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• What is the n in O(n) when comparing sorting algorithms?

  - by Mumfi

  The question is rather simple, but I just can't find a good enough answer. I've taken a look at the most upvoted question regarding the Big-Oh notation, namely this: Plain English explanation of Big O It says there that: For example, sorting algorithms are typically compared based on comparison operations (comparing two nodes to determine their relative ordering). Now let's consider the simple bubble sort algorithm: for (int i = arr.length - 1; i > 0 ; i--) { for (int j = 0; j<i; j++) { if (arr[j] > arr[j+1]) { switchPlaces(...) } } } I know that worst case is O(n^2) and best case is O(n), but what is n exactly? If we attempt to sort an already sorted algorithm (best case), we would end up doing nothing, so why is it still O(n)? We are looping through 2 for-loops still, so if anything it should be O(n^2). n can't be the number of comparison operations, because we still compare all the elements, right? This confuses me, and I appreciate if someone could help me.

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• Big-Oh running time of code in Java (are my answers accurate

  - by Terry Frederick

  the Method hasTwoTrueValues returns true if at least two values in an array of booleans are true. Provide the Big-Oh running time for all three implementations proposed. // Version 1 public boolean has TwoTrueValues( boolean [ ] arr ) { int count = 0; for( int i = 0; i < arr. length; i++ ) if( arr[ i ] ) count++; return count >= 2; } // Version 2 public boolean hasTwoTrueValues( boolean [ ] arr ) { for( int i = 0; i < arr.length; i++ ) for( int j = i + 1; j < arr.length; j++ ) if( arr[ i ] && arr[ j ] ) return true; } // Version 3 public boolean hasTwoTrueValues( boolean [ ] arr ) { for( int i = 0; i < arr.length; i++ if( arr[ i ] ) for( int j = i + 1; j < arr.length; j++ ) if( arr[ j ] ) return true; return false; } For Version 1 I say the running time is O(n) Version 2 I say O(n^2) Version 3 I say O(n^2) I am really new to this Big Oh Notation so if my answers are incorrect could you please explain and help.

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• Common block usage in Fortran

  - by Crystal

  I'm new to Fortran and just doing some simple things for work. And as a new programmer in general, not sure exactly how this works, so excuse me if my explanation or notation is not the best. At the top of the .F file there are common declarations. The person explaining it to me said think of it like a struct in C, and that they are global. Also in that same .F file, they have it declared with what type. So it's something like: COMMON SOMEVAR INTEGER*2 SOMEVAR And then when I actually see it being used in some other file, they declare local variables, (e.g. SOMEVAR_LOCAL) and depending on the condition, they set SOMEVAR_LOCAL = 1 or 0. Then there is another conditional later down the line that will say something like IF (SOMEVAR_LOCAL. eq. 1) SOMEVAR(PARAM) = 1; (Again I apologize if this is not proper Fortran, but I don't have access to the code right now). So it seems to me that there is a "struct" like variable called SOMEVAR that is of some length (2 bytes of data?), then there is a local variable that is used as a flag so that later down the line, the global struct SOMEVAR can be set to that value. But because there is (PARAM), it's like an array for that particular instance? Thanks. Sorry for my bad explanation, but hopefully you will understand what I am asking.

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• Is there such a thing as a MemberExpression that handles a many-to-many relationship?

  - by Jaxidian

  We're trying to make it easy to write strongly-typed code in all areas of our system, so rather than setting var sortColumn = "FirstName" we'd like to say sortOption = (p => p.FirstName). This works great if the sortOption is of type Expression<Func<Person, object>> (we actually use generics in our code but that doesn't matter). However, we run into problems for many-to-many relationships because this notation breaks down. Consider this simple code: internal class Business { public IQueryable<Address> Addresses { get; set; } public string Name { get; set; } } internal class Address { public State MyState { get; set; } } internal class State { public string Abbreviation { get; set; } public int StateID { get; set; } } Is it possible to have this sort of MemberExpression to identify the StateID column off of a business? Again, the purpose of using this is not to return a StateID object, it's to just identify that property off of that entity (for sorting, filtering, and other purposes). It SEEMS to me that there should be some way to do this, even if it's not quite as pretty as foo = business.Addresses.SomeExtension(a => a.State.StateID);. Is this really possible? If more background is needed, take a look at this old question of mine. We've since updated the code significantly, but this should give you the general detailed idea of the context behind this question.

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• Implement two functions with the same name but different, non-covariant return types due to multiple abstract base classes

  - by user1508167

  If I have two abstract classes defining a pure virtual function with the same name, but different, non-covariant return types, how can I derive from these and define an implementation for both their functions? #include <iostream> class ITestA { public: virtual ~ITestA() {}; virtual float test() =0; }; class ITestB { public: virtual ~ITestB() {}; virtual bool test() =0; }; class C : public ITestA, public ITestB { public: /* Somehow implement ITestA::test and ITestB::test */ }; int main() { ITestA *a = new C(); std::cout << a->test() << std::endl; // should print a float, like "3.14" ITestB *b = dynamic_cast<ITestB *>(a); if (b) { std::cout << b->test() << std::endl; // should print "1" or "0" } delete(a); return 0; } As long as I don't call C::test() directly there's nothing ambiguous, so I think that it should work somehow and I guess I just didn't find the right notation yet. Or is this impossible, if so: Why?

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• Runtime of optimized Primehunter

  - by Setton

  Ok so I need some serious runtime help here! This method should take in an int value, check its primality, and return true if the number is indeed a prime. I understand why the loop only needs to go up to i squared, I understand that the worst case scenario is the case in which either the number is prime (or a multiple of a prime). But I don't understand how to quantify the actual runtime. I have done the loop myself by hand to try to understand the pattern or correlation of the number (n) and how many loops occur, but I literally feel like I keep falling into the same trap every time. I need a new way of thinking about this! I have a hint: "Think about the SIZE of the integer" which makes me want to quantify the literal number of integers in a number in relation to how many iterations it does in the for loop (floor log(n)) +1). BUT IT'S NOT WORKIIIING?! I KNOW it isn't square root n, obviously. I'm asking for Big O notation. public class PrimeHunter { public static boolean isPrime(int n) { boolean answer = (n > 1) ? true : false; //runtime = linear runtime for (int i = 2; i * i <= n; i++) //runtime = ????? { if (n % i == 0) //doesn't occur if it is a prime { answer = false; break; } } return answer; //runtime = linear runtime } }

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• ActionResult types in MVC2

  - by rajbk

  In ASP.NET MVC, incoming browser requests gets mapped to a controller action method. The action method returns a type of ActionResult in response to the browser request. A basic example is shown below: public class HomeController : Controller { public ActionResult Index() { return View(); } } Here we have an action method called Index that returns an ActionResult. Inside the method we call the View() method on the base Controller. The View() method, as you will see shortly, is a method that returns a ViewResult. The ActionResult class is the base class for different controller results. The following diagram shows the types derived from the ActionResult type. ASP.NET has a description of these methods ContentResult – Represents a text result. EmptyResult – Represents no result. FileContentResult – Represents a downloadable file (with the binary content). FilePathResult – Represents a downloadable file (with a path). FileStreamResult – Represents a downloadable file (with a file stream). JavaScriptResult – Represents a JavaScript script. JsonResult – Represents a JavaScript Object Notation result that can be used in an AJAX application. PartialViewResult – Represents HTML and markup rendered by a partial view. RedirectResult – Represents a redirection to a new URL. RedirectToRouteResult – Represents a result that performs a redirection by using the specified route values dictionary. ViewResult – Represents HTML and markup rendered by a view. To return the types shown above, you call methods that are available in the Controller base class. A list of these methods are shown below.   Methods without an ActionResult return type The MVC framework will translate action methods that do not return an ActionResult into one. Consider the HomeController below which has methods that do not return any ActionResult types. The methods defined return an int, object and void respectfully. public class HomeController : Controller { public int Add(int x, int y) { return x + y; }   public Employee GetEmployee() { return new Employee(); }   public void DoNothing() { } } When a request comes in, the Controller class hands internally uses a ControllerActionInvoker class which inspects the action parameters and invokes the correct action method. The CreateActionResult method in the ControllerActionInvoker class is used to return an ActionResult. This method is shown below. If the result of the action method is null, an EmptyResult instance is returned. If the result is not of type ActionResult, the result is converted to a string and returned as a ContentResult. protected virtual ActionResult CreateActionResult(ControllerContext controllerContext, ActionDescriptor actionDescriptor, object actionReturnValue) { if (actionReturnValue == null) { return new EmptyResult(); }   ActionResult actionResult = (actionReturnValue as ActionResult) ?? new ContentResult { Content = Convert.ToString(actionReturnValue, CultureInfo.InvariantCulture) }; return actionResult; }   In the HomeController class above, the DoNothing method will return an instance of the EmptyResult() Renders an empty webpage the GetEmployee() method will return a ContentResult which contains a string that represents the current object Renders the text “MyNameSpace.Controllers.Employee” without quotes. the Add method for a request of /home/add?x=3&y=5 returns a ContentResult Renders the text “8” without quotes. Unit Testing The nice thing about the ActionResult types is in unit testing the controller. We can, without starting a web server, create an instance of the Controller, call the methods and verify that the type returned is the expected ActionResult type. We can then inspect the returned type properties and confirm that it contains the expected values. Enjoy! Sulley: Hey, Mike, this might sound crazy but I don't think that kid's dangerous. Mike: Really? Well, in that case, let's keep it. I always wanted a pet that could kill me.

