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  • Genetic programming in c++, library suggestions?

    - by shuttle87
    I'm looking to add some genetic algorithms to an Operations research project I have been involved in. Currently we have a program that aids in optimizing some scheduling and we want to add in some heuristics in the form of genetic algorithms. Are there any good libraries for generic genetic programming/algorithms in c++? Or would you recommend I just code my own? I should add that while I am not new to c++ I am fairly new to doing this sort of mathematical optimization work in c++ as the group I worked with previously had tended to use a proprietary optimization package. We have a fitness function that is fairly computationally intensive to evaluate and we have a cluster to run this on so parallelized code is highly desirable. So is c++ a good language for this? If not please recommend some other ones as I am willing to learn another language if it makes life easier. thanks!

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  • How does one advance in programming?

    - by Joe Barr
    I really have the felling as if I'm stuck in my own craft. I've been developing and learning for a while now and keep having the feeling that I should advance more, or even be more knowledgeable. I've started projects I didn't finish because I thought I lacked the knowledge and the skill to make that feature work just right, or to make that code magically appear on my screen. I've read books I didn't finish, thinking I wasn't advanced enough for the subjects they covered. I've been around long enough to know that everything comes with experience, hard work and dedication. Having said this, I just want to be able to work without getting stuck on a particular problem that involves my cluelessness of a language or a tool feature. My question to you would be, how does one advance in programming? What are the secrets (if any) to advance to the point of fluency in a particular language or a task. Thank you!

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  • Tutorial/resource for implementing VM

    - by zaharpopov
    Hello, I want self-education purpose implement a simple virtual machine for a dynamic language, prefer in C language. Something like the Lua VM, or Parrot, or Python VM, but simpler. Are there any good resources/tutorials on achieving this, apart from looking at code and design documentations of the existing VMs? Thanks in advance for your answers and ideas Edit: why close vote? I don't understand - is this not programming. Please comment if there is specific problem with my question.

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  • css anchor div to foot of page

    - by foxed
    I may bounce my head off the wall shortly, I can't believe that something as stupid as this has utterly defeated me ... therefore I turn to you, Stack Overflow ... for guidance and enlightenment. Problem: Sit div at foot of page, 100% width, outside of any sort of wrapper. Proposed Solution: http://ryanfait.com/sticky-footer/ Implementation with content: http://www.weleasewodewick.com/redesign/index_content.html Implementation with no content: http://www.weleasewodewick.com/redesign/index.html with content - Good, works nicely no content = bad, footer sits exactly height of footer below the viewport. I really would appreciate your input into this, it's completely vexed me for the past hour. I wholly expect some form of ridicule :) Thanks! Foxed

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  • Singletons and other design issues

    - by Ahmed Saleh
    I have worked using different languages like C++/Java and currently AS3. Most applications were computer vision, and small 2D computer games. Most companies that I have worked for, they use Singletons in a language like AS3, to retrieve elements or classes in an easy way. Their problem is basically they needs some variables or to call other functions from other classes. In a language like AS3, there is no private constructor, and they write a hacky code to prevent new instances. In Java and C++ I also faced the situation that I need to use other classe's members or to call their functions in different classes. The question is, is there a better or another design, to let other classes interact with each others without using singletons? I feel that composition is the answer, but I need more detailed solutions or design suggestions.

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  • What are the Ruby Gotchas a newbie should be warned about?

    - by MiniQuark
    I have recently learned the Ruby programming language, and all in all it is a good language. But I was quite surprised to see that it was not as simple as I had expected. More precisely, the "rule of least-surprise" did not seem very respected to me (of course this is quite subjective). For example: x = true and false puts x # displays true! and the famous: puts "zero is true!" if 0 # zero is true! What are the other "Gotchas" you would warn a Ruby newbie about?

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  • how to get $form_state outside of FAPI's functions?

