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• How should I manage/declare dependencies between open source C# projects?

  - by munificent

  I've got a game (a roguelike to be specific) in C# that I'm in the process of cleaning up to open source. One step I'd like to take is splitting it into three distinct pieces: A simple package of utility classes, things like 2D arrays, vectors, etc. A terminal UI package that gives you a curses-like display. It depends on 1. The actual game, which uses 1 and 2. Right now, these are all separate projects in the same solution, but I'd kind of like to make them completely separate projects (in the "open source project" sense, not the "visual studio project" use of the term) with their own names and repos. I think, at the very least, #1 is generally useful even if you aren't building game, and I don't want someone to have to build an entire game just to get some handy functions. What I'm not sure about is how to handle the dependencies if I split up the solution. If someone decides they want to sync the game, how should I ensure they also get 1 and 2? Include the built dependent .dlls in the games repo? Just document, "you need these other projects and they must be in a path relative to the game like this". Just leave it all one giant solution and a single repo. Something I'm not thinking of?

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• Android game logic problem

  - by semajhan

  I'm currently creating a game and have a problem which I think I know why it is occurring but not entirely sure and even if I knew, don't know how to solve. I have a 2D array 10 x 10 and have a "player" class that takes up a tile. Now, I have created 2 instances of the player and move them around via swiping. Around the edges I have put "walls" that the player cannot walk through and everything works fine, until I remove a wall. Once I remove a wall and move the character/player to the edge of the screen, the player cannot go any further. The problem occurs here, where the second instance of the player is not at the edge of the screen but say 2 tiles from the first instance of "player" who is at the edge. If I try moving them further into the direction of the edge, I understand that the first instance of player wouldn't move or do anything but the second instance of player should still move, but it won't. This is the code that executed when the user swipes: if (player.getArrayX() - 1 != player2.getArrayX()) { player.moveLeft(); } else if (player.getArrayX() - 1 == player2.getArrayX() && player.getArrayY() != player2.getArrayY()) { player.moveLeft(); } if (player2.getArrayX() - 1 != player.getArrayX()) { player2.moveLeft(); } else if (player2.getArrayX() - 1 == player.getArrayX() && player2.getArrayY() != player.getArrayY()) { player2.moveLeft(); } In the player class I have: public void moveLeft() { if (alive) { switch (levelMaster.getLevel1(getArrayX() - 1, getArrayY())) { case 0: break; case 1: subX(); // basically moves player left setArrayX(getArrayX() - 1); // shifts x coord of player 1 within tilemap Log.d("semajhan", "x: " + getArrayX()); break; case 9: subX(); setArrayX(getArrayX() - 1); setAlive(false); break; } } } Any help on the matter or further insight would be greatly appreciated, thanks.

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• Rapid taps on an OpenGL ES app introducing input delay

  - by Tim R.

  I am starting out writing a 2D game in OpenGL ES, and I have encountered an odd problem: if I rapidly tap the touchscreen, the input starts lagging behind the display. The more times I tap, the more delay it causes between the input and any indication of that input onscreen. It only happens if I intentionally tap very rapidly, but not from tapping and dragging with any number of fingers. What could be causing this? Excessive details follow: Both accelerometer input and taps are delayed by just tapping. The only events I am responding to are touchesBegan (below) in my EAGLView and accelerometer:(UIAccelerometer *)accelerometer didAccelerate:(UIAcceleration *)acceleration in my Game object. There doesn't seem to be any upper limit to the amount of delay: I've gotten up to 12 seconds of delay by tapping rapidly with five fingers. I have not seen any drops in framerate (it stays constantly at 60 fps) in the OpenGL ES tool in Instruments or by taking 1/the time between updates. Possibly relevant code: - (void) drawView:(id) sender { [game update:allTouches]; [renderer render:game]; } -(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event { allTouches = [event allTouches]; } allTouches is a pointer that gets passed to my Game every update, which passes it to each GameObject in their update methods.

