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  • Enabling Code Coverage in Visual Studio 2010

    - by Anthony Trudeau
    You'll quickly find out that enabling code coverage in Visual Studio 2010 has changed.  With the new version you enable this functionality through the test settings.  The following steps will enable code coverage: Open the local.testsettings which you can access from Test -> Edit Test Settings -> Local (local.testsettings) Select Data and Diagnostics from the list Select the Enabled checkbox on the Code Coverage row Double-click the Code Coverage row Select the assemblies you want to instrument Specify a re-signing key file if your assemblies are strong-named Click OK Click Apply Click Close

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  • How do I draw a scene with 2 nested frames

    - by Guido Granobles
    I have been trying for long time to figure out this: I have loaded a model from a directx file (I am using opengl and Java) the model have a hierarchical system of nested reference frames (there are not bones). There are just 2 frames, one of them is called x3ds_Torso and it has a child frame called x3ds_Arm_01. Each one of them has a mesh. The thing is that I can't draw the arm connected to the body. Sometimes the body is in the center of the screen and the arm is at the top. Sometimes they are both in the center. I know that I have to multiply the matrix transformation of every frame by its parent frame starting from the top to the bottom and after that I have to multiply every vertex of every mesh by its final transformation matrix. So I have this: public void calculeFinalMatrixPosition(Bone boneParent, Bone bone) { System.out.println("-->" + bone.name); if (boneParent != null) { bone.matrixCombined = bone.matrixTransform.multiply(boneParent.matrixCombined); } else { bone.matrixCombined = bone.matrixTransform; } bone.matrixFinal = bone.matrixCombined; for (Bone childBone : bone.boneChilds) { calculeFinalMatrixPosition(bone, childBone); } } Then I have to multiply every vertex of the mesh: public void transformVertex(Bone bone) { for (Iterator<Mesh> iterator = meshes.iterator(); iterator.hasNext();) { Mesh mesh = iterator.next(); if (mesh.boneName.equals(bone.name)) { float[] vertex = new float[4]; double[] newVertex = new double[3]; if (mesh.skinnedVertexBuffer == null) { mesh.skinnedVertexBuffer = new FloatDataBuffer( mesh.numVertices, 3); } mesh.vertexBuffer.buffer.rewind(); while (mesh.vertexBuffer.buffer.hasRemaining()) { vertex[0] = mesh.vertexBuffer.buffer.get(); vertex[1] = mesh.vertexBuffer.buffer.get(); vertex[2] = mesh.vertexBuffer.buffer.get(); vertex[3] = 1; newVertex = bone.matrixFinal.transpose().multiply(vertex); mesh.skinnedVertexBuffer.buffer.put(((float) newVertex[0])); mesh.skinnedVertexBuffer.buffer.put(((float) newVertex[1])); mesh.skinnedVertexBuffer.buffer.put(((float) newVertex[2])); } mesh.vertexBuffer = new FloatDataBuffer( mesh.numVertices, 3); mesh.skinnedVertexBuffer.buffer.rewind(); mesh.vertexBuffer.buffer.put(mesh.skinnedVertexBuffer.buffer); } } for (Bone childBone : bone.boneChilds) { transformVertex(childBone); } } I know this is not the more efficient code but by now I just want to understand exactly how a hierarchical model is organized and how I can draw it on the screen. Thanks in advance for your help.

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  • Can't start Eclipse Juno (Ubuntu 12.10)

    - by Maik Klein
    I installed eclipse though the unbuntu software center but I experienced some issues and I wanted to install the official eclipse version. I downloaded eclipse classic 4.2.1 http://www.eclipse.org/downloads/download.php?file=/eclipse/downloads/drops4/R-4.2.1-201209141800/eclipse-SDK-4.2.1-linux-gtk-x86_64.tar.gz Extracted it, but if I double click "eclipse" it doesn't do anything. Any ideas how I can fix this?

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  • Silverlight Cream for May 12, 2010 -- #860