    - by logii
    I'm writing a custom module and I'd like to use $form_state of the current form in another non-form api function - custom_facet_view_build(). any help is appreciated :) <?php /** * Implementation of hook_perm(). */ function custom_facet_perm() { return array( 'access foo content', 'access baz content', ); } /** * Implementation of hook_menu(). */ function custom_facet_menu() { $items['faceted-search'] = array( 'title' => 'Faceted Search', 'page callback' => 'drupal_get_form', 'access arguments' => array(), ); $items['facet-search-test'] = array( 'page callback' => 'drupal_get_form', 'page arguments' => array('custom_facet_form'), 'access callback' => TRUE, 'type' => MENU_CALLBACK, ); return $items; } /** * Form definition; ahah_helper_demo form. */ function custom_facet_form($form_state) { $form = array(); ahah_helper_register($form, $form_state); if (isset($form_state['storage']['categories'])) { $categories_default_value = $form_state['storage']['categories']["#value"]; } $form['facet_search_form'] = array( '#type' => 'fieldset', '#title' => t('Faceted Search'), '#prefix' => '<div id="billing-info-wrapper">', // This is our wrapper div. '#suffix' => '</div>', '#tree' => TRUE, // Don't forget to set #tree! ); $form['facet_search_form']['categories'] = array( '#type' => 'select', '#title' => t('Category'), '#options' => _custom_facet_taxonomy_query(1), '#multiple' => TRUE, '#default_value' => $categories_default_value, ); $form['save'] = array( '#type' => 'submit', '#value' => t('Save'), ); return $form; } /** * Validate callback for the form. */ function custom_facet_form_validate($form, &$form_state) { } /** * Submit callback for the form. */ function custom_facet_form_submit($form, &$form_state) { drupal_set_message('nothing done'); $form_state['storage']['categories'] = $form['facet_search_form']['categories']; // dpm($form_state); // There's a value returned in form_state['storage] within this function } /** * Implementation of hook_views_api(). */ function custom_facet_views_api() { return array( 'api' => 2, ); } function custom_facet_view_build(&$view) { dpm($form_state); // form_state['storage] remains NULL even though there's a value on previous submission }

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  • markdown to HTML with customised WMD editor

    - by spirytus
    For my application I customized slightly the way WMD behaves so when user enters empty lines, these are reflected in HTML output as <br />'s. Now I came to a point when I should store it somewhere at backend and so after going thru SO posts for a while I'm not sure what is the best way to do it. I have few options and if you could point out which their pros/cons that would be much appreciated. send to server and store as markdown rather than HTML. To me obvious advantage would be keeping exactly same formatting as user originally entered. But then how can I convert it back to HTML for display to a client? It seems very troublesome to convert it on client side as even if it would be possible what would happen if JS would be disabled? If I wanted to do it on the server, then standard server side implementations of markup to HTML might be resource expensive. Would that be an issue in your opinion? Even if it wouldn't be the case then as I mentioned my WMD implementation is customised and those server side solutions wouldn't probably do the right conversion to markdown anyway and there always would be a risk that something would convert wrong. Send to server as converted HTML. Same as above.. conversion on client side would be difficult, server side same with possibility of getting it wrong. send original markdown and converted HTML and store both. No performance issues related to converting markdown to HTML on client side, nor on server side. Users would have always same markdown they originally entered and same HTML they originally saw in preview (possibly sanitized in php though). It would have to take twice that much storage space though and that is my biggest worry. I tend to lean towards 3rd solution as it seems simplest, but there is a worry of doubled storage space needed for this solution. Please bear in mind that my implementation of WMD is slightly modified and also I'm going with PHP/MySql server side implementation. So apart from 3 options I listed above, are there any other possible solutions to my problem? Did I miss anything important that would make one of the options above better then the rest? And what other pros/cons would apply to each solution I listed? Also how is it implemented on SO? I read somwhere that they using option 3, and so if its good enough for SO would be good enough for me :) but not sure if its true anyway, so how is it done? Also please forgive me, but at least for once I got to say that StackOverflow IS THE BEST DAMN RESOURCE ON THE WEB and I truly appreciate all the people trying to help others here! The site and users here are simply amazing!

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  • C# programmer - necessary to learn C or C++?

    - by Kurresmack
    Hey, I have been programming now for a couple of years. But never any low level language. I started off with some java and some VB. Then I went over to VB.NET and now for a while I have been writing C#. As you see, I have never written any low level language where I had to deal with memory management. Is this something I should do, like a route of passage that every programmer should go through? I am a bit keen on trying to perhaps writing in assembler directly. This would suit me personally good as I have 2 parents that have been writing assembler for ages. Is it necessary for a professional programmer these days to know how to manually manage memory?