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• What library to choose to build a user interface for a C++ software that uses SDL

  - by Barth

  Dear all, I have a simulation software (C++) that runs on the command line. It is platform independent (currently compiling and running on Windows, MacOS X and Linux). When the simulation ends, I visualize the result with SDL; it is a very basic 2d view, mainly color squares next to each other. I would like to have a user interface on top of the simulation so that I can start and pause the simulation, and change the parameters on the fly. Something pretty simple I guess. Well, ideally I will also add a grapher somewhere to see the evolution over time of some parameters. Now, I am wondering what direction I should go. Should I try to use one of the UI libraries for SDL ? Or maybe wxwidget in conjunction with SDL ? Or simply wxwidget and get rid of SDL ? Do you have any experience with this ? Thanks in advance Barth PS: I tried to use AGAR, a SDL UI library. It seemed very promising but I couldn't get it working. Not even the helloworld.

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• What's the proper approach for writing multi-path "story" flows?

  - by Basiclife

  Hi, I wonder if you can help me. I'm writing a game (2d) which allows players to take multiple routes, some of which branch/merge - perhaps even loop. Each section of the game will decide which section is loaded next. I'm calling each section an IStoryElement - And I'm wondering how best to link these elements up in a way that is easily changed/configured and at the same time, graphable I'm going to have an engine/factory assembly which will load the appropriate StoryElement(s) based on various config options. I initially planned to give each StoryElement a NextElement() As IStoryElement property and a Completed() event. When the vent fires, the engine reads the NextElement property to find the next StoryElement. The downside to this is that if I ever wanted to graph all the routes through the game, I would be unable to - I couldn't determine all possible targets for each StoryElement. I considered a couple of other solutions but they all feel a little clunky - eg Do I need an additional layer of abstraction? ie StoryElementPlayers or similar - Each one would be responsible for stringing together multiple StoryElement perhaps a Series and a ChoicePlayer with each responsible for graphing its own StoryElement - But this will just move the problem up a layer. In short, I need some way of emulating a simple but dynamic workflow (but I'd rather not actually use WWF). Is there a pattern for something this simple? All the ones I've managed to find relate to more advanced control flow (parallel processing, etc.)

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• Computation overhead in C# - Using getters/setters vs. modifying arrays directly and casting speeds

  - by Jeffrey Kern

  I was going to write a long-winded post, but I'll boil it down here: I'm trying to emulate the graphical old-school style of the NES via XNA. However, my FPS is SLOW, trying to modify 65K pixels per frame. If I just loop through all 65K pixels and set them to some arbitrary color, I get 64FPS. The code I made to look-up what colors should be placed where, I get 1FPS. I think it is because of my object-orented code. Right now, I have things divided into about six classes, with getters/setters. I'm guessing that I'm at least calling 360K getters per frame, which I think is a lot of overhead. Each class contains either/and-or 1D or 2D arrays containing custom enumerations, int, Color, or Vector2D, bytes. What if I combined all of the classes into just one, and accessed the contents of each array directly? The code would look a mess, and ditch the concepts of object-oriented coding, but the speed might be much faster. I'm also not concerned about access violations, as any attempts to get/set the data in the arrays will done in blocks. E.g., all writing to arrays will take place before any data is accessed from them. As for casting, I stated that I'm using custom enumerations, int, Color, and Vector2D, bytes. Which data types are fastest to use and access in the .net Framework, XNA, XBox, C#? I think that constant casting might be a cause of slowdown here. Also, instead of using math to figure out which indexes data should be placed in, I've used precomputed lookup tables so I don't have to use constant multiplication, addition, subtraction, division per frame. :)

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• OpenGL Mipmapping: how does OpenGL decide on map level?

