ko.applyBindings(viewModel); </script>   So, in the page above, the DIV element which uses the TEXT binding is safe from XSS attacks. According to the Knockout documentation: “Since this binding sets your text value using a text node, it’s safe to set any string value without risking HTML or script injection.” Just like server-side HTML encoding, Knockout does not protect you from all types of XSS attacks. For example, there is nothing in Knockout which prevents you from binding JavaScript to a hyperlink like this: <a data-bind="attr:{href:homePageUrl}">Go</a> <script src="Scripts/jquery-1.7.1.min.js"></script> <script src="Scripts/knockout-2.1.0.js"></script> <script> var viewModel = { homePageUrl: "javascript:alert('evil!')" }; ko.applyBindings(viewModel); </script> In the page above, the value “javascript:alert(‘evil’)” is bound to the HREF attribute using Knockout. When you click the link, the JavaScript executes. Cross-Site Request Forgery (CSRF) Attacks Cross-Site Request Forgery (CSRF) attacks rely on the fact that a session cookie does not expire until you close your browser. In particular, if you visit and login to MajorBank.com and then you navigate to Hackers.com then you will still be authenticated against MajorBank.com even after you navigate to Hackers.com. Because MajorBank.com cannot tell whether a request is coming from MajorBank.com or Hackers.com, Hackers.com can submit requests to MajorBank.com pretending to be you. For example, Hackers.com can post an HTML form from Hackers.com to MajorBank.com and change your email address at MajorBank.com. Hackers.com can post a form to MajorBank.com using your authentication cookie. After your email address has been changed, by using a password reset page at MajorBank.com, a hacker can access your bank account. To prevent CSRF attacks, you need some mechanism for detecting whether a request is coming from a page loaded from your website or whether the request is coming from some other website. The recommended way of preventing Cross-Site Request Forgery attacks is to use the “Synchronizer Token Pattern” as described here: https://www.owasp.org/index.php/Cross-Site_Request_Forgery_%28CSRF%29_Prevention_Cheat_Sheet When using the Synchronizer Token Pattern, you include a hidden input field which contains a random token whenever you display an HTML form. When the user opens the form, you add a cookie to the user’s browser with the same random token. When the user posts the form, you verify that the hidden form token and the cookie token match. Preventing Cross-Site Request Forgery Attacks with ASP.NET MVC ASP.NET gives you a helper and an action filter which you can use to thwart Cross-Site Request Forgery attacks. For example, the following razor form for creating a product shows how you use the @Html.AntiForgeryToken() helper: @model MvcApplication2.Models.Product <h2>Create Product</h2> @using (Html.BeginForm()) { @Html.AntiForgeryToken(); <div> @Html.LabelFor( p => p.Name, "Product Name:") @Html.TextBoxFor( p => p.Name) </div> <div> @Html.LabelFor( p => p.Price, "Product Price:") @Html.TextBoxFor( p => p.Price) </div> <input type="submit" /> } The @Html.AntiForgeryToken() helper generates a random token and assigns a serialized version of the same random token to both a cookie and a hidden form field. (Actually, if you dive into the source code, the AntiForgeryToken() does something a little more complex because it takes advantage of a user’s identity when generating the token). Here’s what the hidden form field looks like: <input name=”__RequestVerificationToken” type=”hidden” value=”NqqZGAmlDHh6fPTNR_mti3nYGUDgpIkCiJHnEEL59S7FNToyyeSo7v4AfzF2i67Cv0qTB1TgmZcqiVtgdkW2NnXgEcBc-iBts0x6WAIShtM1″ /> And here’s what the cookie looks like using the Google Chrome developer toolbar: You use the [ValidateAntiForgeryToken] action filter on the controller action which is the recipient of the form post to validate that the token in the hidden form field matches the token in the cookie. If the tokens don’t match then validation fails and you can’t post the form: public ActionResult Create() { return View(); } [ValidateAntiForgeryToken] [HttpPost] public ActionResult Create(Product productToCreate) { if (ModelState.IsValid) { // save product to db return RedirectToAction("Index"); } return View(); } How does this all work? Let’s imagine that a hacker has copied the Create Product page from MajorBank.com to Hackers.com – the hacker grabs the HTML source and places it at Hackers.com. Now, imagine that the hacker trick you into submitting the Create Product form from Hackers.com to MajorBank.com. You’ll get the following exception: The Cross-Site Request Forgery attack is blocked because the anti-forgery token included in the Create Product form at Hackers.com won’t match the anti-forgery token stored in the cookie in your browser. The tokens were generated at different times for different users so the attack fails. Preventing Cross-Site Request Forgery Attacks with a Single Page App In a Single Page App, you can’t prevent