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  • Friday Fun: Omega Crisis

    - by Mysticgeek
    Friday is here once again and it’s time to play a fun flash game on company time. Today we take a look at the space shooter Omega Crisis. Omega Crisis At the start of the game you’re given the basic story of the game, defending the space outpost, and instructions on how to play. Controls are easy, just target the enemy and use the left mouse button to fire. After each level you’re shown the results and how many Tech Points you’ve earned. The more Tech Points you earn, you have a better chance of upgrading your weapons and base defense before the next level.   You can also go into Manage Mode by hitting the Space bar, and select gunners and other types of weapons to help defend the outpost. Choose your mission from the timeline after successfully completing a mission. You can also use A,W,D,S to move around the map and see exactly where the enemy ships are coming from. This makes it easier to destroy them before they get too close to your base. This game is a lot of fun and is similar to different “Desktop Defense” type games. If you’re looking for a fun way to waste the afternoon, and not look at TPS reports, Omega Crisis can get you though until the whistle blows. Play Omega Crisis Similar Articles Productive Geek Tips Friday Fun: Portal, the Flash VersionFriday Fun: Play Bubble QuodFriday Fun: Gravitee 2Friday Fun: Wake Up the BoxFriday Fun: Compulse TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips Acronis Online Backup DVDFab 6 Revo Uninstaller Pro Registry Mechanic 9 for Windows Tech Fanboys Field Guide Check these Awesome Chrome Add-ons iFixit Offers Gadget Repair Manuals Online Vista style sidebar for Windows 7 Create Nice Charts With These Web Based Tools Track Daily Goals With 42Goals

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  • IOC Container Handling State Params in Non-Default Constructor