    - by Dave Campbell
    In this Issue: Miroslav Miroslavov(-2-), Mike Snow(-2-, -3-), Paul Sheriff, Fadi Abdelqader, Jeremy Likness, Marlon Grech, and Victor Gaudioso. Shoutouts: Andy Beaulieu has a cool WP7 game up and is looking for opinions/comments: Droppy Pop: A Windows Phone 7 Game Karl Shifflett has code and video tutorials up for the app he wrote for the WPF LOB tour he just did: Stuff – WPF Line of Business Using MVVM Video Tutorial From SilverlightCream.com: Flipping panels I had missed this 3rd part of the CompleteIT explanation. In this post Miroslav Miroslavov describes the page flipping they're doing. Great explanation and all the code included. Flying objects against you The 4th part of the CompleteIT explanation is blogged by Miroslav Miroslavov where he is discussing the screen elements 'flying toward' the user. Silverlight Tip of the Day #17 – Double Click Mike Snow's Tip of the Day 17 is showing how to implement mouse double-clicks either for an individual control or for an entire app. Silverlight Tip of the Day #18 – Elastic Scrolling In Mike Snow's Tip of the Day 18, he's talking about and showing some 'elastic' scrolling in his image viewer application. He's asking for opinions and suggestions. Silverlight Tip of the Day #19 – Using Bing Maps in Silverlight Mike Snow's Tips are getting more elaborate :) ... Number 19 is about using the BingMap control in your Silverlight app. Control to Control Binding in WPF/Silverlight Paul Sheriff demonstrates control to control binding... saving a bunch of code behind in the process. Project included. Your First Step to the Silverlight Voice/Video Chatting Client/Server Fadi Abdelqader has a post up at CodeProject using the WebCam and Mic features of Silverlight 4 to setup a voice & video chatting app. MVVM Coding by Convention (Convention over Configuration) Jeremy Likness discusses Convention over Configuration and gives up some good MVVM nuggets along the way... check out his nice long post and grab the source for the project too... and also check out the external links he has in there. MEFedMVVM changes >> from cool to cooler Marlon Grech has refactored MEFedMVVM, and in addition is working with other MVVM framework folks to use some of the same MEF techniques in theirs... code on CodePlex New Silverlight Video Tutorial: How to Create a Silverlight Paging System to Load new Pages In Victor Gaudioso's latest video tutorial he builds a ContentHolder UserControl that will load any page on demand into your MainPage.xaml Stay in the 'Light! Twitter SilverlightNews | Twitter WynApse | WynApse.com | Tagged Posts | SilverlightCream Join me @ SilverlightCream | Phoenix Silverlight User Group Technorati Tags: Silverlight    Silverlight 3    Silverlight 4    Windows Phone MIX10

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  • SEO Keyword Research - What Your SEO Campaign Needs

    If you're operating an online company, whether it is an internet shop or a blog with paid advertisements, sooner or later you'll want to double or triple your profits, and thus you will come face-to-face with internet advertising and search engine optimization (SEO). This is then that you'll realize the value of having relevant keywords. Keyword research is crucial to the entire process of SEO.

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  • How to store generated eigen faces for future face recognition?

