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• CodePlex Daily Summary for Friday, April 06, 2012

  CodePlex Daily Summary for Friday, April 06, 2012Popular ReleasesBetter Explorer: Better Explorer 2.0.0.861 Alpha: - fixed new folder button operation not work well in some situations - removed some unnecessary code like subclassing that is not needed anymore - Added option to make Better Exlorer default (at least for WIN+E operations) - Added option to enable file operation replacements (like Terracopy) to work with Better Explorer - Added some basic usability to "Share" button - Other fixesLightFarsiDictionary - ??????? ??? ?????/???????: LightFarsiDictionary - v1: LightFarsiDictionary - v1WPF Application Framework (WAF): WPF Application Framework (WAF) 2.5.0.3: Version: 2.5.0.3 (Milestone 3): This release contains the source code of the WPF Application Framework (WAF) and the sample applications. Requirements .NET Framework 4.0 (The package contains a solution file for Visual Studio 2010) The unit test projects require Visual Studio 2010 Professional Changelog Legend: [B] Breaking change; [O] Marked member as obsolete [O] WAF: Mark the StringBuilderExtensions class as obsolete because the AppendInNewLine method can be replaced with string.Jo...Community TFS Build Extensions: April 2012: Release notes to follow...ClosedXML - The easy way to OpenXML: ClosedXML 0.65.2: Aside from many bug fixes we now have Conditional Formatting The conditional formatting was sponsored by http://www.bewing.nl (big thanks) New on v0.65.1 Fixed issue when loading conditional formatting with default values for icon sets New on v0.65.2 Fixed issue loading conditional formatting Improved inserts performanceLiberty: v3.2.0.0 Release 4th April 2012: Change Log-Added -Halo 3 support (invincibility, ammo editing) -Halo 3: ODST support (invincibility, ammo editing) -The file transfer page now shows its progress in the Windows 7 taskbar -"About this build" settings page -Reach Change what an object is carrying -Reach Change which node a carried object is attached to -Reach Object node viewer and exporter -Reach Change which weapons you are carrying from the object editor -Reach Edit the weapon controller of vehicles and turrets -An error dia...MSBuild Extension Pack: April 2012: Release Blog Post The MSBuild Extension Pack April 2012 release provides a collection of over 435 MSBuild tasks. A high level summary of what the tasks currently cover includes the following: System Items: Active Directory, Certificates, COM+, Console, Date and Time, Drives, Environment Variables, Event Logs, Files and Folders, FTP, GAC, Network, Performance Counters, Registry, Services, Sound Code: Assemblies, AsyncExec, CAB Files, Code Signing, DynamicExecute, File Detokenisation, GUID’...DotNetNuke® Community Edition CMS: 06.01.05: Major Highlights Fixed issue that stopped users from creating vocabularies when the portal ID was not zero Fixed issue that caused modules configured to be displayed on all pages to be added to the wrong container in new pages Fixed page quota restriction issue in the Ribbon Bar Removed restriction that would not allow users to use a dash in page names. Now users can create pages with names like "site-map" Fixed issue that was causing the wrong container to be loaded in modules wh...51Degrees.mobi - Mobile Device Detection and Redirection: 2.1.3.1: One Click Install from NuGet Changes to Version 2.1.3.11. [assembly: AllowPartiallyTrustedCallers] has been added back into the AssemblyInfo.cs file to prevent failures with other assemblies in Medium trust environments. 2. The Lite data embedded into the assembly has been updated to include devices from December 2011. The 42 new RingMark properties will return Unknown if RingMark data is not available. Changes to Version 2.1.2.11Code Changes 1. The project is now licenced under the Mozilla...MVC Controls Toolkit: Mvc Controls Toolkit 2.0.0: Added Support for Mvc4 beta and WebApi The SafeqQuery and HttpSafeQuery IQueryable implementations that works as wrappers aroung any IQueryable to protect it from unwished queries. "Client Side" pager specialized in paging javascript data coming either from a remote data source, or from local data. LinQ like fluent javascript api to build queries either against remote data sources, or against local javascript data, with exactly the same interface. There are 3 different query objects exp...ExtAspNet: ExtAspNet v3.1.2: ExtAspNet - ?? ExtJS ??? ASP.NET 2.0 ???，????? AJAX ?????????? ExtAspNet ????? ExtJS ??? ASP.NET 2.0 ???，????? AJAX ??????????。 ExtAspNet ??????? JavaScript，?? CSS，?? UpdatePanel，?? ViewState，?? WebServices ???????。 ??????: IE 7.0, Firefox 3.6, Chrome 3.0, Opera 10.5, Safari 3.0+ ????：Apache License 2.0 (Apache) ??：http://extasp.net/ ??：http://bbs.extasp.net/ ??：http://extaspnet.codeplex.com/ ??：http://sanshi.cnblogs.com/ ????： +2012-04-04 v3.1.2 -??IE?????????????BUG（??"about:blank"?...nopCommerce. Open source shopping cart (ASP.NET MVC): nopcommerce 2.50: Highlight features & improvements: • Significant performance optimization. • Allow store owners to create several shipments per order. Added a new shipping status: “Partially shipped”. • Pre-order support added. Enables your customers to place a Pre-Order and pay for the item in advance. Displays “Pre-order” button instead of “Buy Now” on the appropriate pages. Makes it possible for customer to buy available goods and Pre-Order items during one session. It can be managed on a product variant ...WiX Toolset: WiX v3.6 RC0: WiX v3.6 RC0 (3.6.2803.0) provides support for VS11 and a more stable Burn engine. For more information see Rob's blog post about the release: http://robmensching.com/blog/posts/2012/4/3/WiX-v3.6-Release-Candidate-Zero-availableSageFrame: SageFrame 2.0: Sageframe is an open source ASP.NET web development framework developed using ASP.NET 3.5 with service pack 1 (sp1) technology. It is designed specifically to help developers build dynamic website by providing core functionality common to most web applications.iTuner - The iTunes Companion: iTuner 1.5.4475: Fix to parse empty playlists in iTunes LibraryDocument.Editor: 2012.2: Whats New for Document.Editor 2012.2: New Save Copy support New Page Setup support Minor Bug Fix's, improvements and speed upsDotNet.Highcharts: DotNet.Highcharts 1.2 with Examples: Tested and adapted to the latest version of Highcharts 2.2.1 