  - by Droozle

  Hi, I am having trouble implementing mipmapping in OpenGL. I am using OpenFrameworks and have modified the ofTexture class to support the creation and rendering of mipmaps. The following code is the original texture creation code from the class (slightly modified for clarity): glEnable(texData.textureTarget); glBindTexture(texData.textureTarget, (GLuint)texData.textureID); glTexSubImage2D(texData.textureTarget, 0, 0, 0, w, h, texData.glType, texData.pixelType, data); glTexParameteri(texData.textureTarget, GL_TEXTURE_MAG_FILTER, GL_LINEAR); glTexParameteri(texData.textureTarget, GL_TEXTURE_MIN_FILTER, GL_LINEAR); glDisable(texData.textureTarget); This is my version with mipmap support: glEnable(texData.textureTarget); glBindTexture(texData.textureTarget, (GLuint)texData.textureID); gluBuild2DMipmaps(texData.textureTarget, texData.glTypeInternal, w, h, texData.glType, texData.pixelType, data); glTexParameteri(texData.textureTarget, GL_TEXTURE_MAG_FILTER, GL_LINEAR_MIPMAP_LINEAR); glTexParameteri(texData.textureTarget, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR); glDisable(texData.textureTarget); The code does not generate errors (gluBuild2DMipmaps returns '0') and the textures are rendered without problems. However, I do not see any difference. The scene I render consists of "flat, square tiles" at z=0. It's basically a 2D scene. I zoom in and out by using "glScale()" before drawing the tiles. When I zoom out, the pixels of the tile textures start to "dance", indicating (as far as I can tell) unfiltered texture look-up. See: http://www.youtube.com/watch?v=b_As2Np3m8A at 25s. My question is: since I do not move the camera position, but only use scaling of the whole scene, does this mean OpenGL can not decide on the appropriate mipmap level and uses the full texture size (level 0)? Paul

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• Vector deltas and moving in unknown areas

  - by dekz

  Hi All, I was in need of a little math help that I can't seem to find the answer to, any links to documentation would be greatly appreciated. Heres my situation, I have no idea where I am in this maze, but I need to move around and find my way back to the start. I was thinking of implementing a waypoint list of places i've been offset from my start at 0,0. This is a 2D cartesian plane. I've been given 2 properties, my translation speed from 0-1 and my rotation speed from -1 to 1. -1 is very left and +1 is very right. These are speed and not angles so thats where my problem lies. If I'm given 0 as a translation speed and 0.2 I will continually turn to my right at a slow speed. How do I figure out the offsets given these 2 variables? I can store it every time I take a 'step'. I just need to figure out the offsets in x and y terms given the translations and rotation speeds. And the rotation to get to those points. Any help is appreciated.

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• Using java to create a logistic model - arrays and properties

  - by Oliver Burdekin

  I'm currently trying to create a java model that will solve a problem we have. On a voluntary expedition each week we have some people leaving and some new people arriving. Accommodation is in tents. The tents sleep different numbers of people and certain rules apply. Males and females cannot be mixed and volunteers can be one of four types - school children/ research assistants/ scientific staff/ school teachers So types of volunteer and sexes cannot be mixed. Each week the manager spends hours trying to work this out so I've offered to make this model to keep my coding skills up. At present I'm working with arrays. Each tent is a 2D array [4][x] where x is the number of people it sleeps (each person sleeping there has 4 attributes). Each person is a 1D array with 4 attributes [4]. The idea is to check where people can go, cause the minimum movement for people staying on and solve this logistic problem. Does anyone have any better suggestions as to how to solve this? At present I'm finding it necessary to write a lot of code setting up and querying arrays. Any help is appreciated.

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• How can i create an n-dimensional array in c

  - by shortCircuit

  I was thinking of making a function that would accept the size of array as a parameter and create a n dimensional array. My room-mate took the liberty of making it complex. He said lets write a function that takes n parameters and returns an n-dimensional array using those parameters as the dimensions. Now i realize an one-day and d array is easy to implement with pointers. For 2d array the snippet would be something like (standard way) : int** x; int* temp; x = (int**)malloc(m * sizeof(int*)); temp = (int*)malloc(m*n * sizeof(int)); for (int i = 0; i < m; i++) { x[i] = temp + (i * n); } where the array is of size m*n; But the problem lies how do we find the nested loop parameters for a n-dimensional array? Is there any way to optimize the code?

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• Detect mouseover and show tooltip text for dots on an HTML Canvas

  - by carl asquith

  Ive recently created a "map" although not very sophisticated (im working on it) it has the basic function and is generally heading in the right direction. If you look at it you can see a tiny red dots and on those tiny red dots i want to mouseover it and see text basically but ive had a bit of trouble getting the code right. http://hummingbird2.x10.mx/website%20creation/mainpage.htm This is all the code so far. <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN""http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Oynx Warrior</title> <link rel="stylesheet" type="text/css" href="mystyle.css" /> </head> <body> <h1>Oynx Warrior</h1> <canvas id="myCanvas" width="500" height="500" style="border:1px solid #c3c3c3;"> Your browser does not support the canvas element. </canvas> <script type="text/javascript"> var c=document.getElementById("myCanvas"); var cxt=c.getContext("2d"); cxt.fillStyle="#red"; cxt.beginPath(); cxt.arc(50,50,1,0,Math.PI*2,true); cxt.closePath(); cxt.fill(); </script> </body> </html>

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• Why does this javascript code have an infinite loop?

