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  • Call Oracle package function using Odbc from C#

    - by Paolo Tedesco
    I have a function defined inside an Oracle package: CREATE OR REPLACE PACKAGE BODY TESTUSER.TESTPKG as FUNCTION testfunc(n IN NUMBER) RETURN NUMBER as begin return n + 1; end testfunc; end testpkg; / How can I call it from C# using Odbc? I tried the following: using System; using System.Data; using System.Data.Odbc; class Program { static void Main(string[] args) { using (OdbcConnection connection = new OdbcConnection("DSN=testdb;UID=testuser;PWD=testpwd")) { connection.Open(); OdbcCommand command = new OdbcCommand("TESTUSER.TESTPKG.testfunc", connection); command.CommandType = System.Data.CommandType.StoredProcedure; command.Parameters.Add("ret", OdbcType.Int).Direction = ParameterDirection.ReturnValue; command.Parameters.Add("n", OdbcType.Int).Direction = ParameterDirection.Input; command.Parameters["n"].Value = 42; command.ExecuteNonQuery(); Console.WriteLine(command.Parameters["ret"].Value); } } } But I get an exception saying "Invalid SQL Statement". What am I doing wrong?

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  • XPath and XML: Multiple namespaces

    - by emragins
    So I have a document that looks like <a xmlns="uri1" xmlns:pre2="uri2"> <b xmlns:pre3="uri3"> <pre3:c> <stuff></stuff> <goes></goes> <here></here> </pre3:c> <pre3:d xmlns="uri4"> <under></under> <the></the> <tree></tree> </pre3:d> </b> </a> I want an xpath expression that will get me <under>. This has a namespaceURI of uri4. Right now my expression looks like: //ns:a/ns:b/pre3:d/pre4:under I have the namespace manager add 'ns' for the default namespace (uri1 in this case) and I have it defined with pre2, pre3, and pre4 for uri2, uri3, and uri4 respectively. I get the error "Expression must evaluate to a node-set." I know that the node exists. I know that everything up until the pre4:under in my xpath works fine as I use it in the rest of the document with no issues. It's the additional pre4:under that causes the error, and I'm not sure why. Any ideas? Thanks.

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  • Setting WCF service for multiple client calls

    - by user348255
    Hi all, I have made a WCF service which is defined like this: [ServiceBehavior(InstanceContextMode = InstanceContextMode.Single, ConcurrencyMode = ConcurrencyMode.Multiple)] binding is done using netTcpBinding. We support 50+ clients that call the server from time to time. Each client opens a channel using channelfactory once it is loaded and uses that channel for all calls (creates the channel and proxy only once). we have built a small load tester that imitates the client by calling the server by 50 different threads at once (using 50 different channels). when we run this tester, after the 10th client tries to connect, all other client fail connecting. We have set throttling to 100. My questions are: 1. is it correct for each client to create a channel and use it through the client life time? or, do i need to use a using statement for each call to the server (create and distroy a new channel for each call). 2. does the service have a limit of channel connections to it? other then throttling? thanks alot, Guy.

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  • C++ linker unresolved external symbol (again;) from other source file *.obj file. (VC++ express)

    - by bua
    Hi there, I'm back to C/C++ after some break. I've a following problem: I've a solution where I've several projects (compilable and linkable). Now I need to add another project to this solution which depends on some sources from other projects. My new project compiles without any problems (I've added "existing sources" to my project). the error: 1>Linking... 1>LicenceManager.obj : error LNK2019: unresolved external symbol "int __cdecl saveLic(char *,struct Auth *)" (?saveLic@@YAHPADPAUAuth@@@Z) referenced in function "public: void __thiscall LicenceManager::generateLicence(int,char *)" (?generateLicence@LicenceManager@@QAEXHPAD@Z) 1>LicenceManager.obj : error LNK2019: unresolved external symbol "void __cdecl getSysInfo(struct Auth *)" (?getSysInfo@@YAXPAUAuth@@@Z) referenced in function "public: void __thiscall LicenceManager::generateLicence(int,char *)" (?generateLicence@LicenceManager@@QAEXHPAD@Z) Functions saveLic, and getSysInfo are defined in files which I've added to my new project from existing ones. There is object file created during compilation with those functions in target dir, but my LicenceManager class doesn't want to link. I use some extern "C" , and #pragma pack somewhere, but no more fancy stuff. I think every directory, lib and other necessary dependencies are visible in settings for this project. Thanks for any advice.

