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  • Store and create game objects at positions along terrain

    - by Alex
    I have a circular character that rolls down terrain like that shown in the picture below. The terrain is created from an array holding 1000 points. The ground is drawn one screen width infront and one screen width behind. So as the character moves, edges are created infront and edges are removed behind. My problem is, I want to create box2d bodies at certain locations along the path and need a way to store these creator methods or objects. I need some way to store a position at which they are created and some pointer to a function to create them, once the character is in range. I guess this would be an array of some sort that is checked each time the ground is updated and then if in range, the function is executed and removed from the array. But I'm not sure if its even possible to store pointers to functions with parameters included... any help is much appreciated!

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  • How to implement Fog Of War with an shader?

    - by Cambrano
    Okay, I'm creating a RTS game and want to implement an AgeOfEmpires-like Fog Of War(FOW). That means a tile(or pixel) can be: 0% transparent (unexplored) 50% transparent black (explored but not in viewrange) 100% transparent(explored and in viewrange) RTS means I'll have many explorers (NPCs, buildings, ...). Okay, so I have an 2d array of bytes byte[,] explored. The byte value correlates the transparency. The question is, how do I pass this array to my shader? Well I think it is not possible to pass an entire array. So: what technique shall I use to let my shader know if a pixel/tile is visible or not?

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  • How best to merge/sort/page through tons of JSON arrays?

    - by Joshiatto
    Here's the scenario: Say you have millions of JSON documents stored as text files. Each JSON document is an array of "activity" objects, each of which contain a "created_datetime" attribute. What is the best way to merge/sort/filter/page through these activities via a web UI? For example, say we want to take a few thousand of the documents, merge them into a gigantic array, sort the array by the "created_datetime" attribute descending and then page through it 10 activities at a time. Also keep in mind that roughly 25% of these JSON documents are updated every day, and updates have to make it into the view within 5 minutes. My first thought is to parse all of the documents into an RDBMS table and then it would just be a simple query such as "select top 10 name, created_datetime from Activity where user_id=12345 order by created_datetime desc". Some have suggested I use NoSQL techniques such as hadoop or map/reduce instead. How exactly would this work? For more background, see: Why is NoSQL better for this scenario?

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  • Read an object from compressed file generated from ActionScript 3

    - by Last Chance
    I have made a simple game Map Editor and I want to save a array that contain map tile info to a file, as below: var arr:Array = [.....2d tile info in it...]; var ba:ByteArray = new ByteArray(); ba.writeObject(arr); ba.compress(); var file:File = new File(); file.save(ba); I had successfully saved a compressed object to a file. Now the problem is my server side need to read this file and decompress the array out from the file, then convert it to a Python list. Is that possible?

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  • Does it make a difference if I declare variables inside or outside a loop in Java?

    - by Puckl
    Does it make a difference if I declare variables inside or outside a loop in Java? Is this for(int i = 0; i < 1000; i++) { int temporaryValue = someMethod(); list.add(temporaryValue) } equal to this (with respect to memory usage)? int temporaryValue = 0; for(int i = 0; i < 1000; i++) { temporaryValue = someMethod(); list.add(temporaryValue) } And what if the temporary variable is for example an ArrayList? for(int i = 0; i < 1000; i++) { ArrayList<Integer> array = new ArrayList<Integer>(); fillArray(array); // do something with the array }

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  • What's a good way to store a series of interconnected pipe and tank objects?

    - by mars
    I am working on a puzzle game with a 6 by 6 grid of storage tanks that are connected to up to 4 tanks adjacent to them via pipes. The gameplay is concerned with combining what's in a tank with an adjacent tank via the pipe than interconnects them. Right now I store the tanks in a 6x6 array, vertical pipes in a 5x6 array, and horizontal pipes in a 6x5 array. Each tank has a reference to the object that contains both tanks and pipes and when a pipe needs to be animated filling with liquid, the selected tank just calls a method on the container object telling it to animate the pipes it is connected to (subtract 1 from row or column to find connected pipes). This feels like the wrong way of doing it, as I've also considered just giving each tank references to the pipes connected to it to access directly.

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  • how should I change the representation (not mimetype) of a resource?

    - by xenoterracide
    I'm looking at how I can change the representation of a payload at runtime for varied potential advantages, but I'm not sure how to do it. Specifically collections. Array of Pairs [{ <resource_uri> : { <entity> }, ...}] Array of Objects [<entity>,...] Array of Resources [<resource_uri>] Map of entities { <resource_uri> : { <entity> }, ... } My problem is, I'm not sure if I should put these different representations of the sets at different URI's, give them slightly varied mime types, e.g. application/foomap+json or perhaps use an optional query parameter ?format=map, or resource /entities/map. The UI is going to hide this, this is for programmatic web service access only (which the "UI's JS will have to call).

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  • C++ function returning pointer, why does this work ? [migrated]

    - by nashmaniac
    So heres a simple c++ function what it does it take an array of characters as its argument and a integer n and then creates a new character array with only n elements of the array. char * cutString(char * ch , int n){ char * p = new char[n]; int i ; for(i = 0 ; i < n ; i++) p[i] = ch[i]; while(i <= n ){ p[i++] = '\0'; } return p ; } this works just fine but if I change char * p = new char[n]; to char p[n]; I see funny characters what happens ? What difference does the former make also p is a temporary variable then how does the function returns it alright ?

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  • pascal triangle in php (anything wrong with this solution?) [migrated]

    - by zhenka
    I saw that one of the interview questions could be building a pascal triangle. Is there anything wrong with this particular solution I came up with? function pascal_r($r){ $local = array(); if($r == 1){ return array(array(1)); } else { $previous = pascal_r($r - 1); array_push($local, 1); for($i = 0; $i < $r - 2 && $r > 2; $i++){ array_push($local, $previous[$r-2][$i] + $previous[$r-2][$i + 1]); } array_push($local, 1); } array_push($previous, $local); return $previous; } print_r(pascal_r(100));

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  • When using RAID10 + BBWC why is it better to separate PostgreSQL data files from OS and transaction logs than to keep them all on the same array?

    - by Vlad
    I've seen the advice everywhere (including here and here): keep your OS partition, DB data files and DB transaction logs on separate discs/arrays. The general recommendation is to use RAID1 for OS, RAID10 for data (or RAID5 if load is very read-biased) and RAID1 for transaction logs. However, considering that you will need at least 6 or 8 drives to build this setup, wouldn't a RAID10 over 6-8 drives with BBWC perform better? What if the drives are SSDs? I'm talking here about internal server drives, not SAN.

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  • With XSLT, how can I use this if-test with an array, when search element is returned by a template call inside the for loop?