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• CodePlex Daily Summary for Sunday, March 07, 2010

  CodePlex Daily Summary for Sunday, March 07, 2010New ProjectsAlgorithminator: Universal .NET algorithm visualizer, which helps you to illustrate any algorithm, written in any .NET language. Still in development.ALToolkit: Contains a set of handy .NET components/classes. Currently it contains: * A Numeric Text Box (an Extended NumericUpDown) * A Splash Screen base fo...Automaton Home: Automaton is a home automation software built with a n-Tier, MVVM pattern utilzing WCF, EF, WPF, Silverlight and XBAP.Developer Controls: Developer Controls contains various controls to help build applications that can script/write code.Dynamic Reference Manager: Dynamic Reference Manager is a set (more like a small group) of classes and attributes written in C# that allows any .NET program to reference othe...indiologic: Utilities of an IndioNeural Cryptography in F#: This project is my magistracy resulting work. It is intended to be an example of using neural networks in cryptography. Hashing functions are chose...Particle Filter Visualization: Particle Filter Visualization Program for the Intel Science and Engineering FairPólya: Efficient, immutable, polymorphic collections. .Net lacks them, we provide them*. * By we, we mean I; and by efficient, I mean hopefully so.project euler solutions from mhinze: mhinze project euler solutionsSilverlight 4 and WCF multi layer: Silverlight 4 and WCF multi layersqwarea: Project for a browser-based, minimalistic, massively multiplayer strategy game. Part of the "Génie logiciel et Cloud Computing" course of the ENS (...SuperSocket: SuperSocket, a socket application framework can build FTP/SMTP/POP server easilyToast (for ASP.NET MVC): Dynamic, developer & designer friendly content injection, compression and optimization for ASP.NET MVCNew ReleasesALToolkit: ALToolkit 1.0: Binary release of the libraries containing: NumericTextBox SplashScreen Based on the VB.NET code, but that doesn't really matter.Blacklist of Providers: 1.0-Milestone 1: Blacklist of Providers.Milestone 1In this development release implemented - Main interface (Work Item #5453) - Database (Work Item #5523)C# Linear Hash Table: Linear Hash Table b2: Now includes a default constructor, and will throw an exception if capacity is not set to a power of 2 or loadToMaintain is below 1.Composure: CassiniDev-Trunk-40745-VS2010.rc1.NET4: A simple port of the CassiniDev portable web server project for Visual Studio 2010 RC1 built against .NET 4.0. The WCF tests currently fail unless...Developer Controls: DevControls: These are the version 1.0 releases of these controls. Download the individually or all together (in a .zip file). More releases coming soon!Dynamic Reference Manager: DRM Alpha1: This is the first release. I'm calling it Alpha because I intend implementing other functions, but I do not intend changing the way current functio...ESB Toolkit Extensions: Tellago SOA ESB Extenstions v0.3: Windows Installer file that installs Library on a BizTalk ESB 2.0 system. This Install automatically configures the esb.config to use the new compo...GKO Libraries: GKO Libraries 0.1 Alpha: 0.1 AlphaHome Access Plus+: v3.0.3.0: Version 3.0.3.0 Release Change Log: Added Announcement Box Removed script files that aren't needed Fixed & issue in directory path Stylesheet...Icarus Scene Engine: Icarus Scene Engine 1.10.306.840: Icarus Professional, Icarus Player, the supporting software for Icarus Scene Engine, with some included samples, and the start of a tutorial (with ...mavjuz WndLpt: wndlpt-0.2.5: New: Response to 5 LPT inputs "test i 1" New: Reaction to 12 LPT outputs "test q 8" New: Reaction to all LPT pins "test pin 15" New: Syntax: ...Neural Cryptography in F#: Neural Cryptography 0.0.1: The most simple version of this project. It has a neural network that works just like logical AND and a possibility to recreate neural network from...Password Provider: 1.0.3: This release fixes a bug which caused the program to crash when double clicking on a generic item.RoTwee: RoTwee 6.2.0.0: New feature is as next. 16649 Add hashtag for tweet of tune.Now you can tweet your playing tune with hashtag.Visual Studio DSite: Picture Viewer (Visual C++ 2008): This example source code allows you to view any picture you want in the click of a button. All you got to do is click the button and browser via th...WatchersNET CKEditor™ Provider for DotNetNuke: CKEditor Provider 1.8.00: Whats New File Browser: Folders & Files View reworked File Browser: Folders & Files View reworked File Browser: Folders are displayed as TreeVi...WSDLGenerator: WSDLGenerator 0.0.0.4: - replaced CommonLibrary.dll by CommandLineParser.dll - added better support for custom complex typesMost Popular ProjectsMetaSharpSilverlight ToolkitASP.NET Ajax LibraryAll-In-One Code FrameworkWindows 7 USB/DVD Download Toolニコ生アラートWindows Double ExplorerVirtual Router - Wifi Hot Spot for Windows 7 / 2008 R2Caliburn: An Application Framework for WPF and SilverlightArkSwitchMost Active ProjectsUmbraco CMSRawrSDS: Scientific DataSet library and toolsBlogEngine.NETjQuery Library for SharePoint Web Servicespatterns & practices – Enterprise LibraryIonics Isapi Rewrite FilterFarseer Physics EngineFasterflect - A Fast and Simple Reflection APIFluent Assertions

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• WP7 “Phantom Data” Source Possibly Revealed?

  - by Bil Simser

  Recently there’s been rumours floating around regarding “phantom” Windows Phone 7 data being magically sent and received on the latest WP7 phones. The news has mostly been floating around twitter so I didn’t pay it much attention. The BBC Technology News picked it up so I thought I would look more into it myself seeing that we have WP7 phones and maybe there was some truth to all this (and more importantly what was the cause). Full disclosure. I don’t have a lot of data points around this. This is from looking at a few phone logs, changing the configuration and looking back again after the change. I haven’t done a clean baseline test nor have I done testing with hundreds of phones. I leave the experience up to the reader to decide. So I went spelunking into the phone logs to see what was up. Most providers will show you data usage, at least on a daily basis. I lucked out with the provider and plan in that they provide hourly breakdowns. Here’s a snapshot from my usage throughout one night. Timestamp Data Usage 12:38:30 AM 2098 Kilobytes 1:30:30 AM 2 Kilobytes 2:38:30 AM 7118 Kilobytes 3:38:30 AM 6622 Kilobytes 4:38:30 AM 76 Kilobytes 5:38:30 AM 29 Kilobytes 6:38:30 AM 19 Kilobytes 7:38:30 AM 20 Kilobytes So a few observations from this data: Data seems to be collected on a regular basis. Looking at some other people phone logs, the times vary but it’s always hourly. There’s not a tremendous amount of data here (about 16 megabytes) but it seems like a lot for 7 hours The phone was connected to my home Wifi during this period Nothing was running and the phone was in a locked state Like I said, not a lot of data but it adds up. 16MB for 7 hours = about 50MB in a 24 hour period. That’s just plain old data being collected (somewhere, somehow) and not actual usage (Marketplace, Email, Browsing, etc.). Besides, when connected to a WiFi network you shouldn’t be charged data usage from your phone company (in theory, YMMV). After reviewing the logs I made a theory that the only thing that could possibly be sending data is the Feedback feature. With no other apps running under lock, what else could it be? In Windows 7 under your Settings the last option is Feedback. This sends feedback to Microsoft to “help improve Windows Phone”. On this page you have three options: Send feedback and use my cellular data connection Send feedback and (presumably) use my WiFi connection Don’t send feedback Knowing what I know about Microsoft, they do use the feedback data. For example some of the placement and inclusion of features in Office 2007 was based on that Feedback data that Office sends (assuming you had opted in). However in the Privacy Statement (it’s long but a good read at least once in your life), the Phone manual, and every other source I could look at there is no information about how much data it’s planning to send, just that it’s sending some data and that “some data charges with your carrier may apply”. Looking back at the logs, I have to wonder. 6MB at 3:30 and *then* 7MB the next hour. That’s a lot of information. And it adds up. 50MB in a 24 hour period X 30 days puts most people over a normal 1GB plan. And frankly why am I paying for a data plan only to have 80% of it chewed up by Microsoft, with no real benefit to me. If they included porn in the 50mb daily transfer I’d be okay with this, but I don’t see any new movies on my phone. So I turned it off. Set Feedback to disabled and wait. I waited. And waited. And generally didn’t use the phone if I could. The next day I went back to look at the data usage logs from the time period after turning the feedback mechanism off. Here are the results. Timestamp Data Usage 1:19:48 PM 0 Kilobytes 2:19:48 PM 0 Kilobytes 3:19:48 PM 0 Kilobytes 4:19:48 PM 678 Kilobytes (took a phone call) 5:19:48 PM 82 Kilobytes 6:19:48 PM 88 Kilobytes 7:20:30 PM 86 Kilobytes (guess they changed their reporting time) 8:20:30 PM 86 Kilobytes 9:20:30 PM 66 Kilobytes 10:20:30 PM 67 Kilobytes 11:20:30 PM 49 Kilobytes 12:20:30 AM 32 Kilobytes 1:20:30 AM 38 Kilobytes 2:20:31 AM 18 Kilobytes 3:20:31 AM 27 Kilobytes 4:20:31 AM 86 Kilobytes 5:20:31 AM 53 Kilobytes 6:20:31 AM 22 Kilobytes 7:22:15 AM 30 Kilobytes (another reporting time change) 8:22:15 AM 29 Kilobytes 9:22:15 AM 74 Kilobytes 10:22:15 AM 154 Kilobytes (phone call) 11:22:15 AM 12 Kilobytes 12:13:27 PM 49 Kilobytes 1:13:27 PM 197 Kilobytes (phone call) Quite a *drastic* change from what Feedback was turned on. I mean for a 24 hour period (sans 3 phone calls) I consumed about 1MB. Still quite a bit of transfer going on but at least it amounts to 30MB per month, not 30MB per day! Like I said this observation is neither scientific or conclusive. You decide what to do but frankly until Microsoft makes this data transfer exempt from your data plan (like that will happen) I would just turn Feedback off. YMMV.