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  • PHP Function parameters - problem with var not being set

    - by Marty
    So I am obviously not a very good programmer. I have written this small function: function dispAdjuggler($atts) { extract(shortcode_atts(array( 'slot' => '' ), $atts)); $adspot = ''; $adtype = ''; // Get blog # we're on global $blog_id; switch ($blog_id) { case 1: // root blog HOME page if (is_home()) { switch ($slot) { case 'top_leaderboard': $adspot = '855525'; $adtype = '608934'; break; case 'right_halfpage': $adspot = '855216'; $adtype = '855220'; break; case 'right_med-rectangle': $adspot = '858222'; $adtype = '613526'; break; default: throw new Exception("Ad slot is not defined"); break; } When I reference the function on a page like so: <?php dispAdjuggler("top_leaderboard"); ?> The switch is throwing the default exception. What am I doing wrong here? Thanks!!

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  • C/C++ macro/template blackmagic to generate unique name.

    - by anon
    Macros are fine. Templates are fine. Pretty much whatever it works is fine. The example is OpenGL; but the technique is C++ specific and relies on no knowledge of OpenGL. Precise problem: I want an expression E; where I do not have to specify a unique name; such that a constructor is called where E is defined, and a destructor is called where the block E is in ends. For example, consider: class GlTranslate { GLTranslate(float x, float y, float z); { glPushMatrix(); glTranslatef(x, y, z); } ~GlTranslate() { glPopMatrix(); } }; Manual solution: { GlTranslate foo(1.0, 0.0, 0.0); // I had ti give it a name ..... } // auto popmatrix Now, I have this not only for glTranslate, but lots of other PushAttrib/PopAttrib calls too. I would prefer not to have to come up with a unique name for each var. Is there some trick involving macros templates ... or something else that will automatically create a variable who's constructor is called at point of definition; and destructor called at end of block? Thanks!

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  • Override java methods without affecting parent behaviour

    - by Timmmm
    suppose I have this classes (sorry it's kind of hard to think of a simple example here; I don't want any "why would you want to do that?" answers!): class Squarer { public void setValue(int v) { mV = v; } public int getValue() { return mV; } private int mV; public void square() { setValue(getValue() * getValue()); } } class OnlyOddInputsSquarer extends Squarer { @Override public void setValue(int v) { if (v % 2 == 0) { print("Sorry, this class only lets you square odd numbers!") return; } super.setValue(v); } } auto s = new OnlyOddInputsSquarer(); s.setValue(3); s.square(); This won't work. When Squarer.square() calls setValue(), it will go to OnlyOddInputsSquarer.setValue() which will reject all its values (since all squares are even). Is there any way I can override setValue() so that all the functions in Squarer still use the method defined there? PS: Sorry, java doesn't have an auto keyword you haven't heard about! Wishful thinking on my part.

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  • Why doesn't the spring @Autowire work with java generics

    - by testing123
    Inspired by spring data awesomeness I wanted to create a abstract RESTController that I could extend for a lot of my controllers. I created the following class: @Controller public abstract class RESTController<E, PK extends Serializable, R extends PagingAndSortingRepository<E, PK>> { @Autowired private R repository; @RequestMapping(method=RequestMethod.GET, params={"id"}) @ResponseBody public E getEntity(@RequestParam PK id) { return repository.findOne(id); } ... } I was hoping that the generics would allow me to @Autowire in the repository but I get the following error: SEVERE: Allocate exception for servlet appServlet org.springframework.beans.factory.NoSuchBeanDefinitionException: No unique bean of type [org.springframework.data.repository.PagingAndSortingRepository] is defined: expected single matching bean but found 3: [groupRepository, externalCourseRepository, managedCourseRepository] at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:800) at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:707) at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:478) at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:87) at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:284) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1106) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:517) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:456) at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:294) I understand what the error is telling me, there is more than one match for the @Autowire. I am confused because I thought by creating the following controller it would work: @Controller @RequestMapping(value="/managedCourse") public class ManagedCourseController extends RESTController<ManagedCourse, Long, ManagedCourseRepository> { ... } This is easy enough to work around by doing having a method like this in the RESTController: protected abstract R getRepository(); and then doing this in your implementing class: @Autowired private ManagedCourseRepository repository; @Override protected ManagedCourseRepository getRepository() { return repository; } I was just wondering if someone had any thoughts of how I could get this to work.

