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  • KVM guest io is much slower than host io: is that normal?

    - by Evolver
    I have a Qemu-KVM host system setup on CentOS 6.3. Four 1TB SATA HDDs working in Software RAID10. Guest CentOS 6.3 is installed on separate LVM. People say that they see guest performance almost equal to host performance, but I don't see that. My i/o tests are showing 30-70% slower performance on guest than on host system. I tried to change scheduler (set elevator=deadline on host and elevator=noop on guest), set blkio.weight to 1000 in cgroup, change io to virtio... But none of these changes gave me any significant results. This is a guest .xml config part: <disk type='file' device='disk'> <driver name='qemu' type='raw'/> <source file='/dev/vgkvmnode/lv2'/> <target dev='vda' bus='virtio'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0'/> </disk> There are my tests: Host system: iozone test # iozone -a -i0 -i1 -i2 -s8G -r64k random random KB reclen write rewrite read reread read write 8388608 64 189930 197436 266786 267254 28644 66642 dd read test: one process and then four simultaneous processes # dd if=/dev/vgkvmnode/lv2 of=/dev/null bs=1M count=1024 iflag=direct 1073741824 bytes (1.1 GB) copied, 4.23044 s, 254 MB/s # dd if=/dev/vgkvmnode/lv2 of=/dev/null bs=1M count=1024 iflag=direct skip=1024 & dd if=/dev/vgkvmnode/lv2 of=/dev/null bs=1M count=1024 iflag=direct skip=2048 & dd if=/dev/vgkvmnode/lv2 of=/dev/null bs=1M count=1024 iflag=direct skip=3072 & dd if=/dev/vgkvmnode/lv2 of=/dev/null bs=1M count=1024 iflag=direct skip=4096 1073741824 bytes (1.1 GB) copied, 14.4528 s, 74.3 MB/s 1073741824 bytes (1.1 GB) copied, 14.562 s, 73.7 MB/s 1073741824 bytes (1.1 GB) copied, 14.6341 s, 73.4 MB/s 1073741824 bytes (1.1 GB) copied, 14.7006 s, 73.0 MB/s dd write test: one process and then four simultaneous processes # dd if=/dev/zero of=test bs=1M count=1024 oflag=direct 1073741824 bytes (1.1 GB) copied, 6.2039 s, 173 MB/s # dd if=/dev/zero of=test bs=1M count=1024 oflag=direct & dd if=/dev/zero of=test2 bs=1M count=1024 oflag=direct & dd if=/dev/zero of=test3 bs=1M count=1024 oflag=direct & dd if=/dev/zero of=test4 bs=1M count=1024 oflag=direct 1073741824 bytes (1.1 GB) copied, 32.7173 s, 32.8 MB/s 1073741824 bytes (1.1 GB) copied, 32.8868 s, 32.6 MB/s 1073741824 bytes (1.1 GB) copied, 32.9097 s, 32.6 MB/s 1073741824 bytes (1.1 GB) copied, 32.9688 s, 32.6 MB/s Guest system: iozone test # iozone -a -i0 -i1 -i2 -s512M -r64k random random KB reclen write rewrite read reread read write 524288 64 93374 154596 141193 149865 21394 46264 dd read test: one process and then four simultaneous processes # dd if=/dev/mapper/VolGroup-lv_home of=/dev/null bs=1M count=1024 iflag=direct skip=1024 1073741824 bytes (1.1 GB) copied, 5.04356 s, 213 MB/s # dd if=/dev/mapper/VolGroup-lv_home of=/dev/null bs=1M count=1024 iflag=direct skip=1024 & dd if=/dev/mapper/VolGroup-lv_home of=/dev/null bs=1M count=1024 iflag=direct skip=2048 & dd if=/dev/mapper/VolGroup-lv_home of=/dev/null bs=1M count=1024 iflag=direct skip=3072 & dd if=/dev/mapper/VolGroup-lv_home of=/dev/null bs=1M count=1024 iflag=direct skip=4096 1073741824 bytes (1.1 GB) copied, 24.7348 s, 43.4 MB/s 1073741824 bytes (1.1 GB) copied, 24.7378 s, 43.4 MB/s 1073741824 bytes (1.1 GB) copied, 24.7408 s, 43.4 MB/s 1073741824 bytes (1.1 GB) copied, 24.744 s, 43.4 MB/s dd write test: one process and then four simultaneous processes # dd if=/dev/zero of=test bs=1M count=1024 oflag=direct 1073741824 bytes (1.1 GB) copied, 10.415 s, 103 MB/s # dd if=/dev/zero of=test bs=1M count=1024 oflag=direct & dd if=/dev/zero of=test2 bs=1M count=1024 oflag=direct & dd if=/dev/zero of=test3 bs=1M count=1024 oflag=direct & dd if=/dev/zero of=test4 bs=1M count=1024 oflag=direct 1073741824 bytes (1.1 GB) copied, 49.8874 s, 21.5 MB/s 1073741824 bytes (1.1 GB) copied, 49.8608 s, 21.5 MB/s 1073741824 bytes (1.1 GB) copied, 49.8693 s, 21.5 MB/s 1073741824 bytes (1.1 GB) copied, 49.9427 s, 21.5 MB/s I wonder is that normal situation or did I missed something?

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  • Code Contracts: Unit testing contracted code

    - by DigiMortal
    Code contracts and unit tests are not replacements for each other. They both have different purpose and different nature. It does not matter if you are using code contracts or not – you still have to write tests for your code. In this posting I will show you how to unit test code with contracts. In my previous posting about code contracts I showed how to avoid ContractExceptions that are defined in code contracts runtime and that are not accessible for us in design time. This was one step further to make my randomizer testable. In this posting I will complete the mission. Problems with current code This is my current code. public class Randomizer {     public static int GetRandomFromRangeContracted(int min, int max)     {         Contract.Requires<ArgumentOutOfRangeException>(             min < max,             "Min must be less than max"         );           Contract.Ensures(             Contract.Result<int>() >= min &&             Contract.Result<int>() <= max,             "Return value is out of range"         );           var rnd = new Random();         return rnd.Next(min, max);     } } As you can see this code has some problems: randomizer class is static and cannot be instantiated. We cannot move this class between components if we need to, GetRandomFromRangeContracted() is not fully testable because we cannot currently affect random number generator output and therefore we cannot test post-contract. Now let’s solve these problems. Making randomizer testable As a first thing I made Randomizer to be class that must be instantiated. This is simple thing to do. Now let’s solve the problem with Random class. To make Randomizer testable I define IRandomGenerator interface and RandomGenerator class. The public constructor of Randomizer accepts IRandomGenerator as argument. public interface IRandomGenerator {     int Next(int min, int max); }   public class RandomGenerator : IRandomGenerator {     private Random _random = new Random();       public int Next(int min, int max)     {         return _random.Next(min, max);     } } And here is our Randomizer after total make-over. public class Randomizer {     private IRandomGenerator _generator;       private Randomizer()     {         _generator = new RandomGenerator();     }       public Randomizer(IRandomGenerator generator)     {         _generator = generator;     }       public int GetRandomFromRangeContracted(int min, int max)     {         Contract.Requires<ArgumentOutOfRangeException>(             min < max,             "Min must be less than max"         );           Contract.Ensures(             Contract.Result<int>() >= min &&             Contract.Result<int>() <= max,             "Return value is out of range"         );           return _generator.Next(min, max);     } } It seems to be inconvenient to instantiate Randomizer now but you can always use DI/IoC containers and break compiled dependencies between the components of your system. Writing tests for randomizer IRandomGenerator solved problem with testing post-condition. Now it is time to write tests for Randomizer class. Writing tests for contracted code is not easy. The main problem is still ContractException that we are not able to access. Still it is the main exception we get as soon as contracts fail. Although pre-conditions are able to throw exceptions with type we want we cannot do much when post-conditions will fail. We have to use Contract.ContractFailed event and this event is called for every contract failure. This way we find ourselves in situation where supporting well input interface makes it impossible to support output interface well and vice versa. ContractFailed is nasty hack and it works pretty weird way. Although documentation sais that ContractFailed is good choice for testing contracts it is still pretty painful. As a last chance I got tests working almost normally when I wrapped them up. Can you remember similar solution from the times of Visual Studio 2008 unit tests? Cannot understand how Microsoft was able to mess up testing again. [TestClass] public class RandomizerTest {     private Mock<IRandomGenerator> _randomMock;     private Randomizer _randomizer;     private string _lastContractError;       public TestContext TestContext { get; set; }       public RandomizerTest()     {         Contract.ContractFailed += (sender, e) =>         {             e.SetHandled();             e.SetUnwind();               throw new Exception(e.FailureKind + ": " + e.Message);         };     }       [TestInitialize()]     public void RandomizerTestInitialize()     {         _randomMock = new Mock<IRandomGenerator>();         _randomizer = new Randomizer(_randomMock.Object);         _lastContractError = string.Empty;     }       #region InputInterfaceTests     [TestMethod]     [ExpectedException(typeof(Exception))]     public void GetRandomFromRangeContracted_should_throw_exception_when_min_is_not_less_than_max()     {         try         {             _randomizer.GetRandomFromRangeContracted(100, 10);         }         catch (Exception ex)         {             throw new Exception(string.Empty, ex);         }     }       [TestMethod]     [ExpectedException(typeof(Exception))]     public void GetRandomFromRangeContracted_should_throw_exception_when_min_is_equal_to_max()     {         try         {             _randomizer.GetRandomFromRangeContracted(10, 10);         }         catch (Exception ex)         {             throw new Exception(string.Empty, ex);         }     }       [TestMethod]     public void GetRandomFromRangeContracted_should_work_when_min_is_less_than_max()     {         int minValue = 10;         int maxValue = 100;         int returnValue = 50;           _randomMock.Setup(r => r.Next(minValue, maxValue))             .Returns(returnValue)             .Verifiable();           var result = _randomizer.GetRandomFromRangeContracted(minValue, maxValue);           _randomMock.Verify();         Assert.AreEqual<int>(returnValue, result);     }     #endregion       #region OutputInterfaceTests     [TestMethod]     [ExpectedException(typeof(Exception))]     public void GetRandomFromRangeContracted_should_throw_exception_when_return_value_is_less_than_min()     {         int minValue = 10;         int maxValue = 100;         int returnValue = 7;           _randomMock.Setup(r => r.Next(10, 100))             .Returns(returnValue)             .Verifiable();           try         {             _randomizer.GetRandomFromRangeContracted(minValue, maxValue);         }         catch (Exception ex)         {             throw new Exception(string.Empty, ex);         }           _randomMock.Verify();     }       [TestMethod]     [ExpectedException(typeof(Exception))]     public void GetRandomFromRangeContracted_should_throw_exception_when_return_value_is_more_than_max()     {         int minValue = 10;         int maxValue = 100;         int returnValue = 102;           _randomMock.Setup(r => r.Next(10, 100))             .Returns(returnValue)             .Verifiable();           try         {             _randomizer.GetRandomFromRangeContracted(minValue, maxValue);         }         catch (Exception ex)         {             throw new Exception(string.Empty, ex);         }           _randomMock.Verify();     }     #endregion        } Although these tests are pretty awful and contain hacks we are at least able now to make sure that our code works as expected. Here is the test list after running these tests. Conclusion Code contracts are very new stuff in Visual Studio world and as young technology it has some problems – like all other new bits and bytes in the world. As you saw then making our contracted code testable is easy only to the point when pre-conditions are considered. When we start dealing with post-conditions we will end up with hacked tests. I hope that future versions of code contracts will solve error handling issues the way that testing of contracted code will be easier than it is right now.