    - by codesforcoffee
    I think this simple example might ask the question a lot more clearly. I have an input file with multiple products. There are 10 types of product (2 product IDs is fine enough for this example), but the input will have 200 products, and I only want to output the info for the first product of each type. (Output info for the lowest priced one, so the first one will be the lowest price because I sort by Price first.) So I want to read in each product, but only output the product's info if I haven't already output a product with that same ID. I couldn't figure out how to get the processID template to return a value that I need to do my if-check on, that uses parameters from inside the for-each Product loop -then properly close the if tag in the right place so it won't output the open Product tag unless it passes the if test. I know the following code does not work, but it illustrates the idea and gives me a place to start: <?xml version="1.0" encoding="utf-8"?> <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"> <xsl:output method="xml" encoding="UTF-8" indent="yes" cdata-section-elements="prod_name adv_notes"/> <xsl:template match="/"> <List> <xsl:for-each select="ProductGroup"> <xsl:sort select="ActiveProducts/Product/Rate"/> <xsl:variable name="IDarray"> <xsl:for-each select="ActiveProducts/Product"> <xsl:variable name="CurrentID"> <xsl:call-template name="processID"> <xsl:with-param name="ProductCode" select="ProductCode" /> </xsl:call-template> </xsl:variable> <xsl:if test="not(contains($IDarray, $CurrentID))"> <child elem="{@elem}"> <xsl:select value-of="$CurrentID" /> </child> <Product> <xsl:attribute name="ID"> <xsl:select value-of="$CurrentID" /> </xsl:attribute> <prod_name> <xsl:value-of select="../ProductName"/> </prod_name> <rate> <xsl:value-of select="../Rate"/> </rate> </Product> </xsl:if> </xsl:for-each> </xsl:variable> </xsl:for-each> </List> </xsl:template> <xsl:template name="processID"> <xsl:param name="ProductCode"/> <xsl:choose> <xsl:when test="starts-with($ProductCode, '515')">5</xsl:when> <xsl:when test="starts-with($ProductCode, '205')">2</xsl:when> </xsl:choose> </xsl:template> Thanks so much in advance, I know some of the awesome programmers here can help! :) -Holly An input would look like this: <ProductGroup> <ActiveProducts> <Product> <ProductCode> 5155 </ProductCode> <ProductName> House </ProductName> <Rate> 3.99 </Rate> </Product> <Product> <ProductCode> 5158 </ProductCode> <ProductName> House </ProductName> <Rate> 4.99 </Rate> </Product> </ActiveProducts> </ProductGroup> <ProductGroup> <ActiveProducts> <Product> <ProductCode> 2058 </ProductCode> <ProductName> House </ProductName> <Rate> 2.99 </Rate> </Product> <Product> <ProductCode> 2055 </ProductCode> <ProductName> House </ProductName> <Rate> 7.99 </Rate> </Product> </ActiveProducts> </ProductGroup> 200 of those with different attributes. I have the translation working, just needed to add that array and if statement somehow. Output would be this for only that simple input file:

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  • Using an alternate search platform in Commerce Server 2009