  - by asdas

  optionElements is a 2d array. Each element has an array of length 2. These are an integer number and an element. I have a select list called linkbox, and i want to add all of the elements to the select list. The order I want them to go in is important, and is determined by the number each element has. It should be smallest to highest. So think of it like this: optionElements is: [ [5, <option>], [3, <option], [4, <option], [1, <option], [2, <option]] and it would add them to link box in order of those numbers. BUT that is not what happens. It is an infinite loop after the first time. I added the x constraint just to stop it from freezing my browser but you can ignore it. var b; var smallest; var samllestIndex; var x = 0; while(optionElements.length > 0 && ++x < 100) { smallestIndex = 0; smallest = optionElements[0][0]; b = 0; while( ++b < optionElements.length) { if(optionElements[b][0] > smallest) { smallestIndex = b; smallest = optionElements[b][0]; } } linkbox.appendChild(optionElements[smallestIndex][1]); optionElements.unshift(optionElements[smallestIndex]); } can someone point out to me where my problem is?

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• Efficient mapping of game entity positions in Java

  - by byte

  In Java (Swing), say I've got a 2D game where I have various types of entities on the screen, such as a player, bad guys, powerups, etc. When the player moves across the screen, in order to do efficient checking of what is in the immediate vicinity of the player, I would think I'd want indexed access to the things that are near the character based on their position. For example, if player 'P' steps onto element 'E' in the following example... | | | | | | | | | |P| | | | |E| | | | | | | | | ... would be to do something like: if(player.getPosition().x == entity.getPosition().x && entity.getPosition.y == thing.getPosition().y) { //do something } And thats fine, but that implies that the entities hold their positions, and therefor if I had MANY entities on the screen I would have to loop through all possible entities available and check each ones position against the player position. This seems really inefficient especially if you start getting tons of entities. So, I would suspect I'd want some sort of map like Map<Point, Entity> map = new HashMap<Point, Entity>(); And store my point information there, so that I could access these entities in constant time. The only problem with that approach is that, if I want to move an entity to a different point on the screen, I'd have to search through the values of the HashMap for the entity I want to move (inefficient since I dont know its Point position ahead of time), and then once I've found it remove it from the HashMap, and re-insert it with the new position information. Any suggestions or advice on what sort of data structure / storage format I ought to be using here in order to have efficient access to Entities based on their position, as well as Position's based on the Entity?

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• Read char from txt file in C++

  - by Jack in the Box

  I have a program that will read the number of rows and columns from a txt file. Also, the program has to read the contents of a 2D array from the same file. Here is the txt file 8 20 * * *** *** 8 and 20 are the number of rows and columns respectively. The spaces and asterisks are the contents of the array, Array[8][20] For example, Array[0][1] = '*' I did make the program reading 8 and 20 as follow: ifstream myFile; myFile.open("life.txt"); if(!myFile) { cout << endl << "Failed to open file"; return 1; } myFile >> rows >> cols; myFile.close(); grid = new char*[rows]; for (int i = 0; i < rows; i++) { grid[i] = new char[cols]; } Now, how to assign the spaces and the asterisks to to the fields in the array? I hope you got the point.

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• how to add data in Table of Jasper Report using Java

  - by Areeb Gillani

  i am here to ask you just a simple question that i am trying to pass data to a jasper report using java but i dont know how to to, because the table data is very dynamic thats y cannot pass sql query. any idea for this. i have a 2D array of object type, where i have all the data... so how can i pass that... Thanx in advance...!:) ConnectionManager con = new ConnectionManager(); con.establishConnection(); String fileName = "Pmc_Bill.jrxml"; String outFileName = "OutputReport.pdf"; HashMap params = new HashMap(); params.put("PName", pname); params.put("PSerial", psrl); params.put("PGender",pgen); params.put("PPhone",pph); params.put("PAge",page); params.put("PRefer",pref); params.put("PDateR",dateNow); try { JasperReport jasperReport = JasperCompileManager.compileReport(fileName); if(jasperReport != null ) System.out.println("so far so good "); // Fill the report using an empty data source JasperPrint jasperPrint = JasperFillManager.fillReport(jasperReport, params, new JRTableModelDataSource(tbl.getModel()));//con.connection); try{ JasperExportManager.exportReportToPdfFile(jasperPrint, outFileName); System.out.printf("File exported sucessfully"); }catch(Exception e){ e.printStackTrace(); } JasperViewer.viewReport(jasperPrint); } catch (JRException e) { JOptionPane.showMessageDialog(null, e); e.printStackTrace(); System.exit(1); }