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  • running multi threads in Java

    - by owca
    My task is to simulate activity of couple of persons. Each of them has few activities to perform in some random time: fast (0-5s), medium(5-10s), slow(10-20s) and very slow(20-30s). Each person performs its task independently in the same time. At the beginning of new task I should print it's random time, start the task and then after time passes show next task's time and start it. I've written run() function that counts time, but now it looks like threads are done one after another and not in the same time or maybe they're just printed in this way. public class People{ public static void main(String[] args){ Task tasksA[]={new Task("washing","fast"), new Task("reading","slow"), new Task("shopping","medium")}; Task tasksM[]={new Task("sleeping zzzzzzzzzz","very slow"), new Task("learning","slow"), new Task(" :** ","slow"), new Task("passing an exam","slow") }; Task tasksJ[]={new Task("listening music","medium"), new Task("doing nothing","slow"), new Task("walking","medium") }; BusyPerson friends[]={ new BusyPerson("Alice",tasksA), new BusyPerson("Mark",tasksM), new BusyPerson("John",tasksJ)}; System.out.println("STARTING....................."); for(BusyPerson f: friends) (new Thread(f)).start(); System.out.println("DONE........................."); } } class Task { private String task; private int time; private Task[]tasks; public Task(String t, String s){ task = t; Speed speed = new Speed(); time = speed.getSpeed(s); } public Task(Task[]tab){ Task[]table=new Task[tab.length]; for(int i=0; i < tab.length; i++){ table[i] = tab[i]; } this.tasks = table; } } class Speed { private static String[]hows = {"fast","medium","slow","very slow"}; private static int[]maxs = {5000, 10000, 20000, 30000}; public Speed(){ } public static int getSpeed( String speedString){ String s = speedString; int up_limit=0; int down_limit=0; int time=0; //get limits of time for(int i=0; i<hows.length; i++){ if(s.equals(hows[i])){ up_limit = maxs[i]; if(i>0){ down_limit = maxs[i-1]; } else{ down_limit = 0; } } } //get random time within the limits Random rand = new Random(); time = rand.nextInt(up_limit) + down_limit; return time; } } class BusyPerson implements Runnable { private String name; private Task[] person_tasks; private BusyPerson[]persons; public BusyPerson(String s, Task[]t){ name = s; person_tasks = t; } public BusyPerson(BusyPerson[]tab){ BusyPerson[]table=new BusyPerson[tab.length]; for(int i=0; i < tab.length; i++){ table[i] = tab[i]; } this.persons = table; } public void run() { int time = 0; double t1=0; for(Task t: person_tasks){ t1 = (double)t.time/1000; System.out.println(name+" is... "+t.task+" "+t.speed+ " ("+t1+" sec)"); while (time == t.time) { try { Thread.sleep(10); } catch(InterruptedException exc) { System.out.println("End of thread."); return; } time = time + 100; } } } } And my output : STARTING..................... DONE......................... Mark is... sleeping zzzzzzzzzz very slow (36.715 sec) Mark is... learning slow (10.117 sec) Mark is... :** slow (29.543 sec) Mark is... passing an exam slow (23.429 sec) Alice is... washing fast (1.209 sec) Alice is... reading slow (23.21 sec) Alice is... shopping medium (11.237 sec) John is... listening music medium (8.263 sec) John is... doing nothing slow (13.576 sec) John is... walking medium (11.322 sec) Whilst it should be like this : STARTING..................... DONE......................... John is... listening music medium (7.05 sec) Alice is... washing fast (3.268 sec) Mark is... sleeping zzzzzzzzzz very slow (23.71 sec) Alice is... reading slow (15.516 sec) John is... doing nothing slow (13.692 sec) Alice is... shopping medium (8.371 sec) Mark is... learning slow (13.904 sec) John is... walking medium (5.172 sec) Mark is... :** slow (12.322 sec) Mark is... passing an exam very slow (27.1 sec)

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  • Cannot find CFML template for custom tag

    - by jerrygarciuh
    Hi folks, I am not a ColdFusion coder. Doing a favor for a friend who ported his CF site from a Windows server to Unix on GoDaddy. Site is displaying error: Cannot find CFML template for custom tag jstk. ColdFusion attempted looking in the tree of installed custom tags but did not find a custom tag with this name. The site as I found it has at document root /CustomTags with the jstk.cfm file and a set of files in cf_jstk My Googling located this You must store custom tag pages in any one of the following: The same directory as the calling page; The cfusion\CustomTags directory; A subdirectory of the cfusion\CustomTags directory; A directory that you specify in the ColdFusion Administrator So I have Tried creating placing /CustomTags in /cfusion/CustomTags Tried copying /cfusion/CustomTags to above document root Tried copying jstk.cfm and subfolders into same directory as calling file(index.cfm). Update: Per GoDaddy support I have also tried adding the following to no effect: Can any one give me some tips on this or should I just tell my guy to look for a CF coder? Thanks! JG

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  • UIView: how to do non-destructive drawing?

    - by Caffeine Coma
    My original question: I'm creating a simple drawing application and need to be able to draw over existing, previously drawn content in my drawRect. What is the proper way to draw on top of existing content without entirely replacing it? Based on answers received here and elsewhere, here is the deal. You should be prepared to redraw the entire rectangle whenever drawRect is called. You cannot prevent the contents from being erased by doing the following: [self setClearsContextBeforeDrawing: NO]; This is merely a hint to the graphics engine that there is no point in having it pre-clear the view for you, since you will likely need to re-draw the whole area anyway. It may prevent your view from being automatically erased, but you cannot depend on it. To draw on top of your view without erasing, do your drawing to an off-screen bitmap context (which is never cleared by the system.) Then in your drawRect, copy from this off-screen buffer to the view. Example: - (id) initWithCoder: (NSCoder*) coder { if (self = [super initWithCoder: coder]) { self.backgroundColor = [UIColor clearColor]; CGSize size = self.frame.size; drawingContext = [self createDrawingBufferContext: size]; } return self; } - (CGContextRef) createOffscreenContext: (CGSize) size { CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB(); CGContextRef context = CGBitmapContextCreate(NULL, size.width, size.height, 8, size.width*4, colorSpace, kCGImageAlphaPremultipliedLast); CGColorSpaceRelease(colorSpace); CGContextTranslateCTM(context, 0, size.height); CGContextScaleCTM(context, 1.0, -1.0); return context; } - (void)drawRect:(CGRect) rect { UIGraphicsPushContext(drawingContext); CGImageRef cgImage = CGBitmapContextCreateImage(drawingContext); UIImage *uiImage = [[UIImage alloc] initWithCGImage:cgImage]; UIGraphicsPopContext(); CGImageRelease(cgImage); [uiImage drawInRect: rect]; [uiImage release]; } TODO: can anyone optimize the drawRect so that only the (usually tiny) modified rectangle region is used for the copy?

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  • Add child to scene from within a class.