Fixed Issue 359: Not implemented serialization array of type: System.Drawing.Color[] Fixed Issue 364: Crosshairs defined as array of CrosshairsForamt generates bad Highchart code For the example project: Added newest version of Highcharts 2.2.1 Added new demos to How To's section: Bind Data From Dictionary Bind Data From Object List Custom Theme Tooltip Crosshairs Theming The Reset Button Plot Band EventsVidCoder: 1.3.2: Added option for the minimum title length to scan. Added support to enable or disable LibDVDNav. Added option to prompt to delete source files after clearing successful completed items. Added option to disable remembering recent files and folders. Tweaked number box to only select all on a quick click.MJP's DirectX 11 Samples: Light Indexed Deferred Rendering: Implements light indexed deferred using per-tile light lists calculated in a compute shader, as well as a traditional deferred renderer that uses a compute shader for per-tile light culling and per-pixel shading.Pcap.Net: Pcap.Net 0.9.0 (66492): Pcap.Net - March 2012 Release Pcap.Net is a .NET wrapper for WinPcap written in C++/CLI and C#. It Features almost all WinPcap features and includes a packet interpretation framework. Version 0.9.0 (Change Set 66492)March 31, 2012 release of the Pcap.Net framework. Follow Pcap.Net on Google+Follow Pcap.Net on Google+ Files Pcap.Net.DevelopersPack.0.9.0.66492.zip - Includes all the tutorial example projects source files, the binaries in a 3rdParty directory and the documentation. It include...New Projects.Net Mutation Testing Tool: This tool will help for making and unit testing mutation changes. Mutation tests improve unit tests and applications.African Honey Bee Application Suite: This is the home of the software behind the African Honey Bee community enrichment project.Create Schema: Object extension method that generates schema creation scripts in SQL (MS SQL SERVER) from c# classes to rapidly get database tables from an existing class structure. Just edit the scripts (they are just guesses of how the database should look) to make them fit your database needs and then run them as a query in SQL Server. Check out vecklare.blogspot.se for more examples. CrtTfsDemo: demo project to test code review tool integration with tfsDolphins Salaam: This Library is a Cross Platform, UDP Broadcast solution for Peer to Peer network client detection. It is written in pure C# and is Mono and .Net compatible. It has been tested on Mac OS X, Windows, Linux, iOS, Android, Xbox and it is expected to be compatible with every other Mono compatible platform. The library is ready to use out of box and there is almost zero configurations needed for it to start working, regarding that, it is also flexible and configurable for your needs.Enhanced Content Query Webpart: This Enhanced Content Query Webpart for SharePoint 2010 is meant for the advanced application developer. You will be able to create any rollup of pages of any Content Type(s), Site Column(s) from any subsite(s) with (any) style you want. Xslt skills are required.fangxue: huijiaFrameworkComponent: frameworkcomponent 4 companyFsXna3DGame: 3D game written in XNA and F# (still very much a work in progress)GeoLock: GeoLock is a proof of concept (PoC). GeoLock demonstrates how to retrieve geolocation data from surrounding Wi-Fi networks triangulation without Global Positioning System (GPS) hardware. grab-libs: A quick hack to bundle up the shared libraries needed to run an i386 executable on an x86_64 machine.Logical Game Of Life: Make Logic Component with a game of life algoritmMagic Box: Magic Box is the application for "hiding" files in NTFS file system. NTFS Alternate Data Streams are used for this.Notes: Application to create fast notes on your Windows Phone.Orchard Google Infographics: **NOTE: Only works with Orchard >= v1.4** This module leverages Google's Infographics api for generating QR codes for each content item that uses the Orchard.Autoroute part. The api documentation may be found at https://developers.google.com/chart/infographics/docs/qr_codesOutlook Calendar Cleaner: If you port your email from a Lotus Notes server to Exchange Server or to Office 365, your Mac Outlook calendar items may be missing. This includes calendar appointments and meeting requests. This may include items that were ported over and also new items created after the port.Polarity: Polarity is a plugin-oriented bot written in C# for deviantArt chat written with simplicity and ease of use for plugin developers as the number one goal.Pool Game Paradise: Pool Game Club of Augmentum Inc. Wuhan Site.RCT2 DatChecker: A utility for Rollercoaster Tycoon 2 that catalogs, displays, and helps manage object files (*.DAT). Examine objects frame by frame or copy object images to the clipboard. Sort objects by size, type, or content. Use DatChecker to find and remove unwanted or duplicate objects, or RecipeML Manager: This project creates C# classes that support the RecipeML standard. It also enhances that standard to support full daily and weekly menus.s0t0o0c0k3246352543: 345234324324324324ScoutGames: scout games portalSharePoint All Page Scripting: This solution is the skeleton of the JavaScript loading in all pages on the SharePoint site collection. This solution can be deployed as a "sandbox solution". Supports the Office365 of course. ??????????SharePoint ?????????????????????????Java?????????????。 ????????????????????????。 ???、????Office365?????????。testtom04052012git02: testtom04052012git02testtom04052012tfs01: testtom04052012tfs01testtom04052012tfs03: testtom04052012tfs03Visual Studio Pattern Automation Toolkit (VSPAT): VSPAT is a set of development and deployment tools from Microsoft that generate and execute Visual Studio extensions called 'Pattern Toolkits' that redeliver best practices, expertise and proven solutions faster, more reliably and more consistently. If you are an *IT professional* are you are looking to build and deploy custom solutions that include proven best practices to improve quality, consistency and time to market. And if you wish to spend significantly less time having to learn all...Wet: Wet, the game.WPF Data Editors: WPF Data Editor controls contains most of editor controls in WPF.xSolon Instructions: Framework to run scripts

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• What's the best name for a non-mutating "add" method on an immutable collection?

