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  • Simple Query tuning with STATISTICS IO and Execution plans

    A great deal can be gleaned from the use of the STATISTICS IO and the execution plan, when you are checking that a query is performing properly. Josef Richberg, the current holder of the 'Exceptional DBA' award, explains how an apparently draconian IT policy turns out to be a useful ways of ensuring that Stored Procedures are carefully checked for performance before they are released

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  • Here’s a Super Simple Trick to Defeating Fake Anti-Virus Malware

    - by The Geek
    You might be wondering why we have a screenshot of what appears to be AVG Anti-Virus, but is in fact a fake anti-virus malware that holds your computer hostage until you pay them. Here’s a really simple tip to defeating these types of malware, and a quick review of other options. Not sure what we’re talking about? Be sure to check out our previous articles on cleaning up fake antivirus infections. How To Remove Internet Security 2010 and other Rogue/Fake Antivirus Malware How To Remove Antivirus Live and Other Rogue/Fake Antivirus Malware How To Remove Advanced Virus Remover and Other Rogue/Fake Antivirus Malware How To Remove Security Tool and other Rogue/Fake Antivirus Malware So what’s the problem? Can’t you just run a anti-virus scan? Well… it’s not quite that simple. What actually happens is that these pieces of malware block you from running almost anything on your PC, and often prevent you from running apps from a Flash drive, with an error like this: Once you encounter this error, there’s a couple things you can do. The first one is almost stupidly simple, and works some of the time Latest Features How-To Geek ETC Here’s a Super Simple Trick to Defeating Fake Anti-Virus Malware How to Change the Default Application for Android Tasks Stop Believing TV’s Lies: The Real Truth About "Enhancing" Images The How-To Geek Valentine’s Day Gift Guide Inspire Geek Love with These Hilarious Geek Valentines RGB? CMYK? Alpha? What Are Image Channels and What Do They Mean? Project M Brings Classic Super Smash Bro Style Gameplay to the Wii Now Together and Complete – McBain: The Movie [Simpsons Video] Be Creative by Using Hex and RGB Codes for Crayola Crayon Colors on Your Next Web or Art Project [Geek Fun] Flash Updates; Finally Supports Full Screen Video on Multiple Monitors 22 Ways to Recycle an Altoids Mint Tin Make Your Desktop Go Native with the Tribal Arts Theme for Windows 7

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  • How to manage focus for a small set of simple widgets

    - by Christoph
    I'm developing a set of simple widgets for a small (128x128) display. For example I'd like to have a main screen with an overlay menu which I can use to toggle visibilty of main screen elements. Each option would be an icon with a box around it while it is selected. Button (left, up, right, down, enter) events should be given to the widget that has "focus". Focus is a simple thing to understand when using a GUI, but I'm having trouble implementing this. Can you suggest a simple concept for managing focus and input events? I have these simple ideas: Only one widget can have focus, so I need a single pointer to that widget. When this widget gets some kind of "cycle" input (as in "highlight the next item in this list"), the focus is given to a different widget. a widget must have a way of telling the application which widget the focus is given to next. if a widget cannot give a "next focus" hint, the application must be able to figure out where the focus should go. Widgets are currently structured like this: A widget can have a parent, which is passed to the constructor. Widgets are created statically, as I want to avoid dynamic memory allocation (I only have 16kB of RAM and I'd like to have control over that). widgets have siblings, implemented as an intrusive linked list (they have a next member). A parent has a pointer to the head of its list of children. Input events are arguments to the widgets buttonEvent methods which can accept or ignore that event. If it ignores the event, it can pass the event to its parent. My Questions: How can I manage focus for these widgets? Am I making this too complicated?

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  • How to make my simple round sprite look right in XNA

    - by Joshua Perina
    Ok, I'm very new to graphics programming (but not new to coding). I'm trying to load a simple image in XNA which I can do fine. It is a simple round circle which I made in photoshop. The problem is the edges show up rough when I draw it on the screen even with the exact size. The anti-aliasing is missing. I'm sure I'm missing something very simple: GraphicsDevice.Clear(Color.Black); // TODO: Add your drawing code here spriteBatch.Begin(); spriteBatch.Draw(circle, new Rectangle(10, 10, 10, 10), Color.White); spriteBatch.End(); Couldn't post picture because I'm a first time poster. But my smooth png circle has rough edges. So I found that if I added: spriteBatch.Begin(SpriteSortMode.FrontToBack, BlendState.NonPremultiplied); I can get a smooth image when the image is the same size as the original png. But if I want to scale that image up or down then the rough edges return. How do I get XNA to smoothly resize my simple round image to a smaller size without getting the rough edges?