    - by Mystagogue
    For the purpose of this discussion, there are two kinds of parameters an object constructor might take: state dependency or service dependency. Supplying a service dependency with an IOC container is easy: DI takes over. But in contrast, state dependencies are usually only known to the client. That is, the object requestor. It turns out that having a client supply the state params through an IOC Container is quite painful. I will show several different ways to do this, all of which have big problems, and ask the community if there is another option I'm missing. Let's begin: Before I added an IOC container to my project code, I started with a class like this: class Foobar { //parameters are state dependencies, not service dependencies public Foobar(string alpha, int omega){...}; //...other stuff } I decide to add a Logger service depdendency to the Foobar class, which perhaps I'll provide through DI: class Foobar { public Foobar(string alpha, int omega, ILogger log){...}; //...other stuff } But then I'm also told I need to make class Foobar itself "swappable." That is, I'm required to service-locate a Foobar instance. I add a new interface into the mix: class Foobar : IFoobar { public Foobar(string alpha, int omega, ILogger log){...}; //...other stuff } When I make the service locator call, it will DI the ILogger service dependency for me. Unfortunately the same is not true of the state dependencies Alpha and Omega. Some containers offer a syntax to address this: //Unity 2.0 pseudo-ish code: myContainer.Resolve<IFoobar>( new parameterOverride[] { {"alpha", "one"}, {"omega",2} } ); I like the feature, but I don't like that it is untyped and not evident to the developer what parameters must be passed (via intellisense, etc). So I look at another solution: //This is a "boiler plate" heavy approach! class Foobar : IFoobar { public Foobar (string alpha, int omega){...}; //...stuff } class FoobarFactory : IFoobarFactory { public IFoobar IFoobarFactory.Create(string alpha, int omega){ return new Foobar(alpha, omega); } } //fetch it... myContainer.Resolve<IFoobarFactory>().Create("one", 2); The above solves the type-safety and intellisense problem, but it (1) forced class Foobar to fetch an ILogger through a service locator rather than DI and (2) it requires me to make a bunch of boiler-plate (XXXFactory, IXXXFactory) for all varieties of Foobar implementations I might use. Should I decide to go with a pure service locator approach, it may not be a problem. But I still can't stand all the boiler-plate needed to make this work. So then I try this: //code named "concrete creator" class Foobar : IFoobar { public Foobar(string alpha, int omega, ILogger log){...}; static IFoobar Create(string alpha, int omega){ //unity 2.0 pseudo-ish code. Assume a common //service locator, or singleton holds the container... return Container.Resolve<IFoobar>( new parameterOverride[] {{"alpha", alpha},{"omega", omega} } ); } //Get my instance: Foobar.Create("alpha",2); I actually don't mind that I'm using the concrete "Foobar" class to create an IFoobar. It represents a base concept that I don't expect to change in my code. I also don't mind the lack of type-safety in the static "Create", because it is now encapsulated. My intellisense is working too! Any concrete instance made this way will ignore the supplied state params if they don't apply (a Unity 2.0 behavior). Perhaps a different concrete implementation "FooFoobar" might have a formal arg name mismatch, but I'm still pretty happy with it. But the big problem with this approach is that it only works effectively with Unity 2.0 (a mismatched parameter in Structure Map will throw an exception). So it is good only if I stay with Unity. The problem is, I'm beginning to like Structure Map a lot more. So now I go onto yet another option: class Foobar : IFoobar, IFoobarInit { public Foobar(ILogger log){...}; public IFoobar IFoobarInit.Initialize(string alpha, int omega){ this.alpha = alpha; this.omega = omega; return this; } } //now create it... IFoobar foo = myContainer.resolve<IFoobarInit>().Initialize("one", 2) Now with this I've got a somewhat nice compromise with the other approaches: (1) My arguments are type-safe / intellisense aware (2) I have a choice of fetching the ILogger via DI (shown above) or service locator, (3) there is no need to make one or more seperate concrete FoobarFactory classes (contrast with the verbose "boiler-plate" example code earlier), and (4) it reasonably upholds the principle "make interfaces easy to use correctly, and hard to use incorrectly." At least it arguably is no worse than the alternatives previously discussed. One acceptance barrier yet remains: I also want to apply "design by contract." Every sample I presented was intentionally favoring constructor injection (for state dependencies) because I want to preserve "invariant" support as most commonly practiced. Namely, the invariant is established when the constructor completes. In the sample above, the invarient is not established when object construction completes. As long as I'm doing home-grown "design by contract" I could just tell developers not to test the invariant until the Initialize(...) method is called. But more to the point, when .net 4.0 comes out I want to use its "code contract" support for design by contract. From what I read, it will not be compatible with this last approach. Curses! Of course it also occurs to me that my entire philosophy is off. Perhaps I'd be told that conjuring a Foobar : IFoobar via a service locator implies that it is a service - and services only have other service dependencies, they don't have state dependencies (such as the Alpha and Omega of these examples). I'm open to listening to such philosophical matters as well, but I'd also like to know what semi-authorative reference to read that would steer me down that thought path. So now I turn it to the community. What approach should I consider that I havn't yet? Must I really believe I've exhausted my options?

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  • Calculating determinant by hand

    - by ldigas
    Okey, this is only half programming, but let's see how you are on terms with manual calculations. I believe many of you did this on your university's while giving "linear systems" ... the problem is it's been so long I can't remember how to do it any more. I know quite a few algorithms for calculating determinants, and they all work fine ... for large systems, where one would never try to do it manually. Unfortunatelly, I'm soon going on an exam, where I do have to calculate it manually, up to the system of 5. So, I have a K(omega) matrix that looks like this: [2-(omega^2)*c -4 2 0 0] [-2 5-(omega^2)*c -4 1 0] [1 -4 6-(omega^2)*c -4 1] [0 1 -4 5-(omega^2)*c -2] [0 0 2 -4 2-(omega^2)*c] and I need all the omegas which satisfy the det[K(omega)]=0 criteria. What would be a good way to calculate it so it can be repeated in a manual process ?

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  • IE 8 Automatically Closing <header> tag