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• Test and Report Add-on Compatibility in Firefox

  - by Asian Angel

  Now that the new version of Firefox is out you probably have a favorite extension or two that has not updated yet. You can get that extension working again, test it, and report back to Mozilla on how well it does with the Add-on Compatibility Reporter extension. Before For our example we chose a great extension that unfortunately has not been updated yet. As you can see here Firefox is refusing to let the extension install. After As soon as you install Add-on Compatibility Reporter you will be presented with an information page on how the extension works and what you can do with it. You should definitely take a moment to read this as it is very helpful. After trying our non-compatible extension again we were able to proceed with the install process. Notice at the bottom that “compatibility checking” has been overridden. Success! As soon as we restarted our browser it was easy to see the “non-compatible icon” in the “Add-ons Manager Window”…but the extension did install though (terrific!). Clicking on the extension’s entry will reveal a new button in the lower right corner. Using the “Compatibility Drop-Down Menu” you can report if the extension is working as well as before or if it is actually having problems. The extension that we used for our example had no problems whatsoever so good news there. Whichever option you choose you will be presented with a small “Report Window” with information about the extension, your browser’s version number, and your operating system. Click “Submit Report” to send it on its’ way. You will see a confirmation message letting you know that your report was successfully submitted. While the extension itself has not been altered in any form at least you have it working again and have helped verify whether it still works well or not. Notice the “notation” present now in place of the “Compatibility Button” that lets you know that you have already taken care of that particular extension. Looking great… Conclusion If you have a favorite extension that you miss using in the newest release of Firefox then this is definitely an extension to add to your browser. Not only will your extension start working again but you can let Mozilla know how well it is working and (hopefully) help get the extension updated. Links Download the Add-on Compatibility Reporter extension (Mozilla Add-ons) Similar Articles Productive Geek Tips Firefox 3.6 Release Candidate Available, Here’s How to Fix Your Incompatible ExtensionsUsing Windows 7 or Vista Compatibility ModeMysticgeek Blog: Generate A System Health Report In VistaCheck Extension Compatibility for Upcoming Firefox ReleasesMake Safari Stop Crashing Every 20 Seconds on Windows Vista TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips Revo Uninstaller Pro Registry Mechanic 9 for Windows PC Tools Internet Security Suite 2010 PCmover Professional Make your Joomla & Drupal Sites Mobile with OSMOBI Integrate Twitter and Delicious and Make Life Easier Design Your Web Pages Using the Golden Ratio Worldwide Growth of the Internet How to Find Your Mac Address Use My TextTools to Edit and Organize Text

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• Big Data – Operational Databases Supporting Big Data – Key-Value Pair Databases and Document Databases – Day 13 of 21

  - by Pinal Dave

  In yesterday’s blog post we learned the importance of the Relational Database and NoSQL database in the Big Data Story. In this article we will understand the role of Key-Value Pair Databases and Document Databases Supporting Big Data Story. Now we will see a few of the examples of the operational databases. Relational Databases (Yesterday’s post) NoSQL Databases (Yesterday’s post) Key-Value Pair Databases (This post) Document Databases (This post) Columnar Databases (Tomorrow’s post) Graph Databases (Tomorrow’s post) Spatial Databases (Tomorrow’s post) Key Value Pair Databases Key Value Pair Databases are also known as KVP databases. A key is a field name and attribute, an identifier. The content of that field is its value, the data that is being identified and stored. They have a very simple implementation of NoSQL database concepts. They do not have schema hence they are very flexible as well as scalable. The disadvantages of Key Value Pair (KVP) database are that they do not follow ACID (Atomicity, Consistency, Isolation, Durability) properties. Additionally, it will require data architects to plan for data placement, replication as well as high availability. In KVP databases the data is stored as strings. Here is a simple example of how Key Value Database will look like: Key Value Name Pinal Dave Color Blue Twitter @pinaldave Name Nupur Dave Movie The Hero As the number of users grow in Key Value Pair databases it starts getting difficult to manage the entire database. As there is no specific schema or rules associated with the database, there are chances that database grows exponentially as well. It is very crucial to select the right Key Value Pair Database which offers an additional set of tools to manage the data and provides finer control over various business aspects of the same. Riak Rick is one of the most popular Key Value Database. It is known for its scalability and performance in high volume and velocity database. Additionally, it implements a mechanism for collection key and values which further helps to build manageable system. We will further discuss Riak in future blog posts. Key Value Databases are a good choice for social media, communities, caching layers for connecting other databases. In simpler words, whenever we required flexibility of the data storage keeping scalability in mind – KVP databases are good options to consider. Document Database There are two different kinds of document databases. 1) Full document Content (web pages, word docs etc) and 2) Storing Document Components for storage. The second types of the document database we are talking about over here. They use Javascript Object Notation (JSON) and Binary JSON for the structure of the documents. JSON is very easy to understand language and it is very easy to write for applications. There are two major structures of JSON used for Document Database – 1) Name Value Pairs and 2) Ordered List. MongoDB and CouchDB are two of the most popular Open Source NonRelational Document Database. MongoDB MongoDB databases are called collections. Each collection is build of documents and each document is composed of fields. MongoDB collections can be indexed for optimal performance. MongoDB ecosystem is highly available, supports query services as well as MapReduce. It is often used in high volume content management system. CouchDB CouchDB databases are composed of documents which consists fields and attachments (known as description). It supports ACID properties. The main attraction points of CouchDB are that it will continue to operate even though network connectivity is sketchy. Due to this nature CouchDB prefers local data storage. Document Database is a good choice of the database when users have to generate dynamic reports from elements which are changing very frequently. A good example of document usages is in real time analytics in social networking or content management system. Tomorrow In tomorrow’s blog post we will discuss about various other Operational Databases supporting Big Data. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Big Data, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL

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• Mixed Emotions: Humans React to Natural Language Computer

  - by Applications User Experience

  There was a big event in Silicon Valley on Tuesday, November 15. Watson, the natural language computer developed at IBM Watson Research Center in Yorktown Heights, New York, and its inventor and principal research investigator, David Ferrucci, were guests at the Computer History Museum in Mountain View, California for another round of the television game Jeopardy. You may have read about or watched on YouTube how Watson beat Ken Jennings and Brad Rutter, two top Jeopardy competitors, last February. This time, Watson swept the floor with two Silicon Valley high-achievers, one a venture capitalist with a background  in math, computer engineering, and physics, and the other a technology and finance writer well-versed in all aspects of culture and humanities. Watson is the product of the DeepQA research project, which attempts to create an artificially intelligent computing system through advances in natural language processing (NLP), among other technologies. NLP is a computing strategy that seeks to provide answers by processing large amounts of unstructured data contained in multiple large domains of human knowledge. There are several ways to perform NLP, but one way to start is by recognizing key words, then processing  contextual  cues associated with the keyword concepts so that you get many more “smart” (that is, human-like) deductions,  rather than a series of “dumb” matches.  Jeopardy questions often require more than key word matching to get the correct answer; typically several pieces of information put together, often from vastly different categories, to come up with a satisfactory word string solution that can be rephrased as a question.  Smarter than your average search engine, but is it as smart as a human? Watson was especially fast at descrambling mixed-up state capital names, and recalling and pairing movie titles where one started and the other ended in the same word (e.g., Billion Dollar Baby Boom, where both titles used the word Baby). David said they had basically removed the variable of how fast Watson hit the buzzer compared to human contestants, but frustration frequently appeared on the faces of the contestants beaten to the punch by Watson. David explained that top Jeopardy winners like Jennings achieved their success with a similar strategy, timing their buzz to the end of the reading of the clue,  and “running the board”, being first to respond on about 60% of the clues.  Similar results for Watson. It made sense that Watson would be good at the technical and scientific stuff, so I figured the venture capitalist was toast. But I thought for sure Watson would lose to the writer in categories such as pop culture, wines and foods, and other humanities. Surprisingly, it held its own. I was amazed it could recognize a word definition of a syllogism in the category of philosophy. So what was the audience reaction to all of this? We started out expecting our formidable human contestants to easily run some of their categories; however, they started off on the wrong foot with the state capitals which Watson could unscramble so efficiently. By the end of the first round, contestants and the audience were feeling a little bit, well, …. deflated. Watson was winning by about $13,000, and the humans had gone into negative dollars. The IBM host said he was going to “slow Watson down a bit,” and the humans came back with respectable scores in Double Jeopardy. This was partially thanks to a very sympathetic audience (and host, also a human) providing “group-think” on many questions, especially baseball ‘s most valuable players, which by the way, couldn’t have been hard because even I knew them.  Yes, that’s right, the humans cheated. Since Watson could speak but not hear us (it didn’t have speech recognition capability), it was probably unaware of this. In Final Jeopardy, the single question had to do with law. I was sure Watson would blow this one, but all contestants were able to answer correctly about a copyright law. In a career devoted to making computers more helpful to people, I think I may have seen how a computer can do too much. I’m not sure I’d want to work side-by-side with a Watson doing my job. Certainly listening and empathy are important traits we humans still have over Watson.  While there was great enthusiasm in the packed room of computer scientists and their friends for this standing-room-only show, I think it made several of us uneasy (especially the poor human contestants whose egos were soundly bashed in the first round). This computer system, by the way , only took 4 years to program. David Ferrucci mentioned several practical uses for Watson, including medical diagnoses and legal strategies. Are you “the expert” in your job? Imagine NLP computing on an Oracle database.   This may be the user interface of the future to enable users to better process big data. How do you think you’d like it? Postscript: There were three little boys sitting in front of me in the very first row. They looked, how shall I say it, … unimpressed!

