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• Calculating moving average/stdev in SAS?

  - by John

  Hye guys, I included a screenshot to help clarify my problem: http://i40.tinypic.com/mcrnmv.jpg. I'm trying to calculate some kind of moving average and moving standard deviation. The thing is I want to calculate the coefficients of variation (stdev/avg) for the actual value. Normally this is done by calculating the stdev and avg for the past 5 years. However sometimes there will be observations in my database for which I do not have the information of the past 5 years (maybe only 3, 2 etc). That's why i want a code that will calculate the avg and stdev even if there is no information for the whole 5 years. Also, as you see in the observations, sometimes I have information over more than 5 years, when this is the case I need some kind of moving average which allows me to calculate the avg and stdev for the past 5 year. So if a company has information for 7 years I need some kind of code that will calculate the avg and stdev for, lets say, 1997 (by 1991-1996), 1998 (by 1992-1997) and 1999 (1993-1998). As i'm not very familiar with sas commands it should look (very very roughly) like: set var if year = i then stdev=stdev(year(i-6) untill year(i-1)) and average = avg(year(i-6) untill year(i-1)) Or something like this, I really have no clue, I'm gonna try and figure it out but it's worth posting it if I won't find it myself. Thanks!

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• Eclipse: PyDev installation difficulties

  - by Rosarch

  I'm having difficulty getting PyDev to work. I had an installation of Eclipse for PHP developers (1.2.1.20090918-0703). A month ago, I installed PyDev, and everything worked great. I go to fire it up this morning, and PyDev is gone. There is no option to create a Python project, the Python language editor is missing, etc. Eclipse for PHP does not say that PyDev is installed, so I grab it from the update URL. The version that comes down is 1.5.6. I restart after the installation, and everything works fine again. Sweet. Then, I grab Subclipse 1.0.7. Upon restarting after that installation, PyDev is now gone. It isn't recognizing Python projects or Python files, etc. So I uninstall Subclipse. PyDev is still gone. Uninstalling and reinstalling PyDev again doesn't bring it back. What am I doing wrong? Do I need a different version of Eclipse?

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• Hide / show div toggle

  - by aa1

  I have the following mark up with a basic and advanced search divs. <div class="form"> <form> <input type="text" name="first_name"> <input type="text" name="last_name"> <div id="Basic" class="slide"> <input type="text" name="location"> </div> <a onclick="ShowDiv('Adv');">+ show advanced fields</a> <div id="Adv" class="slide hidden"> <input type="text" name="first_name2"> <input type="text" name="last_name2"> <input type="text" name="street"> <input type="text" name="town"> <input type="text" name="country"> </div> </form> <a onclick="ShowDiv('Basic');">- hide advanced fields</a> </div> The toggle is achieved with the following script function HideDiv() { $('.slide').hide(); } function ShowDiv(ctrl) { HideDiv(); $('#' + ctrl).show(); } ShowDiv('Basic'); I need to eliminate the need of using both links. I need to have only one link depending on state. So if the div basic is shown as default the link will say show advanced. When the advanced is shown the anchor link should switch to hide advanced How do I need to edit my jQuery and mark up.

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• Is there any algorithm that can solve ANY traditional sudoku puzzles, WITHOUT guessing (or similar techniques)?

  - by justin

  Is there any algorithm that solves ANY traditional sudoku puzzle, WITHOUT guessing? Here Guessing means trying an candidate and see how far it goes, if a contradiction is found with the guess, backtracking to the guessing step and try another candidate; when all candidates are exhausted without success, backtracking to the previous guessing step (if there is one; otherwise the puzzle proofs invalid.), etc. EDIT1: Thank you for your replies. traditional sudoku means 81-box sudoku, without any other constraints. Let us say the we know the solution is unique, is there any algorithm that can GUARANTEE to solve it without backtracking? Backtracking is a universal tool, I have nothing wrong with it but, using a universal tool to solve sudoku decreases the value and fun in deciphering (manually, or by computer) sudoku puzzles. How can a human being solve the so called "the hardest sudoku in the world", does he need to guess? I heard some researcher accidentally found that their algorithm for some data analysis can solve all sudoku. Is that true, do they have to guess too?

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• C/C++ Control Structure Limitations?