    - by user3237134
    My code works in the following manner: 1.First, it obtains several images from the training set 2.After loading these images, we find the normalized faces,mean face and perform several calculation. 3.Next, we ask for the name of an image we want to recognize 4.We then project the input image into the eigenspace, and based on the difference from the eigenfaces we make a decision. 5.Depending on eigen weight vector for each input image we make clusters using kmeans command. Source code i tried: clear all close all clc % number of images on your training set. M=1200; %Chosen std and mean. %It can be any number that it is close to the std and mean of most of the images. um=60; ustd=32; %read and show images(bmp); S=[]; %img matrix for i=1:M str=strcat(int2str(i),'.jpg'); %concatenates two strings that form the name of the image eval('img=imread(str);'); [irow icol d]=size(img); % get the number of rows (N1) and columns (N2) temp=reshape(permute(img,[2,1,3]),[irow*icol,d]); %creates a (N1*N2)x1 matrix S=[S temp]; %X is a N1*N2xM matrix after finishing the sequence %this is our S end %Here we change the mean and std of all images. We normalize all images. %This is done to reduce the error due to lighting conditions. for i=1:size(S,2) temp=double(S(:,i)); m=mean(temp); st=std(temp); S(:,i)=(temp-m)*ustd/st+um; end %show normalized images for i=1:M str=strcat(int2str(i),'.jpg'); img=reshape(S(:,i),icol,irow); img=img'; end %mean image; m=mean(S,2); %obtains the mean of each row instead of each column tmimg=uint8(m); %converts to unsigned 8-bit integer. Values range from 0 to 255 img=reshape(tmimg,icol,irow); %takes the N1*N2x1 vector and creates a N2xN1 matrix img=img'; %creates a N1xN2 matrix by transposing the image. % Change image for manipulation dbx=[]; % A matrix for i=1:M temp=double(S(:,i)); dbx=[dbx temp]; end %Covariance matrix C=A'A, L=AA' A=dbx'; L=A*A'; % vv are the eigenvector for L % dd are the eigenvalue for both L=dbx'*dbx and C=dbx*dbx'; [vv dd]=eig(L); % Sort and eliminate those whose eigenvalue is zero v=[]; d=[]; for i=1:size(vv,2) if(dd(i,i)>1e-4) v=[v vv(:,i)]; d=[d dd(i,i)]; end end %sort, will return an ascending sequence [B index]=sort(d); ind=zeros(size(index)); dtemp=zeros(size(index)); vtemp=zeros(size(v)); len=length(index); for i=1:len dtemp(i)=B(len+1-i); ind(i)=len+1-index(i); vtemp(:,ind(i))=v(:,i); end d=dtemp; v=vtemp; %Normalization of eigenvectors for i=1:size(v,2) %access each column kk=v(:,i); temp=sqrt(sum(kk.^2)); v(:,i)=v(:,i)./temp; end %Eigenvectors of C matrix u=[]; for i=1:size(v,2) temp=sqrt(d(i)); u=[u (dbx*v(:,i))./temp]; end %Normalization of eigenvectors for i=1:size(u,2) kk=u(:,i); temp=sqrt(sum(kk.^2)); u(:,i)=u(:,i)./temp; end % show eigenfaces; for i=1:size(u,2) img=reshape(u(:,i),icol,irow); img=img'; img=histeq(img,255); end % Find the weight of each face in the training set. omega = []; for h=1:size(dbx,2) WW=[]; for i=1:size(u,2) t = u(:,i)'; WeightOfImage = dot(t,dbx(:,h)'); WW = [WW; WeightOfImage]; end omega = [omega WW]; end % Acquire new image % Note: the input image must have a bmp or jpg extension. % It should have the same size as the ones in your training set. % It should be placed on your desktop ed_min=[]; srcFiles = dir('G:\newdatabase\*.jpg'); % the folder in which ur images exists for b = 1 : length(srcFiles) filename = strcat('G:\newdatabase\',srcFiles(b).name); Imgdata = imread(filename); InputImage=Imgdata; InImage=reshape(permute((double(InputImage)),[2,1,3]),[irow*icol,1]); temp=InImage; me=mean(temp); st=std(temp); temp=(temp-me)*ustd/st+um; NormImage = temp; Difference = temp-m; p = []; aa=size(u,2); for i = 1:aa pare = dot(NormImage,u(:,i)); p = [p; pare]; end InImWeight = []; for i=1:size(u,2) t = u(:,i)'; WeightOfInputImage = dot(t,Difference'); InImWeight = [InImWeight; WeightOfInputImage]; end noe=numel(InImWeight); % Find Euclidean distance e=[]; for i=1:size(omega,2) q = omega(:,i); DiffWeight = InImWeight-q; mag = norm(DiffWeight); e = [e mag]; end ed_min=[ed_min MinimumValue]; theta=6.0e+03; %disp(e) z(b,:)=InImWeight; end IDX = kmeans(z,5); clustercount=accumarray(IDX, ones(size(IDX))); disp(clustercount); QUESTIONS: 1.It is working fine for M=50(i.e Training set contains 50 images) but not for M=1200(i.e Training set contains 1200 images).It is not showing any error.There is no output.I waited for 10 min still there is no output. I think it is going infinite loop.What is the problem?Where i was wrong? 2.Instead of running the training set everytime how eigen faces generated are stored so that stored eigen faces are used for future face recoginition for a new input image.So it reduces wastage of time.

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  • How to Use Your Android Phone as a Modem; No Rooting Required

    - by Jason Fitzpatrick
    If your cellular provider’s mobile hotspot/tethering plans are too pricey, skip them and tether your phone to your computer without inflating your monthly bill. Read on to see how you can score free mobile internet. We recently received a letter from a How-To Geek reader, requesting help linking their Android phone to their laptop to avoid the highway robbery their cellular provider was insisting upon: Dear How-To Geek, I recently found out that my cellphone company charges $30 a month to use your smartphone as a data modem. That’s an outrageous price when I already pay an extra $15 a month charge just because they insist that because I have a smartphone I need a data plan because I’ll be using so much more data than other users. They expect me to pay what amounts to a $45 a month premium just to do some occasional surfing and email checking from the comfort of my laptop instead of the much smaller smartphone screen! Surely there is a work around? I’m running Windows 7 on my laptop and I have an Android phone running Android OS 2.2. Help! Sincerely, No Double Dipping! Well Double Dipping, this is a sentiment we can strongly related to as many of us on staff are in a similar situation. It’s absurd that so many companies charge you to use the data connection on the phone you’re already paying for. There is no difference in bandwidth usage if you stream Pandora to your phone or to your laptop, for example. Fortunately we have a solution for you. It’s not free-as-in-beer but it only costs $16 which, over the first year of use alone, will save you $344. Let’s get started! Latest Features How-To Geek ETC What Can Super Mario Teach Us About Graphics Technology? Windows 7 Service Pack 1 is Released: But Should You Install It? How To Make Hundreds of Complex Photo Edits in Seconds With Photoshop Actions How to Enable User-Specific Wireless Networks in Windows 7 How to Use Google Chrome as Your Default PDF Reader (the Easy Way) How To Remove People and Objects From Photographs In Photoshop Make Efficient Use of Tab Bar Space by Customizing Tab Width in Firefox See the Geeky Work Done Behind the Scenes to Add Sounds to Movies [Video] Use a Crayon to Enhance Engraved Lettering on Electronics Adult Swim Brings Their Programming Lineup to iOS Devices Feel the Chill of the South Atlantic with the Antarctica Theme for Windows 7 Seas0nPass Now Offers Untethered Apple TV Jailbreaking