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  • Complex, yet simple crafting system model

    - by KatShot
    I'm working on some arcade shooter/slasher, and the main logline is "Kick'em with everything you want". There's not so many enemies in GDD, main focus is on tons of weapons and gadgets to cause mayhem. To get weapon, you need to craft it, and now crafting system looks simple, like: 1) You got three slots for weapon parts (like A, B, C) 2) You collect misc weapon parts, and when you got atleast one for every slot, you can craft a weapon (for example, if you got A1, B1, B2, B3 and C1, you can craft such models - A1B1C1, A1B2C1, A1B3C1) As for me, this crafting system is too simple, because weapon parts will just fall from the top of screen, often enough. That's why I'm thinking about adding some more crafting system levels, like resources (collect 10 scrap pieces to make part A1 or C3), etc. My question is: How can i add some more complex, still simple, transparent levels in crafting system? upd. For example, in Minecraft or Terraria, first 5-10 crafting recipies quite transparent and simple IMHO. But then it turns into huge mess to understand, how to craft this or that (for example, fishing rod)

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  • Pancake.io Is a Dead Simple Way to Host a Web Site from Your Dropbox Account

    - by Jason Fitzpatrick
    Pancake.io is a web-based app that makes it dead simple to use your Dropbox account as as simple web host. Signup for an account and Pancake.io creates a folder in your Dropbox. You can modify the page in one of two ways: you can simply put files into the folder and use the simple template provided by Pancake.io to share them or you can edit the template (located in the Pancake.io folder) to customize the page. Hit up the link below to read more about Pancake.io and take it for a test drive. Pancake.io [via ReadWriteWeb] HTG Explains: How Hackers Take Over Web Sites with SQL Injection / DDoS Use Your Android Phone to Comparison Shop: 4 Scanner Apps Reviewed How to Run Android Apps on Your Desktop the Easy Way

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  • Which simple Java JPA ORM tool to use ?

    - by Guillaume
    What Java ORM library implementing JPA that match following criteria would you recommend and why ? free & open source alive (at least bug fixes and a mailing list) with good documentation simple not hibernate (this one is well-known :-) ) I need to select a simple ORM tool that can be set up in minutes without and easy to understand for setting simple CRUD daos. A query builder ill be an interesting plus. Later I can have to move to Hibernate, that's why being JPA compliant is a must. I have found some candidates on the web, but not so much feedback, so I will gladly take your advices on the topic. ----- EDIT --------- I have been successfully testing ebean/avaje with a small test cases. Any one has a feedback on using this tool in production ?

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  • Toastr Is a Simple Reminder-on-Unlock Tool for Android

    - by Jason Fitzpatrick
    Android: if you’re looking for a dead simple reminder tool, Toastr pops up a reminder when you unlock your lock screen. While there’s no shortage of calendar and reminder tools in the Android Market, most of them are overkill if all you want to set up is a simple pop-up reminder. Toastr is a free app (the premium option unlocks minor tweaks like the ability to alter the font) that allows you to set a simple pop-up notification that persists for a few seconds after you unlock your phone. Toastr [via Addictive Tips] HTG Explains: Why Linux Doesn’t Need Defragmenting How to Convert News Feeds to Ebooks with Calibre How To Customize Your Wallpaper with Google Image Searches, RSS Feeds, and More

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  • Is SimplePHPBlog a secure blogging engine?

    - by authentictech
    Has anyone used the blog engine SimplePHPBlog? It is a simple blog engine that uses only text files (no database). My problem with it is that the content directory where the texts files are stored appears to require being world writeable/readable (i.e. permission 777) for it to work. This means anyone can access the text files with a browser! These text files include the blog/comment poster's IP and email address! This is not secure or good practice, right?

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  • Which simple Java JPA ORM tool to use ?