  - by STingRaySC

  I have heard of a limitation in VC++ (not sure which version) on the number of nested if statements (somewhere in the ballpark of 300). The code was of the form: if (a) ... else if (b) ... else if (c) ... ... I was surprised to find out there is a limit to this sort of thing, and that the limit is so small. I'm not looking for comments about coding practice and why to avoid this sort of thing altogether. Here's a list of things that I'd imagine could have some limitation: Number of functions in a scope (global, class, or namespace). Number of expressions in a single statement (e.g., compound conditionals). Number of cases in a switch. Number of parameters to a function. Number of classes in a single hierarchy (either inheritance or containment). What other control structures/language features have limits such as this? Do the language standards say anything about these limits (perhaps minimum requirements for an implementation)? Has anyone run into a particular language limitation like this with a particular compiler/implementation? EDIT: Please note that the above form of if statements is indeed "nested." It is equivalent to: if (a) { //... } else { if (b) { //... } else { if (c) { //... } else { //... } } }

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• Cocoa framework development: sharing between projects

  - by e.James

  I am currently developing a handful of similar Cocoa desktop apps. In an effort to share code between them, I have identified a set of core classes and functions that can be common across all of these applications. I would like to bundle this common code into a framework which all of my current applications (and any future ones) can link against. Now, here's the hard part: I'm going to be developing this framework as I go, so I need each of my desktop apps to have a reference to it, but I want to be able to edit the framework source code from within each of the app projects and have the framework automatically rebuilt as required. For example, let's say I have the Xcode project for DesktopAppNumberOne open, and I decide that one of my framework classes needs to be changed. I would like to: Open and edit the source file for that framework class without having to open the framework project in Xcode. Hit "build" on DesktopAppNumberOne, and see the framework rebuilt first (because one of its sources has changed), then see parts of DesktopAppNumberOne rebuilt (because one of the frameworks it links against has changed). I can see how to do this with only one app and one framework, but I'm having trouble figuring out how to do it with multiple apps that share a single framework. Has anyone had success with this approach? Am I perhaps going about this the wrong way? Any help would be appreciated.

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• template specialization of a auto_ptr<T>

  - by Chris Kaminski

  Maybe I'm overcomplicating things, but then again, I do sort of like clean interfaces. Let's say I want a specialization of auto_ptr for an fstream - I want a default fstream for the generic case, but allow a replacement pointer? tempate <> class auto_ptr<fstream> static fstream myfStream; fstream* ptr; public: auto_ptr() { // set ptr to &myfStream; } reset(fstream* newPtr) { // free old ptr if not the static one. ptr = newPtr }; } Would you consider something different or more elegant? And how would you keep something like the above from propagating outside this particular compilation unit? [The actual template is a boost::scoped_ptr.] EDIT: It's a contrived example. Ignore the fstream - it's about providing a default instance of object for an auto_ptr. I may not want to provide a specialized instance, but would like to keep the auto_ptr semantics for this static default object. class UserClass { public: auto_ptr<fstream> ptr; UserClass() { } } I may not provide an dynamic object at construction time - I still want it to have a meaningful default. Since I'm not looking at ownership-transfer semantics, it really shouldn't matter that my pointer class is pointing to a statically allocated object, no?

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• GitHub solution for personal repo

  - by Luke Maurer

  So I've got my private SVN repo on my home server, and it has maybe 30 different modules thrown together in it, ranging from abortive throw-away larks to a few endeavors that might actually go somewhere someday. But a recent filesystem failure (BTW, never ever EVER use XFS without a battery-backed hardware RAID) has me spooked and thinking of using a DVCS for all that. I've also just had quite the swig of the Git koolaid, and I've been working with GitHub of late, so that's where I'm looking right now. Of course, it would be silly to shell out major cash for a separate private Git repo for every little project, and I don't want to have to be selective about what I throw up there (I love all my children :-D ), so I'll have to be somewhat creative about this. I can happily use SSH to my home box to use Git the way I've been using SVN, and I'm thinking from there I could amalgamate everything into, say, a big project with 30 submodules, which I then push to GitHub. What'd be a sane way to set this up? Does using submodules sound feasible? How do I sync it all to my private GitHub repo? Cron job? Git hook? I'd love to hear it if anyone's done something similar. I'm not really married to Git or GitHub, so a sufficiently compelling feature of another solution might sway me. But if your answer does involve a different system (especially a different VCS), be advised it'll be a tougher sell :-)