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  • How to have multiple path separators in Bash

    - by binW
    I have few python scripts which were written by someone else in Windows. These scripts use double backslash as path separator but when run in Ubuntu they don't work because of this. I can change all \ to / and scripts will work but there are lot of scripts and its a lot of effort to change each \ to / So my question is: Is it possible to add \ as path separator in Ubuntu or only in Bash so that I dont have to modify these scripts?

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  • Drawing multiple Textures as tilemap

    - by DocJones
    I am trying to draw a 2d game map and the objects on the map in a single pass. Here is my OpenGL initialization code // Turn off unnecessary operations glDisable(GL_DEPTH_TEST); glDisable(GL_LIGHTING); glDisable(GL_CULL_FACE); glDisable(GL_STENCIL_TEST); glDisable(GL_DITHER); glEnable(GL_BLEND); glEnable(GL_TEXTURE_2D); // activate pointer to vertex & texture array glEnableClientState(GL_VERTEX_ARRAY); glEnableClientState(GL_TEXTURE_COORD_ARRAY); My drawing code is being called by a NSTimer every 1/60 s. Here is the drawing code of my world object: - (void) draw:(NSRect)rect withTimedDelta:(double)d { GLint *t; glActiveTexture(GL_TEXTURE0); glBindTexture(GL_TEXTURE_2D, [_textureManager textureByName:@"blocks"]); glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE); for (int x=0; x<[_map getWidth] ; x++) { for (int y=0; y<[_map getHeight] ; y++) { GLint v[] = { 16*x ,16*y, 16*x+16,16*y, 16*x+16,16*y+16, 16*x ,16*y+16 }; t=[_textureManager getBlockWithNumber:[_map getBlockAtX:x andY:y]]; glVertexPointer(2, GL_INT, 0, v); glTexCoordPointer(2, GL_INT, 0, t); glDrawArrays(GL_QUADS, 0, 4); } } } (_textureManager is a Singelton only loading a texture once!) The object drawing codes is identical (except the nested loops) in terms of OpenGL calls: - (void) drawWithTimedDelta:(double)d { GLint *t; GLint v[] = { 16*xpos ,16*ypos, 16*xpos+16,16*ypos, 16*xpos+16,16*ypos+16, 16*xpos ,16*ypos+16 }; glBindTexture(GL_TEXTURE_2D, [_textureManager textureByName:_textureName]); t=[_textureManager getBlockWithNumber:12]; glVertexPointer(2, GL_INT, 0, v); glTexCoordPointer(2, GL_INT, 0, t); glDrawArrays(GL_QUADS, 0, 4); } As soon as my central drawing routine calls the two drawing methods the second call overlays the first one. i would expect the call to world.draw to draw the map and "stamp" the objects upon it. Debugging shows me, that the first call is performed correctly (world is being drawn), but the following call to all objects ONLY draws the objects, the rest of the scene is getting black. I think i need to blend the drawn textures, but i cant seem to figure out how. Any help is appreciated. Thanks PS: Here is the github link to the project. It may not be in sync of my post here, but for some more in-depth analysis it may help.

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  • How to install Eclipse J2EE IDE from a tarball?

    - by Silambarasan
    I have downloaded Eclipse 3.6.1 as a tar.gz file from eclipse site. Then I extract using cmd: tar -zxvf eclipse-jee-helios-SR1-linux-gtk.tar.gz after execute this cmd I got eclipse folder in this there is eclipse file. When I double click on this eclipse file I'm getting following error: Could not display "/media/D-DEVELOPME/eclipse/eclipse". There is no application installed for executable files is there any solution for it?