  - by Jon Skeet

  Sorry for the waffly title - if I could come up with a concise title, I wouldn't have to ask the question. Suppose I have an immutable list type. It has an operation Foo(x) which returns a new immutable list with the specified argument as an extra element at the end. So to build up a list of strings with values "Hello", "immutable", "world" you could write: var empty = new ImmutableList<string>(); var list1 = empty.Foo("Hello"); var list2 = list1.Foo("immutable"); var list3 = list2.Foo("word"); (This is C# code, and I'm most interested in a C# suggestion if you feel the language is important. It's not fundamentally a language question, but the idioms of the language may be important.) The important thing is that the existing lists are not altered by Foo - so empty.Count would still return 0. Another (more idiomatic) way of getting to the end result would be: var list = new ImmutableList<string>().Foo("Hello"); .Foo("immutable"); .Foo("word"); My question is: what's the best name for Foo? EDIT 3: As I reveal later on, the name of the type might not actually be ImmutableList<T>, which makes the position clear. Imagine instead that it's TestSuite and that it's immutable because the whole of the framework it's a part of is immutable... (End of edit 3) Options I've come up with so far: Add: common in .NET, but implies mutation of the original list Cons: I believe this is the normal name in functional languages, but meaningless to those without experience in such languages Plus: my favourite so far, it doesn't imply mutation to me. Apparently this is also used in Haskell but with slightly different expectations (a Haskell programmer might expect it to add two lists together rather than adding a single value to the other list). With: consistent with some other immutable conventions, but doesn't have quite the same "additionness" to it IMO. And: not very descriptive. Operator overload for + : I really don't like this much; I generally think operators should only be applied to lower level types. I'm willing to be persuaded though! The criteria I'm using for choosing are: Gives the correct impression of the result of the method call (i.e. that it's the original list with an extra element) Makes it as clear as possible that it doesn't mutate the existing list Sounds reasonable when chained together as in the second example above Please ask for more details if I'm not making myself clear enough... EDIT 1: Here's my reasoning for preferring Plus to Add. Consider these two lines of code: list.Add(foo); list.Plus(foo); In my view (and this is a personal thing) the latter is clearly buggy - it's like writing "x + 5;" as a statement on its own. The first line looks like it's okay, until you remember that it's immutable. In fact, the way that the plus operator on its own doesn't mutate its operands is another reason why Plus is my favourite. Without the slight ickiness of operator overloading, it still gives the same connotations, which include (for me) not mutating the operands (or method target in this case). EDIT 2: Reasons for not liking Add. Various answers are effectively: "Go with Add. That's what DateTime does, and String has Replace methods etc which don't make the immutability obvious." I agree - there's precedence here. However, I've seen plenty of people call DateTime.Add or String.Replace and expect mutation. There are loads of newsgroup questions (and probably SO ones if I dig around) which are answered by "You're ignoring the return value of String.Replace; strings are immutable, a new string gets returned." Now, I should reveal a subtlety to the question - the type might not actually be an immutable list, but a different immutable type. In particular, I'm working on a benchmarking framework where you add tests to a suite, and that creates a new suite. It might be obvious that: var list = new ImmutableList<string>(); list.Add("foo"); isn't going to accomplish anything, but it becomes a lot murkier when you change it to: var suite = new TestSuite<string, int>(); suite.Add(x => x.Length); That looks like it should be okay. Whereas this, to me, makes the mistake clearer: var suite = new TestSuite<string, int>(); suite.Plus(x => x.Length); That's just begging to be: var suite = new TestSuite<string, int>().Plus(x => x.Length); Ideally, I would like my users not to have to be told that the test suite is immutable. I want them to fall into the pit of success. This may not be possible, but I'd like to try. I apologise for over-simplifying the original question by talking only about an immutable list type. Not all collections are quite as self-descriptive as ImmutableList<T> :)

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• Compute if a function is pure

  - by Oni

  As per Wikipedia: In computer programming, a function may be described as pure if both these statements about the function hold: The function always evaluates the same result value given the same argument value(s). The function result value cannot depend on any hidden information or state that may change as program execution proceeds or between different executions of the program, nor can it depend on any external input from I/O devices. Evaluation of the result does not cause any semantically observable side effect or output, such as mutation of mutable objects or output to I/O devices. I am wondering if it is possible to write a function that compute if a function is pure or not. Example code in Javascript: function sum(a,b) { return a+b; } function say(x){ console.log(x); } isPure(sum) // True isPure(say) // False

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• Manual memory allocation and purity

  - by Eonil

  Language like Haskell have concept of purity. In pure function, I can't mutate any state globally. Anyway Haskell fully abstracts memory management, so memory allocation is not a problem here. But if languages can handle memory directly like C++, it's very ambiguous to me. In these languages, memory allocation makes visible mutation. But if I treat making new object as impure action, actually, almost nothing can be pure. So purity concept becomes almost useless. How should I handle purity in languages have memory as visible global object?