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  • How much is too much memory allocation in NDK?

    - by Maximus
    The NDK download page notes that, "Typical good candidates for the NDK are self-contained, CPU-intensive operations that don't allocate much memory, such as signal processing, physics simulation, and so on." I came from a C background and was excited to try to use the NDK to operate most of my OpenGL ES functions and any native functions related to physics, animation of vertices, etc... I'm finding that I'm relying quite a bit on Native code and wondering if I may be making some mistakes. I've had no trouble with testing at this point, but I'm curious if I may run into problems in the future. For example, I have game struct defined (somewhat like is seen in the San-Angeles example). I'm loading vertex information for objects dynamically (just what is needed for an active game area) so there's quite a bit of memory allocation happening for vertices, normals, texture coordinates, indices and texture graphic data... just to name the essentials. I'm quite careful about freeing what is allocated between game areas. Would I be safer setting some caps on array sizes or should I charge bravely forward as I'm going now?

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  • Problem Routing domains subfolder

    - by hkda150
    Hi there, I'm pretty new to ASP.NET MVC and I hope it is not a too silly question. So here it comes. I have ... a ASP.NET MVC application with a domain similar to http://mydomain/mysubfoler1/myappfolder My problem... The problem for me is the routing of my application (it worked fine without using a subfolder after the domain-name). The applications homepage loads not to bad, with css files but without ressources like images (defined in css files) and without jQuery ajax calls similar to /mycontroller/myaction links are only working once (the second time I get a page similar to this link: http://mydomain/mysubfoler1/myappfolder/myController/myController/myAction) Here's my Global.asax contaning the routing: public static void RegisterRoutes(RouteCollection routes) { routes.IgnoreRoute("{resource}.axd/{*pathInfo}"); routes.MapRoute( "Default", "{controller}/{action}/{id}", new { controller = "myController", action = "Index", id = "" } defaults ); routes.MapRoute( "Root", "", new { controller = "myController", action = "Index", id = "" } ); } protected void Application_Start() { ViewEngines.Engines.Clear(); ViewEngines.Engines.Add(new MyApplicationWeb.LocalizationWebFormViewEngine()); RegisterRoutes(RouteTable.Routes); //RouteDebug.RouteDebugger.RewriteRoutesForTesting(RouteTable.Routes); } Any suggestions? My first suggestion was to use areas like: "mysubfolder1/myappfolder/{controller}/{action}/{id}" (but without any luck) Thank you very much for your help!

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  • Tips for submitting a library to Boost?

    - by AraK
    Hi everyone, Summer is coming, and a group of friends and I are getting ready for it :) We decided to build a compile-time Arbitrary precision Unsigned Integers. We would like to provide a set of integers algorithms(functions) with the library. We have seen a number of requests for such a library(SoC2010, C++0x Standard Library wishlist). Also, a regular run-time bigint is requested usually with that, but we don't want to go into the hassle of memory management. The idea came to me from a library called TTMath, unfortunately this library works only on specific platforms because Assembly was used extensively in the library. We would like to write a standard library, depending on the C++ standard library and Boost. Also, we would like to use the available C++0x facilities in current compilers like user-defined literals and others. This would technically make the library non-standard for a while, but we think that it is a matter of time the new standards will be official. Your hints on the whole process including design, implementation, documentation, maintainable of the library are more than welcom. We are a group of students and fresh graduates who are looking for something interesting in the summer, but we see that Boost is full of gurus and we don't want to forget something too obvious. We are communicating on-line, so there is no shared white-boards :( Thanks,

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  • C++: Maybe you know this fitfall?