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  • Vectorization of matlab code for faster execution

    - by user3237134
    My code works in the following manner: 1.First, it obtains several images from the training set 2.After loading these images, we find the normalized faces,mean face and perform several calculation. 3.Next, we ask for the name of an image we want to recognize 4.We then project the input image into the eigenspace, and based on the difference from the eigenfaces we make a decision. 5.Depending on eigen weight vector for each input image we make clusters using kmeans command. Source code i tried: clear all close all clc % number of images on your training set. M=1200; %Chosen std and mean. %It can be any number that it is close to the std and mean of most of the images. um=60; ustd=32; %read and show images(bmp); S=[]; %img matrix for i=1:M str=strcat(int2str(i),'.jpg'); %concatenates two strings that form the name of the image eval('img=imread(str);'); [irow icol d]=size(img); % get the number of rows (N1) and columns (N2) temp=reshape(permute(img,[2,1,3]),[irow*icol,d]); %creates a (N1*N2)x1 matrix S=[S temp]; %X is a N1*N2xM matrix after finishing the sequence %this is our S end %Here we change the mean and std of all images. We normalize all images. %This is done to reduce the error due to lighting conditions. for i=1:size(S,2) temp=double(S(:,i)); m=mean(temp); st=std(temp); S(:,i)=(temp-m)*ustd/st+um; end %show normalized images for i=1:M str=strcat(int2str(i),'.jpg'); img=reshape(S(:,i),icol,irow); img=img'; end %mean image; m=mean(S,2); %obtains the mean of each row instead of each column tmimg=uint8(m); %converts to unsigned 8-bit integer. Values range from 0 to 255 img=reshape(tmimg,icol,irow); %takes the N1*N2x1 vector and creates a N2xN1 matrix img=img'; %creates a N1xN2 matrix by transposing the image. % Change image for manipulation dbx=[]; % A matrix for i=1:M temp=double(S(:,i)); dbx=[dbx temp]; end %Covariance matrix C=A'A, L=AA' A=dbx'; L=A*A'; % vv are the eigenvector for L % dd are the eigenvalue for both L=dbx'*dbx and C=dbx*dbx'; [vv dd]=eig(L); % Sort and eliminate those whose eigenvalue is zero v=[]; d=[]; for i=1:size(vv,2) if(dd(i,i)>1e-4) v=[v vv(:,i)]; d=[d dd(i,i)]; end end %sort, will return an ascending sequence [B index]=sort(d); ind=zeros(size(index)); dtemp=zeros(size(index)); vtemp=zeros(size(v)); len=length(index); for i=1:len dtemp(i)=B(len+1-i); ind(i)=len+1-index(i); vtemp(:,ind(i))=v(:,i); end d=dtemp; v=vtemp; %Normalization of eigenvectors for i=1:size(v,2) %access each column kk=v(:,i); temp=sqrt(sum(kk.^2)); v(:,i)=v(:,i)./temp; end %Eigenvectors of C matrix u=[]; for i=1:size(v,2) temp=sqrt(d(i)); u=[u (dbx*v(:,i))./temp]; end %Normalization of eigenvectors for i=1:size(u,2) kk=u(:,i); temp=sqrt(sum(kk.^2)); u(:,i)=u(:,i)./temp; end % show eigenfaces; for i=1:size(u,2) img=reshape(u(:,i),icol,irow); img=img'; img=histeq(img,255); end % Find the weight of each face in the training set. omega = []; for h=1:size(dbx,2) WW=[]; for i=1:size(u,2) t = u(:,i)'; WeightOfImage = dot(t,dbx(:,h)'); WW = [WW; WeightOfImage]; end omega = [omega WW]; end % Acquire new image % Note: the input image must have a bmp or jpg extension. % It should have the same size as the ones in your training set. % It should be placed on your desktop ed_min=[]; srcFiles = dir('G:\newdatabase\*.jpg'); % the folder in which ur images exists for b = 1 : length(srcFiles) filename = strcat('G:\newdatabase\',srcFiles(b).name); Imgdata = imread(filename); InputImage=Imgdata; InImage=reshape(permute((double(InputImage)),[2,1,3]),[irow*icol,1]); temp=InImage; me=mean(temp); st=std(temp); temp=(temp-me)*ustd/st+um; NormImage = temp; Difference = temp-m; p = []; aa=size(u,2); for i = 1:aa pare = dot(NormImage,u(:,i)); p = [p; pare]; end InImWeight = []; for i=1:size(u,2) t = u(:,i)'; WeightOfInputImage = dot(t,Difference'); InImWeight = [InImWeight; WeightOfInputImage]; end noe=numel(InImWeight); % Find Euclidean distance e=[]; for i=1:size(omega,2) q = omega(:,i); DiffWeight = InImWeight-q; mag = norm(DiffWeight); e = [e mag]; end ed_min=[ed_min MinimumValue]; theta=6.0e+03; %disp(e) z(b,:)=InImWeight; end IDX = kmeans(z,5); clustercount=accumarray(IDX, ones(size(IDX))); disp(clustercount); Running time for 50 images:Elapsed time is 103.947573 seconds. QUESTIONS: 1.It is working fine for M=50(i.e Training set contains 50 images) but not for M=1200(i.e Training set contains 1200 images).It is not showing any error.There is no output.I waited for 10 min still there is no output. I think it is going infinite loop.What is the problem?Where i was wrong?