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• OVH ouvre un Cloud pour les développeurs qui veulent passer au SaaS et se lance dans le calcul haute performance à la demande

  OVH ouvre un Cloud pour les développeurs qui veulent passer au SaaS Et se lance dans le calcul haute performance à la demande « Pour accompagner la mutation du marché des logiciels vers le SaaS, OVH.com fait évoluer son offre Private Cloud basée sur vSphere de VMware », voici résumée en une phrase la nouvelle offre de l'hébergeur nordiste. Une offre qui a pour particularité de ne pas mutualiser les ressources des serveurs, mais qui dédie chaque serveur physique à un client. Le but pour les éditeurs et les développeurs est de disposer d'un environnement dans lequel ils peuvent migrer leurs logiciels et les proposer en mode SaaS. « Au lieu d'installer le logiciel c...

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• Suggested GA operators for a TSP problem?

  - by Mark

  I'm building a genetic algorithm to tackle the traveling salesman problem. Unfortunately, I hit peaks that can sustain for over a thousand generations before mutating out of them and getting better results. What crossover and mutation operators generally do well in this case?

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• Is a variable swap guaranteed to be atomic in python?

  - by dhruvbird

  With reference to the following link: http://docs.python.org/faq/library.html#what-kinds-of-global-value-mutation-are-thread-safe I wanted to know if the following: (x, y) = (y, x) will be guaranteed atomic in cPython. (x and y are both python variables)

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• Unmodifiable NavigableSet/NavigableMap in Java?

  - by Greg Mattes

  java.util.Collections has several unmodifiable methods that provide unmodifiable collection views by wrapping collections in decorators that prohibit mutation operations. Java 6 added support for java.util.NavigableSet and java.util.NavigableMap. I'd like to be able to have unmodifiable NavigableSets and NavigableMaps, but java.util.Collections#unmodifiableSortedSet(SortedSet) and java.util.Collections#unmodifiableSortedMap(SortedMap) are not sufficient because they do not support the operations that are particular to NavigableSet and NavigableMap. Are there de-facto implementations for unmodifiableNavigableSet and unmodifiableNavigableMap?

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• ImmutableDictionary has no constructors defined

  - by lukasLansky

  So, I would like to write something like this: var d = new ImmutableDictionary<string, int> { { "a", 1 }, { "b", 2 } }; (using ImmutableDictionary from System.Collections.Immutable). It seems like a straightforward usage as I am declaring all the values upfront -- no mutation there. But this gives me error: The type 'System.Collections.Immutable.ImmutableDictionary<TKey,TValue>' has no constructors defined How I am supposed to create a new immutable dictionary with static content?

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• Using GA in GUI

  - by AlexT

  Sorry if this isn't clear as I'm writing this on a mobile device and I'm trying to make it quick. I've written a basic Genetic Algorithm with a binary encoding (genes) that builds a fitness value and evolves through several iterations using tournament selection, mutation and crossover. As a basic command-line example it seems to work. The problem I've got is with applying a genetic algorithm within a GUI as I am writing a maze-solving program that uses the GA to find a method through a maze. How do I turn my random binary encoded genes and fitness function (add all the binary values together) into a method to control a bot around a maze? I have built a basic GUI in Java consisting of a maze of labels (like a grid) with the available routes being in blue and the walls being in black. To reiterate my GA performs well and contains what any typical GA would (fitness method, get and set population, selection, crossover, etc) but now I need to plug it into a GUI to get my maze running. What needs to go where in order to get a bot that can move in different directions depending on what the GA says? Rough pseudocode would be great if possible As requested, an Individual is built using a separate class (Indiv), with all the main work being done in a Pop class. When a new individual is instantiated an array of ints represent the genes of said individual, with the genes being picked at random from a number between 0 and 1. The fitness function merely adds together the value of these genes and in the Pop class handles selection, mutation and crossover of two selected individuals. There's not much else to it, the command line program just shows evolution over n generations with the total fitness improving over each iteration. EDIT: It's starting to make a bit more sense now, although there are a few things that are bugging me... As Adamski has suggested I want to create an "Agent" with the options shown below. The problem I have is where the random bit string comes into play here. The agent knows where the walls are and has it laid out in a 4 bit string (i.e. 0111), but how does this affect the random 32 bit string? (i.e. 10001011011001001010011011010101) If I have the following maze (x is the start place, 2 is the goal, 1 is the wall): x 1 1 1 1 0 0 1 0 0 1 0 0 0 2 If I turn left I'm facing the wrong way and the agent will move completely off the maze if it moves forward. I assume that the first generation of the string will be completely random and it will evolve as the fitness grows but I don't get how the string will work within a maze. So, to get this straight... The fitness is the result of when the agent is able to move and is by a wall. The genes are a string of 32 bits, split into 16 sets of 2 bits to show the available actions and for the robot to move the two bits need to be passed with four bits from the agent showings its position near the walls. If the move is to go past a wall the move isn't made and it is deemed invalid and if the move is made and if a new wall is found then the fitness goes up. Is that right?

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• Default sort order in Windows folder

  - by Florian Müller

  I am running Windows 7 and I have a folder "Dropbox" inside my Documents folder. However, every time I restart Explorer and enter this folder, it is sorted by mutation date. I'd like to have it default sorted by name, which is still default in all other folders, however not in this one. Please let me know if there is a way to define this properly! Thanks in advance! Note: I actually found out that this is in every folder or library now, not only in some folders. This is the standard sort behaviour when I open explorer the first time.

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• What are some techniques I can use to refactor Object Oriented code into Functional code?