    - by Fecal Brunch
    Hi, I'm new to flash in general and have been writing a program with two classes that extend MovieClip (Stems and Star). I need to create a new Stems object as a child of the scene when the user stops dragging a Star object, but do not know how to reference the scene from within the Star class's code. I've tried passing the scene into the constructor of the Star and doing sometihng like: this.scene.addChild (new Stems ()); But apparently that's not how to do it... Below is the code for Stems and Stars, any advice would be appreciated greatly. package { import flash.display.MovieClip; import flash.events.*; import flash.utils.Timer; public class Stems extends MovieClip { public const centreX=1026/2; public const centreY=600/2; public var isFlowing:Boolean; public var flowerType:Number; public const outerLimit=210; public const innerLimit=100; public function Stems(fType:Number) { this.isFlowing=false; this.scaleX=this.scaleY= .0007* distanceFromCentre(this.x, this.y); this.setXY(); trace(distanceFromCentre(this.x, this.y)); if (fType==2) { gotoAndStop("Aplant"); } } public function distanceFromCentre(X:Number, Y:Number):int { return (Math.sqrt((X-centreX)*(X-centreX)+(Y-centreY)*(Y-centreY))); } public function rotateAwayFromCentre():void { var theX:int=centreX-this.x; var theY:int = (centreY - this.y) * -1; var angle = Math.atan(theY/theX)/(Math.PI/180); if (theX<0) { angle+=180; } if (theX>=0&&theY<0) { angle+=360; } this.rotation = ((angle*-1) + 90)+180; } public function setXY() { do { var tempX=Math.random()*centreX*2; var tempY=Math.random()*centreY*2; } while (distanceFromCentre (tempX, tempY)>this.outerLimit || distanceFromCentre (tempX, tempY)<this.innerLimit); this.x=tempX; this.y=tempY; rotateAwayFromCentre(); } public function getFlowerType():Number { return this.flowerType; } } } package { import flash.display.MovieClip; import flash.events.*; import flash.utils.Timer; public class Star extends MovieClip { public const sWide=1026; public const sTall=600; public var startingX:Number; public var startingY:Number; public var starColor:Number; public var flicker:Timer; public var canUpdatePos:Boolean=true; public const innerLimit=280; public function Star(color:Number, basefl:Number, factorial:Number) { this.setXY(); this.starColor=color; this.flicker = new Timer (basefl + factorial * (Math.ceil(100* Math.random ()))); this.flicker.addEventListener(TimerEvent.TIMER, this.tick); this.addEventListener(MouseEvent.MOUSE_OVER, this.hover); this.addEventListener(MouseEvent.MOUSE_UP, this.drop); this.addEventListener(MouseEvent.MOUSE_DOWN, this.drag); this.addChild (new Stems (2)); this.flicker.start(); this.updateAnimation(0, false); } public function distanceOK(X:Number, Y:Number):Boolean { if (Math.sqrt((X-(sWide/2))*(X-(sWide/2))+(Y-(sTall/2))*(Y-(sTall/2)))>innerLimit) { return true; } else { return false; } } public function setXY() { do { var tempX=this.x=Math.random()*sWide; var tempY=this.y=Math.random()*sTall; } while (distanceOK (tempX, tempY)==false); this.startingX=tempX; this.startingY=tempY; } public function tick(event:TimerEvent) { if (this.canUpdatePos) { this.setXY(); } this.updateAnimation(0, false); this.updateAnimation(this.starColor, false); } public function updateAnimation(color:Number, bright:Boolean) { var brightStr:String; if (bright) { brightStr="bright"; } else { brightStr="low"; } switch (color) { case 0 : this.gotoAndStop("none"); break; case 1 : this.gotoAndStop("N" + brightStr); break; case 2 : this.gotoAndStop("A" + brightStr); break; case 3 : this.gotoAndStop("F" + brightStr); break; case 4 : this.gotoAndStop("E" + brightStr); break; case 5 : this.gotoAndStop("S" + brightStr); break; } } public function hover(event:MouseEvent):void { this.updateAnimation(this.starColor, true); this.canUpdatePos=false; } public function drop(event:MouseEvent):void { this.stopDrag(); this.x=this.startingX; this.y=this.startingY; this.updateAnimation(0, false); this.canUpdatePos=true; } public function drag(event:MouseEvent):void { this.startDrag(false); this.canUpdatePos=false; } } }

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  • We've completed the first iteration

    - by CliveT
    There are a lot of features in C# that are implemented by the compiler and not by the underlying platform. One such feature is a lambda expression. Since local variables cannot be accessed once the current method activation finishes, the compiler has to go out of its way to generate a new class which acts as a home for any variable whose lifetime needs to be extended past the activation of the procedure. Take the following example:     Random generator = new Random();     Func func = () = generator.Next(10); In this case, the compiler generates a new class called c_DisplayClass1 which is marked with the CompilerGenerated attribute. [CompilerGenerated] private sealed class c__DisplayClass1 {     // Fields     public Random generator;     // Methods     public int b__0()     {         return this.generator.Next(10);     } } Two quick comments on this: (i)    A display was the means that compilers for languages like Algol recorded the various lexical contours of the nested procedure activations on the stack. I imagine that this is what has led to the name. (ii)    It is a shame that the same attribute is used to mark all compiler generated classes as it makes it hard to figure out what they are being used for. Indeed, you could imagine optimisations that the runtime could perform if it knew that classes corresponded to certain high level concepts. We can see that the local variable generator has been turned into a field in the class, and the body of the lambda expression has been turned into a method of the new class. The code that builds the Func object simply constructs an instance of this class and initialises the fields to their initial values.     c__DisplayClass1 class2 = new c__DisplayClass1();     class2.generator = new Random();     Func func = new Func(class2.b__0); Reflector already contains code to spot this pattern of code and reproduce the form containing the lambda expression, so this is example is correctly decompiled. The use of compiler generated code is even more spectacular in the case of iterators. C# introduced the idea of a method that could automatically store its state between calls, so that it can pick up where it left off. The code can express the logical flow with yield return and yield break denoting places where the method should return a particular value and be prepared to resume.         {             yield return 1;             yield return 2;             yield return 3;         } Of course, there was already a .NET pattern for expressing the idea of returning a sequence of values with the computation proceeding lazily (in the sense that the work for the next value is executed on demand). This is expressed by the IEnumerable interface with its Current property for fetching the current value and the MoveNext method for forcing the computation of the next value. The sequence is terminated when this method returns false. The C# compiler links these two ideas together so that an IEnumerator returning method using the yield keyword causes the compiler to produce the implementation of an Iterator. Take the following piece of code.         IEnumerable GetItems()         {             yield return 1;             yield return 2;             yield return 3;         } The compiler implements this by defining a new class that implements a state machine. This has an integer state that records which yield point we should go to if we are resumed. It also has a field that records the Current value of the enumerator and a field for recording the thread. This latter value is used for optimising the creation of iterator instances. [CompilerGenerated] private sealed class d__0 : IEnumerable, IEnumerable, IEnumerator, IEnumerator, IDisposable {     // Fields     private int 1__state;     private int 2__current;     public Program 4__this;     private int l__initialThreadId; The body gets converted into the code to construct and initialize this new class. private IEnumerable GetItems() {     d__0 d__ = new d__0(-2);     d__.4__this = this;     return d__; } When the class is constructed we set the state, which was passed through as -2 and the current thread. public d__0(int 1__state) {     this.1__state = 1__state;     this.l__initialThreadId = Thread.CurrentThread.ManagedThreadId; } The state needs to be set to 0 to represent a valid enumerator and this is done in the GetEnumerator method which optimises for the usual case where the returned enumerator is only used once. IEnumerator IEnumerable.GetEnumerator() {     if ((Thread.CurrentThread.ManagedThreadId == this.l__initialThreadId)               && (this.1__state == -2))     {         this.1__state = 0;         return this;     } The state machine itself is implemented inside the MoveNext method. private bool MoveNext() {     switch (this.1__state)     {         case 0:             this.1__state = -1;             this.2__current = 1;             this.1__state = 1;             return true;         case 1:             this.1__state = -1;             this.2__current = 2;             this.1__state = 2;             return true;         case 2:             this.1__state = -1;             this.2__current = 3;             this.1__state = 3;             return true;         case 3:             this.1__state = -1;             break;     }     return false; } At each stage, the current value of the state is used to determine how far we got, and then we generate the next value which we return after recording the next state. Finally we return false from the MoveNext to signify the end of the sequence. Of course, that example was really simple. The original method body didn't have any local variables. Any local variables need to live between the calls to MoveNext and so they need to be transformed into fields in much the same way that we did in the case of the lambda expression. More complicated MoveNext methods are required to deal with resources that need to be disposed when the iterator finishes, and sometimes the compiler uses a temporary variable to hold the return value. Why all of this explanation? We've implemented the de-compilation of iterators in the current EAP version of Reflector (7). This contrasts with previous version where all you could do was look at the MoveNext method and try to figure out the control flow. There's a fair amount of things we have to do. We have to spot the use of a CompilerGenerated class which implements the Enumerator pattern. We need to go to the class and figure out the fields corresponding to the local variables. We then need to go to the MoveNext method and try to break it into the various possible states and spot the state transitions. We can then take these pieces and put them back together into an object model that uses yield return to show the transition points. After that Reflector can carry on optimising using its usual optimisations. The pattern matching is currently a little too sensitive to changes in the code generation, and we only do a limited analysis of the MoveNext method to determine use of the compiler generated fields. In some ways, it is a pity that iterators are compiled away and there is no metadata that reflects the original intent. Without it, we are always going to dependent on our knowledge of the compiler's implementation. For example, we have noticed that the Async CTP changes the way that iterators are code generated, so we'll have to do some more work to support that. However, with that warning in place, we seem to do a reasonable job of decompiling the iterators that are built into the framework. Hopefully, the EAP will give us a chance to find examples where we don't spot the pattern correctly or regenerate the wrong code, and we can improve things. Please give it a go, and report any problems.