    - by Guillaume
    What Java ORM library implementing JPA that match following criteria would you recommend and why ? free & open source alive (at least bug fixes and a mailing list) with good documentation simple (simpler than hibernate) I need to select a simple ORM tool that can be set up in minutes, without too much configuration and easy to understand, for setting simple CRUD DAOs. A query builder will be an interesting plus. Later I can have to move to Hibernate, that's why being JPA compliant is a must. I have found some candidates on the web, but not so much feedback, so I will gladly take your advices on the topic. ----- EDIT --------- I have been successfully testing ebean/avaje with a small test cases. Any one has a feedback on using these tools in production ?

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  • Simple form validation

    - by ElendilTheTall
    Hi, I have a site with a simple contact form using ASP for customers to e-mail quote requests. However, I'm getting quite a few messages through with no contact information; I think people assume that their e-mail address is coming through automatically. I'd like a simple way to make the e-mail and/or telephone number fields required, preferably so that the fields are highlighted as such if they're submitted without anything in them. I've Googled for this but they seem either too simple, diverting people to a separate page and requiring a 'back click', or incredibly complicated with massive reams of code. Any suggestions?

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  • place to host a simple php socket server

    - by bonusbox
    i am running a small project that occasionally requires me to run a php socket script through ssh. it uses a few bytes of bandwidth (just some text) which activates my art installation project. i tried a simple web hosting plan but that didn't support sockets, so know i am using a 32$ vps plan on namecheap.com just to run a simple php script. i don't really need to host anything else on it. i find it kind of excessive for such a simple thing. is there a place i can run my script for a lower cost? any servers that support php sockets and ssh?

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  • Integrating Simple Machines Forum in my custom membership site - login not working?

    - by Ali
    Hi guys I'm trying to integrate simple machines forum into my custom made membership website. I'm using the SMF API which is available here at http://download.simplemachines.org/?tools. The thing is that its working on my localhost testing server - however on my online server where the system is hosted - its not working. I have set it up so that when the user log into my own custom CMS membership site, he/she is logged in automatically to his/her corresponding account on the forum. However it works on my localhost but online its not working at all.. I log into my site and then browse to the forum to find out I havent been logged in there :( - I think its not creating the cookies or registering the session.. where should I look here. Please do help.

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  • Android question. Is there a link to a simple example of changing the screen brightness for an activ

    - by John
    There are apparently at least three different techniques for changing screen brightness in the Android OS. Two of them no longer work post-cupcake and the third accepted technique evidently has a bug. I would like to increase screen brightness at the start of a one-view activity then turn the brightness back to the user setting at the end of the activity. No buttons, no second view or second activity. Just a maxed brightness at start and a return to original brightness setting at the end of the activity. The examples of the current technique using WindowManager.LayoutParams that I have located range from 2 lines of code WindowManager.LayoutParams lp = getWindow().getAttributes(); lp.screenBrightness = 100 / 100.0f; getWindow().setAttributes(lp); to several pages of source code and numerous activities. Is there a simple example of maxing the screen brightness at start that someone can provide a link to? Thank you for reading my question.

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  • Creating a Simple PHP Blog in Azure

    - by Josh Holmes
    In this post, I want to walk through creating a simple Azure application that will show a few pages, leverage Blob storage, Table storage and generally get you started doing PHP on Azure development. In short, we are going to write a very simple PHP Blog engine for Azure. To be very clear, this is not a pro blog engine and I don’t recommend using it in production. It’s a » read more.

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  • Simple Javascript Animation Framework

    A simple framework for performing simple animations in javascript....Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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  • iTorque for a simple arcade game

    - by Herfus
    I have a basic understanding of programming, but I am no programmer. I've had a couple of a semesters with java programming, so we're talking pretty basic here. I have some scripting experience with game editors where I've created a few (simple) encounters, boss AI, abilities, events and so on. I've mostly done level design with UDK, Source and several other toolsets for a few years now, but I'd like to divert some of the focus to iphone-development. I've participated in a few development projects (source, udk, daot) where I've had a variety of roles (yet never beyond simple scripting). I have just finished prototyping an Iphone game (using game maker) and begun a bit more precise planning on what I'll have to do for the real version. The game is fairly simple, perhaps the best comparison in scope and complexity would be Doodlejump for iPhone. The reason I created the prototype was not just to answer a few questions about the gameplay, but to get some insight into what kind of problems I might face when trying to develop the real thing. I've been looking for engines that I can use for this. iTorque looks, so far, like the best option with a scripting language and WYSIWYG-editor. However the price is fairly steep and I'd like to prepare myself as much as possible before jumping into this, which is why I'm going to ask a few questions here. What kind of difficulties do you think I might run into, considering what you've read so far? Not just with torque, but development in general. I'm making this question mostly to have someone to reality check me. I usually achieve to do what I'm trying to do with scripting, but something tells me there's a very big difference between scripting an AI or an event and creating game logic. Will it be too much of a leap? Just how simple is it to use the Torque scripting language? Obviously I don't expect to be prepared, I expect it to be a learning process. However, I'd still like to be at least a bit confident on the time I'll have to dedicate to this first.