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• Inspiring a co-worker to adopt better coding practices?

  - by Aaronaught

  In the Handling my antiquated coworker question, various people discussed strategies for dealing with coworkers who are unwilling to integrate their workflow with the team's. I'd like, if possible, to learn some strategies for "teaching" a coworker who is merely ignorant of modern techniques and tools, and possibly a little apathetic. I've started working with a programmer who until recently has been working in relative isolation, in a different part of the company. He has extensive domain knowledge and most importantly he has demonstrated good problem-solving skills, something which many candidates seem to lack. However, the actual (C#) code I've seen is a throwback to the VB6 days. Procedural structure, Hungarian notation, global variables (abuse of static), no interfaces, no tests, non-use of Generics, throwing System.Exception... you get the idea. This programmer is a fair bit older than I am and, by first impressions at least, doesn't actively seek positive change. I'm not going to say resistant to change, because I think that is largely an issue of how the topic gets broached, and I want to be prepared. Programmers tend to be stubborn people, and going in with guns blazing and instituting rip-it-to-shreds code reviews and strictly-enforced policies is very likely not going to produce the end result that I want. If this were a new hire, a junior programmer, I wouldn't think twice about taking a "mentor" stance, but I'm extremely wary of treating an experienced employee as a clueless newbie (which he's not - he just hasn't kept pace with certain advancements in the field). How might I go about raising this developer's code quality standard the Dale Carnegie way, through gentle persuasion and non-material incentives? What would be the best strategy for effecting subtle, gradual changes, without creating an adversarial situation? Have other people - especially lead developers - been in this type of situation before? Which strategies were successful at stimulating interest and creating a positive group dynamic? Which strategies weren't successful and would be better to avoid? Clarifications: I really feel that several people are answering based on personal feelings without actually reading all of the details of the question. Please note the following, which should have been implied but I am now making explicit: This coworker is only my "senior" by virtue of age. I never said that his title, sphere of influence, or years at the organization exceed mine, and in fact, none of those things are true. He's a LOB programmer who's been absorbed into the main development shop. That's it. I am not a new hire, junior programmer, or other naïve idiot with grand plans to transform the company overnight. I am basically in charge of the software process, but as many who've worked as "leads" will know, responsibilities don't always correlate precisely with the org chart. I'm not asking people how to get my way, come hell or high water. I could do that if I wanted to, with the net result being that this person would become resentful and/or quit. Please try to understand that I am looking for a social, cooperative method of driving change. The mention of "...global variables... no tests... throwing System.Exception" was intended to demonstrate that the problems are not just superficial or aesthetic. Practices that may work for relatively small CRUD apps do not necessarily work for large enterprise apps, and in fact, none of the code so far has actually passed the integration tests. Please, try to take the question at face value, accept that I actually know what I'm talking about, and either answer the question that I actually asked or move on. P.S. My sincerest gratitude to those who -did- offer constructive advice rather than arguing with the premise. I'm going to leave this open for a while longer as I'm hoping to hear more in the way of real-world experiences.

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• Breaking up the Workday– Overcoming the Workaholic Syndrome

  - by dwahlin

  Hi, my name’s Dan Wahlin and I’m a workaholic – I admit it. It’s good from the standpoint that I get a lot done but it also has a lot of cons associated with it as well that I’m not proud of. I literally can’t watch TV without feeling like I should be doing something more productive (although I have no problem going to see movies at a theater or watching sporting events – that’s my escape I guess). On vacation it’s sometimes difficult the first few days to just “let go” of work and enjoy the time with my family. I always feel like I should be checking email and following up with different business projects. Fortunately, my wife knows me really well after 17 years of marriage and “gently” restricts my usage of laptops and other gadgets while we’re out. She also reminds me that constantly burying my face in gadgets just isn’t cool and shows a distinct lack of self control. On a given day I typically put in between 12 (at a minimum) up to 16-18 hours working on projects. My company does .NET consulting (ASP.NET/jQuery, SharePoint and Silverlight) but we also do a lot in the training space so there’s always a client project, some new courseware or some other deliverable that has to be worked on. My normal process for handling that is to just work my butt off and see how much I can get done. That process has worked well for a long time but when you start realizing that your happiness comes from how much work you accomplished that day then you have a problem. That’s especially true if you have kids (which I do….two awesome boys). It’s almost as if working more hours feels like I’m more successful or something which is of course ridiculous. It may actually mean that I’m too distracted or disorganized. Lately I’ve realized that while I’m still productive and always meet my deadlines, I’m really burnt out by the afternoon and have lost some of the excitement I used to have. Part of that’s normal I think given that I’ve been doing this for close to 15 years now, but in thinking through it more I realized that I just need to get away from the desk and take a break. By far, the happiest time of my life was my childhood. Part of that was due to having awesome parents, having far less responsibility (a big factor I suspect), being able to hang-out with friends at school, playing sports, games, etc. but I think a big part of the overall happiness came from being outside a lot. I lived on my bike as a little kid and as I grew up I shared time between riding an ATV all over the place, shooting hoops on the basketball court, playing golf and working on a golf course (all outside work of course).  Being a software developer and trainer I generally spend 95% or more of my day indoors and only see the sun when driving from place to place or by looking out the window (that’s sad because I live in a suburb of Phoenix, AZ where it’s nearly always sunny). I haven’t looked into any scientific studies on the matter, but I’d be willing to bet there’s a direct correlation between overall productivity/happiness and being outside some throughout the day (sunny or not). But, I wasn’t sure what to do about it since I do have a lot of deadlines I need to meet after all. While talking with my wife last night I mentioned how I feel like I’m in a rut and want to get the “fun” back that I used to have. She immediately said that I need to start making time for breaks (a real quick fact – she’s a lot smarter than me and nearly always right). Of course my first thought was that I’d be less productive taking breaks. If I spend 2 hours just relaxing then I’m losing 2 hours of work. But, I thought about it more and realized that I’m probably less productive when I work 10+ hours and only take less than 30 minutes for a lunch break to relax a little. I bet my brain is screaming, “Please let me relax a little so I can figure out these problems you’re trying to resolve!”. So, starting today I’m going to try to break the workaholic habit and spend time outside of the office. That could mean sitting around outside, working out, golfing, or whatever. I’ve decided that no gadgets are allowed during that time and that I shouldn’t work for more than 4 hours straight without taking a break. I have no idea how my little “break the workaholic syndrome” experiment will go or how long it will last, but I’d be very interested in hearing from others on how they keep fresh and focused without working yourself to death. If you have any specific ideas, techniques or practices you follow please share them. There’s a lot more to life than work and some of us (and I’m thinking of myself specifically) need to take a long, hard look at what kind of balance we currently have. I’d hate to look back at my life when I’m 80 years old and say, “The only thing I did was work – I missed out on life!”.