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  • Where'd my sounds go?

    - by Dane Man
    In my Row class I have the initWithCoder method and everything restored in that method works fine, but only within the method. After the method is called I loose an array of sounds that is in my Row class. The sounds class also has the initWithCoder method, and the sound plays fine but only in the Row class initWithCoder method. After decoding the Row object, the sound array disappears completely and is unable to be called. Here's my source for the initWithCoder: - (id) initWithCoder:(NSCoder *)coder { ... soundArray = [coder decodeObjectForKey:@"soundArray"]; NSLog(@"%d",[soundArray count]); return self; } the log shows the count as 8 like it should (this is while unarchiving). Then the row object I create gets assigned. And the resulting row object no longer has a soundArray. [NSKeyedArchiver archiveRootObject:row toFile:@"DefaultRow"]; ... row = [NSKeyedUnarchiver unarchiveObjectWithFile:@"DefaultRow"]; So now whenever I call the soundArray it crashes. //ERROR IS HERE NSLog(@"%d",[[row soundArray] count]); Help please (soundArray is an NSMutableArray).

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  • Adding data (not only text) to a multi column ListView (WPF)

    - by user811804
    I am working on a WPF application in C# (.NET 4.0) where I have a ListView with a GridView that has two columns. I dynamically want to add rows (in code). My dilemma is that only the first column will have regular text added to it. The second column will have an object that includes a multi column Grid with TextBlocks. (see link http://imageshack.us/photo/my-images/803/listview.png/) If I do what you would normally do when you want to enter text in all columns (ie. DisplayMemberBinding) all I get in the second column is the text "System.Windows.Grid", which obviously isn't what I want. For reference if I just try to add the Grid object (with the TextBlocks) with the code listView1.Items.Add(grid1) (not using DisplayMemberBinding) the object gets added to the second column only (with the first column being blank) and not how it normally works with text where the same text ends up in all columns. I hope my question is detailed enough and any help with this would be much appreciated. EDIT: I have tried the following code, howeever every time I click the button to add a new row every single row gets updated with the same datatemplate. (ie. the second column always shows the same data on every row.) xaml: <Window x:Class="TEST.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Name="AAA" Title="MainWindow" Height="350" Width="525" Loaded="Window_Loaded"> <Grid Name="grid1"> <Grid.ColumnDefinitions> <ColumnDefinition Width="374*" /> <ColumnDefinition Width="129*" /> </Grid.ColumnDefinitions> <Button Content="Button" Height="23" HorizontalAlignment="Left" Margin="21,12,0,0" Name="button1" VerticalAlignment="Top" Width="75" Grid.Column="1" Click="button1_Click" /> </Grid> code: public partial class MainWindow : Window { ListView listView1 = new ListView(); GridViewColumn viewCol2 = new GridViewColumn(); public MainWindow() { InitializeComponent(); Style style = new Style(typeof(ListViewItem)); style.Setters.Add(new Setter(ListViewItem.HorizontalContentAlignmentProperty, HorizontalAlignment.Stretch)); listView1.ItemContainerStyle = style; GridView gridView1 = new GridView(); listView1.View = gridView1; GridViewColumn viewCol1 = new GridViewColumn(); viewCol1.Header = "Option"; gridView1.Columns.Add(viewCol1); viewCol2.Header = "Value"; gridView1.Columns.Add(viewCol2); grid1.Children.Add(listView1); viewCol1.DisplayMemberBinding = new Binding("Option"); } private void Window_Loaded(object sender, RoutedEventArgs e) { } private void button1_Click(object sender, RoutedEventArgs e) { DataTemplate dataTemplate = new DataTemplate(); FrameworkElementFactory spFactory = new FrameworkElementFactory(typeof(Grid)); Random random = new Random(); int cols = random.Next(1, 6); int full = 100; for (int i = 0; i < cols; i++) { FrameworkElementFactory col1 = new FrameworkElementFactory(typeof(ColumnDefinition)); int partWidth = random.Next(0, full); full -= partWidth; col1.SetValue(ColumnDefinition.WidthProperty, new GridLength(partWidth, GridUnitType.Star)); spFactory.AppendChild(col1); } if (full > 0) { FrameworkElementFactory col1 = new FrameworkElementFactory(typeof(ColumnDefinition)); col1.SetValue(ColumnDefinition.WidthProperty, new GridLength(full, GridUnitType.Star)); spFactory.AppendChild(col1); } for (int i = 0; i < cols; i++) { FrameworkElementFactory text1 = new FrameworkElementFactory(typeof(TextBlock)); SolidColorBrush sb1 = new SolidColorBrush(); switch (i) { case 0: sb1.Color = Colors.Blue; break; case 1: sb1.Color = Colors.Red; break; case 2: sb1.Color = Colors.Yellow; break; case 3: sb1.Color = Colors.Green; break; case 4: sb1.Color = Colors.Purple; break; case 5: sb1.Color = Colors.Pink; break; case 6: sb1.Color = Colors.Brown; break; } text1.SetValue(TextBlock.BackgroundProperty, sb1); text1.SetValue(Grid.ColumnProperty, i); spFactory.AppendChild(text1); } if (full > 0) { FrameworkElementFactory text1 = new FrameworkElementFactory(typeof(TextBlock)); SolidColorBrush sb1 = new SolidColorBrush(Colors.Black); text1.SetValue(TextBlock.BackgroundProperty, sb1); text1.SetValue(Grid.ColumnProperty, cols); spFactory.AppendChild(text1); } dataTemplate.VisualTree = spFactory; viewCol2.CellTemplate = dataTemplate; int rows = listView1.Items.Count + 1; listView1.Items.Add(new { Option = "Row " + rows }); } }

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  • tips for fixing bad coding/dev habits ?

    - by dfafa
    i want to become a better coder....so i have decided to sign up for computing science program...maybe a formal education can assist me. i started working on smaller projects to learn but currently i have really bad coding/dev habits which is hindering my productivity as the codebase increases.... i have highlighted them and perhaps someone could make suggestions (or redirect to resources) or a more efficient method. most stuff that i made in the past were web apps. i usually develop with putty + nano...i just love the minimalist feel i use winscp and develop directly on my private web server...too lazy to do it on localhost and upload it later. i dont use subversion control...which one do i need ? sometimes ctrl +z doesn't work well. when i run out of ideas for naming variable, i use swear words instead. i swear a lot when i get stuck....how to deal with anger issue ? my codes look ugly with comments everywhere. would rather use procedural coding finds "thinking" in OO difficult and time consuming i "write first think later". refactors code only if i am getting paid for it. dislikes configuring linux distro, Apache, MySQL, scaling, designing graphics and layouts. does not like writing tests likes working alone. does not like sharing codes. has an econ degree dislikes reading other people's code would rather write it on my own it seems my only true desire is to translate my ideas to a working prototype as fast as possible....it seems like i am very uninterested in the other details...could it be that i am not cut out to be a coder after all ? is going back to study comp sci a bad idea ?

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  • Unknown error in Producer/Consumer program, believe it to be an infinite loop.

    - by ray2k
    Hello, I am writing a program that is solving the producer/consumer problem, specifically the bounded-buffer version(i believe they mean the same thing). The producer will be generating x number of random numbers, where x is a command line parameter to my program. At the current moment, I believe my program is entering an infinite loop, but I'm not sure why it is occurring. I believe I am executing the semaphores correctly. You compile it like this: gcc -o prodcon prodcon.cpp -lpthread -lrt Then to run, ./prodcon 100(the number of randum nums to produce) This is my code. typedef int buffer_item; #include <stdlib.h> #include <stdio.h> #include <pthread.h> #include <semaphore.h> #include <unistd.h> #define BUFF_SIZE 10 #define RAND_DIVISOR 100000000 #define TRUE 1 //two threads void *Producer(void *param); void *Consumer(void *param); int insert_item(buffer_item item); int remove_item(buffer_item *item); int returnRandom(); //the global semaphores sem_t empty, full, mutex; //the buffer buffer_item buf[BUFF_SIZE]; //buffer counter int counter; //number of random numbers to produce int numRand; int main(int argc, char** argv) { /* thread ids and attributes */ pthread_t pid, cid; pthread_attr_t attr; pthread_attr_init(&attr); pthread_attr_setscope(&attr, PTHREAD_SCOPE_SYSTEM); numRand = atoi(argv[1]); sem_init(&empty,0,BUFF_SIZE); sem_init(&full,0,0); sem_init(&mutex,0,0); printf("main started\n"); pthread_create(&pid, &attr, Producer, NULL); pthread_create(&cid, &attr, Consumer, NULL); printf("main gets here"); pthread_join(pid, NULL); pthread_join(cid, NULL); printf("main done\n"); return 0; } //generates a randum number between 1 and 100 int returnRandom() { int num; srand(time(NULL)); num = rand() % 100 + 1; return num; } //begin producing items void *Producer(void *param) { buffer_item item; int i; for(i = 0; i < numRand; i++) { //sleep for a random period of time int rNum = rand() / RAND_DIVISOR; sleep(rNum); //generate a random number item = returnRandom(); //acquire the empty lock sem_wait(&empty); //acquire the mutex lock sem_wait(&mutex); if(insert_item(item)) { fprintf(stderr, " Producer report error condition\n"); } else { printf("producer produced %d\n", item); } /* release the mutex lock */ sem_post(&mutex); /* signal full */ sem_post(&full); } return NULL; } /* Consumer Thread */ void *Consumer(void *param) { buffer_item item; int i; for(i = 0; i < numRand; i++) { /* sleep for a random period of time */ int rNum = rand() / RAND_DIVISOR; sleep(rNum); /* aquire the full lock */ sem_wait(&full); /* aquire the mutex lock */ sem_wait(&mutex); if(remove_item(&item)) { fprintf(stderr, "Consumer report error condition\n"); } else { printf("consumer consumed %d\n", item); } /* release the mutex lock */ sem_post(&mutex); /* signal empty */ sem_post(&empty); } return NULL; } /* Add an item to the buffer */ int insert_item(buffer_item item) { /* When the buffer is not full add the item and increment the counter*/ if(counter < BUFF_SIZE) { buf[counter] = item; counter++; return 0; } else { /* Error the buffer is full */ return -1; } } /* Remove an item from the buffer */ int remove_item(buffer_item *item) { /* When the buffer is not empty remove the item and decrement the counter */ if(counter > 0) { *item = buf[(counter-1)]; counter--; return 0; } else { /* Error buffer empty */ return -1; } }