    - by djthoms
    Background I am currently working on the final QA of a responsive website and I'm having an issue with IE 8 and IE 7. My client deals with government contracting so their website needs to be compatible with IE 8 and IE 7. I am using Modernizr with html5shiv built in. I am loading Modernizr in the footer of a WordPress theme that was custom built for this project. I'm not missing a doctype or any other obvious code. I am using the following scripts, all of which are loaded in the footer of WordPress: jQuery 1.10.1 Modernizr 2.6.3 (click for config) respond.js 1.3.0 superfish jQuery Waypoints 2.0.3 jQuery Waypoints Sticky 2.0.3 The Situation I'm having an issue with IE 8 automatically closing a <header> tag. First, I have used two utilities to check this issue: IETester IE 11 emulated to IE 8 w/ IE 8 User agent Here is the correct output <div class="wrapper main-header"> <header class="container"> <div class="sixteen columns alpha omega"> <div class="eight columns alpha omega logo"> <a href="http://example.com"><img src="http://example.com/wp-content/uploads/2013/10/logo.png" alt="Example"></a> </div> <div class="wrapper main-navigation desktop"> <nav id="nav" class="six columns alpha omega"> ... </nav> <div class="eight columns alpha omega overlay" style="display: none;"> ... </div> <div class="two columns alpha omega menu-ss"> ... </div> </div><!-- .wrapper.main-navigation --> </div><!-- /.sixteen.columns --> </header><!--/header--> </div><!-- /.main-header --> What IE 8 is rendering: <div class="wrapper main-header"> <header class="container"></header> <div class="sixteen columns alpha omega"> <div class="eight columns alpha omega logo"> <a href="http://example.com"><img src="http://example.com/wp-content/uploads/2013/10/logo.png" alt="Example"></a> </div> <div class="wrapper main-navigation desktop"> <nav id="nav" class="six columns alpha omega"> ... </nav> <div class="eight columns alpha omega overlay" style="display: none;"> ... </div> <div class="two columns alpha omega menu-ss"> ... </div> </div><!-- .wrapper.main-navigation --> </div><!-- /.sixteen.columns --> </header><//header><!--/header--> </div><!-- /.main-header --> What I have Tried Loading html5shiv with IE conditional in the <head> Loading Modernizr in the <head> I have looked at these Stackoverflow questions/answers: html 5 tags foorter or header in ie 8 and ie 7 html5 not rendering header tags in ie IE 8 self closing tags automatically Any assistance with this is greatly appreciated! I would really really really like to finish this website over the weekend. I've been banging my head against a wall for the past few hours over this issue. Update Here are some images from browsershack to cut out the emulation. I tested the site virtually with Windows 7 and WIndows XP (IE 8 & IE 7). http://www.browserstack.com/screenshots/0d7c1d6dd22927c20495e67f07afe8934957b4d1

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  • algorithm analysis - orders of growth question

    - by cchampion
    I'm studing orders of growth "big oh", "big omega", and "big theta". Since I can't type the little symbols for these I will denote them as follows: ORDER = big oh OMEGA = big omega THETA = big theta For example I'll say n = ORDER(n^2) to mean that the function n is in the order of n^2 (n grows at most as fast n^2). Ok for the most part I understand these: n = ORDER(n^2) //n grows at most as fast as n^2 n^2 = OMEGA(n) //n^2 grows atleast as fast as n 8n^2 + 1000 = THETA(n^2) //same order of growth Ok here comes the example that confuses me: what is n(n+1) vs n^2 I realize that n(n+1) = n^2 + n; I would say it has the same order of growth as n^2; therefore I would say n(n+1) = THETA(n^2) but my question is, would it also be correct to say: n(n+1) = ORDER(n^2) please help because this is confusing to me. thanks.

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  • Wiki-fying a text using LPeg