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  • Troubleshooting Nonpaged and Paged Pool Errors in Windows

    Ben Lye uncovered a memory leak in the nonpaged pool which was crashing his servers with disquieting regularity. Luckily it was relatively easy to troubleshoot, and he's sharing the tools and techniques he used to get his servers back on track in double-quick time....Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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  • C#/.NET Little Wonders: Comparer&lt;T&gt;.Default

    - by James Michael Hare
    I’ve been working with a wonderful team on a major release where I work, which has had the side-effect of occupying most of my spare time preparing, testing, and monitoring.  However, I do have this Little Wonder tidbit to offer today. Introduction The IComparable<T> interface is great for implementing a natural order for a data type.  It’s a very simple interface with a single method: 1: public interface IComparer<in T> 2: { 3: // Compare two instances of same type. 4: int Compare(T x, T y); 5: }  So what do we expect for the integer return value?  It’s a pseudo-relative measure of the ordering of x and y, which returns an integer value in much the same way C++ returns an integer result from the strcmp() c-style string comparison function: If x == y, returns 0. If x > y, returns > 0 (often +1, but not guaranteed) If x < y, returns < 0 (often –1, but not guaranteed) Notice that the comparison operator used to evaluate against zero should be the same comparison operator you’d use as the comparison operator between x and y.  That is, if you want to see if x > y you’d see if the result > 0. The Problem: Comparing With null Can Be Messy This gets tricky though when you have null arguments.  According to the MSDN, a null value should be considered equal to a null value, and a null value should be less than a non-null value.  So taking this into account we’d expect this instead: If x == y (or both null), return 0. If x > y (or y only is null), return > 0. If x < y (or x only is null), return < 0. But here’s the problem – if x is null, what happens when we attempt to call CompareTo() off of x? 1: // what happens if x is null? 2: x.CompareTo(y); It’s pretty obvious we’ll get a NullReferenceException here.  Now, we could guard against this before calling CompareTo(): 1: int result; 2:  3: // first check to see if lhs is null. 4: if (x == null) 5: { 6: // if lhs null, check rhs to decide on return value. 7: if (y == null) 8: { 9: result = 0; 10: } 11: else 12: { 13: result = -1; 14: } 15: } 16: else 17: { 18: // CompareTo() should handle a null y correctly and return > 0 if so. 19: result = x.CompareTo(y); 20: } Of course, we could shorten this with the ternary operator (?:), but even then it’s ugly repetitive code: 1: int result = (x == null) 2: ? ((y == null) ? 0 : -1) 3: : x.CompareTo(y); Fortunately, the null issues can be cleaned up by drafting in an external Comparer.  The Soltuion: Comparer<T>.Default You can always develop your own instance of IComparer<T> for the job of comparing two items of the same type.  The nice thing about a IComparer is its is independent of the things you are comparing, so this makes it great for comparing in an alternative order to the natural order of items, or when one or both of the items may be null. 1: public class NullableIntComparer : IComparer<int?> 2: { 3: public int Compare(int? x, int? y) 4: { 5: return (x == null) 6: ? ((y == null) ? 0 : -1) 7: : x.Value.CompareTo(y); 8: } 9: }  Now, if you want a custom sort -- especially on large-grained objects with different possible sort fields -- this is the best option you have.  But if you just want to take advantage of the natural ordering of the type, there is an easier way.  If the type you want to compare already implements IComparable<T> or if the type is System.Nullable<T> where T implements IComparable, there is a class in the System.Collections.Generic namespace called Comparer<T> which exposes a property called Default that will create a singleton that represents the default comparer for items of that type.  For example: 1: // compares integers 2: var intComparer = Comparer<int>.Default; 3:  4: // compares DateTime values 5: var dateTimeComparer = Comparer<DateTime>.Default; 6:  7: // compares nullable doubles using the null rules! 8: var nullableDoubleComparer = Comparer<double?>.Default;  This helps you avoid having to remember the messy null logic and makes it to compare objects where you don’t know if one or more of the values is null. This works especially well when creating say an IComparer<T> implementation for a large-grained class that may or may not contain a field.  For example, let’s say you want to create a sorting comparer for a stock open price, but if the market the stock is trading in hasn’t opened yet, the open price will be null.  We could handle this (assuming a reasonable Quote definition) like: 1: public class Quote 2: { 3: // the opening price of the symbol quoted 4: public double? Open { get; set; } 5:  6: // ticker symbol 7: public string Symbol { get; set; } 8:  9: // etc. 10: } 11:  12: public class OpenPriceQuoteComparer : IComparer<Quote> 13: { 14: // Compares two quotes by opening price 15: public int Compare(Quote x, Quote y) 16: { 17: return Comparer<double?>.Default.Compare(x.Open, y.Open); 18: } 19: } Summary Defining a custom comparer is often needed for non-natural ordering or defining alternative orderings, but when you just want to compare two items that are IComparable<T> and account for null behavior, you can use the Comparer<T>.Default comparer generator and you’ll never have to worry about correct null value sorting again.     Technorati Tags: C#,.NET,Little Wonders,BlackRabbitCoder,IComparable,Comparer

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  • Executable execution path. Does it depends of the place the executable is called from?