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  • Force close error expecting irregulary

    - by user1506019
    I have problem. I created an application which loads random layour from resources and I have problem because program shows random layout and closes , sometimes after 2 times and sometimes after a dozen, and I dont know where is a problem, I tried to run it on my phone and I added in the manifest write_external_storage permission, and still the same error.Please help me, and try to resolve this problem. here is my code in : java : package ka.ka.ka; import java.util.Random; import android.app.Activity; import android.os.Bundle; import android.view.View; import android.view.View.OnClickListener; import android.widget.Button; public class KAMASActivity extends Activity implements OnClickListener { Button button1; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); button1 = (Button) findViewById(R.id.button1) ; button1.setOnClickListener(this); } @Override public void onClick(View v) { int min = 1; int max = 6; int i1=0; Random r = new Random(); i1 = r.nextInt(max - min + 1) + min; if(i1==1){setContentView(R.layout.image1); button1 = (Button) findViewById(R.id.button1) ; button1.setOnClickListener(this);} if(i1==2){setContentView(R.layout.image2); button1 = (Button) findViewById(R.id.button1) ; button1.setOnClickListener(this);} if(i1==3){setContentView(R.layout.image3); button1 = (Button) findViewById(R.id.button1) ; button1.setOnClickListener(this);} if(i1==4){setContentView(R.layout.image4); button1 = (Button) findViewById(R.id.button1) ; button1.setOnClickListener(this);} if(i1==5){setContentView(R.layout.image5); button1 = (Button) findViewById(R.id.button1) ; button1.setOnClickListener(this);} if(i1==6){setContentView(R.layout.image6); button1 = (Button) findViewById(R.id.button1) ; button1.setOnClickListener(this); } } Android Manifest : <?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="ka.ka.ka" android:versionCode="1" android:versionName="1.0" > <uses-sdk android:minSdkVersion="7" /> <uses-permission android:name="android.permission.ACCESS_CHECKIN_PROPERTIES" /> <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" /> <application android:icon="@drawable/ikona" android:label="@string/app_name" > <activity android:name=".KAMASActivity" android:label="@string/app_name" > <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> </application> </manifest> And he is logcat : 07-10 10:58:51.062: D/ddm-heap(218): Got feature list request 07-10 10:58:51.311: D/dalvikvm(218): GC freed 506 objects / 46032 bytes in 122ms 07-10 10:59:30.081: D/AndroidRuntime(218): Shutting down VM 07-10 10:59:30.081: W/dalvikvm(218): threadid=3: thread exiting with uncaught exception (group=0x4001b188) 07-10 10:59:30.081: E/AndroidRuntime(218): Uncaught handler: thread main exiting due to uncaught exception 07-10 10:59:30.102: E/AndroidRuntime(218): java.lang.NullPointerException 07-10 10:59:30.102: E/AndroidRuntime(218): at ka.ka.ka.KAMASActivity.onClick(KAMASActivity.java:32) 07-10 10:59:30.102: E/AndroidRuntime(218): at android.view.View.performClick(View.java:2364) 07-10 10:59:30.102: E/AndroidRuntime(218): at android.view.View.onTouchEvent(View.java:4179) 07-10 10:59:30.102: E/AndroidRuntime(218): at android.widget.TextView.onTouchEvent(TextView.java:6541) 07-10 10:59:30.102: E/AndroidRuntime(218): at android.view.View.dispatchTouchEvent(View.java:3709) 07-10 10:59:30.102: E/AndroidRuntime(218): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884) 07-10 10:59:30.102: E/AndroidRuntime(218): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884) 07-10 10:59:30.102: E/AndroidRuntime(218): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884) 0 7-10 10:59:30.102: E/AndroidRuntime(218): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884) 07-10 10:59:30.102: E/AndroidRuntime(218): at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow. java:1659) 07-10 10:59:30.102: E/AndroidRuntime(218): at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1107) 07-10 10:59:30.102: E/AndroidRuntime(218): at android.app.Activity.dispatchTouchEvent(Activity.java:2061) 07-10 10:59:30.102: E/AndroidRuntime(218): at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:1643) 07-10 10:59:30.102: E/AndroidRuntime(218): at android.view.ViewRoot.handleMessage(ViewRoot.java:1691) 07-10 10:59:30.102: E/AndroidRuntime(218): at android.os.Handler.dispatchMessage(Handler.java:99) 07-10 10:59:30.102: E/AndroidRuntime(218): at android.os.Looper.loop(Looper.java:123) 07-10 10:59:30.102: E/AndroidRuntime(218): at android.app.ActivityThread.main(ActivityThread.java:4363) 07-10 10:59:30.102: E/AndroidRuntime(218): at java.lang.reflect.Method.invokeNative(Native Method) 07-10 10:59:30.102: E/AndroidRuntime(218): at java.lang.reflect.Method.invoke(Method.java:521) 07-10 10:59:30.102: E/AndroidRuntime(218): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860) 07-10 10:59:30.102: E/AndroidRuntime(218): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618) 07-10 10:59:30.102: E/AndroidRuntime(218): at dalvik.system.NativeStart.main(Native Method) 07-10 10:59:30.121: I/dalvikvm(218): threadid=7: reacting to signal 3 07-10 10:59:30.121: E/dalvikvm(218): Unable to open stack trace file '/data/anr/traces.txt': Permission denied 07-10 10:59:32.562: I/Process(218): Sending signal. PID: 218 SIG: 9

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  • Creating a new plugin for mpld3