    - by Lewis Benge
    Although Microsoft Commerce Server 2009's architecture is built upon Microsoft SQL Server, and has the full power of the SQL Full Text Indexing Search Platform, there are time however when you may require a richer or alternate search platform. One of these scenarios if when you want to implement a faceted (refinement) search into your site, which provides dynamic refinements based on the search results dataset. Faceted search is becoming popular in most online retail environments as a way of providing an enhanced user experience when browsing a larger catalogue. This is powerful for two reasons, firstly with a traditional search it is down to a user to think of a search term suitable for the product they are trying to find. This typically will not return similar products or help in any way to refine a larger dataset. Faceted searches on the other hand provide a comprehensive list of product properties, grouped together by similarity to help the user narrow down the results returned, as the user progressively restricts the search criteria by selecting additional criteria to search again, these facets needs to continually refresh. The whole experience allows users to explore alternate brands, price-ranges, or find products they hadn't initially thought of or where looking for in a bid to enhance cross sell in the retail environment. The second advantage of this type of search from a business perspective is also to harvest the search result to start to profile your user. Even though anonymous users may routinely visit your site, and will not necessarily register or complete a transaction to build up marketing data- profiling, you can still achieve the same result by recording search facets used within the search sequence. Below is a faceted search scenario generated from eBay using the search term "server". By creating a search profile of clicking through Computer & Networking -> Servers -> Dell - > New and recording this information against my user profile you can start to predict with a lot more certainty what types of products I am interested in. This will allow you to apply shopping-cart analysis against your search data and provide great cross-sale or advertising opportunity, or personalise the user experience based on your prediction of what the user may be interested in. This type of search is extremely beneficial in e-Commerce environments but achieving it out of the box with Commerce Server and SQL Full Text indexing can be challenging. In many deployments it is often easier to use an alternate search platform such as Microsoft's FAST, Apache SOLR, or Endecca, however you still want these products to integrate natively into Commerce Server to ensure that up-to-date inventory information is presented, profile information is generated, and you provide a consistant API. To do so we make the most of the Commerce Server extensibilty points called operation sequence components. In this example I will be talking about Apache Solr hosted on Apache Tomcat, in this specific example I have used the SolrNet C# library to interface to the Java platform. Also I am not going to talk about Solr configuration of indexing – but in a production envionrment this would typically happen by using Powershell to call the Commerce Server management webservice to export your catalog as XML, apply an XSLT transform to the file to make it conform to SOLR and use a simple HTTP Post to send it to the search enginge for indexing. Essentially a sequance component is a step in a serial workflow used to call a data repository (which in most cases is usually the Commerce Server pipelines or databases) and map to and from a Commerce Entity object whilst enforcing any business rules. So the first step in the process is to add a new class library to your existing Commerce Server site. You will need to use a new library as Sequence Components will need to be strongly named to be deployed. Once you are inside of your new project, add a new class file and add a reference to the Microsoft.Commerce.Providers, Microsoft.Commerce.Contracts and the Microsoft.Commerce.Broker assemblies. Now make your new class derive from the base object Microsoft.Commerce.Providers.Components.OperationSequanceComponent and overide the ExecuteQueryMethod. Your screen will then look something similar ot this: As all we are doing on this component is conducting a search we are only interested in the ExecuteQuery method. This method accepts three arguments, queryOperation, operationCache, and response. The queryOperation will be the object in which we receive our search parameters, the cache allows access to the Commerce Server cache allowing us to store regulary accessed information, and the response object is the object which we will return the result of our search upon. Inside this method is simply where we are going to inject our logic for our third party search platform. As I am not going to explain the inner-workings of actually making a SOLR call, I'll simply provide the sample code here. I would highly recommend however looking at the SolrNet wiki as they have some great explinations of how the API works. What you will find however is that there are some further extensions required when attempting to integrate a custom search provider. Firstly you out of the box the CommerceQueryOperation you will receive into the method when conducting a search against a catalog is specifically geared towards a SQL Full Text Search with properties such as a Where clause. To make the operation you receive more relevant you will need to create another class, this time derived from Microsoft.Commerce.Contract.Messages.CommerceSearchCriteria and within this you need to detail the properties you will require to allow you to submit as parameters to the SOLR search API. My exmaple looks like this: [DataContract(Namespace = "http://schemas.microsoft.com/microsoft-multi-channel-commerce-foundation/types/2008/03")] public class CommerceCatalogSolrSearch : CommerceSearchCriteria { private Dictionary<string, string> _facetQueries;   public CommerceCatalogSolrSearch() { _facetQueries = new Dictionary<String, String>();   }     public Dictionary<String, String> FacetQueries { get { return _facetQueries; } set { _facetQueries = value; } }   public String SearchPhrase{ get; set; } public int PageIndex { get; set; } public int PageSize { get; set; } public IEnumerable<String> Facets { get; set; }   public string Sort { get; set; }   public new int FirstItemIndex { get { return (PageIndex-1)*PageSize; } }   public int LastItemIndex { get { return FirstItemIndex + PageSize; } } }  To allow you to construct a CommerceQueryOperation call within the API you will also need to construct another class to derived from Microsoft.Commerce.Common.MessageBuilders.CommerceSearchCriteriaBuilder and is simply used to construct an instance of the CommerceQueryOperation you have just created and expose the properties you want set. My Message builder looks like this: public class CommerceCatalogSolrSearchBuilder : CommerceSearchCriteriaBuilder { private CommerceCatalogSolrSearch _solrSearch;   public CommerceCatalogSolrSearchBuilder() { _solrSearch = new CommerceCatalogSolrSearch(); }   public String SearchPhrase { get { return _solrSearch.SearchPhrase; } set { _solrSearch.SearchPhrase = value; } }   public int PageIndex { get { return _solrSearch.PageIndex; } set { _solrSearch.PageIndex = value; } }   public int PageSize { get { return _solrSearch.PageSize; } set { _solrSearch.PageSize = value; } }   public Dictionary<String,String> FacetQueries { get { return _solrSearch.FacetQueries; } set { _solrSearch.FacetQueries = value; } }   public String[] Facets { get { return _solrSearch.Facets.ToArray(); } set { _solrSearch.Facets = value; } } public override CommerceSearchCriteria ToSearchCriteria() { return _solrSearch; } }  Once you have these two classes in place you can now safely cast the CommerceOperation you receive as an argument of the overidden ExecuteQuery method in the SequenceComponent to the CommerceCatalogSolrSearch operation you have just created, e.g. public CommerceCatalogSolrSearch TryGetSearchCriteria(CommerceOperation operation) { var searchCriteria = operation as CommerceQueryOperation; if (searchCriteria == null) throw new Exception("No search criteria present");   var local = (CommerceCatalogSolrSearch) searchCriteria.SearchCriteria; if (local == null) throw new Exception("Unexpected Search Criteria in Operation");   return local; }  Now you have all of your search parameters present, you can go off an call the external search platform API. You will of-course get proprietry objects returned, so the next step in the process is to convert the results being returned back into CommerceEntities. You do this via another extensibility point within the Commerce Server API called translatators. Translators are another separate class, this time derived inheriting the interface Microsoft.Commerce.Providers.Translators.IToCommerceEntityTranslator . As you can imaginge this interface is specific for the conversion of the object TO a CommerceEntity, you will need to implement a separate interface if you also need to go in the opposite direction. If you implement the required method for the interace you will get a single translate method which has a source onkect, destination CommerceEntity, and a collection of properties as arguments. For simplicity sake in this example I have hard-coded the mappings, however best practice would dictate you map the objects using your metadatadefintions.xml file . Once complete your translator would look something like the following: public class SolrEntityTranslator : IToCommerceEntityTranslator { #region IToCommerceEntityTranslator Members   public void Translate(object source, CommerceEntity destinationCommerceEntity, CommercePropertyCollection propertiesToReturn) { if (source.GetType().Equals(typeof (SearchProduct))) { var searchResult = (SearchProduct) source;   destinationCommerceEntity.Id = searchResult.ProductId; destinationCommerceEntity.SetPropertyValue("DisplayName", searchResult.Title); destinationCommerceEntity.ModelName = "Product";   } }  Once you have a translator in place you can then safely map the results of your search platform into Commerce Entities and attach them on to the CommerceResponse object in a fashion similar to this: foreach (SearchProduct result in matchingProducts) { var destinationEntity = new CommerceEntity(_returnModelName);   Translator.ToCommerceEntity(result, destinationEntity, _queryOperation.Model.Properties); response.CommerceEntities.Add(destinationEntity); }  In SOLR I actually have two objects being returned – a product, and a collection of facets so I have an additional translator for facet (which maps to a custom facet CommerceEntity) and my facet response from SOLR is passed into the Translator helper class seperatley. When all of this is pieced together you have sucessfully completed the extensiblity point coding. You would have created a new OperationSequanceComponent, a custom SearchCritiera object and message builder class, and translators to convert the objects into Commerce Entities. Now you simply need to configure them, and can start calling them in your code. Make sure you sign you assembly, compile it and identiy its signature. Next you need to put this a reference of your new assembly into the Channel.Config configuration file replacing that of the existing SQL Full Text component: You will also need to add your translators to the Translators node of your Channel.Config too: Lastly add any custom CommerceEntities you have developed to your MetaDataDefintions.xml file. Your configuration is now complete, and you should now be able to happily make a call to the Commerce Foundation API, which will act as a proxy to your third party search platform and return back CommerceEntities of your search results. If you require data to be enriched, or logged, or any other logic applied then simply add further sequence components into the OperationSequence (obviously keeping the search response first) to the node of your Channel.Config file. Now to call your code you simply request it as per any other CommerceQuery operation, but taking into account you may be receiving multiple types of CommerceEntity returned: public KeyValuePair<FacetCollection ,List<Product>> DoFacetedProductQuerySearch(string searchPhrase, string orderKey, string sortOrder, int recordIndex, int recordsPerPage, Dictionary<string, string> facetQueries, out int totalItemCount) { var products = new List<Product>(); var query = new CommerceQuery<CatalogEntity, CommerceCatalogSolrSearchBuilder>();   query.SearchCriteria.PageIndex = recordIndex; query.SearchCriteria.PageSize = recordsPerPage; query.SearchCriteria.SearchPhrase = searchPhrase; query.SearchCriteria.FacetQueries = facetQueries;     totalItemCount = 0; CommerceResponse response = SiteContext.ProcessRequest(query.ToRequest()); var queryResponse = response.OperationResponses[0] as CommerceQueryOperationResponse;   // No results. Return the empty list if (queryResponse != null && queryResponse.CommerceEntities.Count == 0) return new KeyValuePair<FacetCollection, List<Product>>();   totalItemCount = (int)queryResponse.TotalItemCount;   // Prepare a multi-operation to retrieve the product variants var multiOperation = new CommerceMultiOperation();     //Add products to results foreach (Product product in queryResponse.CommerceEntities.Where(x => x.ModelName == "Product")) { var productQuery = new CommerceQuery<Product>(Product.ModelNameDefinition); productQuery.SearchCriteria.Model.Id = product.Id; productQuery.SearchCriteria.Model.CatalogId = product.CatalogId;   var variantQuery = new CommerceQueryRelatedItem<Variant>(Product.RelationshipName.Variants);   productQuery.RelatedOperations.Add(variantQuery);   multiOperation.Add(productQuery); }   CommerceResponse variantsResponse = SiteContext.ProcessRequest(multiOperation.ToRequest()); foreach (CommerceQueryOperationResponse queryOpResponse in variantsResponse.OperationResponses) { if (queryOpResponse.CommerceEntities.Count() > 0) products.Add(queryOpResponse.CommerceEntities[0]); }   //Get facet collection FacetCollection facetCollection = queryResponse.CommerceEntities.Where(x => x.ModelName == "FacetCollection").FirstOrDefault();     return new KeyValuePair<FacetCollection, List<Product>>(facetCollection, products); }    ..And that is it – simply a few classes and some configuration will allow you to extend the Commerce Server query operations to call a third party search platform, whilst still maintaing a unifed API in the remainder of your code. This logic stands for any extensibility within CommerceServer, which requires excution in a serial fashioon such as call to LOB systems or web service to validate or enrich data. Feel free to use this example on other applications, and if you have any questions please feel free to e-mail and I'll help out where I can!