Cross-Site Request Forgery attacks using the same method as a server-side ASP.NET MVC app. In a Single Page App, HTML forms are not generated on the server. Instead, in a Single Page App, forms are loaded dynamically in the browser. Phil Haack has a blog post on this topic where he discusses passing the anti-forgery token in an Ajax header instead of a hidden form field. He also describes how you can create a custom anti-forgery token attribute to compare the token in the Ajax header and the token in the cookie. See: http://haacked.com/archive/2011/10/10/preventing-csrf-with-ajax.aspx Also, take a look at Johan’s update to Phil Haack’s original post: http://johan.driessen.se/posts/Updated-Anti-XSRF-Validation-for-ASP.NET-MVC-4-RC (Other server frameworks such as Rails and Django do something similar. For example, Rails uses an X-CSRF-Token to prevent CSRF attacks which you generate on the server – see http://excid3.com/blog/rails-tip-2-include-csrf-token-with-every-ajax-request/#.UTFtgDDkvL8 ). For example, if you are creating a Durandal app, then you can use the following razor view for your one and only server-side page: @{ Layout = null; } <!DOCTYPE html> <html> <head> <title>Index</title> </head> <body> @Html.AntiForgeryToken() <div id="applicationHost"> Loading app.... </div> @Scripts.Render("~/scripts/vendor") <script type="text/javascript" src="~/App/durandal/amd/require.js" data-main="/App/main"></script> </body> </html> Notice that this page includes a call to @Html.AntiForgeryToken() to generate the anti-forgery token. Then, whenever you make an Ajax request in the Durandal app, you can retrieve the anti-forgery token from the razor view and pass the token as a header: var csrfToken = $("input[name='__RequestVerificationToken']").val(); $.ajax({ headers: { __RequestVerificationToken: csrfToken }, type: "POST", dataType: "json", contentType: 'application/json; charset=utf-8', url: "/api/products", data: JSON.stringify({ name: "Milk", price: 2.33 }), statusCode: { 200: function () { alert("Success!"); } } }); Use the following code to create an action filter which you can use to match the header and cookie tokens: using System.Linq; using System.Net.Http; using System.Web.Helpers; using System.Web.Http.Controllers; namespace MvcApplication2.Infrastructure { public class ValidateAjaxAntiForgeryToken : System.Web.Http.AuthorizeAttribute { protected override bool IsAuthorized(HttpActionContext actionContext) { var headerToken = actionContext .Request .Headers .GetValues("__RequestVerificationToken") .FirstOrDefault(); ; var cookieToken = actionContext .Request .Headers .GetCookies() .Select(c => c[AntiForgeryConfig.CookieName]) .FirstOrDefault(); // check for missing cookie or header if (cookieToken == null || headerToken == null) { return false; } // ensure that the cookie matches the header try { AntiForgery.Validate(cookieToken.Value, headerToken); } catch { return false; } return base.IsAuthorized(actionContext); } } } Notice that the action filter derives from the base AuthorizeAttribute. The ValidateAjaxAntiForgeryToken only works when the user is authenticated and it will not work for anonymous requests. Add the action filter to your ASP.NET Web API controller actions like this: [ValidateAjaxAntiForgeryToken] public HttpResponseMessage PostProduct(Product productToCreate) { // add product to db return Request.CreateResponse(HttpStatusCode.OK); } After you complete these steps, it won’t be possible for a hacker to pretend to be you at Hackers.com and submit a form to MajorBank.com. The header token used in the Ajax request won’t travel to Hackers.com. This approach works, but I am not entirely happy with it. The one thing that I don’t like about this approach is that it creates a hard dependency on using razor. Your single page in your Single Page App must be generated from a server-side razor view. A better solution would be to generate the anti-forgery token in JavaScript. Unfortunately, until all browsers support a way to generate cryptographically strong random numbers – for example, by supporting the window.crypto.getRandomValues() method — there is no good way to generate anti-forgery tokens in JavaScript. So, at least right now, the best solution for generating the tokens is the server-side solution with the (regrettable) dependency on razor. Conclusion The goal of this blog entry was to explore some ways in which you need to handle security differently in the case of a Single Page App than in the case of a traditional server app. In particular, I focused on how to prevent Cross-Site Scripting and Cross-Site Request Forgery attacks in the case of a Single Page App. I want to emphasize that I am not suggesting that Single Page Apps are inherently less secure than server-side apps. Whatever type of web application you build – regardless of whether it is a Single Page App, an ASP.NET MVC app, an ASP.NET Web Forms app, or a Rails app – you must constantly guard against security vulnerabilities.

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