  - by tieTYT

  I've spent about 20-40 hours developing part of a game using JavaScript and HTML5 canvas. When I started I had no idea what I was doing. So it started as a proof of concept and is coming along nicely now, but it has no automated tests. The game is starting to become complex enough that it could benefit from some automated testing, but it seems tough to do because the code depends on mutating global state. I'd like to refactor the whole thing using Underscore.js, a functional programming library for JavaScript. Part of me thinks I should just start from scratch using a Functional Programming style and testing. But, I think refactoring the imperative code into declarative code might be a better learning experience and a safer way to get to my current state of functionality. Problem is, I know what I want my code to look like in the end, but I don't know how to turn my current code into it. I'm hoping some people here could give me some tips a la the Refactoring book and Working Effectively With Legacy Code. For example, as a first step I'm thinking about "banning" global state. Take every function that uses a global variable and pass it in as a parameter instead. Next step may be to "ban" mutation, and to always return a new object. Any advice would be appreciated. I've never taken OO code and refactored it into Functional code before.

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• How to structure a Genetic Algorithm class hierarchy?

  - by MahlerFive

  I'm doing some work with Genetic Algorithms and want to write my own GA classes. Since a GA can have different ways of doing selection, mutation, cross-over, generating an initial population, calculating fitness, and terminating the algorithm, I need a way to plug in different combinations of these. My initial approach was to have an abstract class that had all of these methods defined as pure virtual, and any concrete class would have to implement them. If I want to try out two GAs that are the same but with different cross-over methods for example, I would have to make an abstract class that inherits from GeneticAlgorithm and implements all the methods except the cross-over method, then two concrete classes that inherit from this class and only implement the cross-over method. The downside to this is that every time I want to swap out a method or two to try out something new I have to make one or more new classes. Is there another approach that might apply better to this problem?

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• how to work with strings and integers as bit strings in python?

  - by Manuel

  Hello! I'm developing a Genetic Algorithm in python were chromosomes are composed of strings and integers. To apply the genetic operations, I want to convert these groups of integers and strings into bit strings. For example, if one chromosome is: ["Hello", 4, "anotherString"] I'd like it to become something like: 0100100100101001010011110011 (this is not actual translation). So... How can I do this? Chromosomes will contain the same amount of strings and integers, but this numbers can vary from one algorithm run to another. To be clear, what I want to obtain is the bit representation of each element in the chromosome concatenated. If you think this would not be the best way to apply genetic operators (such as mutation and simple crossover) just tell me! I'm open to new ideas. Thanks a lot! Manuel

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• Grails/Spring HttpServletRequest synchronization

  - by Jeff Storey

  I was writing a simple Grails app and I have a spot in a gsp where one of my java beans in modified. <g:each in="${myList}" status="i" var="myVar"> // if the user performs some view action, update one of the myVar elements </g:each> This works, but I don't think it's quite threadsafe. myList is an http request variable but in cases of pages that use ajax (or other client side manipulations), it is possible for two threads to be modifying the same request scope variable The Spring AbstractController class provides a setSynchronizeOnSession method. Does grails provide any equivalent functionality? If not, what's the best way to protect this non-threadsafe mutation? thanks, Jeff

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• Does "Value Restriction" mean that there is no higher order functional programming?

  - by Sadache

  Does "Value Restriction" mean that there is no higher order functional programming? I have a problem that each time I try to do a bit of HOP I get caught by a VR error. Example: let simple (s:string)= fun rq->1 let oops= simple "" type 'a SimpleType= F of (int ->'a-> 'a) let get a = F(fun req -> id) let oops2= get "" and I would like to know whether it is a problem of a prticular implementation of VR or it is a general problem that has no solution in a mutable type-infered language that doesn't include mutation in the type system.

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• Does "Value Restriction" practically mean that there is no higher order functional programming?

  - by Sadache

  Does "Value Restriction" practically mean that there is no higher order functional programming? I have a problem that each time I try to do a bit of HOP I get caught by a VR error. Example: let simple (s:string)= fun rq->1 let oops= simple "" type 'a SimpleType= F of (int ->'a-> 'a) let get a = F(fun req -> id) let oops2= get "" and I would like to know whether it is a problem of a prticular implementation of VR or it is a general problem that has no solution in a mutable type-infered language that doesn't include mutation in the type system.

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• Diagram to show code responsibility

  - by Mike Samuel

  Does anyone know how to visually diagram the ways in which the flow of control in code passes between code produced by different groups and how that affects the amount of code that needs to be carefully written/reviewed/tested for system properties to hold? What I am trying to help people visualize are arguments of the form: For property P to hold, nd developers have to write application code, Ca, without certain kinds of errors, and nm maintainers have to make sure that the code continues to not have these kinds of errors over the project lifetime. We could reduce the error rate by educating nd developers and nm maintainers. For us to be confident that the property holds, ns specialists still need to test or check |Ca| lines of code and continue to test/check the changes by nm maintainers. Alternatively, we could be confident that P holds if all code paths that could violate P went through tool code, Ct, written by our specialists. In our case, test suites alone cannot give confidence that P holdsnd » nsnm ns|Ca| » |Ct| so writing and maintaining Ct is economical, frees up our developers to worry about other things, and reduces the ongoing education commitment by our specialists. or those conditions do not hold, so focusing on education and testing is preferable. Example 1 As a concrete example, suppose we want to ensure that our web-service only produces valid JSON output. Our web-service provides several query and mutation operators that can be composed in interesting ways. We could try to educate everyone who maintains those operations about the JSON syntax, the importance of conformance, and libraries available so that when they write to an output buffer, every possible sequence of appends results in syntactically valid JSON. Alternatively, we don't expose an output stream handle to application code, and instead expose a JSON sink so that every code path that writes a response is channeled through a JSON sink that is written and maintained by a specialist who knows JSON syntax and can use well-written libraries to produce only valid output. Example 2 We need to make sure that a service that receives a URL from an untrusted source and tries to fetch its content does not end up revealing sensitive files from the file-system, like file:///etc/passwd. If there is a single standard way that any developer familiar with the application language's libraries would use to fetch URLs, which has file-system access turned off by default, then simply educating developers about the standard mechanism, and testing that file probing fails for some inputs, will probably be sufficient.