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• jsf messed up links

  - by Mateusz

  I'm new to JSF. My application is working, but I'm confused with links in browser when using controller. BTW, there is also PrimeFaces in my app so don't be suprised with p: tags. Let's say I have 'list' and 'show' pages with controller doing redirection between them. First I'm on http://localhost:8080/y/r/conversation/list.xhtml page. There is link created with line <p:commandLink action="#{lazyConversationBean.doShow(conv)}" ajax="false" value="View"/>. lazyConversationBean acts here as my Controller. There is method: public String doShow(Conversation c) { this.setSelectedConversation(c); return "view"; } from which I got redirected to ...... again http://localhost:8080/y/r/conversation/list.xhtml (browser shows it) even when it's correct http://localhost:8080/y/r/conversation/view.xhtml page. There I have link <p:commandButton action="#{lazyConversationBean.doList()}" ajax="false" value="Back to list"/> and again controller has method: public String doList() { return "list"; } from which I got redirected to ... yeah, you guessed right ... http://localhost:8080/y/r/conversation/view.xhtml (that is again what browser shows) even when again it is correct http://localhost:8080/y/r/conversation/list.xhtml page. It seams as browser link area is always one step behind page currently being displayed. I don't even know if it's some incorrect behaviour as I have no idea how to query google for this :D Just for test I did this short tutorial, where netbeans created whole stack of code on one of my entities, and behaviour was the same, so it's not PrimeFaces magic related. Can you tell my why it happens, and how to fix it? Users likes to copy correct links ;)

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• Lookup table size reduction

  - by Ryan

  Hello: I have an application in which I have to store a couple of millions of integers, I have to store them in a Look up table, obviously I cannot store such amount of data in memory and in my requirements I am very limited I have to store the data in an embebedded system so I am very limited in the space, so I would like to ask you about recommended methods that I can use for the reduction of the look up table. I cannot use function approximation such as neural networks, the values needs to be in a table. The range of the integers is not known at the moment. When I say integers I mean a 32 bit value. Basically the idea is use some copmpression method to reduce the amount of memory but without losing many precision. This thing needs to run in hardware so the computation overhead cannot be very high. In my algorithm I have to access to one value of the table do some operations with it and after update the value. In the end what I should have is a function which I pass an index to it and then I get a value, and after I have to use another function to write a value in the table. I found one called tile coding http://www.cs.ualberta.ca/~sutton/book/8/node6.html, this one is based on several look up tables, does anyone know any other method?. Thanks.

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• How to Make my application handle Errors for a few different scenarios?

  - by NightsEVil

  so i have this code to extract a program to the temp directory then run it, the problem is it doesn't work perfectly on every computer (for some reason it hits a error or exception sometimes) string tempFolder = System.IO.Path.Combine(System.IO.Path.GetTempPath(), ""); System.Diagnostics.Process defrag1 = System.Diagnostics.Process.Start(@"Programs\Optimize\AusLogics_Defrag.exe", string.Format(" -o{0} -y", tempFolder)); defrag1.WaitForExit(); string executableDirectoryName = Path.GetDirectoryName(Application.ExecutablePath); System.Diagnostics.Process defrag2 = System.Diagnostics.Process.Start(tempFolder + "\\" + "AusLogics_Defrag" + "\\" + "DiskDefrag.exe", ""); defrag2.WaitForExit(); System.IO.Directory.Delete(tempFolder + "\\" + "AusLogics_Defrag", true); and what i wanna know is there a way that say if it starts to extract but hits a error (no matter what it is) it will automatically change and go to this code, but if it DOESN'T hit a error it continues as it was meant to? string tempFolder = Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData); System.Diagnostics.Process defrag1 = System.Diagnostics.Process.Start(@"Programs\Optimize\AusLogics_Defrag.exe", string.Format(" -o{0} -y", tempFolder)); defrag1.WaitForExit(); string executableDirectoryName = Path.GetDirectoryName(Application.ExecutablePath); System.Diagnostics.Process defrag2 = System.Diagnostics.Process.Start(tempFolder + "\\" + "AusLogics_Defrag" + "\\" + "DiskDefrag.exe", ""); defrag2.WaitForExit(); System.IO.Directory.Delete(tempFolder + "\\" + "AusLogics_Defrag", true); with the path going to the application data folder? and if THAT hits a error it would change that path to this, but if it DOESN'T hit a error it continues as it was meant to? string tempFolder = System.Environment.GetEnvironmentVariable("HomeDrive");