    - by sjp14051
    Toward learning how to create a new mpld3 plugin, I took an existing example, LinkedDataPlugin (http://mpld3.github.io/examples/heart_path.html), and modified it slightly by deleting references to lines object. That is, I created the following: class DragPlugin(plugins.PluginBase): JAVASCRIPT = r""" mpld3.register_plugin("drag", DragPlugin); DragPlugin.prototype = Object.create(mpld3.Plugin.prototype); DragPlugin.prototype.constructor = DragPlugin; DragPlugin.prototype.requiredProps = ["idpts", "idpatch"]; DragPlugin.prototype.defaultProps = {} function DragPlugin(fig, props){ mpld3.Plugin.call(this, fig, props); }; DragPlugin.prototype.draw = function(){ var patchobj = mpld3.get_element(this.props.idpatch, this.fig); var ptsobj = mpld3.get_element(this.props.idpts, this.fig); var drag = d3.behavior.drag() .origin(function(d) { return {x:ptsobj.ax.x(d[0]), y:ptsobj.ax.y(d[1])}; }) .on("dragstart", dragstarted) .on("drag", dragged) .on("dragend", dragended); patchobj.path.attr("d", patchobj.datafunc(ptsobj.offsets, patchobj.pathcodes)); patchobj.data = ptsobj.offsets; ptsobj.elements() .data(ptsobj.offsets) .style("cursor", "default") .call(drag); function dragstarted(d) { d3.event.sourceEvent.stopPropagation(); d3.select(this).classed("dragging", true); } function dragged(d, i) { d[0] = ptsobj.ax.x.invert(d3.event.x); d[1] = ptsobj.ax.y.invert(d3.event.y); d3.select(this) .attr("transform", "translate(" + [d3.event.x,d3.event.y] + ")"); patchobj.path.attr("d", patchobj.datafunc(ptsobj.offsets, patchobj.pathcodes)); } function dragended(d, i) { d3.select(this).classed("dragging", false); } } mpld3.register_plugin("drag", DragPlugin); """ def __init__(self, points, patch): print "Points ID : ", utils.get_id(points) self.dict_ = {"type": "drag", "idpts": utils.get_id(points), "idpatch": utils.get_id(patch)} However, when I try to link the plugin to a figure, as in plugins.connect(fig, DragPlugin(points[0], patch)) I get an error, 'module' is not callable, pointing to this line. What does this mean and why doesn't it work? Thanks. I'm adding additional code to show that linking more than one Plugin might be problematic. But this may be entirely due to some silly mistake on my part, or there is a way around it. The following code based on LinkedViewPlugin generates three panels, in which the top and the bottom panel are supposed to be identical. Mouseover in the middle panel was expected to control the display in the top and bottom panels, but updates occur in the bottom panel only. It would be nice to be able to figure out how to reflect the changes in multiple panels. Thanks. import matplotlib import matplotlib.pyplot as plt import numpy as np import mpld3 from mpld3 import plugins, utils class LinkedView(plugins.PluginBase): """A simple plugin showing how multiple axes can be linked""" JAVASCRIPT = """ mpld3.register_plugin("linkedview", LinkedViewPlugin); LinkedViewPlugin.prototype = Object.create(mpld3.Plugin.prototype); LinkedViewPlugin.prototype.constructor = LinkedViewPlugin; LinkedViewPlugin.prototype.requiredProps = ["idpts", "idline", "data"]; LinkedViewPlugin.prototype.defaultProps = {} function LinkedViewPlugin(fig, props){ mpld3.Plugin.call(this, fig, props); }; LinkedViewPlugin.prototype.draw = function(){ var pts = mpld3.get_element(this.props.idpts); var line = mpld3.get_element(this.props.idline); var data = this.props.data; function mouseover(d, i){ line.data = data[i]; line.elements().transition() .attr("d", line.datafunc(line.data)) .style("stroke", this.style.fill); } pts.elements().on("mouseover", mouseover); }; """ def __init__(self, points, line, linedata): if isinstance(points, matplotlib.lines.Line2D): suffix = "pts" else: suffix = None self.dict_ = {"type": "linkedview", "idpts": utils.get_id(points, suffix), "idline": utils.get_id(line), "data": linedata} class LinkedView2(plugins.PluginBase): """A simple plugin showing how multiple axes can be linked""" JAVASCRIPT = """ mpld3.register_plugin("linkedview", LinkedViewPlugin2); LinkedViewPlugin2.prototype = Object.create(mpld3.Plugin.prototype); LinkedViewPlugin2.prototype.constructor = LinkedViewPlugin2; LinkedViewPlugin2.prototype.requiredProps = ["idpts", "idline", "data"]; LinkedViewPlugin2.prototype.defaultProps = {} function LinkedViewPlugin2(fig, props){ mpld3.Plugin.call(this, fig, props); }; LinkedViewPlugin2.prototype.draw = function(){ var pts = mpld3.get_element(this.props.idpts); var line = mpld3.get_element(this.props.idline); var data = this.props.data; function mouseover(d, i){ line.data = data[i]; line.elements().transition() .attr("d", line.datafunc(line.data)) .style("stroke", this.style.fill); } pts.elements().on("mouseover", mouseover); }; """ def __init__(self, points, line, linedata): if isinstance(points, matplotlib.lines.Line2D): suffix = "pts" else: suffix = None self.dict_ = {"type": "linkedview", "idpts": utils.get_id(points, suffix), "idline": utils.get_id(line), "data": linedata} fig, ax = plt.subplots(3) # scatter periods and amplitudes np.random.seed(0) P = 0.2 + np.random.random(size=20) A = np.random.random(size=20) x = np.linspace(0, 10, 100) data = np.array([[x, Ai * np.sin(x / Pi)] for (Ai, Pi) in zip(A, P)]) points = ax[1].scatter(P, A, c=P + A, s=200, alpha=0.5) ax[1].set_xlabel('Period') ax[1].set_ylabel('Amplitude') # create the line object lines = ax[0].plot(x, 0 * x, '-w', lw=3, alpha=0.5) ax[0].set_ylim(-1, 1) ax[0].set_title("Hover over points to see lines") linedata = data.transpose(0, 2, 1).tolist() plugins.connect(fig, LinkedView(points, lines[0], linedata)) # second set of lines exactly the same but in a different panel lines2 = ax[2].plot(x, 0 * x, '-w', lw=3, alpha=0.5) ax[2].set_ylim(-1, 1) ax[2].set_title("Hover over points to see lines #2") plugins.connect(fig, LinkedView2(points, lines2[0], linedata)) mpld3.show()

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  • HTML relative links with URL Rewrite

    - by Adam Kiss
    I have quickie: When you code/develop themes, how do you link to various files in your html/css code? Example: We at our firm use mostly <base target="http://whatever"> in our main template and then just <img src="./images/file.png"> in our html, "/category/page" as links and something alike in our css. However, when testing on different machines, we use ip address rather than localhost on main dev station of coder, so all base links don't work (because localhost goes to viewing machine, not coder's, in our network). Same thing happens when updating pages - on dev server, we have to edit base target, so browsing site won't take us to live site - this part is actually rather simple PHP (if ... echo else echo something else), but it still not solve problem of more coding-testing problems. So, my question is, how do YOU solve it? How do you use relative links, which basically don't care for what domain is the page on and don't care for url rewrite? (because ../images/ is different for / and different for /something/somethingElse/page)?

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  • How difficult is it for an old-school programmer to pick up an FPGA kit and make something useful wi

    - by JUST MY correct OPINION
    I'm an old, old, old coder. (How old? I've used paper tape in anger.) I've programmed in a lot of languages and under a lot of paradigms (spaghetti, structured, object-oriented, functional and a smattering of logical). I'm getting bored. FPGAs look interesting to me. I have the crazy notion of resurrecting some of the ancient hardware I worked on in the days using FPGAs. I know this can be done because I've seen PDP-10 and PDP-11 implementations in FPGAs. I'd like to do the same for a few machines that are perhaps not as popular as those two, however. While I am an old, old coder, what I am not is an electronics or computer systems engineer. I'll be learning from scratch if I go down this path. My question, therefore, is two-fold: How difficult will it be for this old dinosaur to pick up and learn FPGAs to the point that interesting (not necessarily practical -- more from a hobbyist perspective) projects can be made? What should I start with learning-wise to go down this path? I know where to get FPGA kits, but I haven't found anything like "FPGAs for Complete Dinosaurs" yet anywhere out there.

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  • HTML relative links on various domains

    - by Adam Kiss
    I have quickie: When you code/develop themes, how do you link to various files in your html/css code? Example: We at our firm use mostly <base target="http://whatever"> in our main template and then just <img src="./images/file.png"> in our html, "/category/page" as links and something alike in our css. However, when testing on different machines, we use ip address rather than localhost on main dev station of coder, so all base links don't work (because localhost goes to viewing machine, not coder's, in our network). Same thing happens when updating pages - on dev server, we have to edit base target, so browsing site won't take us to live site - this part is actually rather simple PHP (if ... echo else echo something else), but it still not solve problem of more coding-testing problems. So, my question is, how do YOU solve it? How do you use relative links, which basically don't care for what domain is the page on and don't care for url rewrite? (because ../images/ is different for / and different for /something/somethingElse/page)?

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  • To sample or not to sample...

    - by [email protected]
    Ideally, we would know the exact answer to every question. How many people support presidential candidate A vs. B? How many people suffer from H1N1 in a given state? Does this batch of manufactured widgets have any defective parts? Knowing exact answers is expensive in terms of time and money and, in most cases, is impractical if not impossible. Consider asking every person in a region for their candidate preference, testing every person with flu symptoms for H1N1 (assuming every person reported when they had flu symptoms), or destructively testing widgets to determine if they are "good" (leaving no product to sell). Knowing exact answers, fortunately, isn't necessary or even useful in many situations. Understanding the direction of a trend or statistically significant results may be sufficient to answer the underlying question: who is likely to win the election, have we likely reached a critical threshold for flu, or is this batch of widgets good enough to ship? Statistics help us to answer these questions with a certain degree of confidence. This focuses on how we collect data. In data mining, we focus on the use of data, that is data that has already been collected. In some cases, we may have all the data (all purchases made by all customers), in others the data may have been collected using sampling (voters, their demographics and candidate choice). Building data mining models on all of your data can be expensive in terms of time and hardware resources. Consider a company with 40 million customers. Do we need to mine all 40 million customers to get useful data mining models? The quality of models built on all data may be no better than models built on a relatively small sample. Determining how much is a reasonable amount of data involves experimentation. When starting the model building process on large datasets, it is often more efficient to begin with a small sample, perhaps 1000 - 10,000 cases (records) depending on the algorithm, source data, and hardware. This allows you to see quickly what issues might arise with choice of algorithm, algorithm settings, data quality, and need for further data preparation. Instead of waiting for a model on a large dataset to build only to find that the results don't meet expectations, once you are satisfied with the results on the initial sample, you can  take a larger sample to see if model quality improves, and to get a sense of how the algorithm scales to the particular dataset. If model accuracy or quality continues to improve, consider increasing the sample size. Sampling in data mining is also used to produce a held-aside or test dataset for assessing classification and regression model accuracy. Here, we reserve some of the build data (data that includes known target values) to be used for an honest estimate of model error using data the model has not seen before. This sampling transformation is often called a split because the build data is split into two randomly selected sets, often with 60% of the records being used for model building and 40% for testing. Sampling must be performed with care, as it can adversely affect model quality and usability. Even a truly random sample doesn't guarantee that all values are represented in a given attribute. This is particularly troublesome when the attribute with omitted values is the target. A predictive model that has not seen any examples for a particular target value can never predict that target value! For other attributes, values may consist of a single value (a constant attribute) or all unique values (an identifier attribute), each of which may be excluded during mining. Values from categorical predictor attributes that didn't appear in the training data are not used when testing or scoring datasets. In subsequent posts, we'll talk about three sampling techniques using Oracle Database: simple random sampling without replacement, stratified sampling, and simple random sampling with replacement.