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• Flow-Design Cheat Sheet &ndash; Part II, Translation

  - by Ralf Westphal

  In my previous post I summarized the notation for Flow-Design (FD) diagrams. Now is the time to show you how to translate those diagrams into code. Hopefully you feel how different this is from UML. UML leaves you alone with your sequence diagram or component diagram or activity diagram. They leave it to you how to translate your elaborate design into code. Or maybe UML thinks it´s so easy no further explanations are needed? I don´t know. I just know that, as soon as people stop designing with UML and start coding, things end up to be very different from the design. And that´s bad. That degrades graphical designs to just time waste on paper (or some designer). I even believe that´s the reason why most programmers view textual source code as the only and single source of truth. Design and code usually do not match. FD is trying to change that. It wants to make true design a first class method in every developers toolchest. For that the first prerequisite is to be able to easily translate any design into code. Mechanically, without thinking. Even a compiler could do it :-) (More of that in some other article.) Translating to Methods The first translation I want to show you is for small designs. When you start using FD you should translate your diagrams like this. Functional units become methods. That´s it. An input-pin becomes a method parameter, an output-pin becomes a return value: The above is a part. But a board can be translated likewise and calls the nested FUs in order: In any case be sure to keep the board method clear of any and all business logic. It should not contain any control structures like if, switch, or a loop. Boards do just one thing: calling nested functional units in proper sequence. What about multiple input-pins? Try to avoid them. Replace them with a join returning a tuple: What about multiple output-pins? Try to avoid them. Or return a tuple. Or use out-parameters: But as I said, this simple translation is for simple designs only. Splits and joins are easily done with method translation: All pretty straightforward, isn´t it. But what about wires, named pins, entry points, explicit dependencies? I suggest you don´t use this kind of translation when your designs need these features. Translating to methods is for small scale designs like you might do once you´re working on the implementation of a part of a larger design. Or maybe for a code kata you´re doing in your local coding dojo. Instead of doing TDD try doing FD and translate your design into methods. You´ll see that way it´s much easier to work collaboratively on designs, remember them more easily, keep them clean, and lessen the need for refactoring. Translating to Events [coming soon]

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• My Feelings About Microsoft Surface

  - by Valter Minute

  Advice: read the title carefully, I’m talking about “feelings” and not about advanced technical points proved in a scientific and objective way I still haven’t had a chance to play with a MS Surface tablet (I would love to, of course) and so my ideas just came from reading different articles on the net and MS official statements. Remember also that the MVP motto begins with “Independent” (“Independent Experts. Real World Answers.”) and this is just my humble opinion about a product and a technology. I know that, being an MS MVP you can be called an “MS-fanboy”, I don’t care, I hope that people can appreciate my opinion, even if it doesn’t match theirs. The “Surface” brand can be confusing for techies that knew the “original” surface concept but I think that will be a fresh new brand name for most of the people out there. But marketing department are here to confuse people… so I can understand this “recycle” of an existing name. So Microsoft is entering the hardware arena… for me this is good news. Microsoft developed some nice hardware in the past: the xbox, zune (even if the commercial success was quite limited) and, last but not least, the two arc mices (old and new model) that I use and appreciate. In the past Microsoft worked with OEMs and that model lead to good and bad things. Good thing (for microsoft, at least) is market domination by windows-based PCs that only in the last years has been reduced by the return of the Mac and tablets. Google is also moving in the hardware business with its acquisition of Motorola, and Apple leveraged his control of both the hardware and software sides to develop innovative products. Microsoft can scare OEMs and make them fly away from windows (but where?) or just lead the pack, showing how devices should be designed to compete in the market and bring back some of the innovation that disappeared from recent PC products (look at the shelves of your favorite electronics store and try to distinguish a laptop between the huge mass of anonymous PCs on displays… only Macs shine out there…). Having to compete with MS “official” hardware will force OEMs to develop better product and bring back some real competition in a market that was ruled only by prices (the lower the better even when that means low quality) and no innovative features at all (when it was the last time that a new PC surprised you?). Moving into a new market is a big and risky move, but with Windows 8 Microsoft is playing a crucial move for its future, trying to be back in the innovation run against apple and google. MS can’t afford to fail this time. I saw the new devices (the WinRT and Pro) and the specifications are scarce, misleading and confusing. The first impression is that the device looks like an iPad with a nice keyboard cover… Using “HD” and “full HD” to define display resolution instead of using the real figures and reviving the “ClearType” brand (now dead on Win8 as reported here and missed by people who hate to read text on displays, like myself) without providing clear figures (couldn’t you count those damned pixels?) seems to imply that MS was caught by surprise by apple recent “retina” displays that brought very high definition screens on tablets.Also there are no specifications about the processors used (even if some sources report NVidia Tegra for the ARM tablet and i5 for the x86 one) and expected battery life (a critical point for tablets and the point that killed Windows7 x86 based tablets). Also nothing about the price, and this will be another critical point because other platform out there already provide lots of applications and have a good user base, if MS want to enter this market tablets pricing must be competitive. There are some expansion ports (SD and USB), so no fixed storage model (even if the specs talks about 32-64GB for RT and 128-256GB for pro). I like this and don’t like the apple model where flash memory (that it’s dirt cheap used in thumdrives or SD cards) is as expensive as gold (or cocaine to have a more accurate per gram measurement) when mounted inside a tablet/phone. For big files you’ll be able to use external media and an SD card could be used to store files that don’t require super-fast SSD-like access times, I hope. To be honest I really don’t like the marketplace model and the limitation of Windows RT APIs (no local database? from a company that based a good share of its success on VB6+Access!) and lack of desktop support on the ARM (even if the support is here and has been used to port office). It’s a step toward the consumer market (where competitors are making big money), but may impact enterprise (and embedded) users that may not appreciate Windows 8 new UI or the limitations of the new app model (if you aren’t connected you are dead ). Not having compatibility with the desktop will require brand new applications and honestly made all the CPU cycles spent to convert .NET IL into real machine code in the past like a huge waste of time… as soon as a new processor architecture is supported by Windows you still have to rewrite part of your application (and MS is pushing HTML5+JS and native code more than .NET in my perception). On the other side I believe that the development experience provided by Visual Studio is still miles (or kilometres) ahead of the competition and even the all-uppercase menu of VS2012 hasn’t changed this situation. The new metro UI got mixed reviews. On my side I should say that is very pleasant to use on a touch screen, I like the minimalist design (even if sometimes is too minimal and hides stuff that, in my opinion, should be visible) but I should also say that using it with mouse and keyboard is like trying to pick your nose with boxing gloves… Metro is also very interesting for embedded devices where touch screen usage is quite common and where having an application taking all the screen is the norm. For devices like kiosks, vending machines etc. this kind of UI can be a great selling point. I don’t need a new tablet (to be honest I’m pretty happy with my wife’s iPad and with my PC), but I may change my opinion after having a chance to play a little bit with those new devices and understand what’s hidden under all this mysterious and generic announcements and specifications!

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• What is in your Mathematica tool bag?

  - by Timo

  We all know that Mathematica is great, but it also often lacks critical functionality. What kind of external packages / tools / resources do you use with Mathematica? I'll edit (and invite anyone else to do so too) this main post to include resources which are focused on general applicability in scientific research and which as many people as possible will find useful. Feel free to contribute anything, even small code snippets (as I did below for a timing routine). Also, undocumented and useful features in Mathematica 7 and beyond you found yourself, or dug up from some paper/site are most welcome. Please include a short description or comment on why something is great or what utility it provides. If you link to books on Amazon with affiliate links please mention it, e.g., by putting your name after the link. Packages: LevelScheme is a package that greatly expands Mathematica's capability to produce good looking plots. I use it if not for anything else then for the much, much improved control over frame/axes ticks. David Park's Presentation Package ($50 - no charge for updates) Tools: MASH is Daniel Reeves's excellent perl script essentially providing scripting support for Mathematica 7. (This is finally built in as of Mathematica 8 with the -script option.) Resources: Wolfram's own repository MathSource has a lot of useful if narrow notebooks for various applications. Also check out the other sections such as Current Documentation, Courseware for lectures, and Demos for, well, demos. Books: Mathematica programming: an advanced introduction by Leonid Shifrin (web, pdf) is a must read if you want to do anything more than For loops in Mathematica. Quantum Methods with Mathematica by James F. Feagin (amazon) The Mathematica Book by Stephen Wolfram (amazon) (web) Schaum's Outline (amazon) Mathematica in Action by Stan Wagon (amazon) - 600 pages of neat examples and goes up to Mathematica version 7. Visualization techniques are especially good, you can see some of them on the author's Demonstrations Page. Mathematica Programming Fundamentals by Richard Gaylord (pdf) - A good concise introduction to most of what you need to know about Mathematica programming. Undocumented (or scarcely documented) Features: How to customize Mathematica keyboard shortcuts. See this question. How to inspect patterns and functions used by Mathematica's own functions. See this answer How to achieve Consistent size for GraphPlots in Mathematica? See this question.

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• How to optimize Core Data query for full text search

  - by dk

  Can I optimize a Core Data query when searching for matching words in a text? (This question also pertains to the wisdom of custom SQL versus Core Data on an iPhone.) I'm working on a new (iPhone) app that is a handheld reference tool for a scientific database. The main interface is a standard searchable table view and I want as-you-type response as the user types new words. Words matches must be prefixes of words in the text. The text is composed of 100,000s of words. In my prototype I coded SQL directly. I created a separate "words" table containing every word in the text fields of the main entity. I indexed words and performed searches along the lines of SELECT id, * FROM textTable JOIN (SELECT DISTINCT textTableId FROM words WHERE word BETWEEN 'foo' AND 'fooz' ) ON id=textTableId LIMIT 50 This runs very fast. Using an IN would probably work just as well, i.e. SELECT * FROM textTable WHERE id IN (SELECT textTableId FROM words WHERE word BETWEEN 'foo' AND 'fooz' ) LIMIT 50 The LIMIT is crucial and allows me to display results quickly. I notify the user that there are too many to display if the limit is reached. This is kludgy. I've spent the last several days pondering the advantages of moving to Core Data, but I worry about the lack of control in the schema, indexing, and querying for an important query. Theoretically an NSPredicate of textField MATCHES '.*\bfoo.*' would just work, but I'm sure it will be slow. This sort of text search seems so common that I wonder what is the usual attack? Would you create a words entity as I did above and use a predicate of "word BEGINSWITH 'foo'"? Will that work as fast as my prototype? Will Core Data automatically create the right indexes? I can't find any explicit means of advising the persistent store about indexes. I see some nice advantages of Core Data in my iPhone app. The faulting and other memory considerations allow for efficient database retrievals for tableview queries without setting arbitrary limits. The object graph management allows me to easily traverse entities without writing lots of SQL. Migration features will be nice in the future. On the other hand, in a limited resource environment (iPhone) I worry that an automatically generated database will be bloated with metadata, unnecessary inverse relationships, inefficient attribute datatypes, etc. Should I dive in or proceed with caution?