    - by Stigma
    Long story coming up, but I'll try to keep it brief. I have many pure-text paragraphs which I extract from a system and re-output in wiki format so that the copying of said data is not such an arduous task. This all goes really well, except that there are no automatic references being generated for the 'topics' we have pages for, which end up needing to be added by reading through all the text and adding it in manually by changing Topic to [[Topic]]. First requirement: each topic is only to be made clickable once, which is the first occurrence. Otherwise, it would become a really spammy linkfest, which would detract from readability. To avoid issues with topics that start with the same words Second requirement: overlapping topic names should be handled in such a way that the most 'precise' topic gets the link, and in later occurrences, the less precise topics do not get linked, since they're likely not correct. Example: topics = { "Project", "Mary", "Mr. Moore", "Project Omega"} input = "Mary and Mr. Moore work together on Project Omega. Mr. Moore hates both Mary and Project Omega, but Mary simply loves the Project." output = function_to_be_written(input) -- "[[Mary]] and [[Mr. Moore]] work together on [[Project Omega]]. Mr. Moore hates both Mary and Project Omega, but Mary simply loves the [[Project]]." Now, I quickly figured out a simple or complicated string.gsub() could not get me what I need to satisfy the second requirement, as it provides no way to say 'Consider this match as if it did not happen - I want you to backtrack further'. I need the engine to do something akin to: input = "abc def ghi" -- Looping over the input would, in this order, match the following strings: -- 1) abc def ghi -- 2) abc def -- 3) abc -- 4) def ghi -- 5) def -- 6) ghi Once a string matches an actual topic and has not been replaced before by its wikified version, it is replaced. If this topic has been replaced by a wikified version before, don't replace, but simply continue the matching at the end of the topic. (So for a topic "abc def", it would test "ghi" next in both cases.) Thus I arrive at LPeg. I have read up on it, played with it, but it is considerably complex, and while I think I need to use lpeg.Cmt and lpeg.Cs somehow, I am unable to mix the two properly to make what I want to do work. I am refraining from posting my practice attempts as they are of miserable quality and probably more likely to confuse anyone than assist in clarifying my problem. (Why do I want to use a PEG instead of writing a triple-nested loop myself? Because I don't want to, and it is a great excuse to learn PEGs.. except that I am in over my head a bit. Unless it is not possible with LPeg, the first is not an option.)

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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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  • 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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  • recursion tree and binary tree cost calculation

    - by Tony
    Hi all, I've got the following recursion: T(n) = T(n/3) + T(2n/3) + O(n) The height of the tree would be log3/2 of 2. Now the recursion tree for this recurrence is not a complete binary tree. It has missing nodes lower down. This makes sense to me, however I don't understand how the following small omega notation relates to the cost of all leaves in the tree. "... the total cost of all leaves would then be Theta (n^log3/2 of 2) which, since log3/2 of 2 is a constant strictly greater then 1, is small omega(n lg n)." Can someone please help me understand how the Theta(n^log3/2 of 2) becomes small omega(n lg n)?

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  • Speed up math code in C# by writing a C dll?

    - by Projectile Fish
    I have a very large nested for loop in which some multiplications and additions are performed on floating point numbers. for (int i = 0; i < length1; i++) { s = GetS(i); c = GetC(i); for(int j = 0; j < length2; j++) { double oldU = u[j]; u[j] = c * oldU + s * omega[i][j]; omega[i][j] = c * omega[i][j] - s * oldU; } } This loop is taking up the majority of my processing time and is a bottleneck. Would I be likely to see any speed improvements if I rewrite this loop in C and interface to it from C#?

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  • Intermittent access to Win7 Share

    - by Omega
    I ave a share on a Windows 7 machine that is sometimes accessible from Ubuntu and sometimes isn't. When I try to access it currently, I get the message: "Failed to mount Windows share", and nothing more. Gnome doesn't appear to want to provide me with any more detailed information. I've verified that the workgroup is set correctly and as noted in the title, sometimes the share DOES work. It seems like I can only access it once and then subsequent mounts are blocked. What is going on?! Thanks!

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  • Does it matter the direction of a Huffman's tree child node?

    - by Omega
    So, I'm on my quest about creating a Java implementation of Huffman's algorithm for compressing/decompressing files (as you might know, ever since Why create a Huffman tree per character instead of a Node?) for a school assignment. I now have a better understanding of how is this thing supposed to work. Wikipedia has a great-looking algorithm here that seemed to make my life way easier. Taken from http://en.wikipedia.org/wiki/Huffman_coding: Create a leaf node for each symbol and add it to the priority queue. While there is more than one node in the queue: Remove the two nodes of highest priority (lowest probability) from the queue Create a new internal node with these two nodes as children and with probability equal to the sum of the two nodes' probabilities. Add the new node to the queue. The remaining node is the root node and the tree is complete. It looks simple and great. However, it left me wondering: when I "merge" two nodes (make them children of a new internal node), does it even matter what direction (left or right) will each node be afterwards? I still don't fully understand Huffman coding, and I'm not very sure if there is a criteria used to tell whether a node should go to the right or to the left. I assumed that, perhaps the highest-frequency node would go to the right, but I've seen some Huffman trees in the web that don't seem to follow such criteria. For instance, Wikipedia's example image http://upload.wikimedia.org/wikipedia/commons/thumb/8/82/Huffman_tree_2.svg/625px-Huffman_tree_2.svg.png seems to put the highest ones to the right. But other images like this one http://thalia.spec.gmu.edu/~pparis/classes/notes_101/img25.gif has them all to the left. However, they're never mixed up in the same image (some to the right and others to the left). So, does it matter? Why?