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  • C#, Delegates and LINQ

    - by JustinGreenwood
    One of the topics many junior programmers struggle with is delegates. And today, anonymous delegates and lambda expressions are profuse in .net APIs.  To help some VB programmers adapt to C# and the many equivalent flavors of delegates, I walked through some simple samples to show them the different flavors of delegates. using System; using System.Collections.Generic; using System.Linq; namespace DelegateExample { class Program { public delegate string ProcessStringDelegate(string data); public static string ReverseStringStaticMethod(string data) { return new String(data.Reverse().ToArray()); } static void Main(string[] args) { var stringDelegates = new List<ProcessStringDelegate> { //========================================================== // Declare a new delegate instance and pass the name of the method in new ProcessStringDelegate(ReverseStringStaticMethod), //========================================================== // A shortcut is to just and pass the name of the method in ReverseStringStaticMethod, //========================================================== // You can create an anonymous delegate also delegate (string inputString) //Scramble { var outString = inputString; if (!string.IsNullOrWhiteSpace(inputString)) { var rand = new Random(); var chs = inputString.ToCharArray(); for (int i = 0; i < inputString.Length * 3; i++) { int x = rand.Next(chs.Length), y = rand.Next(chs.Length); char c = chs[x]; chs[x] = chs[y]; chs[y] = c; } outString = new string(chs); } return outString; }, //========================================================== // yet another syntax would be the lambda expression syntax inputString => { // ROT13 var array = inputString.ToCharArray(); for (int i = 0; i < array.Length; i++) { int n = (int)array[i]; n += (n >= 'a' && n <= 'z') ? ((n > 'm') ? 13 : -13) : ((n >= 'A' && n <= 'Z') ? ((n > 'M') ? 13 : -13) : 0); array[i] = (char)n; } return new string(array); } //========================================================== }; // Display the results of the delegate calls var stringToTransform = "Welcome to the jungle!"; System.Console.ForegroundColor = ConsoleColor.Cyan; System.Console.Write("String to Process: "); System.Console.ForegroundColor = ConsoleColor.Yellow; System.Console.WriteLine(stringToTransform); stringDelegates.ForEach(delegatePointer => { System.Console.WriteLine(); System.Console.ForegroundColor = ConsoleColor.Cyan; System.Console.Write("Delegate Method Name: "); System.Console.ForegroundColor = ConsoleColor.Magenta; System.Console.WriteLine(delegatePointer.Method.Name); System.Console.ForegroundColor = ConsoleColor.Cyan; System.Console.Write("Delegate Result: "); System.Console.ForegroundColor = ConsoleColor.White; System.Console.WriteLine(delegatePointer(stringToTransform)); }); System.Console.ReadKey(); } } } The output of the program is below: String to Process: Welcome to the jungle! Delegate Method Name: ReverseStringStaticMethod Delegate Result: !elgnuj eht ot emocleW Delegate Method Name: ReverseStringStaticMethod Delegate Result: !elgnuj eht ot emocleW Delegate Method Name: b__1 Delegate Result: cg ljotWotem!le une eh Delegate Method Name: b__2 Delegate Result: dX_V|`X ?| ?[X ]?{Z_X!

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  • The long road to bug-free software

    - by Tony Davis
    The past decade has seen a burgeoning interest in functional programming languages such as Haskell or, in the Microsoft world, F#. Though still on the periphery of mainstream programming, functional programming concepts are gradually seeping into the imperative C# language (for example, Lambda expressions have their root in functional programming). One of the more interesting concepts from functional programming languages is the use of formal methods, the lofty ideal behind which is bug-free software. The idea is that we write a specification that describes exactly how our function (say) should behave. We then prove that our function conforms to it, and in doing so have proved beyond any doubt that it is free from bugs. All programmers already use one form of specification, specifically their programming language's type system. If a value has a specific type then, in a type-safe language, the compiler guarantees that value cannot be an instance of a different type. Many extensions to existing type systems, such as generics in Java and .NET, extend the range of programs that can be type-checked. Unfortunately, type systems can only prevent some bugs. To take a classic problem of retrieving an index value from an array, since the type system doesn't specify the length of the array, the compiler has no way of knowing that a request for the "value of index 4" from an array of only two elements is "unsafe". We restore safety via exception handling, but the ideal type system will prevent us from doing anything that is unsafe in the first place and this is where we start to borrow ideas from a language such as Haskell, with its concept of "dependent types". If the type of an array includes its length, we can ensure that any index accesses into the array are valid. The problem is that we now need to carry around the length of arrays and the values of indices throughout our code so that it can be type-checked. In general, writing the specification to prove a positive property, even for a problem very amenable to specification, such as a simple sorting algorithm, turns out to be very hard and the specification will be different for every program. Extend this to writing a specification for, say, Microsoft Word and we can see that the specification would end up being no simpler, and therefore no less buggy, than the implementation. Fortunately, it is easier to write a specification that proves that a program doesn't have certain, specific and undesirable properties, such as infinite loops or accesses to the wrong bit of memory. If we can write the specifications to prove that a program is immune to such problems, we could reuse them in many places. The problem is the lack of specification "provers" that can do this without a lot of manual intervention (i.e. hints from the programmer). All this might feel a very long way off, but computing power and our understanding of the theory of "provers" advances quickly, and Microsoft is doing some of it already. Via their Terminator research project they have started to prove that their device drivers will always terminate, and in so doing have suddenly eliminated a vast range of possible bugs. This is a huge step forward from saying, "we've tested it lots and it seems fine". What do you think? What might be good targets for specification and verification? SQL could be one: the cost of a bug in SQL Server is quite high given how many important systems rely on it, so there's a good incentive to eliminate bugs, even at high initial cost. [Many thanks to Mike Williamson for guidance and useful conversations during the writing of this piece] Cheers, Tony.