    - by Martijn Courteaux
    Hi, I'm developing a game. I have a header GameSystem (just methods like the game loop, no class) with two variables: int mouseX and int mouseY. These are updated in my game loop. Now I want to access them from Game.cpp file (a class built by a header-file and the source-file). So, I #include "GameSystem.h" in Game.h. After doing this I get a lot of compile errors. When I remove the include he says of course: Game.cpp:33: error: ‘mouseX’ was not declared in this scope Game.cpp:34: error: ‘mouseY’ was not declared in this scope Where I want to access mouseX and mouseY. All my .h files have Header Guards, generated by Eclipse. I'm using SDL and if I remove the lines that wants to access the variables, everything compiles and run perfectly (*). I hope you can help me... This is the error-log when I #include "GameSystem.h" (All the code he is refering to works, like explained by the (*)): In file included from ../trunk/source/domein/Game.h:14, from ../trunk/source/domein/Game.cpp:8: ../trunk/source/domein/GameSystem.h:30: error: expected constructor, destructor, or type conversion before ‘*’ token ../trunk/source/domein/GameSystem.h:46: error: variable or field ‘InitGame’ declared void ../trunk/source/domein/GameSystem.h:46: error: ‘Game’ was not declared in this scope ../trunk/source/domein/GameSystem.h:46: error: ‘g’ was not declared in this scope ../trunk/source/domein/GameSystem.h:46: error: expected primary-expression before ‘char’ ../trunk/source/domein/GameSystem.h:46: error: expected primary-expression before ‘bool’ ../trunk/source/domein/FPS.h:46: warning: ‘void FPS_SleepMilliseconds(int)’ defined but not used This is the code which try to access the two variables: SDL_Rect pointer; pointer.x = mouseX; pointer.y = mouseY; pointer.w = 3; pointer.h = 3; SDL_FillRect(buffer, &pointer, 0xFF0000);

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  • Codeigniter .htaccess not working in subdirectory

    - by xzdead
    I have this codeingniter project structure webRoot | |/application | | | |/controllers | | | |/admin | |/public | | | |/admin | | | | | |/css | | |/img | |/css | |/img And this is my .htacess file, located in /public. I use this in every local project running xampp: <IfModule mod_rewrite.c> RewriteEngine On RewriteBase / RewriteCond %{REQUEST_FILENAME} !-f RewriteRule ^(.*)$ index.php/$1 [L] </IfModule> <IfModule !mod_rewrite.c> # If we don't have mod_rewrite installed, all 404's # can be sent to index.php, and everything works as normal. # Submitted by: ElliotHaughin ErrorDocument 404 /index.php </IfModule> It works fine in localhost, but doesn't work in a dreamhost server. I always get "no input file specified". So after searching the web and trying lots of combinations, the best I got is this .htaccess file: Options +FollowSymLinks RewriteEngine On RewriteCond %{REQUEST_FILENAME} !-d RewriteCond %{REQUEST_FILENAME} !-f RewriteRule ^ index.php [L] With this one, if I go to http://development.mydomain.com - I see the codeigniter welcome page But if I go to: http://development.mydomain.com/admin - I see the directory listing of /public/admin and doesn't execute the controller in /application/controllers/admin Again, if I go to: http://development.mydomain.com/admin/admin - I see the private area, it executes the controller and goes to the default controller defined in routes, "dashboard" This works fine too: http://development.mydomain.com/admin/dashboard I have set in my config file: $config['index_page'] = ''; $config['base_url'] = ''; $config['uri_protocol'] = 'AUTO'; I think that whatever is wrong in my .htaccess is causing other path issues I have with my project. Any help would be great. Thanks to all in advance EDIT: I removed this line: RewriteCond %{REQUEST_FILENAME} !-d because admin directory exists, that's why I see the public directory listing. But now I see the codeigniter welcome page when I go to http://development.mydomain.com/admin So now my .htaccess file looks like: Options +FollowSymLinks RewriteEngine On RewriteCond %{REQUEST_FILENAME} !-f RewriteRule ^ index.php [L] #RewriteRule ^(.*)$ /index.php?/$1 [L] I also tried with the commented RewriteRule but I get the same result.

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  • Recoverable error while running XSL

    - by Kate
    XSL: <?xml version="1.0" encoding="utf-8"?> <xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:ve="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:r="http://schemas.openxmlformats.org/officeDocument/2006/relationships" xmlns:m="http://schemas.openxmlformats.org/officeDocument/2006/math" xmlns:v="urn:schemas-microsoft-com:vml" xmlns:wp="http://schemas.openxmlformats.org/drawingml/2006/wordprocessingDrawing" xmlns:w10="urn:schemas-microsoft-com:office:word" xmlns:w="http://schemas.openxmlformats.org/wordprocessingml/2006/main" xmlns:wne="http://schemas.microsoft.com/office/word/2006/wordml" exclude-result-prefixes="wp wne w10 w ve o r m v" version="2.0"> <xsl:output method="text"/> <xsl:param name="styleName"/> <xsl:template match="w:p"> <xsl:apply-templates/><xsl:text>&#10;</xsl:text> </xsl:template> <xsl:template match="w:r[not ((parent::w:hyperlink[@w:anchor[matches(.,concat('^(',$styleName,')')),'i']]))]"> <xsl:value-of select="replace(., '.', '&#xFF00;')"/> </xsl:template> </xsl:stylesheet> While processing the above XSL, I am getting the below error, Recoverable Error: Recoverable error on line 11 FORG0006: An error occurred matching pattern {w:r[not ((parent::w:hyperlink[@w:anchor[matches(.,concat('^(',$styleName,')')),'i']]))]}: Effective boolean value is not defined for a sequence of two or more items starting with a boolean Please Help. I am not able to figure out this.