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  • Simple Web Marketing, Search Engine Optimization Strategies For an Online Small Business

    There are a number of simple web marketing, search engine optimization strategies you should keep in mind when you are dealing with an online small business. Regardless of whether you are an offline small business entrepreneur with a company website or, exclusively, an online small-business entrepreneur, these are the simple web marketing, search engine optimization guidelines you ought to keep in mind.

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  • Check If a SQL Server Database Is In Pseudo-Simple Recovery Model Using Windows PowerShell

    Check if databases are really in FULL recovery model with a recovery model called pseudo-simple, where the database still behaves like it is still in SIMPLE recovery model until a full database backup is taken. Get your SQL Server database under version control now!Version control is standard for applications, but databases haven’t caught up. So how can you bring database development up to speed? Why should you start? Find out…

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  • ASP.NET Web API and Simple Value Parameters from POSTed data

    - by Rick Strahl
    In testing out various features of Web API I've found a few oddities in the way that the serialization is handled. These are probably not super common but they may throw you for a loop. Here's what I found. Simple Parameters from Xml or JSON Content Web API makes it very easy to create action methods that accept parameters that are automatically parsed from XML or JSON request bodies. For example, you can send a JavaScript JSON object to the server and Web API happily deserializes it for you. This works just fine:public string ReturnAlbumInfo(Album album) { return album.AlbumName + " (" + album.YearReleased.ToString() + ")"; } However, if you have methods that accept simple parameter types like strings, dates, number etc., those methods don't receive their parameters from XML or JSON body by default and you may end up with failures. Take the following two very simple methods:public string ReturnString(string message) { return message; } public HttpResponseMessage ReturnDateTime(DateTime time) { return Request.CreateResponse<DateTime>(HttpStatusCode.OK, time); } The first one accepts a string and if called with a JSON string from the client like this:var client = new HttpClient(); var result = client.PostAsJsonAsync<string>(http://rasxps/AspNetWebApi/albums/rpc/ReturnString, "Hello World").Result; which results in a trace like this: POST http://rasxps/AspNetWebApi/albums/rpc/ReturnString HTTP/1.1Content-Type: application/json; charset=utf-8Host: rasxpsContent-Length: 13Expect: 100-continueConnection: Keep-Alive "Hello World" produces… wait for it: null. Sending a date in the same fashion:var client = new HttpClient(); var result = client.PostAsJsonAsync<DateTime>(http://rasxps/AspNetWebApi/albums/rpc/ReturnDateTime, new DateTime(2012, 1, 1)).Result; results in this trace: POST http://rasxps/AspNetWebApi/albums/rpc/ReturnDateTime HTTP/1.1Content-Type: application/json; charset=utf-8Host: rasxpsContent-Length: 30Expect: 100-continueConnection: Keep-Alive "\/Date(1325412000000-1000)\/" (yes still the ugly MS AJAX date, yuk! This will supposedly change by RTM with Json.net used for client serialization) produces an error response: The parameters dictionary contains a null entry for parameter 'time' of non-nullable type 'System.DateTime' for method 'System.Net.Http.HttpResponseMessage ReturnDateTime(System.DateTime)' in 'AspNetWebApi.Controllers.AlbumApiController'. An optional parameter must be a reference type, a nullable type, or be declared as an optional parameter. Basically any simple parameters are not parsed properly resulting in null being sent to the method. For the string the call doesn't fail, but for the non-nullable date it produces an error because the method can't handle a null value. This behavior is a bit unexpected to say the least, but there's a simple solution to make this work using an explicit [FromBody] attribute:public string ReturnString([FromBody] string message) andpublic HttpResponseMessage ReturnDateTime([FromBody] DateTime time) which explicitly instructs Web API to read the value from the body. UrlEncoded Form Variable Parsing Another similar issue I ran into is with POST Form Variable binding. Web API can retrieve parameters from the QueryString and Route Values but it doesn't explicitly map parameters from POST values either. Taking our same ReturnString function from earlier and posting a message POST variable like this:var formVars = new Dictionary<string,string>(); formVars.Add("message", "Some Value"); var content = new FormUrlEncodedContent(formVars); var client = new HttpClient(); var result = client.PostAsync(http://rasxps/AspNetWebApi/albums/rpc/ReturnString, content).Result; which produces this trace: POST http://rasxps/AspNetWebApi/albums/rpc/ReturnString HTTP/1.1Content-Type: application/x-www-form-urlencodedHost: rasxpsContent-Length: 18Expect: 100-continue message=Some+Value When calling ReturnString:public string ReturnString(string message) { return message; } unfortunately it does not map the message value to the message parameter. This sort of mapping unfortunately is not available in Web API. Web API does support binding to form variables but only as part of model binding, which binds object properties to the POST variables. Sending the same message as in the previous example you can use the following code to pick up POST variable data:public string ReturnMessageModel(MessageModel model) { return model.Message; } public class MessageModel { public string Message { get; set; }} Note that the model is bound and the message form variable is mapped to the Message property as would other variables to properties if there were more. This works but it's not very dynamic. There's no real easy way to retrieve form variables (or query string values for that matter) in Web API's Request object as far as I can discern. Well only if you consider this easy:public string ReturnString() { var formData = Request.Content.ReadAsAsync<FormDataCollection>().Result; return formData.Get("message"); } Oddly FormDataCollection does not allow for indexers to work so you have to use the .Get() method which is rather odd. If you're running under IIS/Cassini you can always resort to the old and trusty HttpContext access for request data:public string ReturnString() { return HttpContext.Current.Request.Form["message"]; } which works fine and is easier. It's kind of a bummer that HttpRequestMessage doesn't expose some sort of raw Request object that has access to dynamic data - given that it's meant to serve as a generic REST/HTTP API that seems like a crucial missing piece. I don't see any way to read query string values either. To me personally HttpContext works, since I don't see myself using self-hosted code much.© Rick Strahl, West Wind Technologies, 2005-2012Posted in Web Api   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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  • SIMPLE PHP MVC Framework!