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  • Just a small problem regarding javscript BOM question

    - by caramel1991
    The question is this: Create a page with a number of links. Then write code that fires on the window onload event, displaying the href of each of the links on the page. And this is my solution <html> <body language="Javascript" onload="displayLink()"> <a href="http://www.google.com/">First link</a> <a href="http://www.yahoo.com/">Second link</a> <a href="http://www.msn.com/">Third link</a> <script type="text/javascript" language="Javascript"> function displayLink() { for(var i = 0;document.links[i];i++) { alert(document.links[i].href); } } </script> </body> </html> This is the answer provided by the book <html> <head> <script language=”JavaScript” type=”text/javascript”> function displayLinks() { var linksCounter; for (linksCounter = 0; linksCounter < document.links.length; linksCounter++) { alert(document.links[linksCounter].href); } } </script> </head> <body onload=”displayLinks()”> <A href=”link0.htm” >Link 0</A> <A href=”link1.htm”>Link 2</A> <A href=”link2.htm”>Link 2</A> </body> </html> Before I get into the javascript tutorial on how to check user browser version or model,I was using the same method as the example,by acessing the length property of the links array for the loop,but after I read through the tutorial,I find out that I can also use this alternative ways,by using the method that the test condition will evalute to true only if the document.links[i] return a valid value,so does my code is written using the valid method??If it's not,any comment regarding how to write a better code??Correct me if I'm wrong,I heard some of the people say "a good code is not evaluate solely on whether it works or not,but in terms of speed,the ability to comprehend the code,and could posssibly let others to understand the code easily".Is is true??

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  • Festival TTS showing SIOD:ran out off storage message

    - by Peeyush
    Hello i am designing a front end for Festival TTS using it's C++ API Everything is working fine in my programme but i have a problem that i am giving a drop down option to user to select other languages when user select a language from drop down then festival tts shows a message on console saying: SIOD:ran out of storage This message only shows if the text given to festival TTS is greater then 5 or 6 lines. i think this message comes because SIOD's heap is not free when i am going to call a new language. So please tell me the solution of this problem. Thanks

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  • Teaching a mainframe COBOL programmer Java?

    - by Jared
    I’m trying to help someone learn Java who’s only programming experience is COBOL on the mainframe. I was wondering if anyone knew any good resources for object oriented concepts. I learned how to program with C++ so just understand the theory behind basic OOP. I’m more concerned about a way to get the basic concepts across, such as encapsulation and inheritance rather then Java syntax. I think it’d be better to teach the concepts of OOP then a language rather then trying to cram both a new language and paradigm in at the same time. Does anyone have any resources or ideas that could help this person learn OOP followed by Java?

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  • russian characters not accepted in php / phpmyadmin ?

    - by Bob Deckx
    I have a website in 3 languages: english, dutch and russian. There's a little CMS where the user can update the text on the website. everything works good, except for the russian text.. If I enter any russian text in the form in the CMS, I get "????" in the phpmyadmin database and on the website. I am completely new to charsets, it's the first time I am building a website in a language that is not supported like in this case.. Could someone please tell me what's the problem here? and what I have to do to make this work in russian language?

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  • how to use expressons as function parameters in powershell

    - by rmeador
    This is a very simple task in every language I have ever used, but I can't seem to figure it out in PowerShell. An example of what I'm talking about in C: abs(x + y) The expression x + y is evaluated, and the result passed to abs as the parameter... how do I do that in PowerShell? The only way I have figured out so far is to create a temporary variable to store the result of the expression, and pass that. PowerShell seems to have very strange grammar and parsing rules that are constantly catching me by surprise, just like this situation. Does anyone know of documentation or a tutorial that explains the basic underlying theory of the language? I can't believe these are all special cases, there must be some rhyme or reason that no tutorial I have yet read explains. And yes, I've read this question, and all of those tutorials are awful. I've pretty much been relegated to learning from existing code.

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  • Programming languages: out of the box legibility and extensibility

    - by sova
    Two excellent results of SOLID development ideology are - Legibility - Extensibility over the life of a project (http://en.m.wikipedia.org/wiki/Solid_(object-oriented_design) Although SOLID is a set of language-agnostic design ideas, some languages inherently support these ideas better than others. Out-of-the-box or after various customizations, in your opinion which language is best-suited to be both easily readable and easy to extend functionality in? Some definitions to pre-empt biases and flamewars: Legibility: amount of thinking done to understand the code proportional to the amount of code: (amount_think-energy / amount_code) is fairly constant and as low as possible in the optimal case. Extensibility: Addition of X amount of functionality requires a change in code or code additions in proportion to X (amount_added_functionality / amount_added_code) is fairly constant and as high as possible in the optimal case. Supporting information and tutorials encouraged. Code snippets welcome.

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  • Is Python appropriate for algorithms focused on scientific computing?