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  • How to prevent multiple definitions in C?

    - by Jordi
    I'm a C newbie and I was just trying to write a console application with Code::Blocks. Here's the (simplified) code: main.c: #include <stdio.h> #include <stdlib.h> #include "test.c" // include not necessary for error in Code::Blocks int main() { //t = test(); // calling of method also not necessary return 0; } test.c: void test() {} When I try to build this program, it gives the following errors: *path*\test.c|1|multiple definition of `_ test'| obj\Debug\main.o:*path*\test.c|1|first defined here| There is no way that I'm multiply defining test (although I don't know where the underscore is coming from) and it seems highly unlikely that the definition is somehow included twice. This is all the code there is. I've ruled out that this error is due to some naming conflict with other functions or files being called test or test.c. Note that the multiple and the first definition are on the same line in the same file. Does anyone know what is causing this and what I can do about it? Thanks!

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  • My list item's child label elements disappear in IE on accordion menu opening

    - by Scott B
    I've got an app that's working pretty flawlessly in Chrome and FF, however, when I view it in IE, all is well until I click on a header element to activate it (jQuery accordion). What happens then is that I see a brief flash where the content is there, then suddenly the entire left column disappears. This column is generated by a floated label element with a class of ".left" as seen below... <ul class="menu collapsible"> <li class='expand sectionTitle'><a href='#'>General Settings</a> <ul class='acitem'> <li class="section"> <label class="left">This item if floated left with a defined width of 190px via css. This is the item that's disappearing after a brief display</label> <input class="input" value="input element here" /> <label class="description">This element has a margin-left:212px; set via css in order to be positioned to the right of the label element as if in an adjacent table cell. When I add a max-width property to this element, it disappears in IE too!</label> </li> </ul> </li> </ul> As you can see from the comments in the code above (for the two label elements) the description label disappears once I set a max-width on it (I don't have a max-width on the left label element, but it disappears nonetheless). The initial view of this UL menu is fine (note the expand class declaration which makes this part of the accordion open at startup. Its not until I click the "General Settings" to toggle it closed, then back open, that the left class elements disappear (and only in IE)

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  • Is there a module for parsing numbers (inkl. ranges)?

    - by sid_com
    Is there a module, which does this for me? #!/usr/bin/env perl use warnings; use strict; use 5.012; sub aw_parse { my( $in, $max ) = @_; chomp $in; my @array = split ( /\s*,\s*/, $in ); my %zahlen; for ( @array ) { if ( /^\s*(\d+)\s*$/ ) { $zahlen{$1}++; } elsif ( /^\s*(\d+)\s*-\s*(\d+)\s*$/ ) { die "'$1-$2' not a valid input $!" if $1 >= $2; for ( $1 .. $2 ) { $zahlen{$_}++; } } else { die "'$_' not a valid input $!"; } } @array = sort { $a <=> $b } keys ( %zahlen ); if ( defined $max ) { for ( @array ) { die "Input '0' not allowed $!" if $_ == 0; die "Input ($_) greater than $max not allowed $!" if $_ > $max; } } return \@array; } my $max = 20; print "Input (max $max): "; my $in = <>; my $out = aw_parse( $in, $max ); say "@$out";

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  • Adding Variables to JavaScript in Joomla