    - by Valkea
    as I'm still a new Linux user, I still discover some behaviours and I'm unable to tell if they are "normals" or not. I searched the Internet but as I can't really find an answer I guess it's time to ask here. Few weeks ago I installed a small game called "Machinarium" and I played it... but few days later when I wanted to continue my game I was unable to make the game start correctly. And as I didn't had the time to search I given up. But yesterday as I was working on a program of mine, I had the exactly same behaviour. So I searched a bit and I discovered that when using Nautilus with the "List view", I was able to run the program (ie: the program does find the sound, images etc resources) when I was literally "inside" the executable folder, but unable when I was in a parent folder and expanding it to the executable folder to run it. To illustrate the behaviour here are two screen shots. It doesn't works if the executable is double clicked from here It does works if the executable is double clicked from here This is indeed the same "place", but the Nautilus view is slightly different as the current folder is not the same and it seems to make a difference for the program. Furthermore, when I create a menu items via System Settings/Main Menu to the executable, it behaves just like if the executable can't find the resources (that's why I was unable to play Machinarium the second time as I created a menu short-cut after my first game). So I asked my program to generate a text file at it's root when running, and I started to launch it from different "parent" folders to see where is generated the text file. Each time the file was generated on the top folder of the current Nautilus view. I was expected to see it appears in the same folder of the executable (well not as I was guessing what as happening, but before that I would have expected to see it appears in the exe folder). Does anyone can explain me why it does works like this (I guess it's normal) ? How I'm supposed to solve this when creating programs (Should I detect the executable path in my C++ code or should I organize the resources files another way than on windows ?)

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  • Memory Glutton

    - by AreYouSerious
    I have to admit that I can't get enough storage. I have hard drives just sitting around in case I need to move somthing, or I'm going to a friends and either they want something I have or I want something they might have. What I'm going to talk about today is cost effective memory for devices. I don't know how this particualr device will work in a camera, as That's not what I use in my camera, in fact I don't have a camera that doesn't either use SD, or the old compact flash card, that's not so compact anymore. There's this thing that uses two micro sd cards to double the capacity of your memory, and it costs about 4 bucks, without the Micro SD card. I have had one for about a year and was going to throw it away because I couldn't get it to work with my computer, or with my Sony Reader. However I found out by one last ditch effort that this thing works beautifully with my Sony PSP. there is no software to speak of associated with this thing, you simply put in two SD cards of the same size... (if you put in two different sizes it will still work, you'll only double the smallest cards size though) and format through the psp. Viola you know have a 29 GB memory card for your PSP. why is this important ? well for starters you can carry more music and more videos. Second if you have gone the way of the hacker.... you can store more games on your card... There are just a few things you have to note.... I speak from experience... you have to use the usb connection to the PSP to do any file moving, as I said previously said card doesn't play well with my computers or card readers... I not saying it won't work at all, just hasn't work with anything I own. Second. If for some reason you try to Hack/crack your PSP don't attempt to delete a game from the psp, use the usb file browser to remove games. if you delete from the PSP you are likely to have to move all your files off, reformat and start again... just a couple things I have noticed... if I had done something like that.   anyway, Here's a link.... http://www.photofast-adapter.com/  and if you want to buy one, get it off ebay, I've seen them as low as $1.99

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  • Your interesting code tricks/ conventions? [closed]

    - by Paul
    What interesting conventions, rules, tricks do you use in your code? Preferably some that are not so popular so that the rest of us would find them as novelties. :) Here's some of mine... Input and output parameters This applies to C++ and other languages that have both references and pointers. This is the convention: input parameters are always passed by value or const reference; output parameters are always passed by pointer. This way I'm able to see at a glance, directly from the function call, what parameters might get modified by the function: Inspiration: Old C code int a = 6, b = 7, sum = 0; calculateSum(a, b, &sum); Ordering of headers My typical source file begins like this (see code below). The reason I put the matching header first is because, in case that header is not self-sufficient (I forgot to include some necessary library, or forgot to forward declare some type or function), a compiler error will occur. // Matching header #include "example.h" // Standard libraries #include <string> ... Setter functions Sometimes I find that I need to set multiple properties of an object all at once (like when I just constructed it and I need to initialize it). To reduce the amount of typing and, in some cases, improve readability, I decided to make my setters chainable: Inspiration: Builder pattern class Employee { public: Employee& name(const std::string& name); Employee& salary(double salary); private: std::string name_; double salary_; }; Employee bob; bob.name("William Smith").salary(500.00); Maybe in this particular case it could have been just as well done in the constructor. But for Real WorldTM applications, classes would have lots more fields that should be set to appropriate values and it becomes unmaintainable to do it in the constructor. So what about you? What personal tips and tricks would you like to share?