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  • How should I manage persistent score in Game Center leaderboards?

    - by Omega
    Let's say that I'm developing an iOS RPG where the player gains 1 point per monster kill. The amount of monsters killed is persistent data: it is an endless adventure, and the score keeps on growing. It isn't a "session score" like Fruit Ninja, but rather a "reputation score". There are Game Center leaderboards for that score. Keep killing monsters, your score goes up, and the leaderboards are updated. My problem is that, technically, you can log out and log in using a different Game Center account, kill one monster, and the leaderboards will be updated for the new GC account. Supposing that this score is a big deal, this could be considered as cheating, because if you have a score of 2000, any of your friends who have never played the game can simply log into your iPhone, play the game, and the system will update the score for their accounts, essentially giving them 2000 points in the leaderboards for doing nothing. I have considered linking one GC account to a specific save game. It won't update your score unless you're using the linked GC account. But what if the player actually needs to change their GC account? Technically they would be forced to start a new game and link their account to that profile. How should I prevent this kind of cheat? Essentially, I don't want someone to distribute a high schore to multiple GC accounts, given the fact that the game updates the score constantly since it isn't a "session score". I do realize that it isn't quite a big deal. But I'm curious about how to avoid this.

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  • Help comparing Cocos2d and Unity3d for this project.....

    - by Omega
    I will not go into details, but I would like to hear your opinions about this: Essentially, my project will be a 2d game, with lots of complex levels, where some might be simple and others might be a bit more deep, with physics, etc. We want to implement our very own online structure: logging in, leaderboards, achievements, friends etc with our own servers. This means no OpenFeint nor GameCenter at all. We expect this game to be very large in both graphics and audio. We wish to use in-app purchases. Now, we considered two options. Cocos2d and Unity3d. We need help deciding using the factors I mentioned before (networking, good performance even for a large game in terms of graphics and audio like this, in-app purchases, etc) which option would fit better this? Technically, both options can create 2d games. I'd like to hear your opinion.

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  • Can a recursive function have iterations/loops?

    - by Omega
    I've been studying about recursive functions, and apparently, they're functions that call themselves, and don't use iterations/loops (otherwise it wouldn't be a recursive function). However, while surfing the web for examples (the 8-queens-recursive problem), I found this function: private boolean placeQueen(int rows, int queens, int n) { boolean result = false; if (row < n) { while ((queens[row] < n - 1) && !result) { queens[row]++; if (verify(row,queens,n)) { ok = placeQueen(row + 1,queens,n); } } if (!result) { queens[row] = -1; } }else{ result = true; } return result; } There is a while loop involved. ... so I'm a bit lost now. Can I use loops or not?

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  • How do I know when should I package my classes in Ruby?

    - by Omega
    In Ruby, I'm creating a small game development framework. Just some personal project - a very small group of friends helping. Now I am in need of handling geometric concepts. Rectangles, Circles, Polygons, Vectors, Lines, etc. So I made a class for each of these. I'm stuck deciding whether I should package such classes in a module, such as Geometry. So I'd access them like Geometry::Rectangle, or just Rectangle if I include the module. Now then, my question isn't about this specific scenario. I'd like to know, when is it suitable to package similar classes into one module in Ruby? What factors should I consider? Amount of classes? Usage frequency? Complexity?

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  • How to execute a Ruby file in Java, capable of calling functions from the Java program and receiving primitive-type results?