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• Opening HTML Table in Excel - numbers are getting changed

  - by nickfranceschina

  so I have this HTML table with a bunch of big numbers in it that I want to open in Excel 2007... you can follow along at home: <table> <tr> <td>this is a big number</td> </tr><tr> <td>1111111</td> </tr><tr> <td>2335322864</td> </tr><tr> <td>23353228641</td> </tr><tr> <td>233532286418</td> </tr><tr> <td>2335322864187</td> </tr><tr> <td>23353228641877</td> </tr><tr> <td>233532286418777</td> </tr><tr> <td>2335322864187774</td> </tr><tr> <td>23353228641877745</td> </tr><tr> <td>233532286418777456</td> </tr><tr> <td>2335322864187774562</td> </tr><tr> <td>23353228641877745623</td> </tr><tr> <td>233532286418777456238</td> </tr> when I open this file in Excel it starts converting those numbers to scientific notation when they get over 10 digits in length... and in doing so, it starts changing the actual number and replaces least significant digits to zeros how can I tell Excel not to do this?

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• Problem getting correct parameters for C# P/Invoke call to C++ dll

  - by Jim Jones

  Trying to Interop a functionality from the Outside In API from Oracle. Have the following function: SCCERR EXOpenExport {VTHDOC hDoc, VTDWORD dwOutputId, VTDWORD dwSpecType, VTLPVOID pSpec, VTDWORD dwFlags, VTSYSPARAM dwReserved, VTLPVOID pCallbackFunc, VTSYSPARAM dwCallbackData, VTLPHEXPORT phExport); From the header files I reduced the parameters to: typedef VTSYSPARAM VTHDOC, VTLPHDOC * typedef DWORD_PTR VTSYSPARAM typedef unsigned long DWORD_PTR typedef unsigned long VTDWORD typedef VTVOID* VTLPVOID #define VTVOID void typedef VTHDOC VTHEXPORT, *VTLPEXPORT These are for 32 bit windows Going through the header files, the example programs, and the documentation I found: 1. That pSpec could be a pointer to a buffer or NULL, so I set it to a IntPtr.Zero (documentation). 2. That dwFlags and dwReserved according to the documentation "Must be set by the developer to 0". 3. That pCallbackFunc can be set to NULL if I don't want to handle callbacks. 4. That the last two are based on structs that I wrote C# wrappers for using the [StructLayout(LayoutKind.Sequential)]. Then instatiated an instance and generated the parameters by first creating a IntPtr with Marshal.AllocHGlobal(Marshal.SizeOf(instance)), then getting the address value which is passed as a uint for dwCallbackData and a IntPtr for phExport. The final parameter list is as follows: 1. phDoc as a IntPtr which was loaded with an address by the DAOpenDocument function called before. 2. dwOutputId as uint set to 1535 which represents FI_JPEGFIF 3. dwSpecType as int set to 2 which represents IOTYPE_ANSIPATH 4. pSpec as an IntPtr.Zero where the output will be written 5. dwFlags as uint set to 0 as directed 6. dwReserved as uint set to 0 as directed 7. pCallbackFunc as IntPtr set to NULL as I will handle results 8. dwCallBackDate as uint the address of a buffer for a struct 9. phExport as IntPtr to another struct buffer still get an undefined error from the API. Meaning that the call returns a 961 which is not defined in any of the header files. In the past I have gotten this when my choice of parameter types are incorrect. I started out using Interop Assistant which was helpful in learning how many of the parameter types get translated. It is however limited by how well I am able to glean the correct native type from the header files. For example the hDoc parameter used in the preceding function was defined as a non-filesytem handle, so attempted to use Marshal to create a handle, then used an IntPtr, and finally it turned out to be an int (actually it was &phDoc used here). So is there a more scientific way of doing this, other than trial and error? Jim

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• Why do I get rows of zeros in my 2D fft?

  - by Nicholas Pringle

  I am trying to replicate the results from a paper. "Two-dimensional Fourier Transform (2D-FT) in space and time along sections of constant latitude (east-west) and longitude (north-south) were used to characterize the spectrum of the simulated flux variability south of 40degS." - Lenton et al(2006) The figures published show "the log of the variance of the 2D-FT". I have tried to create an array consisting of the seasonal cycle of similar data as well as the noise. I have defined the noise as the original array minus the signal array. Here is the code that I used to plot the 2D-FT of the signal array averaged in latitude: import numpy as np from numpy import ma from matplotlib import pyplot as plt from Scientific.IO.NetCDF import NetCDFFile ### input directory indir = '/home/nicholas/data/' ### get the flux data which is in ### [time(5day ave for 10 years),latitude,longitude] nc = NetCDFFile(indir + 'CFLX_2000_2009.nc','r') cflux_southern_ocean = nc.variables['Cflx'][:,10:50,:] cflux_southern_ocean = ma.masked_values(cflux_southern_ocean,1e+20) # mask land nc.close() cflux = cflux_southern_ocean*1e08 # change units of data from mmol/m^2/s ### create an array that consists of the seasonal signal fro each pixel year_stack = np.split(cflux, 10, axis=0) year_stack = np.array(year_stack) signal_array = np.tile(np.mean(year_stack, axis=0), (10, 1, 1)) signal_array = ma.masked_where(signal_array > 1e20, signal_array) # need to mask ### average the array over latitude(or longitude) signal_time_lon = ma.mean(signal_array, axis=1) ### do a 2D Fourier Transform of the time/space image ft = np.fft.fft2(signal_time_lon) mgft = np.abs(ft) ps = mgft**2 log_ps = np.log(mgft) log_mgft= np.log(mgft) Every second row of the ft consists completely of zeros. Why is this? Would it be acceptable to add a randomly small number to the signal to avoid this. signal_time_lon = signal_time_lon + np.random.randint(0,9,size=(730, 182))*1e-05 EDIT: Adding images and clarify meaning The output of rfft2 still appears to be a complex array. Using fftshift shifts the edges of the image to the centre; I still have a power spectrum regardless. I expect that the reason that I get rows of zeros is that I have re-created the timeseries for each pixel. The ft[0, 0] pixel contains the mean of the signal. So the ft[1, 0] corresponds to a sinusoid with one cycle over the entire signal in the rows of the starting image. Here are is the starting image using following code: plt.pcolormesh(signal_time_lon); plt.colorbar(); plt.axis('tight') Here is result using following code: ft = np.fft.rfft2(signal_time_lon) mgft = np.abs(ft) ps = mgft**2 log_ps = np.log1p(mgft) plt.pcolormesh(log_ps); plt.colorbar(); plt.axis('tight') It may not be clear in the image but it is only every second row that contains completely zeros. Every tenth pixel (log_ps[10, 0]) is a high value. The other pixels (log_ps[2, 0], log_ps[4, 0] etc) have very low values.

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• Nullpointerexcption & abrupt IOStream closure with inheritence and subclasses