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• "Collection Wrapper" pattern - is this common?

  - by Prog

  A different question of mine had to do with encapsulating member data structures inside classes. In order to understand this question better please read that question and look at the approach discussed. One of the guys who answered that question said that the approach is good, but if I understood him correctly - he said that there should be a class existing just for the purpose of wrapping the collection, instead of an ordinary class offering a number of public methods just to access the member collection. For example, instead of this: class SomeClass{ // downright exposing the concrete collection. Things[] someCollection; // other stuff omitted Thing[] getCollection(){return someCollection;} } Or this: class SomeClass{ // encapsulating the collection, but inflating the class' public interface. Thing[] someCollection; // class functionality omitted. public Thing getThing(int index){ return someCollection[index]; } public int getSize(){ return someCollection.length; } public void setThing(int index, Thing thing){ someCollection[index] = thing; } public void removeThing(int index){ someCollection[index] = null; } } We'll have this: // encapsulating the collection - in a different class, dedicated to this. class SomeClass{ CollectionWrapper someCollection; CollectionWrapper getCollection(){return someCollection;} } class CollectionWrapper{ Thing[] someCollection; public Thing getThing(int index){ return someCollection[index]; } public int getSize(){ return someCollection.length; } public void setThing(int index, Thing thing){ someCollection[index] = thing; } public void removeThing(int index){ someCollection[index] = null; } } This way, the inner data structure in SomeClass can change without affecting client code, and without forcing SomeClass to offer a lot of public methods just to access the inner collection. CollectionWrapper does this instead. E.g. if the collection changes from an array to a List, the internal implementation of CollectionWrapper changes, but client code stays the same. Also, the CollectionWrapper can hide certain things from the client code - from example, it can disallow mutation to the collection by not having the methods setThing and removeThing. This approach to decoupling client code from the concrete data structure seems IMHO pretty good. Is this approach common? What are it's downfalls? Is this used in practice?

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• Need help with fixing Genetic Algorithm that's not evolving correctly