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• SQL string manipulation to return multiple rows

  - by Andy Jacobs

  I'm an experienced programmer, but relatively new to SQL. We're using Oracle 10 and 11. I have a system in place using SQL that combines actual rows with virtual rows (e.g. "SELECT 1 from DUAL") doing unions and intersects as needed, which all seems to work. My problem is that I need to combine this system which is expecting rows of data, with new data that will have the data in (let's say for simplification) comma delimited strings. So I think what I need is a way to convert a string like: "5,6,7,8" into 4 rows with one column each, with "5" in the first row, "6" in the second, etc. In other languages, I'd do a "Split" with comma as the delimiter. Of course, the data won't always have 4 entries. There's a second question, but I'll ask it separately. But I suspect it will simplify things, if possible, if the solution to the above could be used as a table in another SQL statement (i.e., to work with my existing system). Thanks for any help.

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• IDE framework for a dynamic language?

  - by Kevin Reid

  Let's say I have a super-wonderful new programming language, and I want there to be an IDE for it. What IDE platform/framework could I use to get this done efficiently? I mean things like: Collection of files in a project, searching them, tabbed/split editors etc. — the basics. Syntax highlighting and auto-indent/reformatting. Providing the user interface for code completion — hit tab, get a list (I'll have to implement the necessary partial evaluation myself (it's a dynamic language)). This is the feature I'm most wishing for. Built-in parser framework which is good at recovering from the sort of syntax errors occurring in code that is in the middle of being edited would be helpful. In-editor annotation of syntax/runtime error locations fed back from the language runtime. REPL (interactive evaluator) interaction with the same completion as in the editor. This system should be Linux/Mac/Windows cross-platform (in that priority order). Being implemented in Java (or rather, accepting language plugins written in Java) is possibly useful, but anything else is worth a try too.

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• Placing PHP array values into a javascript array?

  - by Michael Harringon

  Is these a way i can loop through a PHP array and have the data outputted into a JavaScript array? For example, the JS script below will not work var mon_Loop = <?php echo $rowCount_Mon ?>; var mon_Events = new Array(); for(i = 0; i < mon_Loop; i++) { mon_Events[i] = <?php $divMon[i] ?> } I Know its because the "i" is not a php variable so therefore invalid inside the php section, but its just an way to show what i would like to achieve. The $rowCount variable count the number of rows and is then used to for the loop. Lets say, for example that I want to place the contents of the PHP array "$divMon[0]" into the javascript array mon_Events[0]. I know that i can do it manually, like below mon_Events[0] = <?php echo $divMon[0] ?> But i have lots of these and therefore need the loop, Is there some JS or PHP that could do this? Cheers.

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• VSTO - Outlook 2007 How do I show a user property even when it's not present?

  - by Yandros

  I have added user property in a mail folder, let's call it UserProperty01. Some of the folder items have this property, some don't. I need to show in the folder's view if that property is set or not, so I added another property called UserProperty01Present, and I set it to true when I set the original property and false when I deleted it; then I added it to the folder's view. The problem is that the little checkbox appears checked in those mails where the property is set, blank in those where the property was deleted... and nowhere at all in those where the property was never set in the first place. My question is, is there any way to show the blank checkbox when the property is not set? The only alternative I found so far is looking in every mail item and setting it to false when it's not set every time the folder is opened; needless to say, I'm not very happy with this solution. Is there any other way? Thank you for your time.

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• How to check if two records have a self-referencing relation?