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  • Algorithm for querying linearly through a non-linear list of questions

    - by JoshLeaves
    For a multiplayers trivia game, I need to supply my users with a new quizz in a desired subject (Science, Maths, Litt. and such) at the start of every game. I've generated about 5K quizzes for each subject and filled my database with them. So my 'Quizzes' database looks like this: |ID |Subject |Question +-----+------------+---------------------------------- | 23 |Science | What's water? | 42 |Maths | What's 2+2? | 99 |Litt. | Who wrote "Pride and Prejudice"? | 123 |Litt. | Who wrote "On The Road"? | 146 |Maths | What's 2*2? | 599 |Science | You know what's cool? |1042 |Maths | What's the Fibonacci Sequence? |1056 |Maths | What's 42? And so on... (Much more detailed/complex but I'll keep the exemple simple) As you can see, due to technical constraints (MongoDB), my IDs are not linear but I can use them as an increasing suite. So far, my algorithm to ensure two users get a new quizz when they play together is the following: // Take the last played quizzes by P1 and P2 var q_one = player_one.getLastPlayedQuizz('Maths'); var q_two = player_two.getLastPlayedQuizz('Maths'); // If both of them never played in the subject, return first quizz in the list if ((q_one == NULL) && (q_two == NULL)) return QuizzDB.findOne({subject: 'Maths'}); // If one of them never played, play the next quizz for the other player // This quizz is found by asking for the first quizz in the desired subject where // the ID is greater than the last played quizz's ID (if the last played quizz ID // is 42, this will return 146 following the above example database) if (q_one == NULL) return QuizzDB.findOne({subject: 'Maths', ID > q_two}); if (q_two == NULL) return QuizzDB.findOne({subject: 'Maths', ID > q_one}); // And if both of them have a lastPlayedQuizz, we return the next quizz for the // player whose lastPlayedQuizz got the higher ID if (q_one > q_two) return QuizzDB.findOne({subject: 'Maths', ID > q_one}); else return QuizzDB.findOne({subject: 'Maths', ID > q_two}); Now here comes the real problem: Once I get to the end of my database (let's say, P1's last played quizz in 'Maths' is 1056, P2's is 146 and P3 is 1042), following my algorithm, P1's ID is the highest so I ask for the next question in 'Maths' where ID is superior to 1056. There is nothing, so I roll back to the beginning of my quizz list (with a random skipper to avoid having the first question always show up). P1 and P2's last played will then be 42 and they will start fresh from the beginning of the list. However, if P1 (42) plays against P3 (1042), the resulting ID will be 1056...which P1 already played two games ago. Basically, players who just "rolled back" to the beginning of the list will be brought back to the end of the list by players who still haven't rolled back. The rollback WILL happen in the end, but it'll take time and there'll be a "bottleneck" at the beginning and at the end. Thus my question: What would be the best algorith to avoid this bottleneck and ensure players don't get stuck endlessly on the same quizzes? Also bear in mind that I've got some technical constraints: I can't get a random question in a subject (ie: no "QuizzDB.findOne({subject: 'Maths'}).skip(random());"). It's cool to skip on one to twenty records, but the MongoDB documentation warns against skipping too many documents. I would like to avoid building an array of every quizz played by each player and find the next non-played in the database with a $nin. Thanks for your help

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  • What C++ coding standard do you use?

    - by gablin
    For some time now, I've been unable to settle on a coding standard and use it concistently between projects. When starting a new project, I tend to change some things around (add a space there, remove a space there, add a line break there, an extra indent there, change naming conventions, etc.). So I figured that I might provide a piece of sample code, in C++, and ask you to rewrite it to fit your standard of coding. Inspiration is always good, I say. ^^ So here goes: #ifndef _DERIVED_CLASS_H__ #define _DERIVED_CLASS_H__ /** * This is an example file used for sampling code layout. * * @author Firstname Surname */ #include <stdio> #include <string> #include <list> #include "BaseClass.h" #include "Stuff.h" /** * The DerivedClass is completely useless. It represents uselessness in all its * entirety. */ class DerivedClass : public BaseClass { //////////////////////////////////////////////////////////// // CONSTRUCTORS / DESTRUCTORS //////////////////////////////////////////////////////////// public: /** * Constructs a useless object with default settings. * * @param value * Is never used. * @throws Exception * If something goes awry. */ DerivedClass (const int value) : uselessSize_ (0) {} /** * Constructs a copy of a given useless object. * * @param object * Object to copy. * @throws OutOfMemoryException * If necessary data cannot be allocated. */ ItemList (const DerivedClass& object) {} /** * Destroys this useless object. */ ~ItemList (); //////////////////////////////////////////////////////////// // PUBLIC METHODS //////////////////////////////////////////////////////////// public: /** * Clones a given useless object. * * @param object * Object to copy. * @return This useless object. */ DerivedClass& operator= (const DerivedClass& object) { stuff_ = object.stuff_; uselessSize_ = object.uselessSize_; } /** * Does absolutely nothing. * * @param useless * Pointer to useless data. */ void doNothing (const int* useless) { if (useless == NULL) { return; } else { int womba = *useless; switch (womba) { case 0: cout << "This is output 0"; break; case 1: cout << "This is output 1"; break; case 2: cout << "This is output 2"; break; default: cout << "This is default output"; break; } } } /** * Does even less. */ void doEvenLess () { int mySecret = getSecret (); int gather = 0; for (int i = 0; i < mySecret; i++) { gather += 2; } } //////////////////////////////////////////////////////////// // PRIVATE METHODS //////////////////////////////////////////////////////////// private: /** * Gets the secret value of this useless object. * * @return A secret value. */ int getSecret () const { if ((RANDOM == 42) && (stuff_.size() > 0) || (1000000000000000000 > 0) && true) { return 420; } else if (RANDOM == -1) { return ((5 * 2) + (4 - 1)) / 2; } int timer = 100; bool stopThisMadness = false; while (!stopThisMadness) { do { timer--; } while (timer > 0); stopThisMadness = true; } } //////////////////////////////////////////////////////////// // FIELDS //////////////////////////////////////////////////////////// private: /** * Don't know what this is used for. */ static const int RANDOM = 42; /** * List of lists of stuff. */ std::list <Stuff> stuff_; /** * Specifies the size of this object's uselessness. */ size_t uselessSize_; }; #endif

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  • Collision between sprites in game programming?

    - by Lyn Maxino
    I've since just started coding for an android game using eclipse. I've read Beginning Android Game Programming and various other e-books. Recently, I've encountered a problem with collision between sprites. I've used this code template for my program. package com.project.CAI_test; import java.util.Random; import android.graphics.Bitmap; import android.graphics.Canvas; import android.graphics.Rect; public class Sprite { // direction = 0 up, 1 left, 2 down, 3 right, // animation = 3 back, 1 left, 0 front, 2 right int[] DIRECTION_TO_ANIMATION_MAP = { 3, 1, 0, 2 }; private static final int BMP_ROWS = 4; private static final int BMP_COLUMNS = 3; private static final int MAX_SPEED = 5; private GameView gameView; private Bitmap bmp; private int x = 0; private int y = 0; private int xSpeed; private int ySpeed; private int currentFrame = 0; private int width; private int height; public Sprite(GameView gameView, Bitmap bmp) { this.width = bmp.getWidth() / BMP_COLUMNS; this.height = bmp.getHeight() / BMP_ROWS; this.gameView = gameView; this.bmp = bmp; Random rnd = new Random(); x = rnd.nextInt(gameView.getWidth() - width); y = rnd.nextInt(gameView.getHeight() - height); xSpeed = rnd.nextInt(MAX_SPEED * 2) - MAX_SPEED; ySpeed = rnd.nextInt(MAX_SPEED * 2) - MAX_SPEED; } private void update() { if (x >= gameView.getWidth() - width - xSpeed || x + xSpeed <= 0) { xSpeed = -xSpeed; } x = x + xSpeed; if (y >= gameView.getHeight() - height - ySpeed || y + ySpeed <= 0) { ySpeed = -ySpeed; } y = y + ySpeed; currentFrame = ++currentFrame % BMP_COLUMNS; } public void onDraw(Canvas canvas) { update(); int srcX = currentFrame * width; int srcY = getAnimationRow() * height; Rect src = new Rect(srcX, srcY, srcX + width, srcY + height); Rect dst = new Rect(x, y, x + width, y + height); canvas.drawBitmap(bmp, src, dst, null); } private int getAnimationRow() { double dirDouble = (Math.atan2(xSpeed, ySpeed) / (Math.PI / 2) + 2); int direction = (int) Math.round(dirDouble) % BMP_ROWS; return DIRECTION_TO_ANIMATION_MAP[direction]; } public boolean isCollition(float x2, float y2) { return x2 > x && x2 < x + width && y2 > y && y2 < y + height; } } The above code only detects collision between the generated sprites and the surface border. What I want to achieve is a collision detection that is controlled by the update function without having to change much of the coding. Probably several lines placed in the update() function. Tnx for any comment/suggestion.