  - by EnderMB

  I am working on a maze solving application that uses a Genetic Algorithm to evolve a set of genes (within Individuals) to evolve a Population of Individuals that power an Agent through a maze. The majority of the code used appears to be working fine but when the code runs it's not selecting the best Individual's to be in the new Population correctly. When I run the application it outputs the following: Total Fitness: 380.0 - Best Fitness: 11.0 Total Fitness: 406.0 - Best Fitness: 15.0 Total Fitness: 344.0 - Best Fitness: 12.0 Total Fitness: 373.0 - Best Fitness: 11.0 Total Fitness: 415.0 - Best Fitness: 12.0 Total Fitness: 359.0 - Best Fitness: 11.0 Total Fitness: 436.0 - Best Fitness: 13.0 Total Fitness: 390.0 - Best Fitness: 12.0 Total Fitness: 379.0 - Best Fitness: 15.0 Total Fitness: 370.0 - Best Fitness: 11.0 Total Fitness: 361.0 - Best Fitness: 11.0 Total Fitness: 413.0 - Best Fitness: 16.0 As you can clearly see the fitnesses are not improving and neither are the best fitnesses. The main code responsible for this problem is here, and I believe the problem to be within the main method, most likely where the selection methods are called: package GeneticAlgorithm; import GeneticAlgorithm.Individual.Action; import Robot.Robot.Direction; import Maze.Maze; import Robot.Robot; import java.util.ArrayList; import java.util.Random; public class RunGA { protected static ArrayList tmp1, tmp2 = new ArrayList(); // Implementation of Elitism protected static int ELITISM_K = 5; // Population size protected static int POPULATION_SIZE = 50 + ELITISM_K; // Max number of Iterations protected static int MAX_ITERATIONS = 200; // Probability of Mutation protected static double MUTATION_PROB = 0.05; // Probability of Crossover protected static double CROSSOVER_PROB = 0.7; // Instantiate Random object private static Random rand = new Random(); // Instantiate Population of Individuals private Individual[] startPopulation; // Total Fitness of Population private double totalFitness; Robot robot = new Robot(); Maze maze; public void setElitism(int result) { ELITISM_K = result; } public void setPopSize(int result) { POPULATION_SIZE = result + ELITISM_K; } public void setMaxIt(int result) { MAX_ITERATIONS = result; } public void setMutProb(double result) { MUTATION_PROB = result; } public void setCrossoverProb(double result) { CROSSOVER_PROB = result; } /** * Constructor for Population */ public RunGA(Maze maze) { // Create a population of population plus elitism startPopulation = new Individual[POPULATION_SIZE]; // For every individual in population fill with x genes from 0 to 1 for (int i = 0; i < POPULATION_SIZE; i++) { startPopulation[i] = new Individual(); startPopulation[i].randGenes(); } // Evaluate the current population's fitness this.evaluate(maze, startPopulation); } /** * Set Population * @param newPop */ public void setPopulation(Individual[] newPop) { System.arraycopy(newPop, 0, this.startPopulation, 0, POPULATION_SIZE); } /** * Get Population * @return */ public Individual[] getPopulation() { return this.startPopulation; } /** * Evaluate fitness * @return */ public double evaluate(Maze maze, Individual[] newPop) { this.totalFitness = 0.0; ArrayList<Double> fitnesses = new ArrayList<Double>(); for (int i = 0; i < POPULATION_SIZE; i++) { maze = new Maze(8, 8); maze.fillMaze(); fitnesses.add(startPopulation[i].evaluate(maze, newPop)); //this.totalFitness += startPopulation[i].evaluate(maze, newPop); } //totalFitness = (Math.round(totalFitness / POPULATION_SIZE)); StringBuilder sb = new StringBuilder(); for(Double tmp : fitnesses) { sb.append(tmp + ", "); totalFitness += tmp; } // Progress of each Individual //System.out.println(sb.toString()); return this.totalFitness; } /** * Roulette Wheel Selection * @return */ public Individual rouletteWheelSelection() { // Calculate sum of all chromosome fitnesses in population - sum S. double randNum = rand.nextDouble() * this.totalFitness; int i; for (i = 0; i < POPULATION_SIZE && randNum > 0; ++i) { randNum -= startPopulation[i].getFitnessValue(); } return startPopulation[i-1]; } /** * Tournament Selection * @return */ public Individual tournamentSelection() { double randNum = rand.nextDouble() * this.totalFitness; // Get random number of population (add 1 to stop nullpointerexception) int k = rand.nextInt(POPULATION_SIZE) + 1; int i; for (i = 1; i < POPULATION_SIZE && i < k && randNum > 0; ++i) { randNum -= startPopulation[i].getFitnessValue(); } return startPopulation[i-1]; } /** * Finds the best individual * @return */ public Individual findBestIndividual() { int idxMax = 0; double currentMax = 0.0; double currentMin = 1.0; double currentVal; for (int idx = 0; idx < POPULATION_SIZE; ++idx) { currentVal = startPopulation[idx].getFitnessValue(); if (currentMax < currentMin) { currentMax = currentMin = currentVal; idxMax = idx; } if (currentVal > currentMax) { currentMax = currentVal; idxMax = idx; } } // Double check to see if this has the right one //System.out.println(startPopulation[idxMax].getFitnessValue()); // Maximisation return startPopulation[idxMax]; } /** * One Point Crossover * @param firstPerson * @param secondPerson * @return */ public static Individual[] onePointCrossover(Individual firstPerson, Individual secondPerson) { Individual[] newPerson = new Individual[2]; newPerson[0] = new Individual(); newPerson[1] = new Individual(); int size = Individual.SIZE; int randPoint = rand.nextInt(size); int i; for (i = 0; i < randPoint; ++i) { newPerson[0].setGene(i, firstPerson.getGene(i)); newPerson[1].setGene(i, secondPerson.getGene(i)); } for (; i < Individual.SIZE; ++i) { newPerson[0].setGene(i, secondPerson.getGene(i)); newPerson[1].setGene(i, firstPerson.getGene(i)); } return newPerson; } /** * Uniform Crossover * @param firstPerson * @param secondPerson * @return */ public static Individual[] uniformCrossover(Individual firstPerson, Individual secondPerson) { Individual[] newPerson = new Individual[2]; newPerson[0] = new Individual(); newPerson[1] = new Individual(); for(int i = 0; i < Individual.SIZE; ++i) { double r = rand.nextDouble(); if (r > 0.5) { newPerson[0].setGene(i, firstPerson.getGene(i)); newPerson[1].setGene(i, secondPerson.getGene(i)); } else { newPerson[0].setGene(i, secondPerson.getGene(i)); newPerson[1].setGene(i, firstPerson.getGene(i)); } } return newPerson; } public double getTotalFitness() { return totalFitness; } public static void main(String[] args) { // Initialise Environment Maze maze = new Maze(8, 8); maze.fillMaze(); // Instantiate Population //Population pop = new Population(); RunGA pop = new RunGA(maze); // Instantiate Individuals for Population Individual[] newPop = new Individual[POPULATION_SIZE]; // Instantiate two individuals to use for selection Individual[] people = new Individual[2]; Action action = null; Direction direction = null; String result = ""; /*result += "Total Fitness: " + pop.getTotalFitness() + " - Best Fitness: " + pop.findBestIndividual().getFitnessValue();*/ // Print Current Population System.out.println("Total Fitness: " + pop.getTotalFitness() + " - Best Fitness: " + pop.findBestIndividual().getFitnessValue()); // Instantiate counter for selection int count; for (int i = 0; i < MAX_ITERATIONS; i++) { count = 0; // Elitism for (int j = 0; j < ELITISM_K; ++j) { // This one has the best fitness newPop[count] = pop.findBestIndividual(); count++; } // Build New Population (Population size = Steps (28)) while (count < POPULATION_SIZE) { // Roulette Wheel Selection people[0] = pop.rouletteWheelSelection(); people[1] = pop.rouletteWheelSelection(); // Tournament Selection //people[0] = pop.tournamentSelection(); //people[1] = pop.tournamentSelection(); // Crossover if (rand.nextDouble() < CROSSOVER_PROB) { // One Point Crossover //people = onePointCrossover(people[0], people[1]); // Uniform Crossover people = uniformCrossover(people[0], people[1]); } // Mutation if (rand.nextDouble() < MUTATION_PROB) { people[0].mutate(); } if (rand.nextDouble() < MUTATION_PROB) { people[1].mutate(); } // Add to New Population newPop[count] = people[0]; newPop[count+1] = people[1]; count += 2; } // Make new population the current population pop.setPopulation(newPop); // Re-evaluate the current population //pop.evaluate(); pop.evaluate(maze, newPop); // Print results to screen System.out.println("Total Fitness: " + pop.totalFitness + " - Best Fitness: " + pop.findBestIndividual().getFitnessValue()); //result += "\nTotal Fitness: " + pop.totalFitness + " - Best Fitness: " + pop.findBestIndividual().getFitnessValue(); } // Best Individual Individual bestIndiv = pop.findBestIndividual(); //return result; } } I have uploaded the full project to RapidShare if you require the extra files, although if needed I can add the code to them here. This problem has been depressing me for days now and if you guys can help me I will forever be in your debt.