  - by Machine

  Consider the following schema with users and their collegues (friends): Users User: columns: user_id: name: user_id as userId type: integer(8) unsigned: 1 primary: true autoincrement: true first_name: name: first_name as firstName type: string(45) notnull: true last_name: name: last_name as lastName type: string(45) notnull: true email: type: string(45) notnull: true unique: true relations: Collegues: class: User local: invitor foreign: invitee refClass: CollegueStatus equal: true onDelete: CASCADE onUpdate: CASCADE Join table: CollegueStatus: columns: invitor: type: integer(8) unsigned: 1 primary: true invitee: type: integer(8) unsigned: 1 primary: true status: type: enum(8) values: [pending, accepted, denied] default: pending notnull: true Now, let's say I two records, one for the user making a HTTP request (the logged in user), and one record for a user he wants to send a message to. I want to check if these users are collegues. Questions: Does Doctrine have any pre-build functionality to check if two records with with self-relations are related? If not, how would you write a method to check this? Where would you put said method? (In the User-class, UserTable-class etc) I could probably do something like this: public function (User $user1, User $user2) { // Ensure we load collegues if $user1 was fetched with DQL that // doesn't load this relation $collegues = $user1->get('Collegues'); $areCollegues = false; foreach($collegues as $collegue) { if($collegue['userId'] === $user2['userId']) { $areCollegues = true; break; } } return $areCollegues; } But this looks a neither efficient nor pretty. I just feel that it should be solved already for self-referencing relations to be nice to use.

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• How to make placeholder varablies in jquery validate 1.7?

  - by chobo2

  Hi I am using jquery 1.4.2 and jquery validate 1.7(http://bassistance.de/jquery-plugins/jquery-plugin-validation/) Say I have this example that I just grabbed off some random site(http://www.webreference.com/programming/javascript/jquery/form_validation/) 8 <script type="text/javascript"> 9 $(document).ready(function() { 10 $("#form1").validate({ 11 rules: { 12 name: "required",// simple rule, converted to {required:true} 13 email: {// compound rule 14 required: true, 15 email: true 16 }, 17 url: { 18 url: true 19 }, 20 comment: { 21 required: true 22 } 23 }, 24 messages: { 25 comment: "Please enter a comment." 26 } 27 }); 28 }); 29 </script> now is it possible to do something like this 10 $("#form1").validate({ var NameHolder = "name" 11 rules: { 12 NameHolder: "required",// simple rule, converted to {required:true} 13 email: {// compound rule 14 required: true, 15 email: true So basically I want to make sort of a global variable to hold theses rule names( what correspond to the names on that html control). My concern is the names of html controls can change and it kinda sucks that I will have to go around and change it in many places of my code to make it work again. So basically I am wondering is there away to make a global variable to store this name. So if I need to change the name I only have to change it in one spot in my javascript file sort of the way stopping magic numbers ?

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• SharePoint: Filtering a List that has Folders

  - by Gary McGill

  I have a SharePoint document library that has a folder structure used for organizing the documents (but also for controlling access, via permissions on the folders). The documents in the library are updated every month, and we store every month's version of the document in the same folder; there's a "month" column used for filtering that will contain values like Jan 09, Feb 09, etc. It looks like this: Title Month ----- ----- SubFolder 1 SubFolder 2 [] Interesting Facts Jan 09 [] Interesting Facts Feb 09 [] Interesting Facts Mar 09 [] Fascinating Numbers Jan 09 [] Fascinating Numbers Feb 09 ... Now, because users will generally be most interested in the 'current' month, I'd like them to be able to apply a filter, and select (say) Mar 09. However, if they do this using the built-in filtering, it also filters out the folders, and they can no longer navigate the folder hierarchy. This is no good - I want them to be able to move between folders with the filter intact, so that they don't need to keep switching it off and on again. I figured I might be able to use a custom view (selecting where type=folder or month=[month]), and to an extent that does work. However, I can only get it to work for a fixed month, whereas I need the user to be able to select the month - perhaps via a drop-down control on the page (and I don't want to create 60 views for 5 years' worth of months, nor do I want to have to create a new view every month). I thought it might be possible to create a view in code (rather than via the UI), but I've not been able to figure out how to get a dynamic value (a user-specific setting) into the CAML query. Any pointers gratefully appreciated! And by the way, I am aware of the dogma that folders are bad, and that everything should just be a list. However, having considered the alternatives, I still favour using folders - if I can solve this problem. Thanks in advance.