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  • Graphics trouble after resuming from hibernate or suspend

    - by Voyagerfan5761
    I have a Dell Inspiron 2650 (with NVidia graphics, using nouveau drivers) that I'm using to try out Ubuntu. It's all great, except that Hibernate and Suspend aren't usable. Yes, I know that questions about power-save issues are rampant in the Linux support universe, but it seems that every time I find a solution it's for a very specific hardware combination and doesn't apply to me. So anyway, here goes. When I resume from either power-saving mode, I'll get graphics problems anywhere on the range from a few scattered random-colored pixels that won't change; all the way to full-screen patterns that don't change as I move the mouse, hit keys on the keyboard, or even bring up the shutdown dialog using the power button. Those full-screen issues (which may involve stripes with random pixels, partial black screen, or both) always end in me forcing the machine to shut down by holding the power button. I haven't done much testing yet to determine what severity level is most commonly associated with each mode, but I do avoid using either power-save option because of these issues. I'll add info on my hardware as I can gather it (no home internet connection, and this laptop is tethered to my desk by a dead battery and casing degradation). Please feel free to request something specific in the question comments. Hardware Info See this hardinfo report for my system's hardware configuration. (No, my username is not "myuser"; I sanitized hardinfo's output before publishing it.) Screenshots These screenshots are from a relatively mild occurrence, which happened after the second hibernation I took that session. The first one worked great, though I used the wireless card and Firefox heavily between the two hibernation attempts. Take a look at what happened when I opened my home directory in Nautilus and scrolled it: See below for the situations I've tested so far. The real trouble comes when the machine resumes to an unusable state; in such cases I can't even unlock the screen or properly reboot, much less take a screenshot. I have a hunch that putting a CD in the drive will cause such major failures, and I will try that at some point; see related question. Situations Tested Maverick (10.10) Suspend Seems to suspend nicely with nothing running Seems to suspend nicely with flash drive plugged in On resume from suspend with no flash drive, Terminal and gedit running: Funky graphics on top of log output, then blank screen with pixelated cursor; no response to power button (normally will shutdown 60 seconds later) Hibernate Seems to hibernate nicely with nothing running Seems to hibernate nicely with a few apps (Terminal, Mouse preferences) running Seems to not hibernate when flash drive plugged in Seems to not hibernate when System Monitor is running Have encountered failed hibernation (after several hours and one successful hibernate/thaw cycle) with no external media connected and no programs running except normal background stuff Natty LiveCD (11.04_2010-12-22) When I tested it, Natty wouldn't stay logged in. It played part of the login sound and then [ OK ] appeared in the top right corner (white-on-black terminal text) for a few seconds. Then it kicked me back to the Unlock screen. It did that four times before I gave up and just tested suspend from the Unlock screen. Suspend Resumed to vertical gray and black lines 2px (?) wide, then shifted to vertical "jail bars" of black over a black screen with above-described random pixels and mouse pointer. No apparent response to input from mouse (clicking randomly). Keyboard and touchpad unrecognized.

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  • How to place rooms proceduraly (rule based) on in a game word

    - by gardian06
    I am trying to design the algorithm for my level generation which is a rule driven system. I have created all the rules for the system. I have taken care to insure that all rooms make sense in a grid type setup. for example: these rooms could make this configuration The logic flow code that I have so far Door{ Vector3 position; POD orient; // 5 possible values (up is not an option) bool Open; } Room{ String roomRule; Vector3 roomPos; Vector3 dimensions; POD roomOrient; // 4 possible values List doors<Door>; } LevelManager{ float scale = 18f; List usedRooms<Room>; List openDoors<Door> bool Grid[][][]; Room CreateRoom(String rule, Vector3 position, POD Orient){ place recieved values based on rule fill in other data } Vector3 getDimenstions(String rule){ return dimensions of the room } RotateRoom(POD rotateAmount){ rotate all items in the room } MoveRoom(Room toBeMoved, POD orientataion, float distance){ move the position of the room based on inputs } GenerateMap(Vector3 size, Vector3 start, Vector3 end){ Grid = array[size.y][size.x][size.z]; Room floatingRoom; floatingRoom = Room.CreateRoom(S01, start, rand(4)); usedRooms.Add(floatingRoom); for each Door in floatingRoom.doors{ openDoors.Add(door); } // fill used grid spaces floatingRoom = Room.CreateRoom(S02, end, rand(4); usedRooms.Add(floatingRoom); for each Door in floatingRoom.doors{ openDoors.Add(door); } Vector3 nRoomLocation; Door workingDoor; string workingRoom; // fill used grid spaces // pick random door on the openDoors list workingDoor = /*randomDoor*/ // get a random rule nRoomLocation = workingDoor.position; // then I'm lost } } I know that I have to make sure for convergence (namely the end is reachable), and to do this until there are no more doors on the openDoors list. right now I am simply trying to get this to work in 2D (there are rules that introduce 3D), but I am working on a presumption that a rigorous algorithm can be trivially extended to 3D. EDIT: my thought pattern so far is to take an existing open door and then pick a random room (restrictions can be put in later) place that room's center at the doors location move the room in the direction of the doors orientation half the rooms dimension w/respect to that axis then test against the 3D array to see if all the grid points are open, or have been used, or if there is even space to put the room (caseEdge) if caseEdge (which can also occur in between rooms) then put the door on a toBeClosed list, and remove it from the open list (placing a wall or something there). then to do some kind of test that both the start, and the goal are connected, and reachable from each other (each room has nodes for AI, but I don't want to "have" to pull those out to accomplish this). but this logic has the problem for say the U, or L shaped rooms in my example, and then I also have a problem conceptually if the room needs to be rotated.

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  • while loop ignore the event listener

    - by Tamer
    so when i run this code to try to change the background the GUI crashes and gets stuck in a infinite while loop ignoring the event listeners. here is the code: `private Panel getPanel1() { if (panel1 == null) { panel1 = new Panel(); panel1.setLayout(new GridBagLayout()); while(frame.isVisible()){ panel1.addMouseListener(new java.awt.event.MouseAdapter() { public void mouseClicked(java.awt.event.MouseEvent e) { frame.setVisible(false); } }); int r = (int) (Math.random()*255); int g = (int) (Math.random()*255); int b = (int) (Math.random()*255); Color c = new Color(r, g, b); panel1.setBackground(c); try { Thread.sleep(4000); } catch (InterruptedException e1) { e1.printStackTrace(); } panel1.addMouseListener(new java.awt.event.MouseAdapter() { public void mouseClicked(java.awt.event.MouseEvent e) { /*panel1.setVisible(false); frame.setVisible(false);*/ System.exit(0); } }); } } return panel1; }` instead of exiting the loop of terminating the program or event changing the background it just displays the panel and does nothing else and i have to force it to quit. what should i do?

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  • picturebox image randomisation C#

    - by cheesebunz
    Hi everyone, i am working on a puzzle slider program and trying to randomize images inside of pictureboxes. I did some research on the internet can't find any examples i could work on. These are my code: Random r = new Random(); PictureBox[] picBox = new PictureBox[9]; picBox[0] = new PictureBox(); picBox[1] = new PictureBox(); picBox[2] = new PictureBox(); picBox[3] = new PictureBox(); picBox[4] = new PictureBox(); picBox[5] = new PictureBox(); picBox[6] = new PictureBox(); picBox[7] = new PictureBox(); picBox[8] = new PictureBox(); i have bitmap array too: Bitmap[] pictures = new Bitmap[9]; pictures[0] = new Bitmap(@"1.1Bright.jpg"); pictures[1] = new Bitmap(@"1.2Bright.jpg"); pictures[2] = new Bitmap(@"1.3Bright.jpg"); pictures[3] = new Bitmap(@"2.1Bright.jpg"); pictures[4] = new Bitmap(@"2.2Bright.jpg"); pictures[5] = new Bitmap(@"2.3Bright.jpg"); pictures[6] = new Bitmap(@"3.1Bright.jpg"); pictures[7] = new Bitmap(@"3.2Bright.jpg"); pictures[8] = new Bitmap(@"3.3Dark.jpg"); i tried a few ways but i don't know how to set random pictures[] into the picBox[]: for(int i=0; i<=8;i++) { picBox[i].Image= pictures[r.Next(0,9)]; } the problem here is that some pictureboxes e.g picBox[1] and picBox[6] are repeated pictures. How do i make them non repeats? Examples are greatly appreciated thanks.

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  • cleaning up noise in an edge detection algoritum

    - by Faken
    I recently wrote an extremely basic edge detection algorithm that works on an array of chars. The program was meant to detect the edges of blobs of a single particular value on the array and worked by simply looking left, right, up and down on the array element and checking if one of those values is not the same as the value it was currently looking at. The goal was not to produce a mathematical line but rather a set of ordered points that represented a descritized closed loop edge. The algorithm works perfectly fine, except that my data contained a bit of noise hence would randomly produce edges where there should be no edges. This in turn wreaked havoc on some of my other programs down the line. There is two types of noise that the data contains. The first type is fairly sparse and somewhat random. The second type is a semi continuous straight line on the x=y axis. I know the source of the first type of noise, its a feature of the data and there is nothing i can do about it. As for the second type, i know it's my program's fault for causing it...though i haven't a hot clue exactly what is causing it. My question is: How should I go about removing the noise completely? I know that the correct data has points that are always beside each other and is very compact and ordered (with no gaps) and is a closed loop or multiple loops. The first type of noise is usually sparse and random, that could be easily taken care of by checking if any edges is next that noise point is also counted as an edge. If not, then the point is most defiantly noise and should be removed. However, the second type of noise, where we have a semi continuous line about x=y poses more of a problem. The line is sometimes continuous for random lengths (the longest was it went half way across my entire array unbroken). It is even possible for it to intersect the actual edge. Any ideas on how to do this?

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