    - by Vikram
    Hello friends! This is the script I am using to display an accordion in my Joomla site: <?php defined('JPATH_BASE') or die(); gantry_import('core.gantryfeature'); class GantryFeatureAccordion extends GantryFeature { var $_feature_name = 'accordion'; function init() { global $gantry; if ($this->get('enabled')) { $gantry->addScript('accordion.js'); $gantry->addInlineScript($this->_accordion()); } } function render($position="") { ob_start(); ?> <div id="accordion"> <dl> <?php foreach (glob("templates/rt_gantry_j15/features/accordion/*.php") as $filename) {include($filename);} ?> </dl> </div> <?php return ob_get_clean(); } function _accordion() { global $gantry; $js = " jQuery.noConflict(); (function($){ $(document).ready(function () { $('#accordion').easyAccordion({ slideNum: true, autoStart: true, slideInterval: 4000 }); }); })(jQuery); "; return $js; } } I want to call these three values in the templateDetails.XML file as a user input. slideNum: true, autoStart: true, slideInterval: 4000 Like this in the templateDetails.xml file: <param name="accordion" type="chain" label="ACCORDION" description="ACCORDION_DESC"> <param name="slideNum" type="text" default="true" label="Offset Y" class="text-short" /> <param name="autoStart" type="text" default="true" label="Offset Y" class="text-short" /> <param name="autoStart" type="text" default="4000" label="Offset Y" class="text-short" /> </param> How can I do so? What will be the exact syntax for the same. I am very new to programming ans specially to JavaScript. Kindly help.

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  • 2D vector value replacement using classes; genetic algorithm mutation

    - by gcolumbus
    I have a 2D vector as defined by the classes below. Note that I've used classes because I'm trying to program a genetic algorithm such that many, many 2D vectors will be created and they will all be different. class Quad: public std::vector<int> { public: Quad() : std::vector<int>(4,0) {} }; class QuadVec : public std::vector<Quad> { }; An important part of my algorithm, however, is that I need to be able to "mutate" (randomly change) particular values in a certain number of randomly chosen 2D vectors. This has me stumped. I can easily write code to randomly select the value within the 2D vector that will be selected for "mutation" but how do I actually enact that change using classes? I understand how this would be done with one 2D vector that has already been initialized but how do I do this if it hasn't? Please let me know if I haven't provided enough info or am not clear as I tend to do that. Thanks for your time and help!

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  • Get the first and last posts in a thread

    - by Grampa
    I am trying to code a forum website and I want to display a list of threads. Each thread should be accompanied by info about the first post (the "head" of the thread) as well as the last. My current database structure is the following: threads table: id - int, PK, not NULL, auto-increment name - varchar(255) posts table: id - int, PK, not NULL, auto-increment thread_id - FK for threads The tables have other fields as well, but they are not relevant for the query. I am interested in querying threads and somehow JOINing with posts so that I obtain both the first and last post for each thread in a single query (with no subqueries). So far I am able to do it using multiple queries, and I have defined the first post as being: SELECT * FROM threads t LEFT JOIN posts p ON t.id = p.thread_id ORDER BY p.id LIMIT 0, 1 The last post is pretty much the same except for ORDER BY id DESC. Now, I could select multiple threads with their first or last posts, by doing: SELECT * FROM threads t LEFT JOIN posts p ON t.id = p.thread_id ORDER BY p.id GROUP BY t.id But of course I can't get both at once, since I would need to sort both ASC and DESC at the same time. What is the solution here? Is it even possible to use a single query? Is there any way I could change the structure of my tables to facilitate this? If this is not doable, then what tips could you give me to improve the query performance in this particular situation?

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  • SSE (SIMD extensions) support in gcc

    - by goldenmean
    Hi, I see a code as below: include "stdio.h" #define VECTOR_SIZE 4 typedef float v4sf __attribute__ ((vector_size(sizeof(float)*VECTOR_SIZE))); // vector of four single floats typedef union f4vector { v4sf v; float f[VECTOR_SIZE]; } f4vector; void print_vector (f4vector *v) { printf("%f,%f,%f,%f\n", v->f[0], v->f[1], v->f[2], v->f[3]); } int main() { union f4vector a, b, c; a.v = (v4sf){1.2, 2.3, 3.4, 4.5}; b.v = (v4sf){5., 6., 7., 8.}; c.v = a.v + b.v; print_vector(&a); print_vector(&b); print_vector(&c); } This code builds fine and works expectedly using gcc (it's inbuild SSE / MMX extensions and vector data types. this code is doing a SIMD vector addition using 4 single floats. I want to understand in detail what does each keyword/function call on this typedef line means and does: typedef float v4sf __attribute__ ((vector_size(sizeof(float)*VECTOR_SIZE))); What is the vector_size() function return; What is the __attribute__ keyword for Here is the float data type being type defined to vfsf type? I understand the rest part. thanks, -AD