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• Kindle Fire Cant Fit My Webpage inside a Webview of specific size

  - by Madhavan Rangarao

  This is baffling to me. Please help, I could not figure it out ... In my sample html file I have set the meta tag to be <meta name="viewport" content="target-densitydpi=device-dpi, user-scalable=no"> to fit the webpage inside my webview of custom size say 800x600. In Android, I had to specify "target-densitydpi=device-dpi" and it did the job nicely. I tested my custom web page with nexus 7 tablet and the web page fits inside my web view correctly. The same code does not work in Kindle Fire. Only a part of my web page is shown and even if I set the 'initial-scale=1.0' did not help. I tried various settings programmatically but it did not help either. webview.getSettings().setBuiltInZoomControls(true); webview.getSettings().setSupportZoom(true); webview.getSettings().setLoadWithOverviewMode(true); webview.setInitialScale(1); webview.getSettings().setUseWideViewPort(true); Any pointers?

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• problem in working with thread

  - by Xaver

  Ihave the tree view in which i have file system of logical disk. When user select some files and folders and press button programm evaluate the size of selected files and folders. this function may takes a long time. i decide do thread which will run this function. This function works with array of TreeNode. but then i want to now was it node expaned or not compiler say: "attempt to access control "treeview1" not from the thread, in which it was created." Why it appeared? Next code is show how i create array of Nodes which i send to new thread: void frmMain::FillSelected(TreeNode^ a, array<TreeNode^>^ *Paths) { if (a->Parent == nullptr) { for(int j = 0;j < a->Nodes->Count;j++) { if ((a->Nodes[j]->ImageIndex == 1)&&(a->Nodes[j]->Checked==true)) { (*Paths)->Resize((*Paths), (*Paths)->Length + 1); (*Paths)[(*Paths)->Length-1] = a->Nodes[j]; } } } for(int i = 0;i < a->Nodes->Count;i++) { if (a->Parent == nullptr) { FillSelected(a->Nodes[i], Paths); } else { if(a->Nodes[i]->Checked == true) { (*Paths)->Resize((*Paths), (*Paths)->Length + 1); (*Paths)[(*Paths)->Length-1] = a->Nodes[i]; } if ((a->Nodes[i]->Nodes->Count > 0)&&(a->Nodes[i]->Nodes[0]->FullPath != (a->Nodes[i]->FullPath + "\\"))) { FillSelected(a->Nodes[i], Paths); } } } return; }

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• Google app engine: Poor Performance with JDO + Datastore

  - by Bosh

  I have a simple data model that includes USERS: store basic information (key, name, phone # etc) RELATIONS: describe, e.g. a friendship between two users (supplying a relationship_type + two user keys) I'm getting very poor performance, for instance, if I try to print the first names of all of a user's friends. Say the user has 500 friends: I can fetch the list of friend user_ids very easily in a single query. But then, to pull out first names, I have to do 500 back-and-forth trips to the Datastore, each of which seems to take on the order of 30 ms. If this were SQL, I'd just do a JOIN and get the answer out fast. I understand there are rudimentary facilities for performing joins across un-owned relations in a relaxed implementation of JDO (as described at http://gae-java-persistence.blogspot.com) but they sound experimental and non-standard (e.g. my code won't work in any other JDO implementation). Is this really my best bet? Otherwise, how do people extract satisfactory performance from JDO/Datastore in this kind of (very common) situation? -Bosh

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• floating point equality in Python and in general

  - by eric.frederich

  I have a piece of code that behaves differently depending on whether I go through a dictionary to get conversion factors or whether I use them directly. The following piece of code will print 1.0 == 1.0 -> False But if you replace factors[units_from] with 10.0 and factors[units_to ] with 1.0 / 2.54 it will print 1.0 == 1.0 -> True #!/usr/bin/env python base = 'cm' factors = { 'cm' : 1.0, 'mm' : 10.0, 'm' : 0.01, 'km' : 1.0e-5, 'in' : 1.0 / 2.54, 'ft' : 1.0 / 2.54 / 12.0, 'yd' : 1.0 / 2.54 / 12.0 / 3.0, 'mile' : 1.0 / 2.54 / 12.0 / 5280, 'lightyear' : 1.0 / 2.54 / 12.0 / 5280 / 5.87849981e12, } # convert 25.4 mm to inches val = 25.4 units_from = 'mm' units_to = 'in' base_value = val / factors[units_from] ret = base_value * factors[units_to ] print ret, '==', 1.0, '->', ret == 1.0 Let me first say that I am pretty sure what is going on here. I have seen it before in C, just never in Python but since Python in implemented in C we're seeing it. I know that floating point numbers will change values going from a CPU register to cache and back. I know that comparing what should be two equal variables will return false if one of them was paged out while the other stayed resident in a register. Questions What is the best way to avoid problems like this?... In Python or in general. Am I doing something completely wrong? Side Note This is obviously part of a stripped down example but what I'm trying to do is come with with classes of length, volume, etc that can compare against other objects of the same class but with different units. Rhetorical Questions If this is a potentially dangerous problem since it makes programs behave in an undetermanistic matter, should compilers warn or error when they detect that you're checking equality of floats Should compilers support an option to replace all float equality checks with a 'close enough' function? Do compilers already do this and I just can't find the information.