    - by Allen
    I need a simple and basic MVC example to get me started. I dont want to use any of the available packaged frameworks. I am in need of a simple example of a simple PHP MVC framework that would allow, at most, the basic creation of a simple multi-page site. I am asking for a simple example because I learn best from simple real world examples. Big popular frameworks (such as code ignighter) are to much for me to even try to understand and any other "simple" example I have found are not well explained or seem a little sketchy in general. I should add that most examples of simple MVC frameworks I see use mod_rewrite (for URL routing) or some other Apache-only method. I run PHP on IIS. I need to be able to understand a basic MVC framework, so that I could develop my own that would allow me to easily extend functionality with classes. I am at the point where I understand basic design patterns and MVC pretty well. I understand them in theory, but when it comes down to actually building a real world, simple, well designed MVC framework in PHP, i'm stuck. I would really appreciate some help! Edit: I just want to note that I am looking for a simple example that an experienced programmer could whip up in under an hour. I mean simple as in bare bones simple. I dont want to use any huge frameworks, I am trying to roll my own. I need a decent SIMPLE example to get me going.

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  • SIMPLE PHP MVC Framework [closed]

    - by Allen
    I need a simple and basic MVC example to get me started. I don't want to use any of the available packaged frameworks. I am in need of a simple example of a simple PHP MVC framework that would allow, at most, the basic creation of a simple multi-page site. I am asking for a simple example because I learn best from simple real world examples. Big popular frameworks (such as code igniter) are to much for me to even try to understand and any other "simple" example I have found are not well explained or seem a little sketchy in general. I should add that most examples of simple MVC frameworks I see use mod_rewrite (for URL routing) or some other Apache-only method. I run PHP on IIS. I need to be able to understand a basic MVC framework, so that I could develop my own that would allow me to easily extend functionality with classes. I am at the point where I understand basic design patterns and MVC pretty well. I understand them in theory, but when it comes down to actually building a real world, simple, well designed MVC framework in PHP, I'm stuck. Edit: I just want to note that I am looking for a simple example that an experienced programmer could whip up in under an hour. I mean simple as in bare bones simple. I don't want to use any huge frameworks, I am trying to roll my own. I need a decent SIMPLE example to get me going.