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• Fun things you can do by mutating Java strings

  - by polygenelubricants

  So I've come around since I asked how to limit setAccessible to only “legitimate” uses and have come to embrace its power for fun. Enabled by its power, of course, is string mutation. import java.lang.reflect.Field; public class Mutator { static void mutate(Object obj, String field, Object newValue) { try { Field f = obj.getClass().getDeclaredField(field); f.setAccessible(true); f.set(obj, newValue); } catch (Exception e) { } } public static void mutate(String from, String to) { mutate(from, "value", to.toCharArray()); mutate(from, "count", to.length()); } public static void main(String args[]) { Mutator.mutate(System.getProperty("line.separator"), "<br/>\n"); System.out.println("Hello world!"); Mutator.mutate(Integer.toString(Integer.MIN_VALUE), "OMG!"); System.out.println(-2147483648); Mutator.mutate(String.valueOf((Object) null), "LOL!"); System.out.println(Arrays.toString(new int[3][])); Mutator.mutate(Arrays.toString(new int[0]), ":("); System.out.println(Arrays.toString(new byte[0])); } } Output (if no exception is thrown): Hello world!<br/> OMG!<br/> [LOL!, LOL!, LOL!]<br/> :(<br/> Let's see what other fun things we can come up with.

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• Randomly sorting an array

  - by Cam

  Does there exist an algorithm which, given an ordered list of symbols {a1, a2, a3, ..., ak}, produces in O(n) time a new list of the same symbols in a random order without bias? "Without bias" means the probability that any symbol s will end up in some position p in the list is 1/k. Assume it is possible to generate a non-biased integer from 1-k inclusive in O(1) time. Also assume that O(1) element access/mutation is possible, and that it is possible to create a new list of size k in O(k) time. In particular, I would be interested in a 'generative' algorithm. That is, I would be interested in an algorithm that has O(1) initial overhead, and then produces a new element for each slot in the list, taking O(1) time per slot. If no solution exists to the problem as described, I would still like to know about solutions that do not meet my constraints in one or more of the following ways (and/or in other ways if necessary): the time complexity is worse than O(n). the algorithm is biased with regards to the final positions of the symbols. the algorithm is not generative. I should add that this problem appears to be the same as the problem of randomly sorting the integers from 1-k, since we can sort the list of integers from 1-k and then for each integer i in the new list, we can produce the symbol ai.

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• Working with fields which can mutate or be new instances altogether

  - by dotnetdev

  Structs are usually used for immutable data, eg a phone number, which does not mutate, but instead you get a new one (eg the number 000 becoming 0001 would mean two seperate numbers). However, pieces of information like Name, a string, can either mutate (company abc changing its name to abcdef, or being given a new name like def). For fields like this, I assume they should reside in the mutable class and not an immutable structure? My way of structuring code is to have an immutable concept, like Address (any change is a new address completely), in a struct and then reference it from a class like Customer, since Customer always has an address. So I would put CompanyName, or Employer, in the class as it is mutable. But a name can either mutate and so be the same 1 instance, or a new name setup and while the company still owning the first name too. Would the correct pattern for assigning a new instance (eg a new company name but the old name still owned by the company) be?: string name = ""; string newName = new string(); newName = "new"; name = newName; And a mutation just the standard assignment pattern? Thanks

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• Explicit method tables in C# instead of OO - good? bad?

  - by FunctorSalad

  Hi! I hope the title doesn't sound too subjective; I absolutely do not mean to start a debate on OO in general. I'd merely like to discuss the basic pros and cons for different ways of solving the following sort of problem. Let's take this minimal example: you want to express an abstract datatype T with functions that may take T as input, output, or both: f1 : Takes a T, returns an int f2 : Takes a string, returns a T f3 : Takes a T and a double, returns another T I'd like to avoid downcasting and any other dynamic typing. I'd also like to avoid mutation whenever possible. 1: Abstract-class-based attempt abstract class T { abstract int f1(); // We can't have abstract constructors, so the best we can do, as I see it, is: abstract void f2(string s); // The convention would be that you'd replace calls to the original f2 by invocation of the nullary constructor of the implementing type, followed by invocation of f2. f2 would need to have side-effects to be of any use. // f3 is a problem too: abstract T f3(double d); // This doesn't express that the return value is of the *same* type as the object whose method is invoked; it just expresses that the return value is *some* T. } 2: Parametric polymorphism and an auxilliary class (all implementing classes of TImpl will be singleton classes): abstract class TImpl<T> { abstract int f1(T t); abstract T f2(string s); abstract T f3(T t, double d); } We no longer express that some concrete type actually implements our original spec -- an implementation is simply a type Foo for which we happen to have an instance of TImpl. This doesn't seem to be a problem: If you want a function that works on arbitrary implementations, you just do something like: // Say we want to return a Bar given an arbitrary implementation of our abstract type Bar bar<T>(TImpl<T> ti, T t); At this point, one might as well skip inheritance and singletons altogether and use a 3 First-class function table class /* or struct, even */ TDictT<T> { readonly Func<T,int> f1; readonly Func<string,T> f2; readonly Func<T,double,T> f3; TDict( ... ) { this.f1 = f1; this.f2 = f2; this.f3 = f3; } } Bar bar<T>(TDict<T> td; T t); Though I don't see much practical difference between #2 and #3. Example Implementation class MyT { /* raw data structure goes here; this class needn't have any methods */ } // It doesn't matter where we put the following; could be a static method of MyT, or some static class collecting dictionaries static readonly TDict<MyT> MyTDict = new TDict<MyT>( (t) => /* body of f1 goes here */ , // f2 (s) => /* body of f2 goes here */, // f3 (t,d) => /* body of f3 goes here */ ); Thoughts? #3 is unidiomatic, but it seems rather safe and clean. One question is whether there are any performance concerns with it. I don't usually need dynamic dispatch, and I'd prefer if these function bodies get statically inlined in places where the concrete implementing type is known statically. Is #2 better in that regard?

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