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  • SolidQ Journal - free SQL goodness for February

    - by Greg Low
    The SolidQ Journal for February just made it out by the end of February 28th. But again, it's great to see the content appearing. I've included the second part of the article on controlling the execution context of stored procedures. The first part was in December. Also this month, along with Fernando Guerrero's editorial, Analysis Services guru Craig Utley has written about aggregations, Herbert Albert and Gianluca Holz have continued their double-act and described how to automate database migrations,...(read more)

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  • Adding complexity to remove duplicate code

    - by Phil
    I have several classes that all inherit from a generic base class. The base class contains a collection of several objects of type T. Each child class needs to be able to calculate interpolated values from the collection of objects, but since the child classes use different types, the calculation varies a tiny bit from class to class. So far I have copy/pasted my code from class to class and made minor modifications to each. But now I am trying to remove the duplicated code and replace it with one generic interpolation method in my base class. However that is proving to be very difficult, and all the solutions I have thought of seem way too complex. I am starting to think the DRY principle does not apply as much in this kind of situation, but that sounds like blasphemy. How much complexity is too much when trying to remove code duplication? EDIT: The best solution I can come up with goes something like this: Base Class: protected T GetInterpolated(int frame) { var index = SortedFrames.BinarySearch(frame); if (index >= 0) return Data[index]; index = ~index; if (index == 0) return Data[index]; if (index >= Data.Count) return Data[Data.Count - 1]; return GetInterpolatedItem(frame, Data[index - 1], Data[index]); } protected abstract T GetInterpolatedItem(int frame, T lower, T upper); Child class A: public IGpsCoordinate GetInterpolatedCoord(int frame) { ReadData(); return GetInterpolated(frame); } protected override IGpsCoordinate GetInterpolatedItem(int frame, IGpsCoordinate lower, IGpsCoordinate upper) { double ratio = GetInterpolationRatio(frame, lower.Frame, upper.Frame); var x = GetInterpolatedValue(lower.X, upper.X, ratio); var y = GetInterpolatedValue(lower.Y, upper.Y, ratio); var z = GetInterpolatedValue(lower.Z, upper.Z, ratio); return new GpsCoordinate(frame, x, y, z); } Child class B: public double GetMph(int frame) { ReadData(); return GetInterpolated(frame).MilesPerHour; } protected override ISpeed GetInterpolatedItem(int frame, ISpeed lower, ISpeed upper) { var ratio = GetInterpolationRatio(frame, lower.Frame, upper.Frame); var mph = GetInterpolatedValue(lower.MilesPerHour, upper.MilesPerHour, ratio); return new Speed(frame, mph); }

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  • Extremely large spike in traffic on the 1st - 4th of every month from mobile browsers

    - by wsanville
    I've noticed that on the 1st - 4th of the recent months (since January), several sites I maintain are getting thousands of requests from mobile browsers, whereas throughout the rest of the month, the numbers are in the single or double digits. Has anybody else noticed this sort of behavior? I don't have the exact user agents logged, but my analysis software (WebTrends) reports the traffic as mostly iPhone/iPad/iPod, Android, and Blackberry.

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  • How could I shutdown, over my network, with one click?

    - by DeLiK
    The question is simple. What would be the script I would have to use to shut down a computer in my network thru ssh. Normaly i would go to command line and: ssh desktop delik@desktop's password: delik@desktop:~$ sudo shutdown -P 0 To power on I created a file and wrote: wakeonlan xx:xx:xx:xx:xx:xx And gave it the executable bit That way to power on it requires only a double click. Would i be capable of doing the same to shutdown?

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  • Thunderbird FireTray Add-on - Must close twice

    - by Marcin
    I've installed Thunderbird and FireTray addon, then checked to minimize to tray on close. Now, if I start Thunderbird after quitting (Win+Q) and try to close with Alt+f4: for the first time it's minimised properly to tray on each next time I need to double press "close button", and if the window is not maximised firstly it maximizes (first Alt+f4), then closes(second Alt+f4) Could you help me, please? Ubuntu 11.10, Unity 2d

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