    - by Omega
    I do not fully understand what am I asking (lol!), well, in the sense of if it is even possible, that is. If it isn't, sorry. Suppose I have a Java program. It has a Main and a JavaCalculator class. JavaCalculator has some basic functions like public int sum(int a,int b) { return a + b } Now suppose I have a ruby file. Called MyProgram.rb. MyProgram.rb may contain anything you could expect from a ruby program. Let us assume it contains the following: class RubyMain def initialize print "The sum of 5 with 3 is #{sum(5,3)}" end def sum(a,b) # <---------- Something will happen here end end rubyMain = RubyMain.new Good. Now then, you might already suspect what I want to do: I want to run my Java program I want it to execute the Ruby file MyProgram.rb When the Ruby program executes, it will create an instance of JavaCalculator, execute the sum function it has, get the value, and then print it. The ruby file has been executed successfully. The Java program closes. Note: The "create an instance of JavaCalculator" is not entirely necessary. I would be satisfied with just running a sum function from, say, the Main class. My question: is such possible? Can I run a Java program which internally executes a Ruby file which is capable of commanding the Java program to do certain things and get results? In the above example, the Ruby file asks the Java program to do a sum for it and give the result. This may sound ridiculous. I am new in this kind of thing (if it is possible, that is). WHY AM I ASKING THIS? I have a Java program, which is some kind of game engine. However, my target audience is a bunch of Ruby coders. I don't want to have them learn Java at all. So I figured that perhaps the Java program could simply offer the functionality (capacity to create windows, display sprites, play sounds...) and then, my audience can simply code with Ruby the logic, which basically justs asks my Java engine to do things like displaying sprites or playing sounds. That's when I though about asking this.

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  • Photoshop, slice, Dreamweaver, web?

    - by Omega
    So I am playing around with Photoshop and Dreamweaver. I have created a site layout, and have used the slice function on it. Next, I saved as html & images. In Dreamweaver, I open such html file and I fill the page with content, links, etc. I have a website and everything, and I would like to use my newly created html page on it. But, obviously, if I copy & paste the html to my website it won't work because it will lack the images. But two things: I can't find the images, and apparently they are a lot. I am sure I am doing a great mistake regarding the images. Can someone help me?

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  • How to discriminate from two nodes with identical frequencies in a Huffman's tree?

    - by Omega
    Still on my quest to compress/decompress files with a Java implementation of Huffman's coding (http://en.wikipedia.org/wiki/Huffman_coding) for a school assignment. From the Wikipedia page, I quote: Create a leaf node for each symbol and add it to the priority queue. While there is more than one node in the queue: Remove the two nodes of highest priority (lowest probability) from the queue Create a new internal node with these two nodes as children and with probability equal to the sum of the two nodes' probabilities. Add the new node to the queue. The remaining node is the root node and the tree is complete. Now, emphasis: Remove the two nodes of highest priority (lowest probability) from the queue Create a new internal node with these two nodes as children and with probability equal to the sum of the two nodes' probabilities. So I have to take two nodes with the lowest frequency. What if there are multiple nodes with the same low frequency? How do I discriminate which one to use? The reason I ask this is because Wikipedia has this image: And I wanted to see if my Huffman's tree was the same. I created a file with the following content: aaaaeeee nnttmmiihhssfffouxprl And this was the result: Doesn't look so bad. But there clearly are some differences when multiple nodes have the same frequency. My questions are the following: What is Wikipedia's image doing to discriminate the nodes with the same frequency? Is my tree wrong? (Is Wikipedia's image method the one and only answer?) I guess there is one specific and strict way to do this, because for our school assignment, files that have been compressed by my program should be able to be decompressed by other classmate's programs - so there must be a "standard" or "unique" way to do it. But I'm a bit lost with that. My code is rather straightforward. It literally just follows Wikipedia's listed steps. The way my code extracts the two nodes with the lowest frequency from the queue is to iterate all nodes and if the current node has a lower frequency than any of the two "smallest" known nodes so far, then it replaces the highest one. Just like that.

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  • Why create a Huffman tree per character instead of a Node?

    - by Omega
    For a school assignment we're supposed to make a Java implementation of a compressor/decompresser using Huffman's algorithm. I've been reading a bit about it, specially this C++ tutorial: http://www.cprogramming.com/tutorial/computersciencetheory/huffman.html In my program, I've been thinking about having Nodes that have the following properties: Total Frequency Character (if a leaf) Right child (if any) Left child (if any) Parent (if any) So when building the Huffman tree, it is just a matter of linking a node to others, etc. However, I'm a bit confused with the following quote (emphasis mine): First, every letter starts off as part of its own tree and the trees are ordered by the frequency of the letters in the original string. Then the two least-frequently used letters are combined into a single tree, and the frequency of that tree is set to be the combined frequency of the two trees that it links together. My question: why should I create a tree per letter, instead of just a node per letter and then do the linking later? I have not begun coding, I'm just studying the algorithm first, so I guess I'm missing an important detail. What is it?