    - by gmatt
    My interests in programming lie mainly in algorithms, and lately I have seen many reputable researchers write a lot of their code in python. How easy and convenient is python for scientific computing? Does it have a library of algorithms that compares to matlab's? Is Python a scripting language or does it compile? Is it a great language for prototyping an algorithm? How long would it take me to learn enough of it to be productive provided I know C well and OO programming somewhat? Is it OO based? Sorry for the condensed format of questions, but I'm very curious and was hoping a more experienced programmer could help me out.

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  • Haskell: variant of `show` that doesn't wrap String and Char in quotes

    - by Joey Adams
    I'd like a variant of show (let's call it label) that acts just like show, except that it doesn't wrap Strings in " " or Chars in ' '. Examples: > label 5 "5" > label "hello" "hello" > label 'c' "c" I tried implementing this manually, but I ran into some walls. Here is what I tried: {-# LANGUAGE FlexibleInstances #-} {-# LANGUAGE UndecidableInstances #-} module Label where class (Show a) => Label a where label :: a -> String instance Label [Char] where label str = str instance Label Char where label c = [c] -- Default case instance Show a => Label a where label x = show x However, because the default case's class overlaps instance Label [Char] and instance Label Char, those types don't work with the label function. Is there a library function that provides this functionality? If not, is there a workaround to get the above code to work?

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  • Is there a alternative to DCOM on unix?

    - by comguy
    Hi All, Is there a COM implementation on UNIX platform. My requirements is that I have a COM client on windows , But I want the server on a AIX servers. I want to write COM clients and servers on unix platforms. Is there anyway to do this?. I tried looking for EntireX from software ag, but couldn't find it. also tried other commercial implementation of DCOM .like COMbridge , Java com bridge. But I need a open source production ready alternative. Am I asking for too much? Thanks all

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  • c++ "interface"-like classes similar to Java?

    - by William the Coderer
    In Java, you can define an interface as a class with no actual code implementation, but only to define the methods that a class must implement. Those types can be passed as parameters to methods and returned from methods. In C++, a pure virtual class can't be used as a parameter or return type, from what I can tell. Any way to mimic Java's interface classes? I have a string class in C++, and several subclasses for different encodings (like UTFxxx, ISOxxx, etc) that derive from the base string class. However, since there are so many different encodings, the base class has no meaningful implementation. But it would serve well as an interface if I could handle it as its own object and calls to that object would call on the correct subclass it was inherited to.

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  • Java vs c++ types

    - by folone
    I've recently had a question about coledatetime java implementation, and Chris said, that the problem might lay in type conversions: cpp-float vs java-float (Or maybe cpp-date vs java-date. Not types, but..). Now I have several questions on this: Is there a table of comparison for java vs c++ types? If type conversions is the problem, in my situation (I have a db with OLEDate records, already created with some c++ program. I need to read and write to that db, so that the OLEDate field compatibility remained: my java code reads proper dates, and c++ program is not affected with what the java program wrote to the db.), what would you do: Use COleDateTime to retrieve the date with JNI? Create your own implementation at all costs (using broader types, or anything else)? Is there anything, I'm missing here?

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  • Will PHP Die In Web Page Development World?

    - by Morgan Cheng
    I know that PHP is still the most popular web programming language in the world. This question just want to bring some of my concerns about PHP. PHP is naturally bound to C10K problem. Since PHP (generally run in Apache) cannot be event-driven or asynchronous, each HTTP request will occupy at least one thread or process. This makes it resistant to be more scalable. Currently, a lot of web sites (like Facebook) with high performance and scalability still depends on PHP in their front end servers. I suppose it is due to legacy reason. Is it possible that PHP will be replaced by language more suitable for C10K?

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  • What are the pro and cons of having localization files vs hard coded variables in source code?

    - by corgrath
    Definitions: Files: Having the localization phrases stored in a physical file that gets read at application start-up and the phrases are stored in the memory to be accessed via util-methods. The phrases are stored in key-value format. One file per language. Variables: The localization texts are stored as hard code variables in the application's source code. The variables are complex data types and depending on the current language, the appropriate phrase is returned. Background: The application is a Java Servlet and the developers use Eclipse as their primary IDE. Some brief pro and cons: Since Eclipse is use, tracking and finding unused localizations are easier when they are saved as variables, compared to having them in a file. However the application's source code becomes bigger and bloated. What are the pro and cons of having localization text in files versus hard coded varibles in source code? What do you do and why?

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