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  • NHibernate - Retrieving Lots of Data Becomes Exponentially Slow

    - by nfplee
    Hi, I have an issue when I retrieve lots of data in NHibernate (such as when producing a report) the page becomes exponentially slower the more data it has to retrieve. I found the following article: http://nhforge.org/blogs/nhibernate/archive/2008/10/30/bulk-data-operations-with-nhibernate-s-stateless-sessions.aspx It explains how doing bulk data operations in NHibernate is slow since the first level cache grows too large and how you should use the IStatelessSession instead. The trouble I have is that I don't wish to tie my application to NHibernate so I've added a wrapper around ISession. I then use Linq as my query mechanism but IStatelessSession does not support Linq (it may do in NHibernate 3 but the Linq provider is not stable as it stands at the moment). I then read that you could do a clear after so many iterations to clear out the first level cache. The problem now is that you can't use lazy loading. The linq provider doesn't allow you to override the mapping defined (or eagerly fetch the additional data) so whenever I grab data which is lazy loaded after I have cleared the session an exception is thrown. I'm completely lost on what do now. I like the ease of producing reports with linq but the limitations of the inbuilt linq provider in NHibernate seem to be holding me back. I'd really appreciate it if someone could show me an alternative approach. Thanks

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  • Error running web project in eclipse

    - by DarkKnight
    I am a newbie to servlets. I created a dynamic web project in eclipse. I have following files in my project home.html validateServlet.java I have defined validated servlet as an action in home.html form. However when I run it, I get http status 404. Below is the hierarchy of my project Project Java Resources src com.servlets ValidateServlet.java build WebContent META-INF WEB-INF web.xml hello.html Contents of my web.xml are as follows: <?xml version="1.0" encoding="UTF-8"?> <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web- app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0"> <display-name>Website</display-name> <servlet> <description></description> <display-name>ValidateServlet</display-name> <servlet-name>validate</servlet-name> <servlet-class>com.oracle.coen235.servlets.ValidateServlet</servlet-class> </servlet> </web-app> In my hello.html, action is specified as , What might be the issue? I guess I am not able to generate the class file for my servlet. Can anyone guide me through this problem?

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  • Python coin-toss

    - by Andy
    i am new to Python, and i can't wrap my head around this. I have following function defined: def FlipCoins(num_flips): heads_rounds_won = 0 for i in range(10000): heads = 0 tails = 0 for j in range(num_flips): dice = random.randint(0,1) if dice==1: heads += 1 else: tails += 1 if heads > tails: heads_rounds_won += 1 return heads_rounds_won Here is what it should do (but apparently doesn't): flip a coin num_flip times, count heads and tails, and see if there are more heads than tails. If yes, increment head_rounds_won by 1. Repeat 10000 times. I would assume that head_rounds_won will approximate 5000 (50%). And it does that for odd numbers as input. For example, 3, 5 or 7 will produce about 50%. However, even numbers will produce much lower results, more like 34%. Small numbers especially, with higher even numbers, like for example 800, the difference to 50% is much narrower. Why is this the case? Shouldn't any input produce about 50% heads/tails?

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  • Design by contracts and constructors

    - by devoured elysium
    I am implementing my own ArrayList for school purposes, but to spice up things a bit I'm trying to use C# 4.0 Code Contracts. All was fine until I needed to add Contracts to the constructors. Should I add Contract.Ensures() in the empty parameter constructor? public ArrayList(int capacity) { Contract.Requires(capacity > 0); Contract.Ensures(Size == capacity); _array = new T[capacity]; } public ArrayList() : this(32) { Contract.Ensures(Size == 32); } I'd say yes, each method should have a well defined contract. On the other hand, why put it if it's just delegating work to the "main" constructor? Logicwise, I wouldn't need to. The only point I see where it'd be useful to explicitly define the contract in both constructors is if in the future we have Intelisense support for contracts. Would that happen, it'd be useful to be explicit about which contracts each method has, as that'd appear in Intelisense. Also, are there any books around that go a bit deeper on the principles and usage of Design by Contracts? One thing is having knowledge of the syntax of how to use Contracts in a language (C#, in this case), other is knowing how and when to use it. I read several tutorials and Jon Skeet's C# in Depth article about it, but I'd like to go a bit deeper if possible. Thanks

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