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  • DirectX particle system. ConstantBuffer

    - by Liuka
    I'm new in DirectX and I'm making a 2D game. I want to use a particle system to simulate a 3D starfield, so each star has to set its own constant buffer for the vertexshader es. to set it's world matrix. So if i have 500 stars (that move every frame) i need to call 500 times VSsetconstantbuffer, and map/unmap each buffer. with 500 stars i have an average of 220 fps and that's quite good. My bottelneck is Vs/PsSetconstantbuffer. If i dont call this function i have 400 fps(obliviously nothing is display, since i dont set the position of the stars). So is there a method to speed up the render of the particle system?? Ps. I'm using intel integrate graphic (hd 2000-3000). with a nvidia (or amd) gpu will i have the same bottleneck?? If, for example, i dont call setshaderresource i have 10-20 fps more (for 500 objcets), that is not 180.Why does SetConstantBuffer take so long?? LPVOID VSdataPtr = VSmappedResource.pData; memcpy(VSdataPtr, VSdata, CszVSdata); context->Unmap(VertexBuffer, 0); result = context->Map(PixelBuffer, 0, D3D11_MAP_WRITE_DISCARD, 0, &PSmappedResource); if (FAILED(result)) { outputResult.OutputErrorMessage(TITLE, L"Cannot map the PixelBuffer", &result, OUTPUT_ERROR_FILE); return; } LPVOID PSdataPtr = PSmappedResource.pData; memcpy(PSdataPtr, PSdata, CszPSdata); context->Unmap(PixelBuffer, 0); context->VSSetConstantBuffers(0, 1, &VertexBuffer); context->PSSetConstantBuffers(0, 1, &PixelBuffer); this update and set the buffer. It's part of the render method of a sprite class that contains a the vertex buffer and the texture to apply to the quads(it's a 2d game) too. I have an array of 500 stars (sprite setup with a star texture). Every frame: clear back buffer; draw the array of stars; present the backbuffer; draw also call the function update( which calculate the position of the sprite on screen based on a "camera class") Ok, create a vertex buffer with the vertices of each quads(stars) seems to be good, since the stars don't change their "virtual" position; so.... In a particle system (where particles move) it's better to have all the object in only one vertices array, rather then an array of different sprite/object in order to update all the vertices' position with a single setbuffer call. In this case i have to use a dynamic vertex buffer with the vertices positions like this: verticesForQuad={{ XMFLOAT3((float)halfDImensions.x-1+pos.x, (float)halfDImensions.y-1+pos.y, 1.0f), XMFLOAT2(1.0f, 0.0f) }, { XMFLOAT3((float)halfDImensions.x-1+pos.x, -(float)halfDImensions.y-1+pos.y, 1.0f), XMFLOAT2(1.0f, 1.0f) }, { XMFLOAT3(-(float)halfDImensions.x-1+pos.x, (float)halfDImensions.y-1.pos.y, 1.0f), XMFLOAT2(0.0f, 0.0f) }, { XMFLOAT3(-(float)halfDImensions.x-1.pos.x, -(float)halfDImensions.y-1+pos.y, 1.0f), XMFLOAT2(0.0f, 1.0f) }, ....other quads} where halfDimensions is the halfsize in pixel of a texture and pos the virtual position of a star. than create an array of verticesForQuad and create the vertex buffer ZeroMemory(&vertexDesc, sizeof(vertexDesc)); vertexDesc.Usage = D3D11_USAGE_DEFAULT; vertexDesc.BindFlags = D3D11_BIND_VERTEX_BUFFER; vertexDesc.ByteWidth = sizeof(VertexType)* 4*numStars; ZeroMemory(&resourceData, sizeof(resourceData)); resourceData.pSysMem = verticesForQuad; result = device->CreateBuffer(&vertexDesc, &resourceData, &CvertexBuffer); and call each frame Context->IASetVertexBuffers(0, 1, &CvertexBuffer, &stride, &offset); But if i want to add and remove obj i have to recreate the buffer each time, havent i?? There is a faster way? I think i can create a vertex buffer with a max size (es. 10000 objs) and when i update it set only the 250 position (for 250 onjs for example) and pass this number as the vertexCount to the draw function (numObjs*4), or i'm worng

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  • The long road to bug-free software

    - by Tony Davis
    The past decade has seen a burgeoning interest in functional programming languages such as Haskell or, in the Microsoft world, F#. Though still on the periphery of mainstream programming, functional programming concepts are gradually seeping into the imperative C# language (for example, Lambda expressions have their root in functional programming). One of the more interesting concepts from functional programming languages is the use of formal methods, the lofty ideal behind which is bug-free software. The idea is that we write a specification that describes exactly how our function (say) should behave. We then prove that our function conforms to it, and in doing so have proved beyond any doubt that it is free from bugs. All programmers already use one form of specification, specifically their programming language's type system. If a value has a specific type then, in a type-safe language, the compiler guarantees that value cannot be an instance of a different type. Many extensions to existing type systems, such as generics in Java and .NET, extend the range of programs that can be type-checked. Unfortunately, type systems can only prevent some bugs. To take a classic problem of retrieving an index value from an array, since the type system doesn't specify the length of the array, the compiler has no way of knowing that a request for the "value of index 4" from an array of only two elements is "unsafe". We restore safety via exception handling, but the ideal type system will prevent us from doing anything that is unsafe in the first place and this is where we start to borrow ideas from a language such as Haskell, with its concept of "dependent types". If the type of an array includes its length, we can ensure that any index accesses into the array are valid. The problem is that we now need to carry around the length of arrays and the values of indices throughout our code so that it can be type-checked. In general, writing the specification to prove a positive property, even for a problem very amenable to specification, such as a simple sorting algorithm, turns out to be very hard and the specification will be different for every program. Extend this to writing a specification for, say, Microsoft Word and we can see that the specification would end up being no simpler, and therefore no less buggy, than the implementation. Fortunately, it is easier to write a specification that proves that a program doesn't have certain, specific and undesirable properties, such as infinite loops or accesses to the wrong bit of memory. If we can write the specifications to prove that a program is immune to such problems, we could reuse them in many places. The problem is the lack of specification "provers" that can do this without a lot of manual intervention (i.e. hints from the programmer). All this might feel a very long way off, but computing power and our understanding of the theory of "provers" advances quickly, and Microsoft is doing some of it already. Via their Terminator research project they have started to prove that their device drivers will always terminate, and in so doing have suddenly eliminated a vast range of possible bugs. This is a huge step forward from saying, "we've tested it lots and it seems fine". What do you think? What might be good targets for specification and verification? SQL could be one: the cost of a bug in SQL Server is quite high given how many important systems rely on it, so there's a good incentive to eliminate bugs, even at high initial cost. [Many thanks to Mike Williamson for guidance and useful conversations during the writing of this piece] Cheers, Tony.