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• Two dimensional strings in C++

  - by dada

  I want to write something like 2d strings in C++. I tried with : vector< vector<string> > table; int m,n,i,j; string s; cin>>n>>m; for(i=0;i<n;i++) { for(j=0;j<m;j++) { cin>>s; table[i][j] = s; } } cout << "\n\n\n\n"; for(i=0;i<n;i++) { for(j=0;j<m;j++) { cout<<table[i][j]<<" "; } cout<<"\n"; } no compile errors, but when i enter input like: 10 20 .....#.............. .....#.............. .....#.............. .....#.............. ######.............. .......###.......... .......#.#.......... .......###...####### .............#.....# .............####### It gives me segmentation fault. Why ? What's wrong ? And how it should be done so it would work correctly ? Thank you.

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• OpenGL Pixel Format Attributes (NSOpenGLPixelFormatAttibutes) explanation?

  - by nacho4d

  Hi, I am not new to OpenGL, but not an expert. Many tutorials teach how to draw, 3D, 2D, projections, orthogonal, etc, but How about setting a the view? (NSOpenGLView in Cocoa, Macs). For example I have this: - (id) initWithFrame: (NSRect) frame { GLuint attribs[] = { //PF: PixelAttibutes NSOpenGLPFANoRecovery, NSOpenGLPFAWindow, NSOpenGLPFAAccelerated, NSOpenGLPFADoubleBuffer, NSOpenGLPFAColorSize, 24, NSOpenGLPFAAlphaSize, 8, NSOpenGLPFADepthSize, 24, NSOpenGLPFAStencilSize, 8, NSOpenGLPFAAccumSize, 0, 0 }; NSOpenGLPixelFormat* fmt = [[NSOpenGLPixelFormat alloc] initWithAttributes: (NSOpenGLPixelFormatAttribute*) attribs]; return self = [super initWithFrame:frame pixelFormat: [fmt autorelease]]; } And I don't understand very well their usage, specially when combining them. For example: If I want my view to be capable of full screen should I write NSOpenGLPFAFullScreen only ? or both? (by capable I mean not always in full screen) Regarding Double Buffer, what is this exactly? (Below: Apple's definition) If present, this attribute indicates that only double-buffered pixel formats are considered. Otherwise, only single-buffered pixel formats are considered Regarding Color: if NSOpenGLPFAColorSize is 24 and NSOpenGLPFAColorSize is 8 then it means that alpha and RGB components are treated differently? what happen if I set the former to 32 and the later to 0? Etc, etc,In general how do I learn to set my view from scratch? Thanks in advance. Ignacio.

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• Python lists/arrays: disable negative indexing wrap-around

  - by wim

  While I find the negative number wraparound (i.e. A[-2] indexing the second-to-last element) extremely useful in many cases, there are often use cases I come across where it is more of an annoyance than helpful, and I find myself wishing for an alternate syntax to use when I would rather disable that particular behaviour. Here is a canned 2D example below, but I have had the same peeve a few times with other data structures and in other numbers of dimensions. import numpy as np A = np.random.randint(0, 2, (5, 10)) def foo(i, j, r=2): '''sum of neighbours within r steps of A[i,j]''' return A[i-r:i+r+1, j-r:j+r+1].sum() In the slice above I would rather that any negative number to the slice would be treated the same as None is, rather than wrapping to the other end of the array. Because of the wrapping, the otherwise nice implementation above gives incorrect results at boundary conditions and requires some sort of patch like: def ugly_foo(i, j, r=2): def thing(n): return None if n < 0 else n return A[thing(i-r):i+r+1, thing(j-r):j+r+1].sum() I have also tried zero-padding the array or list, but it is still inelegant (requires adjusting the lookup locations indices accordingly) and inefficient (requires copying the array). Am I missing some standard trick or elegant solution for slicing like this? I noticed that python and numpy already handle the case where you specify too large a number nicely - that is, if the index is greater than the shape of the array it behaves the same as if it were None.