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  • Parallelism in .NET – Part 2, Simple Imperative Data Parallelism

    - by Reed
    In my discussion of Decomposition of the problem space, I mentioned that Data Decomposition is often the simplest abstraction to use when trying to parallelize a routine.  If a problem can be decomposed based off the data, we will often want to use what MSDN refers to as Data Parallelism as our strategy for implementing our routine.  The Task Parallel Library in .NET 4 makes implementing Data Parallelism, for most cases, very simple. Data Parallelism is the main technique we use to parallelize a routine which can be decomposed based off data.  Data Parallelism refers to taking a single collection of data, and having a single operation be performed concurrently on elements in the collection.  One side note here: Data Parallelism is also sometimes referred to as the Loop Parallelism Pattern or Loop-level Parallelism.  In general, for this series, I will try to use the terminology used in the MSDN Documentation for the Task Parallel Library.  This should make it easier to investigate these topics in more detail. Once we’ve determined we have a problem that, potentially, can be decomposed based on data, implementation using Data Parallelism in the TPL is quite simple.  Let’s take our example from the Data Decomposition discussion – a simple contrast stretching filter.  Here, we have a collection of data (pixels), and we need to run a simple operation on each element of the pixel.  Once we know the minimum and maximum values, we most likely would have some simple code like the following: for (int row=0; row < pixelData.GetUpperBound(0); ++row) { for (int col=0; col < pixelData.GetUpperBound(1); ++col) { pixelData[row, col] = AdjustContrast(pixelData[row, col], minPixel, maxPixel); } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } This simple routine loops through a two dimensional array of pixelData, and calls the AdjustContrast routine on each pixel. As I mentioned, when you’re decomposing a problem space, most iteration statements are potentially candidates for data decomposition.  Here, we’re using two for loops – one looping through rows in the image, and a second nested loop iterating through the columns.  We then perform one, independent operation on each element based on those loop positions. This is a prime candidate – we have no shared data, no dependencies on anything but the pixel which we want to change.  Since we’re using a for loop, we can easily parallelize this using the Parallel.For method in the TPL: Parallel.For(0, pixelData.GetUpperBound(0), row => { for (int col=0; col < pixelData.GetUpperBound(1); ++col) { pixelData[row, col] = AdjustContrast(pixelData[row, col], minPixel, maxPixel); } }); Here, by simply changing our first for loop to a call to Parallel.For, we can parallelize this portion of our routine.  Parallel.For works, as do many methods in the TPL, by creating a delegate and using it as an argument to a method.  In this case, our for loop iteration block becomes a delegate creating via a lambda expression.  This lets you write code that, superficially, looks similar to the familiar for loop, but functions quite differently at runtime. We could easily do this to our second for loop as well, but that may not be a good idea.  There is a balance to be struck when writing parallel code.  We want to have enough work items to keep all of our processors busy, but the more we partition our data, the more overhead we introduce.  In this case, we have an image of data – most likely hundreds of pixels in both dimensions.  By just parallelizing our first loop, each row of pixels can be run as a single task.  With hundreds of rows of data, we are providing fine enough granularity to keep all of our processors busy. If we parallelize both loops, we’re potentially creating millions of independent tasks.  This introduces extra overhead with no extra gain, and will actually reduce our overall performance.  This leads to my first guideline when writing parallel code: Partition your problem into enough tasks to keep each processor busy throughout the operation, but not more than necessary to keep each processor busy. Also note that I parallelized the outer loop.  I could have just as easily partitioned the inner loop.  However, partitioning the inner loop would have led to many more discrete work items, each with a smaller amount of work (operate on one pixel instead of one row of pixels).  My second guideline when writing parallel code reflects this: Partition your problem in a way to place the most work possible into each task. This typically means, in practice, that you will want to parallelize the routine at the “highest” point possible in the routine, typically the outermost loop.  If you’re looking at parallelizing methods which call other methods, you’ll want to try to partition your work high up in the stack – as you get into lower level methods, the performance impact of parallelizing your routines may not overcome the overhead introduced. Parallel.For works great for situations where we know the number of elements we’re going to process in advance.  If we’re iterating through an IList<T> or an array, this is a typical approach.  However, there are other iteration statements common in C#.  In many situations, we’ll use foreach instead of a for loop.  This can be more understandable and easier to read, but also has the advantage of working with collections which only implement IEnumerable<T>, where we do not know the number of elements involved in advance. As an example, lets take the following situation.  Say we have a collection of Customers, and we want to iterate through each customer, check some information about the customer, and if a certain case is met, send an email to the customer and update our instance to reflect this change.  Normally, this might look something like: foreach(var customer in customers) { // Run some process that takes some time... DateTime lastContact = theStore.GetLastContact(customer); TimeSpan timeSinceContact = DateTime.Now - lastContact; // If it's been more than two weeks, send an email, and update... if (timeSinceContact.Days > 14) { theStore.EmailCustomer(customer); customer.LastEmailContact = DateTime.Now; } } Here, we’re doing a fair amount of work for each customer in our collection, but we don’t know how many customers exist.  If we assume that theStore.GetLastContact(customer) and theStore.EmailCustomer(customer) are both side-effect free, thread safe operations, we could parallelize this using Parallel.ForEach: Parallel.ForEach(customers, customer => { // Run some process that takes some time... DateTime lastContact = theStore.GetLastContact(customer); TimeSpan timeSinceContact = DateTime.Now - lastContact; // If it's been more than two weeks, send an email, and update... if (timeSinceContact.Days > 14) { theStore.EmailCustomer(customer); customer.LastEmailContact = DateTime.Now; } }); Just like Parallel.For, we rework our loop into a method call accepting a delegate created via a lambda expression.  This keeps our new code very similar to our original iteration statement, however, this will now execute in parallel.  The same guidelines apply with Parallel.ForEach as with Parallel.For. The other iteration statements, do and while, do not have direct equivalents in the Task Parallel Library.  These, however, are very easy to implement using Parallel.ForEach and the yield keyword. Most applications can benefit from implementing some form of Data Parallelism.  Iterating through collections and performing “work” is a very common pattern in nearly every application.  When the problem can be decomposed by data, we often can parallelize the workload by merely changing foreach statements to Parallel.ForEach method calls, and for loops to Parallel.For method calls.  Any time your program operates on a collection, and does a set of work on each item in the collection where that work is not dependent on other information, you very likely have an opportunity to parallelize your routine.