  - by user1401652

  A brief background before so we can communicate on the same wave length. I've had about 8-10 university courses on programming from data structure, to one on all languages, to specific ones such as java & c++. I'm a bit rusty because i usually take 2-3 month breaks from coding. This is a personal project that I started thinking of two years back. Okay down to the details, and a specific question, I'm having problems with my mutator functions. It seems to be that I am trying to access a private variable incorrectly. The question is, am I nesting my classes too much and trying to mutate a base class variable the incorrect way. If so point me in the way of the correct literature, or confirm this is my problem so I can restudy this information. Thanks package GroceryReceiptProgram; import java.io.*; import java.util.Vector; public class Date { private int hour, minute, day, month, year; Date() { try { BufferedReader keyboard = new BufferedReader(new InputStreamReader(System.in)); System.out.println("What's the hour? (Use 1-24 military notation"); hour = Integer.parseInt(keyboard.readLine()); System.out.println("what's the minute? "); minute = Integer.parseInt(keyboard.readLine()); System.out.println("What's the day of the month?"); day = Integer.parseInt(keyboard.readLine()); System.out.println("Which month of the year is it, use an integer"); month = Integer.parseInt(keyboard.readLine()); System.out.println("What year is it?"); year = Integer.parseInt(keyboard.readLine()); keyboard.close(); } catch (IOException e) { System.out.println("Yo houston we have a problem"); } } public void setHour(int hour) { this.hour = hour; } public void setHour() { try { BufferedReader keyboard = new BufferedReader(new InputStreamReader(System.in)); System.out.println("What hour, use military notation?"); this.hour = Integer.parseInt(keyboard.readLine()); keyboard.close(); } catch (NumberFormatException e) { System.out.println(e.toString() + ":doesnt seem to be a number"); } catch (IOException e) { System.out.println(e.toString()); } } public int getHour() { return hour; } public void setMinute(int minute) { this.minute = minute; } public void setMinute() { try (BufferedReader keyboard = new BufferedReader(new InputStreamReader(System.in))) { System.out.println("What minute?"); this.minute = Integer.parseInt(keyboard.readLine()); } catch (NumberFormatException e) { System.out.println(e.toString() + ": doesnt seem to be a number"); } catch (IOException e) { System.out.println(e.toString() + ": minute shall not cooperate"); } catch (NullPointerException e) { System.out.println(e.toString() + ": in the setMinute function of the Date class"); } } public int getMinute() { return minute; } public void setDay(int day) { this.day = day; } public void setDay() { try { BufferedReader keyboard = new BufferedReader(new InputStreamReader(System.in)); System.out.println("What day 0-6?"); this.day = Integer.parseInt(keyboard.readLine()); keyboard.close(); } catch (NumberFormatException e) { System.out.println(e.toString() + ":doesnt seem to be a number"); } catch (IOException e) { System.out.println(e.toString()); } } public int getDay() { return day; } public void setMonth(int month) { this.month = month; } public void setMonth() { try { BufferedReader keyboard = new BufferedReader(new InputStreamReader(System.in)); System.out.println("What month 0-11?"); this.month = Integer.parseInt(keyboard.readLine()); keyboard.close(); } catch (NumberFormatException e) { System.out.println(e.toString() + ":doesnt seem to be a number"); } catch (IOException e) { System.out.println(e.toString()); } } public int getMonth() { return month; } public void setYear(int year) { this.year = year; } public void setYear() { try { BufferedReader keyboard = new BufferedReader(new InputStreamReader(System.in)); System.out.println("What year?"); this.year = Integer.parseInt(keyboard.readLine()); keyboard.close(); } catch (NumberFormatException e) { System.out.println(e.toString() + ":doesnt seem to be a number"); } catch (IOException e) { System.out.println(e.toString()); } } public int getYear() { return year; } public void set() { setMinute(); setHour(); setDay(); setMonth(); setYear(); } public Vector<Integer> get() { Vector<Integer> holder = new Vector<Integer>(5); holder.add(hour); holder.add(minute); holder.add(month); holder.add(day); holder.add(year); return holder; } }; That is the Date class obviously, next is the other base class Location. package GroceryReceiptProgram; import java.io.*; import java.util.Vector; public class Location { String streetName, state, city, country; int zipCode, address; Location() { try { BufferedReader keyboard = new BufferedReader(new InputStreamReader(System.in)); System.out.println("What is the street name"); streetName = keyboard.readLine(); System.out.println("Which state?"); state = keyboard.readLine(); System.out.println("Which city?"); city = keyboard.readLine(); System.out.println("Which country?"); country = keyboard.readLine(); System.out.println("Which zipcode?");//if not u.s. continue around this step zipCode = Integer.parseInt(keyboard.readLine()); System.out.println("What address?"); address = Integer.parseInt(keyboard.readLine()); } catch (IOException e) { System.out.println(e.toString()); } } public void setZipCode(int zipCode) { this.zipCode = zipCode; } public void setZipCode() { try { BufferedReader keyboard = new BufferedReader(new InputStreamReader(System.in)); System.out.println("What zipCode?"); this.zipCode = Integer.parseInt(keyboard.readLine()); keyboard.close(); } catch (NumberFormatException e) { System.out.println(e.toString() + ":doesnt seem to be a number"); } catch (IOException e) { System.out.println(e.toString()); } } public void set() { setAddress(); setCity(); setCountry(); setState(); setStreetName(); setZipCode(); } public int getZipCode() { return zipCode; } public void setAddress(int address) { this.address = address; } public void setAddress() { try { BufferedReader keyboard = new BufferedReader(new InputStreamReader(System.in)); System.out.println("What minute?"); this.address = Integer.parseInt(keyboard.readLine()); keyboard.close(); } catch (NumberFormatException e) { System.out.println(e.toString() + ":doesnt seem to be a number"); } catch (IOException e) { System.out.println(e.toString()); } } public int getAddress() { return address; } public void setStreetName(String streetName) { this.streetName = streetName; } public void setStreetName() { try { BufferedReader keyboard = new BufferedReader(new InputStreamReader(System.in)); System.out.println("What minute?"); this.streetName = keyboard.readLine(); keyboard.close(); } catch (IOException e) { System.out.println(e.toString()); } } public String getStreetName() { return streetName; } public void setState(String state) { this.state = state; } public void setState() { try { BufferedReader keyboard = new BufferedReader(new InputStreamReader(System.in)); System.out.println("What minute?"); this.state = keyboard.readLine(); keyboard.close(); } catch (IOException e) { System.out.println(e.toString()); } } public String getState() { return state; } public void setCity(String city) { this.city = city; } public void setCity() { try { BufferedReader keyboard = new BufferedReader(new InputStreamReader(System.in)); System.out.println("What minute?"); this.city = keyboard.readLine(); keyboard.close(); } catch (IOException e) { System.out.println(e.toString()); } } public String getCity() { return city; } public void setCountry(String country) { this.country = country; } public void setCountry() { try { BufferedReader keyboard = new BufferedReader(new InputStreamReader(System.in)); System.out.println("What minute?"); this.country = keyboard.readLine(); keyboard.close(); } catch (IOException e) { System.out.println(e.toString()); } } public String getCountry() { return country; } }; their parent(What is the proper name?) class package GroceryReceiptProgram; import java.io.*; public class FoodGroup { private int price, count; private Date purchaseDate, expirationDate; private Location location; private String name; public FoodGroup() { try { setPrice(); setCount(); expirationDate.set(); purchaseDate.set(); location.set(); } catch (NullPointerException e) { System.out.println(e.toString() + ": in the constructor of the FoodGroup class"); } } public void setPrice(int price) { this.price = price; } public void setPrice() { try (BufferedReader keyboard = new BufferedReader(new InputStreamReader(System.in))) { System.out.println("What Price?"); price = Integer.parseInt(keyboard.readLine()); } catch (NumberFormatException e) { System.out.println(e.toString() + ":doesnt seem to be a number"); } catch (IOException e) { System.out.println(e.toString() + ": in the FoodGroup class, setPrice function"); } catch (NullPointerException e) { System.out.println(e.toString() + ": in FoodGroup class. SetPrice()"); } } public int getPrice() { return price; } public void setCount(int count) { this.count = count; } public void setCount() { try (BufferedReader keyboard = new BufferedReader(new InputStreamReader(System.in))) { System.out.println("What count?"); count = Integer.parseInt(keyboard.readLine()); } catch (NumberFormatException e) { System.out.println(e.toString() + ":doesnt seem to be a number"); } catch (IOException e) { System.out.println(e.toString() + ": in the FoodGroup class, setCount()"); } catch (NullPointerException e) { System.out.println(e.toString() + ": in FoodGroup class, setCount"); } } public int getCount() { return count; } public void setName(String name) { this.name = name; } public void setName() { try { BufferedReader keyboard = new BufferedReader(new InputStreamReader(System.in)); System.out.println("What minute?"); this.name = keyboard.readLine(); } catch (IOException e) { System.out.println(e.toString()); } } public String getName() { return name; } public void setLocation(Location location) { this.location = location; } public Location getLocation() { return location; } public void setPurchaseDate(Date purchaseDate) { this.purchaseDate = purchaseDate; } public void setPurchaseDate() { this.purchaseDate.set(); } public Date getPurchaseDate() { return purchaseDate; } public void setExpirationDate(Date expirationDate) { this.expirationDate = expirationDate; } public void setExpirationDate() { this.expirationDate.set(); } public Date getExpirationDate() { return expirationDate; } } and finally the main class, so I can get access to all of this work. package GroceryReceiptProgram; public class NewMain { public static void main(String[] args) { FoodGroup test = new FoodGroup(); } } If anyone is further interested, here is a link the UML for this. https://www.dropbox.com/s/1weigjnxih70tbv/GRP.dia

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• Re-order form fields on submit url

  - by user2521764

  I have a get form with several visible and hidden input fields. When the form is submitted, selected fileds with their values are appended to the url in the order they are placed in the form. Is there a way to re-order the parameters in the url using jQuery? Note that for the reasons of usability, I can not re-order the elements on the form itself. I know it beggs the question "why would I want to do it?", but the reason is that I will be hitting a static page, so the order of the parameters have to be exactly how they are in the static page url. For example, my form returns a url: http://someurl??names=comm&search=all&type=list while the static page has a url: http://someurl??search=all&type=list&names=comm A simplified form example is here: <form id="search_form" method="get" action="http://www.cbif.gc.ca/pls/pp/ppack.jump" > <h2>Choose which names you want to be displayed</h2> <select name="names"> <option value="comm">Common names</option> <option value="sci">Scientific names</option> </select> <h2>Choose how you want to view the results</h2> <input type="radio" name="search" value="all" id="complete" checked = "checked" /> <label for="complete" id="completeLabel">Complete list</label> <br/> <input type="radio" name="p_null" value="house" id="house" /> <label for="house" id="houseLabel">House plants only</label> <br/> <input type="radio" name="p_null" value="illust" id="illustrat" /> <label for="illustrat" id="illustratLabel">Plants with Illustrations</label> <br/> <input type="hidden" name="type" value="list" /> <input type="submit" value="Submit" /> </form> I can get form fields with values using $(#search_form).serializeArray() and massage the array like I want to, but I don't know how to set it back, i.e. modify the serialized values so that the submitted url has my order of parameters. I'm not even sure if this is the right way to go about it, so any pointers would be greatly appreciated.