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• Efficient way to get highly correlated pairs from large data set in Python or R

  - by Akavall

  I have a large data set (Let's say 10,000 variables with about 1000 elements each), we can think of it as 2D list, something like: [[variable_1], [variable_2], ............ [variable_n] ] I want to extract highly correlated variable pairs from that data. I want "highly correlated" to be a parameter that I can choose. I don't need all pairs to be extracted, and I don't necessarily want the most correlated pairs. As long as there is an efficient method that gets me highly correlated pairs I am happy. Also, it would be nice if a variable does not show up in more than one pair. Although this might not be crucial. Of course, there is a brute force way to finding such pairs, but it is too slow for me. I've googled around for a bit and found some theoretical work on this issue, but I wasn't able for find a package that could do what I am looking for. I mostly work in python, so a package in python would be most helpful, but if there exists a package in R that does what I am looking for it will be great. Does anyone know of a package that does the above in Python or R? Or any other ideas? Thank You in Advance

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• C# struct with an array

  - by Whitey

  I am making a game using C# with the XNA framework. The player is a 2D soldier on screen and the user is able to fire bullets. The bullets are stored in an array. I have looked into using Lists and arrays for this and I came to the conclusion that an array is a lot better for me, as there will be a lot of bullets firing and being destroyed at once, something that I read Lists don't handle so well. After reading through some posts on the XNA forums, this came to my attention: http://forums.xna.com/forums/p/16037/84353.aspx I have created a struct like so: // Bullets struct Bullet { Vector2 Position; Vector2 Velocity; float Rotation; Rectangle BoundingRect; bool Active; } And I made the array like this: Bullet[] bulletCollection = new Bullet[100]; But when I try to do some code like this: // Fire bullet if (mouseState.LeftButton == ButtonState.Pressed) { for (int i = 0; i < bulletCollection.Length; i++) { if (!bulletCollection[i].Active) { // something } } I get the following error: 'Zombie_Apocalypse.Game1.Bullet.Active' is inaccessible due to its protection level Can anyone lend a hand? I have no idea why this error is popping up, or even if I'm declaring the array properly or anything... as the post on the XNA forums doesn't go into detail about that. Thank you for any help you can provide. :)

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• Optimization of a c++ matrix/bitmap class

  - by Andrew

  I am searching a 2D matrix (or bitmap) class which is flexible but also fast element access. The contents A flexible class should allow you to choose dimensions during runtime, and would look something like this (simplified): class Matrix { public: Matrix(int w, int h) : data(new int[x*y]), width(w) {} void SetElement(int x, int y, int val) { data[x+y*width] = val; } // ... private: // symbols int width; int* data; }; A faster often proposed solution using templates is (simplified): template <int W, int H> class TMatrix { TMatrix() data(new int[W*H]) {} void SetElement(int x, int y, int val) { data[x+y*W] = val; } private: int* data; }; This is faster as the width can be "inlined" in the code. The first solution does not do this. However this is not very flexible anymore, as you can't change the size anymore at runtime. So my question is: Is there a possibility to tell the compiler to generate faster code (like when using the template solution), when the size in the code is fixed and generate flexible code when its runtime dependend? I tried to achieve this by writing "const" where ever possible. I tried it with gcc and VS2005, but no success. This kind of optimization would be useful for many other similar cases.

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• Parallelize or vectorize all-against-all operation on a large number of matrices?