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  • QR Code encoding and decoding using zxing

    - by helixed
    Okay, so I'm going to take the off chance that someone here has used zxing before. I'm developing a Java application, and one of the things it needs to do is encode a byte array of data into a QR Code and then decode it at a later time. Here's an example of what my encoder looks like: byte[] b = {0x48, 0x45, 0x4C, 0x4C, 0x4F}; //convert the byte array into a UTF-8 string String data; try { data = new String(b, "UTF8"); } catch (UnsupportedEncodingException e) { //the program shouldn't be able to get here return; } //get a byte matrix for the data ByteMatrix matrix; com.google.zxing.Writer writer = new QRCodeWriter(); try { matrix = writer.encode(data, com.google.zxing.BarcodeFormat.QR_CODE, width, height); } catch (com.google.zxing.WriterException e) { //exit the method return; } //generate an image from the byte matrix int width = matrix.getWidth(); int height = matrix.getHeight(); byte[][] array = matrix.getArray(); //create buffered image to draw to BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); //iterate through the matrix and draw the pixels to the image for (int y = 0; y < height; y++) { for (int x = 0; x < width; x++) { int grayValue = array[y][x] & 0xff; image.setRGB(x, y, (grayValue == 0 ? 0 : 0xFFFFFF)); } } //write the image to the output stream ImageIO.write(image, "png", outputStream); The beginning byte array in this code is just used to test it. The actual byte data will be varied. Here's what my decoder looks like: //get the data from the input stream BufferedImage image = ImageIO.read(inputStream); //convert the image to a binary bitmap source LuminanceSource source = new BufferedImageLuminanceSource(image); BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source)); //decode the barcode QRCodeReader reader = new QRCodeReader(); Result result; try { result = reader.decode(bitmap, hints); } catch (ReaderException e) { //the data is improperly formatted throw new MCCDatabaseMismatchException(); } byte[] b = result.getRawBytes(); System.out.println(ByteHelper.convertUnsignedBytesToHexString(result.getText().getBytes("UTF8"))); System.out.println(ByteHelper.convertUnsignedBytesToHexString(b)); convertUnsignedBytesToHexString(byte) is a method which converts an array of bytes in a string of hexadecimal characters. When I try to run these two blocks of code together, this is the output: 48454c4c4f 202b0b78cc00ec11ec11ec11ec11ec11ec11ec Clearly the text is being encoded, but the actual bytes of data are completely off. Any help would be appreciated here. Thanks, helixed

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  • Yii urlManager language in URL

    - by TaMeR
    I am trying to add a language to the url with following syntax: http://www.example.com/en/site/page/view/about What I have so far works with short urls like: http://www.example.com/en/site/contact but not with long once as in my first example Here is what I have so far: /config/main.php 'urlManager'=>array( 'class'=>'application.components.MyCUrlManager', 'urlFormat'=>'path', 'showScriptName'=>false, 'rules'=>array( '<language:\w+>/<controller:\w+>/<id:\d+>'=>'<controller>/view', '<language:\w+>/<controller:\w+>/<action:\w+>/<id:\d+>'=>'<controller>/<action>', '<language:\w+>/<controller:\w+>/<action:\w+>'=>'<controller>/<action>', ), ), <?php // components/MyCUrlManager.php class MyCUrlManager extends CUrlManager { public function createUrl($route,$params=array(),$ampersand='&') { if(isset($_POST['_lang'])){ Yii::app()->language = $_POST['_lang']; }elseif (!isset($route['language']) && $controller != 'srbac'){ $route['language']=Yii::app()->language; }else{ Yii::app()->language = $route['language']; } return parent::createUrl($route, $params, $ampersand); } } ?> class Controller extends CController: { /// ..... function init() { parent::init(); if (isset($_POST['_lang'])) { Yii::app()->setLanguage($_POST['_lang']); Yii::app()->session['_lang'] = Yii::app()->language; }elseif (isset(Yii::app()->session['_lang'])) { Yii::app()->setLanguage(Yii::app()->session['_lang']); } } } class LangBox extends CWidget { public function run() { $currentLang = Yii::app()->language; require_once 'Zend/Locale.php'; $locale = new Zend_Locale(); //$siteLanguages = $this->getLang(); $siteLanguages = array('en','de','tr'); foreach($siteLanguages as $value){ $list[$value] = $locale->getTranslation($value, 'Language', $value); } asort($list); $this->render('langBox', array('currentLang' => $currentLang, 'list'=>$list)); } }

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  • python numpy roll with padding

    - by Marshall Ward
    I'd like to roll a 2D numpy in python, except that I'd like pad the ends with zeros rather than roll the data as if its periodic. Specifically, the following code import numpy as np x = np.array([[1, 2, 3],[4, 5, 6]]) np.roll(x,1,axis=1) returns array([[3, 1, 2],[6, 4, 5]]) but what I would prefer is array([[0, 1, 2], [0, 4, 5]]) I could do this with a few awkward touchups, but I'm hoping that there's a way to do it with fast built-in commands. Thanks

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  • Tableview reload data problem iphone sdk

    - by neha
    Hi all, I have a class A which is a subclass of uitableviewcontroller and one more class B which actually displays my tableview with its content is a subclass of A. There's an xml parser which parses my xml and stores the content in an nsmutablearray of application delegate. Now, I fetch this delegate array into a local nsmutablearray in class B to minimise the communication between the two classes i.e. delegate and class B and display that. After certain condition is met in class A, I'm calling xml parser to refill the delegate array and I'm calling class B's tableview reload method. The problem is when I call the tableview's reload data, class B's delegate methods are called. But before that I need to grab this delegate array in local array in class B. How shall I do that? Can anybody please help? Thanx in advance.