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• Few Basic Questions in Overriding

  - by Dahlia

  I have few problems with my basic and would be thankful if someone can clear this. What does it mean when I say base *b = new derived; Why would one go for this? We very well separately can create objects for class base and class derived and then call the functions accordingly. I know that this base *b = new derived; is called as Object Slicing but why and when would one go for this? I know why it is not advisable to convert the base class object to derived class object (because base class is not aware of the derived class members and methods). I even read in other StackOverflow threads that if this is gonna be the case then we have to change/re-visit our design. I understand all that, however, I am just curious, Is there any way to do this? class base { public: void f(){cout << "In Base";} }; class derived:public base { public: void f(){cout << "In Derived";} }; int _tmain(int argc, _TCHAR* argv[]) { base b1, b2; derived d1, d2; b2 = d1; d2 = reinterpret_cast<derived*>(b1); //gives error C2440 b1.f(); // Prints In Base d1.f(); // Prints In Derived b2.f(); // Prints In Base d1.base::f(); //Prints In Base d2.f(); getch(); return 0; } In case of my above example, is there any way I could call the base class f() using derived class object? I used d1.base()::f() I just want to know if there any way without using scope resolution operator? Thanks a lot for your time in helping me out!

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• Standard and reliable mouse-reporting with GLUT

  - by Victor

  Hello! I'm trying to use GLUT (freeglut) in my OpenGL application, and I need to register some callbacks for mouse wheel events. I managed to dig out a fairly undocumented function: api documentation But the man page and the API entry for this function both state the same thing: Note: Due to lack of information about the mouse, it is impossible to implement this correctly on X at this time. Use of this function limits the portability of your application. (This feature does work on X, just not reliably.) You are encouraged to use the standard, reliable mouse-button reporting, rather than wheel events. Fair enough, but how do I use this standard, reliable mouse-reporting? And how do I know which is the standard? Do I just use glutMouseFunc() and use button values like 4 and 5 for the scroll up and down values respectively, say if 1, 2 and 3 are the left, middle and right buttons? Is this the reliable method? Bonus question: it seems the `xev' tool is reporting different values for my buttons. My mouse buttons are numbered from 1 to 5 with xev, but glut is reporting buttons from 0 to 4, i.e. an off-by-one. Is this common?

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• Static files in (Java) App Engine not accessible.

  - by fiXedd

  The example documentation says that you simply need to place your files in war/ (or a subdirectory) and they should be accessible from the host (as long as they aren't JSPs or in WEB-INF). For example, if you place foo.css in war/ then you should be able to access it at http://localhost:8080/foo.css. However, this isn't working for me at all. NONE of my static files are accessible. The docs on appengine-web.xml say that you can also specifically denote certain types as static. I've tried this as well and it makes no difference. Am I missing something obvious? UPDATE: Turns out one of the mappings in my web.xml was a little too aggressive. The following was the culprit: <servlet> <servlet-name>Main</servlet-name> <servlet-class>MainServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>Main</servlet-name> <url-pattern>/</url-pattern> </servlet-mapping> It seems that it was grabbing everything that wasn't grabbed be one of the other rules, which I don't understand because there was no * on the end of the url-pattern. It also seems to be directly contradictory to the documentation that says: Note: Static files, files that are served verbatim to users such as images, CSS or JavaScript, are handled separately from paths mentioned in the deployment descriptor. A request for a URL path that matches a path to a file in the WAR that's considered a static file will serve the file, regardless of servlet and filter mappings in the deployment descriptor. You can exclude files from those treated as static files using the appengine-web.xml file. So, how can I have a rule that matches the base of my domain (eg. http://www.example.com/) and still allows the static files to filter through?

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