  - by reve_etrange

  I have approximately 5,000 matrices with the same number of rows and varying numbers of columns (20 x ~200). Each of these matrices must be compared against every other in a dynamic programming algorithm. In this question, I asked how to perform the comparison quickly and was given an excellent answer involving a 2D convolution. Serially, iteratively applying that method, like so list = who('data_matrix_prefix*') H = cell(numel(list),numel(list)); for i=1:numel(list) for j=1:numel(list) if i ~= j eval([ 'H{i,j} = compare(' char(list(i)) ',' char(list(j)) ');']); end end end is fast for small subsets of the data (e.g. for 9 matrices, 9*9 - 9 = 72 calls are made in ~1 s). However, operating on all the data requires almost 25 million calls. I have also tried using deal() to make a cell array composed entirely of the next element in data, so I could use cellfun() in a single loop: # who(), load() and struct2cell() calls place k data matrices in a 1D cell array called data. nextData = cell(k,1); for i=1:k [nextData{:}] = deal(data{i}); H{:,i} = cellfun(@compare,data,nextData,'UniformOutput',false); end Unfortunately, this is not really any faster, because all the time is in compare(). Both of these code examples seem ill-suited for parallelization. I'm having trouble figuring out how to make my variables sliced. compare() is totally vectorized; it uses matrix multiplication and conv2() exclusively (I am under the impression that all of these operations, including the cellfun(), should be multithreaded in MATLAB?). Does anyone see a (explicitly) parallelized solution or better vectorization of the problem?

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• is there a Java GUI for dummies ?

  - by MHero

  Hello, first I want to apologize about my english, it may be not clear enough. Well, I'm new to Java programming, and I search over this web about use of Swing, AWT, 2D, etc. but I didn't get the answer I was looking for. I want to know about a book or method to learn Java GUI programming (not even sure this is a propper term). Previous answers guide me to Filthy Rich Clients by Romain Guy and also to The Swing Tutorial in Sun Web Page. and No offense, but...the first one seems too complex and the second one a bit disorganize. so I ask about a more "for dummies" method. Thanks EDIT: Thanks everyboy, you're very kind and serious. I want to clear some things that I didn't state for being my first question. I dont' want to use autogenerated code(Don't want to say why only focus on my question for consistency) Also I've read Deitel & Deitel and it's a good beginners book but it seems to me that doesn't cover layout(and other details) Finally, I tried to read netbeans generated code but it's a mess find method by method and function by function the way that the IDE does it I hope this edition helps to solve my question

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• Use of Java [Interfaces / Abstract classes]

  - by Samuel

  Hello, Lately i decided to take a look at Java so i am still pretty new to it and also to the approach of OO programming, so i wanted to get some things straight before learning more, (i guess it's never to soon to start with good practices). I am programming a little 2D game for now but i think my question applies to any non trivial project. For the simplicity i'll provide examples from my game. I have different kinds of zombies, but they all have the same attributes (x, y, health, attack etc) so i wrote an interface Zombie which i implement by WalkingZombie, RunningZombie TeleportingZombie etc. Is this the best thing to do? Am i better of with an abstract class? Or with a super class? (I am not planning to partially implement functions - therefor my choice for an interface instead of an abstract class) I have one class describing the main character (Survivor) and since it is pretty big i wanted to write an interface with the different functions, so that i can easily see and share the structure of it. Is it good practice? Or is it simply a waste of space and time? I hope this question will not be rated as subjective because i thought that experienced programmers won't disagree about this kind of topic since the use of interfaces / super classes / abstract classes follows logical rules and is thereby not simply a personal choice. Thank you for your time -Samuel

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• C++: Vector of objects vs. vector of pointers to new objects?

  - by metamemetics

  Hello, I am seeking to improve my C++ skills by writing a sample software renderer. It takes objects consisting of points in a 3d space and maps them to a 2d viewport and draws circles of varying size for each point in view. Which is better: class World{ vector<ObjectBaseClass> object_list; public: void generate(){ object_list.clear(); object_list.push_back(DerivedClass1()); object_list.push_back(DerivedClass2()); or... class World{ vector<ObjectBaseClass*> object_list; public: void generate(){ object_list.clear(); object_list.push_back(new DerivedClass1()); object_list.push_back(new DerivedClass2()); ?? Would be using pointers in the 2nd example to create new objects defeat the point of using vectors, because vectors automatically call the DerivedClass destructors in the first example but not in the 2nd? Are pointers to new objects necessary when using vectors because they handle memory management themselves as long as you use their access methods? Now let's say I have another method in world: void drawfrom(Viewport& view){ for (unsigned int i=0;i<object_list.size();++i){ object_list.at(i).draw(view); } } When called this will run the draw method for every object in the world list. Let's say I want derived classes to be able to have their own versions of draw(). Would the list need to be of pointers then in order to use the method selector (-) ?

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