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  • cakephp routing problem, plugin routing works but not others

    - by Paul
    I'm having a strange routing problem with a site I just uploaded, and I've made a number of changes to test what's happening. It doesn't make any sense. My setup is: - I'm using one plugin, which I've included all the routing in the routes.php file. - I've also included the routes for two other controllers, 'events' and 'updates' they look like this: Router::connect('/login', array('plugin' = 'pippoacl', 'controller' = 'users', 'action' = 'login')); Router::connect('/logout', array('plugin' = 'pippoacl', 'controller' = 'users', 'action' = 'logout')); Router::connect( '/events/', array( 'controller' = 'events', 'action' = 'index')); Router::connect('/updates', array('controller' = 'updates', 'action' = 'index')); What happens when I try to get to 'events' is that I get an error message saying: "Not Found Error: The requested address '/Events' was not found on this server." I've checked the database and it's accessible, through the plugin's model/controller/view. I've also made sure the model/controllers for 'events' and 'updates' are there. Can anyone tell me how to trouble shoot this? Thanks, Paul

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  • PHP SimpleXML recursive function to list children and attibutes

    - by Phill Pafford
    I need some help on the SimpleXML calls for a recursive function that lists the elements name and attributes. Making a XML config file system but each script will have it's own config file as well as a new naming convention. So what I need is an easy way to map out all the elements that have attributes, so like in example 1 I need a simple way to call all the processes but I don't know how to do this without hard coding the elements name is the function call. Is there a way to recursively call a function to match a child element name? I did see the xpath functionality but I don't see how to use this for attributes. Any ideas? Also does the XML in the examples look correct? can I structure my XML like this? Example 1: <application> <processes> <process id="123" name="run batch A" /> <process id="122" name="run batch B" /> <process id="129" name="run batch C" /> </processes> <connections> <databases> <database usr="test" pss="test" hst="test" dbn="test" /> </databases> <shells> <ssh usr="test" pss="test" hst="test-2" /> <ssh usr="test" pss="test" hst="test-1" /> </shells> </connections> </application> Example 2: <config> <queues> <queue id="1" name="test" /> <queue id="2" name="production" /> <queue id="3" name="error" /> </queues> </config> Pseudo code: // Would return matching process id getProcess($process_id) { return the process attributes as array that are in the XML } // Would return matching DBN (database name) getDatabase($database_name) { return the database attributes as array that are in the XML } // Would return matching SSH Host getSSHHost($ssh_host) { return the ssh attributes as array that are in the XML } // Would return matching SSH User getSSHUser($ssh_user) { return the ssh attributes as array that are in the XML } // Would return matching Queue getQueue($queue_id) { return the queue attributes as array that are in the XML } EDIT: Can I pass two parms? on the first method you have suggested @Gordon public function findProcessById($id, $name) { $attr = false; $el = $this->xml->xpath("//process[@id='$id']"); // How do I also filter by the name? if($el && count($el) === 1) { $attr = (array) $el[0]->attributes(); $attr = $attr['@attributes']; } return $attr; }

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  • C# Neural Networks with Encog

    - by JoshReuben
    Neural Networks ·       I recently read a book Introduction to Neural Networks for C# , by Jeff Heaton. http://www.amazon.com/Introduction-Neural-Networks-C-2nd/dp/1604390093/ref=sr_1_2?ie=UTF8&s=books&qid=1296821004&sr=8-2-spell. Not the 1st ANN book I've perused, but a nice revision.   ·       Artificial Neural Networks (ANNs) are a mechanism of machine learning – see http://en.wikipedia.org/wiki/Artificial_neural_network , http://en.wikipedia.org/wiki/Category:Machine_learning ·       Problems Not Suited to a Neural Network Solution- Programs that are easily written out as flowcharts consisting of well-defined steps, program logic that is unlikely to change, problems in which you must know exactly how the solution was derived. ·       Problems Suited to a Neural Network – pattern recognition, classification, series prediction, and data mining. Pattern recognition - network attempts to determine if the input data matches a pattern that it has been trained to recognize. Classification - take input samples and classify them into fuzzy groups. ·       As far as machine learning approaches go, I thing SVMs are superior (see http://en.wikipedia.org/wiki/Support_vector_machine ) - a neural network has certain disadvantages in comparison: an ANN can be overtrained, different training sets can produce non-deterministic weights and it is not possible to discern the underlying decision function of an ANN from its weight matrix – they are black box. ·       In this post, I'm not going to go into internals (believe me I know them). An autoassociative network (e.g. a Hopfield network) will echo back a pattern if it is recognized. ·       Under the hood, there is very little maths. In a nutshell - Some simple matrix operations occur during training: the input array is processed (normalized into bipolar values of 1, -1) - transposed from input column vector into a row vector, these are subject to matrix multiplication and then subtraction of the identity matrix to get a contribution matrix. The dot product is taken against the weight matrix to yield a boolean match result. For backpropogation training, a derivative function is required. In learning, hill climbing mechanisms such as Genetic Algorithms and Simulated Annealing are used to escape local minima. For unsupervised training, such as found in Self Organizing Maps used for OCR, Hebbs rule is applied. ·       The purpose of this post is not to mire you in technical and conceptual details, but to show you how to leverage neural networks via an abstraction API - Encog   Encog ·       Encog is a neural network API ·       Links to Encog: http://www.encog.org , http://www.heatonresearch.com/encog, http://www.heatonresearch.com/forum ·       Encog requires .Net 3.5 or higher – there is also a Silverlight version. Third-Party Libraries – log4net and nunit. ·       Encog supports feedforward, recurrent, self-organizing maps, radial basis function and Hopfield neural networks. ·       Encog neural networks, and related data, can be stored in .EG XML files. ·       Encog Workbench allows you to edit, train and visualize neural networks. The Encog Workbench can generate code. Synapses and layers ·       the primary building blocks - Almost every neural network will have, at a minimum, an input and output layer. In some cases, the same layer will function as both input and output layer. ·       To adapt a problem to a neural network, you must determine how to feed the problem into the input layer of a neural network, and receive the solution through the output layer of a neural network. ·       The Input Layer - For each input neuron, one double value is stored. An array is passed as input to a layer. Encog uses the interface INeuralData to hold these arrays. The class BasicNeuralData implements the INeuralData interface. Once the neural network processes the input, an INeuralData based class will be returned from the neural network's output layer. ·       convert a double array into an INeuralData object : INeuralData data = new BasicNeuralData(= new double[10]); ·       the Output Layer- The neural network outputs an array of doubles, wraped in a class based on the INeuralData interface. ·        The real power of a neural network comes from its pattern recognition capabilities. The neural network should be able to produce the desired output even if the input has been slightly distorted. ·       Hidden Layers– optional. between the input and output layers. very much a “black box”. If the structure of the hidden layer is too simple it may not learn the problem. If the structure is too complex, it will learn the problem but will be very slow to train and execute. Some neural networks have no hidden layers. The input layer may be directly connected to the output layer. Further, some neural networks have only a single layer. A single layer neural network has the single layer self-connected. ·       connections, called synapses, contain individual weight matrixes. These values are changed as the neural network learns. Constructing a Neural Network ·       the XOR operator is a frequent “first example” -the “Hello World” application for neural networks. ·       The XOR Operator- only returns true when both inputs differ. 0 XOR 0 = 0 1 XOR 0 = 1 0 XOR 1 = 1 1 XOR 1 = 0 ·       Structuring a Neural Network for XOR  - two inputs to the XOR operator and one output. ·       input: 0.0,0.0 1.0,0.0 0.0,1.0 1.0,1.0 ·       Expected output: 0.0 1.0 1.0 0.0 ·       A Perceptron - a simple feedforward neural network to learn the XOR operator. ·       Because the XOR operator has two inputs and one output, the neural network will follow suit. Additionally, the neural network will have a single hidden layer, with two neurons to help process the data. The choice for 2 neurons in the hidden layer is arbitrary, and often comes down to trial and error. ·       Neuron Diagram for the XOR Network ·       ·       The Encog workbench displays neural networks on a layer-by-layer basis. ·       Encog Layer Diagram for the XOR Network:   ·       Create a BasicNetwork - Three layers are added to this network. the FinalizeStructure method must be called to inform the network that no more layers are to be added. The call to Reset randomizes the weights in the connections between these layers. var network = new BasicNetwork(); network.AddLayer(new BasicLayer(2)); network.AddLayer(new BasicLayer(2)); network.AddLayer(new BasicLayer(1)); network.Structure.FinalizeStructure(); network.Reset(); ·       Neural networks frequently start with a random weight matrix. This provides a starting point for the training methods. These random values will be tested and refined into an acceptable solution. However, sometimes the initial random values are too far off. Sometimes it may be necessary to reset the weights again, if training is ineffective. These weights make up the long-term memory of the neural network. Additionally, some layers have threshold values that also contribute to the long-term memory of the neural network. Some neural networks also contain context layers, which give the neural network a short-term memory as well. The neural network learns by modifying these weight and threshold values. ·       Now that the neural network has been created, it must be trained. Training a Neural Network ·       construct a INeuralDataSet object - contains the input array and the expected output array (of corresponding range). Even though there is only one output value, we must still use a two-dimensional array to represent the output. public static double[][] XOR_INPUT ={ new double[2] { 0.0, 0.0 }, new double[2] { 1.0, 0.0 }, new double[2] { 0.0, 1.0 }, new double[2] { 1.0, 1.0 } };   public static double[][] XOR_IDEAL = { new double[1] { 0.0 }, new double[1] { 1.0 }, new double[1] { 1.0 }, new double[1] { 0.0 } };   INeuralDataSet trainingSet = new BasicNeuralDataSet(XOR_INPUT, XOR_IDEAL); ·       Training is the process where the neural network's weights are adjusted to better produce the expected output. Training will continue for many iterations, until the error rate of the network is below an acceptable level. Encog supports many different types of training. Resilient Propagation (RPROP) - general-purpose training algorithm. All training classes implement the ITrain interface. The RPROP algorithm is implemented by the ResilientPropagation class. Training the neural network involves calling the Iteration method on the ITrain class until the error is below a specific value. The code loops through as many iterations, or epochs, as it takes to get the error rate for the neural network to be below 1%. Once the neural network has been trained, it is ready for use. ITrain train = new ResilientPropagation(network, trainingSet);   for (int epoch=0; epoch < 10000; epoch++) { train.Iteration(); Debug.Print("Epoch #" + epoch + " Error:" + train.Error); if (train.Error > 0.01) break; } Executing a Neural Network ·       Call the Compute method on the BasicNetwork class. Console.WriteLine("Neural Network Results:"); foreach (INeuralDataPair pair in trainingSet) { INeuralData output = network.Compute(pair.Input); Console.WriteLine(pair.Input[0] + "," + pair.Input[1] + ", actual=" + output[0] + ",ideal=" + pair.Ideal[0]); } ·       The Compute method accepts an INeuralData class and also returns a INeuralData object. Neural Network Results: 0.0,0.0, actual=0.002782538818034049,ideal=0.0 1.0,0.0, actual=0.9903741937121177,ideal=1.0 0.0,1.0, actual=0.9836807956566187,ideal=1.0 1.0,1.0, actual=0.0011646072586172778,ideal=0.0 ·       the network has not been trained to give the exact results. This is normal. Because the network was trained to 1% error, each of the results will also be within generally 1% of the expected value.