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  • How to refactor my design, if it seems to require multiple inheritance?

    - by Omega
    Recently I made a question about Java classes implementing methods from two sources (kinda like multiple inheritance). However, it was pointed out that this sort of need may be a sign of a design flaw. Hence, it is probably better to address my current design rather than trying to simulate multiple inheritance. Before tackling the actual problem, some background info about a particular mechanic in this framework: It is a simple game development framework. Several components allocate some memory (like pixel data), and it is necessary to get rid of it as soon as you don't need it. Sprites are an example of this. Anyway, I decided to implement something ala Manual-Reference-Counting from Objective-C. Certain classes, like Sprites, contain an internal counter, which is increased when you call retain(), and decreased on release(). Thus the Resource abstract class was created. Any subclass of this will obtain the retain() and release() implementations for free. When its count hits 0 (nobody is using this class), it will call the destroy() method. The subclass needs only to implement destroy(). This is because I don't want to rely on the Garbage Collector to get rid of unused pixel data. Game objects are all subclasses of the Node class - which is the main construction block, as it provides info such as position, size, rotation, etc. See, two classes are used often in my game. Sprites and Labels. Ah... but wait. Sprites contain pixel data, remember? And as such, they need to extend Resource. But this, of course, can't be done. Sprites ARE nodes, hence they must subclass Node. But heck, they are resources too. Why not making Resource an interface? Because I'd have to re-implement retain() and release(). I am avoiding this in virtue of not writing the same code over and over (remember that there are multiple classes that need this memory-management system). Why not composition? Because I'd still have to implement methods in Sprite (and similar classes) that essentially call the methods of Resource. I'd still be writing the same code over and over! What is your advice in this situation, then?

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  • Is excessive indirection and/or redundant encapsulation a recognized concept?

    - by Omega
    I'm curious if there's a series of tendencies or anti-patterns when programming whereby a developer will always locally re-wrap external dependencies when consuming them. A slightly less vague example might be say when consuming an implementation of an interface or abstract, and mapping every touch-point locally before interacting with them. Like an overcomplicated take on composition. Given my example, would the interface not be reliable enough and any change to it never be surmountable any any level of indirection? Is this a good or a bad practice? Can it ever go too far? Does it have a proper name?

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  • Recommended flexible website solution?

    - by Omega
    My site has a MyBB forums installation, and that is pretty much all I need. Forums. However, I need a homepage and a couple other static pages, for showing relevant information, links, etc. I don't need something fancy, all I need is something very flexible regarding theme and style editing, and just a couple simple modules, like public polls. That's all. I am very graphical, and I am looking for something to let me edit pretty much every aspect of the site. These are static pages, mainly, so I don't need something very complex. Some people tell me to use Dreamweaver, but quite honestly, that is not what I am looking for, even thought it does offer a lot of flexibility. I want something like, you know, Drupal or.. some other simple, deeply-editable in terms of graphics and style web platform. What would you recommend to me? Thank you.

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  • Why is my ruby application running faster the second time?

    - by Omega
    I'm creating a Ruby game using the Gosu framework. All good. Sometimes, when I run the game, it has some kind of slow startup, and probably it will be rather slow during the whole game. So I close it and... open it again. It is very likely that it will startup quickly and the whole game will run smoothly and fast. Why is that? What is this phenomenon? Is it faster because of some cache stored or whatever since the first run? (But why would cache be stored? If the app dies, I would expect no references at all etc...) Ruby, Windows 7.

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  • What are the differences between programming languages? [closed]

    - by Omega
    Once upon a time, I heard from someone the only difference between programming languages is the syntax I wanted to deny it - to say that there are other fundamental aspects that truly set a language apart from others than just syntax. But I couldn't... So, can you? Whenever I search Google for something like "differences between programming languages", the results tend to be debates between two specific languages (I'd like something more general) - however, some of the aspects that people seemed to debate the most were: Object-Oriented Method/Operator overloading (I actually see this rather related to syntax) Garbage-Collection (While it seems like a good difference, for some reason it doesn't seem that "fundamental") What important aspects other than syntax can you think of?

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