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  • Jailbreak Your Kindle for Dead Simple Screensaver Customization

    - by Jason Fitzpatrick
    If you’re less than delighted with the default screensaver pack on the Kindle relief is just a simple hack and a reboot away. Read on to learn how to apply a painless jailbreak to your Kindle and create custom screensavers. Unlike jailbreaking other devices like the iPad and Android devices—which usually includes deep mucking about in the guts of your devices and the potential, however remote, for catastrophic bricking—jailbreaking the Kindle is not only extremely safe but Amazon, by releasing the Kindle sourcecode, has practically approved the process with a wink and a nod. Installing the jailbreak and the screensaver hack to replace the default screensavers is so simple we promise you’ll spend 1000% more time messing around making fun screensaver images than you will actually installing the hack. The default screensaver pack for the Amazon Kindle is a collection of 23 images that include portraits of famous authors, woodcarvings from centuries past, blueprints, book reliefs, and other suitably literature-oriented subjects. If you’re not a big fan of the pack—and we don’t blame you if, despite Emily Dickinson being your favorite single lady, you want to mix things up—it’s extremely simple to replace the default screen saver pack with as many custom images as your Kindle can hold. This hack works on every Kindle except the first generation; we’ll be demonstrating it on the brand new Kindle 3 with accompanying notes to direct users with older Kindles. Latest Features How-To Geek ETC The How-To Geek Holiday Gift Guide (Geeky Stuff We Like) LCD? LED? Plasma? The How-To Geek Guide to HDTV Technology The How-To Geek Guide to Learning Photoshop, Part 8: Filters Improve Digital Photography by Calibrating Your Monitor Our Favorite Tech: What We’re Thankful For at How-To Geek The How-To Geek Guide to Learning Photoshop, Part 7: Design and Typography Happy Snow Bears Theme for Chrome and Iron [Holiday] Download Full Command and Conquer: Tiberian Sun Game for Free Scorched Cometary Planet Wallpaper Quick Fix: Add the RSS Button Back to the Firefox Awesome Bar Dropbox Desktop Client 1.0.0 RC for Windows, Linux, and Mac Released Hang in There Scrat! – Ice Age Wallpaper

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