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  • [AS3/C#] Byte encryption ( DES-CBC zero pad )

    - by mark_dj
    Hi there, Currently writing my own AMF TcpSocketServer. Everything works good so far i can send and recieve objects and i use some serialization/deserialization code. Now i started working on the encryption code and i am not so familiar with this stuff. I work with bytes , is DES-CBC a good way to encrypt this stuff? Or are there other more performant/secure ways to send my data? Note that performance is a must :). When i call: ReadAmf3Object with the decrypter specified i get an: InvalidOperationException thrown by my ReadAmf3Object function when i read out the first byte the Amf3TypeCode isn't specified ( they range from 0 to 16 i believe (Bool, String, Int, DateTime, etc) ). I got Typecodes varying from 97 to 254? Anyone knows whats going wrong? I think it has something to do with the encryption part. Since the deserializer works fine w/o the encryption. I am using the right padding/mode/key? I used: http://code.google.com/p/as3crypto/ as as3 encryption/decryption library. And i wrote an Async tcp server with some abuse of the threadpool ;) Anyway here some code: C# crypter initalization code System.Security.Cryptography.DESCryptoServiceProvider crypter = new DESCryptoServiceProvider(); crypter.Padding = PaddingMode.Zeros; crypter.Mode = CipherMode.CBC; crypter.Key = Encoding.ASCII.GetBytes("TESTTEST"); AS3 private static var _KEY:ByteArray = Hex.toArray(Hex.fromString("TESTTEST")); private static var _TYPE:String = "des-cbc"; public static function encrypt(array:ByteArray):ByteArray { var pad:IPad = new NullPad; var mode:ICipher = Crypto.getCipher(_TYPE, _KEY, pad); pad.setBlockSize(mode.getBlockSize()); mode.encrypt(array); return array; } public static function decrypt(array:ByteArray):ByteArray { var pad:IPad = new NullPad; var mode:ICipher = Crypto.getCipher(_TYPE, _KEY, pad); pad.setBlockSize(mode.getBlockSize()); mode.decrypt(array); return array; } C# read/unserialize/decrypt code public override object Read(int length) { object d; using (MemoryStream stream = new MemoryStream()) { stream.Write(this._readBuffer, 0, length); stream.Position = 0; if (this.Decrypter != null) { using (CryptoStream c = new CryptoStream(stream, this.Decrypter, CryptoStreamMode.Read)) using (AmfReader reader = new AmfReader(c)) { d = reader.ReadAmf3Object(); } } else { using (AmfReader reader = new AmfReader(stream)) { d = reader.ReadAmf3Object(); } } } return d; }

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  • CakePHP: 2-level JOIN with one Query

    - by Daniel Magliola
    I have the following models in CakePHP: A Deposit belongs to an Account An Account belongs to a Customer I want to have a list of Deposits, and I need to show the name of the customer (so I have to join through the Customer). I also need to paginate this list. If I set Deposit->recursive = 2, I can get the Customer, however, CakePHP runs one query joining Deposit and Account, and then runs one query per each Deposit, to get the Customer. How can I make it get both models with only one query? I tried this, but it didn't work: $this->paginate = array('joins' => array( array( 'table' => 'customers', 'alias' => 'AccountCustomer', 'type' => 'inner', 'foreignKey' => false, 'conditions' => array('Account.customer_id = AccountCustomer.id') ) )); Any ideas? Thanks! Daniel

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