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• Independence Day for Software Components &ndash; Loosening Coupling by Reducing Connascence

  - by Brian Schroer

  Today is Independence Day in the USA, which got me thinking about loosely-coupled “independent” software components. I was reminded of a video I bookmarked quite a while ago of Jim Weirich’s “Grand Unified Theory of Software Design” talk at MountainWest RubyConf 2009. I finally watched that video this morning. I highly recommend it. In the video, Jim talks about software connascence. The dictionary definition of connascence (con-NAY-sense) is: 1. The common birth of two or more at the same time 2. That which is born or produced with another. 3. The act of growing together. The brief Wikipedia page about Connascent Software Components says that: Two software components are connascent if a change in one would require the other to be modified in order to maintain the overall correctness of the system. Connascence is a way to characterize and reason about certain types of complexity in software systems. The term was introduced to the software world in Meilir Page-Jones’ 1996 book “What Every Programmer Should Know About Object-Oriented Design”. The middle third of that book is the author’s proposed graphical notation for describing OO designs. UML became the standard about a year later, so a revised version of the book was published in 1999 as “Fundamentals of Object-Oriented Design in UML”. Weirich says that the third part of the book, in which Page-Jones introduces the concept of connascence “is worth the price of the entire book”. (The price of the entire book, by the way, is not much – I just bought a used copy on Amazon for $1.36, so that was a pretty low-risk investment. I’m looking forward to getting the book and learning about connascence from the original source.) Meanwhile, here’s my summary of Weirich’s summary of Page-Jones writings about connascence: The stronger the form of connascence, the more difficult and costly it is to change the elements in the relationship. Some of the connascence types, ordered from weak to strong are: Connascence of Name Connascence of name is when multiple components must agree on the name of an entity. If you change the name of a method or property, then you need to change all references to that method or property. Duh. Connascence of name is unavoidable, assuming your objects are actually used. My main takeaway about connascence of name is that it emphasizes the importance of giving things good names so you don’t need to go changing them later. Connascence of Type Connascence of type is when multiple components must agree on the type of an entity. I assume this is more of a problem for languages without compilers (especially when used in apps without tests). I know it’s an issue with evil JavaScript type coercion. Connascence of Meaning Connascence of meaning is when multiple components must agree on the meaning of particular values, e.g that “1” means normal customer and “2” means preferred customer. The solution to this is to use constants or enums instead of “magic” strings or numbers, which reduces the coupling by changing the connascence form from “meaning” to “name”. Connascence of Position Connascence of positions is when multiple components must agree on the order of values. This refers to methods with multiple parameters, e.g.: eMailer.Send("[email protected]", "[email protected]", "Your order is complete", "Order completion notification"); The more parameters there are, the stronger the connascence of position is between the component and its callers. In the example above, it’s not immediately clear when reading the code which email addresses are sender and receiver, and which of the final two strings are subject vs. body. Connascence of position could be improved to connascence of type by replacing the parameter list with a struct or class. This “introduce parameter object” refactoring might be overkill for a method with 2 parameters, but would definitely be an improvement for a method with 10 parameters. This points out two “rules” of connascence:  The Rule of Degree: The acceptability of connascence is related to the degree of its occurrence. The Rule of Locality: Stronger forms of connascence are more acceptable if the elements involved are closely related. For example, positional arguments in private methods are less problematic than in public methods. Connascence of Algorithm Connascence of algorithm is when multiple components must agree on a particular algorithm. Be DRY – Don’t Repeat Yourself. If you have “cloned” code in multiple locations, refactor it into a common function.   Those are the “static” forms of connascence. There are also “dynamic” forms, including… Connascence of Execution Connascence of execution is when the order of execution of multiple components is important. Consumers of your class shouldn’t have to know that they have to call an .Initialize method before it’s safe to call a .DoSomething method. Connascence of Timing Connascence of timing is when the timing of the execution of multiple components is important. I’ll have to read up on this one when I get the book, but assume it’s largely about threading. Connascence of Identity Connascence of identity is when multiple components must reference the entity. The example Weirich gives is when you have two instances of the “Bob” Employee class and you call the .RaiseSalary method on one and then the .Pay method on the other does the payment use the updated salary?   Again, this is my summary of a summary, so please be forgiving if I misunderstood anything. Once I get/read the book, I’ll make corrections if necessary and share any other useful information I might learn.   See Also: Gregory Brown: Ruby Best Practices Issue #24: Connascence as a Software Design Metric (That link is failing at the time I write this, so I had to go to the Google cache of the page.)

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• OpenBSD configuration: Client unable to mount via NFS using Berkeley Automounter (amd)

  - by Rilindo

  What I am trying to do is to have my openBSD client (OpenBSD 4.9) auto mount a Linux NFS file system (Scientific Linux 6.1). So far, I am not sure if it is configured correctly. To get things out of the way, I am able to mount nfs manually: # mount_nfs -T -3 192.168.15.100:/exports /mnt # ls -la /mnt total 52 drwxr-xr-x 7 root wheel 4096 Oct 4 22:42 . drwxr-xr-x 16 root wheel 512 Nov 26 16:33 .. drwxrwxr-x 5 _sndio _sndio 4096 Oct 31 21:58 centos drwxr-xr-x 15 root wheel 4096 Nov 6 09:17 home drwxr-xr-x 5 root wheel 4096 Oct 31 21:27 sl drwxr-xr-x 3 root wheel 4096 Nov 19 16:02 sles drwxr-xr-x 17 503 503 4096 Nov 10 17:37 users # So connectivity is not an issue, as far as I can tell. As per man page, the following is configured in /etc/amd/auto.home: /defaults type:=nfs;sublink:=${key};opts:=rw,soft,intr,vers=3,proto=tcp * rhost:=192.168.15.100;rfs:=/exports In turn, /etc/amd/master is configured as such: # cat /etc/amd/master /exports amd.home Upon reboot, I can it see mount, but curiously enough, instead of the hostname: amd:24490 0 0 0 100% /exports From what I understand, amd acts a little different from FreeBSD. Still, I tried to see if I it can automount. Nope: ksh: cd: /exports/users - Resource temporarily unavailable # cd /exports/192.168.15.100/host/users ksh: cd: /exports/192.168.15.100/host/users - Resource temporarily unavailable A search in google doesn't help too much - it seems that automounting NFS with OpenBSD is not something that is usually done. Other than this, information is fairly sparse. I can, of course, always mount is permanently, but I tend to be a bit anal on convention, so no for now. :) Some direction would be appreciation. (And oh, in case you are a wondering, I tried FreeBSD way of using amd and that hasn't worked out - although I wouldn't mind an explanation of the difference between how FreeBSD implements and how OpenBSD implements it) UPDATE: After re-writing the map file several times, I got as far as actually communicating with the NFS server with this configuration: /defaults type:=nfs;rhost:=kerberos.monzell.com;rfs:=/exports;\ sublink:=${key};opts:=rw,nodev,nosuid,soft,intr,tcp,resvport * ${host}==${rhost};type:=nfs;fs:=${rfs};opts:=rw,nodev,nosuid,soft,intr,tcp,resvport However, for some reason, it seems that amd will only default to NFS version 2 over udp: # tcpdump dst kerberos tcpdump: listening on pcn0, link-type EN10MB tcpdump: WARNING: compensating for unaligned libpcap packets 20:38:28.558385 openbsd.monzell.com.856 > kerberos.monzell.com.sunrpc: udp 100 20:38:28.559154 openbsd.monzell.com.856 > kerberos.monzell.com.892: udp 96 20:38:30.592761 openbsd.monzell.com.856 > kerberos.monzell.com.nfsd: xid 0x22000000 (NFSv2) 40 null 20:38:33.558107 arp reply openbsd.monzell.com is-at 52:54:00:52:8f:66 I tried various options of forcing it to try to mount as nfsv3 such as: /defaults type:=nfs;rhost:=kerberos.monzell.com;rfs:=/exports;\ sublink:=${key};opts:=rw,nodev,nosuid,soft,intr,vers=3,proto=tcp,resvport * ${host}==${rhost};type:=nfs;fs:=${rfs};opts:=rw,nodev,nosuid,soft,intr,vers=3,proto=tcp,resvport or: /defaults type:=nfs;rhost:=kerberos.monzell.com;rfs:=/exports;\ sublink:=${key};opts:=rw,nodev,nosuid,soft,intr,vers=-3,proto=tcp,resvport * ${host}==${rhost};type:=nfs;fs:=${rfs};opts:=rw,nodev,nosuid,soft,intr,vers=3,proto=tcp,resvport Nothing yet still. Curious enough, OpenBSD mounts defaults to version 3, so I am not sure why it would start with version in amd. What would be the correct options to pass?

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