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  • Programação paralela no .NET Framework 4 – Parte II

    - by anobre
    Olá pessoal, tudo bem? Este post é uma continuação da série iniciada neste outro post, sobre programação paralela. Meu objetivo hoje é apresentar o PLINQ, algo que poderá ser utilizado imediatamente nos projetos de vocês. Parallel LINQ (PLINQ) PLINQ nada mais é que uma implementação de programação paralela ao nosso famoso LINQ, através de métodos de extensão. O LINQ foi lançado com a versão 3.0 na plataforma .NET, apresentando uma maneira muito mais fácil e segura de manipular coleções IEnumerable ou IEnumerable<T>. O que veremos hoje é a “alteração” do LINQ to Objects, que é direcionado a coleções de objetos em memória. A principal diferença entre o LINQ to Objects “normal” e o paralelo é que na segunda opção o processamento é realizado tentando utilizar todos os recursos disponíveis para tal, obtendo uma melhora significante de performance. CUIDADO: Nem todas as operações ficam mais rápidas utilizando recursos de paralelismo. Não deixe de ler a seção “Performance” abaixo. ParallelEnumerable Tudo que a gente precisa para este post está organizado na classe ParallelEnumerable. Esta classe contém os métodos que iremos utilizar neste post, e muito mais: AsParallel AsSequential AsOrdered AsUnordered WithCancellation WithDegreeOfParallelism WithMergeOptions WithExecutionMode ForAll … O exemplo mais básico de como executar um código PLINQ é utilizando o métodos AsParallel, como o exemplo: var source = Enumerable.Range(1, 10000); var evenNums = from num in source.AsParallel() where Compute(num) > 0 select num; Algo tão interessante quanto esta facilidade é que o PLINQ não executa sempre de forma paralela. Dependendo da situação e da análise de alguns itens no cenário de execução, talvez seja mais adequado executar o código de forma sequencial – e nativamente o próprio PLINQ faz esta escolha.  É possível forçar a execução para sempre utilizar o paralelismo, caso seja necessário. Utilize o método WithExecutionMode no seu código PLINQ. Um teste muito simples onde podemos visualizar a diferença é demonstrado abaixo: static void Main(string[] args) { IEnumerable<int> numbers = Enumerable.Range(1, 1000); IEnumerable<int> results = from n in numbers.AsParallel() where IsDivisibleByFive(n) select n; Stopwatch sw = Stopwatch.StartNew(); IList<int> resultsList = results.ToList(); Console.WriteLine("{0} itens", resultsList.Count()); sw.Stop(); Console.WriteLine("Tempo de execução: {0} ms", sw.ElapsedMilliseconds); Console.WriteLine("Fim..."); Console.ReadKey(true); } static bool IsDivisibleByFive(int i) { Thread.SpinWait(2000000); return i % 5 == 0; }   Basta remover o AsParallel da instrução LINQ que você terá uma noção prática da diferença de performance. 1. Instrução utilizando AsParallel   2. Instrução sem utilizar paralelismo Performance Apesar de todos os benefícios, não podemos utilizar PLINQ sem conhecer todos os seus detalhes. Lembre-se de fazer as perguntas básicas: Eu tenho trabalho suficiente que justifique utilizar paralelismo? Mesmo com o overhead do PLINQ, vamos ter algum benefício? Por este motivo, visite este link e conheça todos os aspectos, antes de utilizar os recursos disponíveis. Conclusão Utilizar recursos de paralelismo é ótimo, aumenta a performance, utiliza o investimento realizado em hardware – tudo isso sem custo de produtividade. Porém, não podemos usufruir de qualquer tipo de tecnologia sem conhece-la a fundo antes. Portanto, faça bom uso, mas não esqueça de manter o conhecimento a frente da empolgação. Abraços.

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  • How can I retain the editing in the search result with UISearchDisplayController?

    - by wal
    I want to search a table in editing mode, but when I type a letter the variable tableView.editing is changed to NO. And when I cancel the search, the tableView.editing return to YES. I'd like to retain the editing YES in the result of the search. I put breakpoint in several methods. Until the filterContentForSearchText method, the variable is YES, but in the cellForRowAtIndexPath, it is NO. Image of the table in editing mode just before type a letter in the search bar. Image of the search Image of the table after the searching (editing mode again)

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  • Learning Java, how to type text on canvas?

    - by Voley
    I'm reading a book by Eric Roberts - Art and science of java and it got an excersise that I can't figure out - You have to make calendar, with GRect's, 7 by 6, that goes ok, the code part is easy, but also you have to type the numbers of the date on those rectangles, and it's kinda hard for me, there is nothing about it in the book. I tried using GLabel thing, but here arises the problem that I need to work on those numbers, and it says "can't convert from int to string and vice versa". GLabel (string, posX, posY) - it is not accepting int as a parameter, only string, I even tried typecasting, still not working. For example I want to make a loop int currentDate = 1; while (currentDate < 31) { add(new Glabel(currentDate, 100, 100); currentDate++; This code is saying that no man, can't convert int to string. If i try changing currentDate to string, it works, but I got a problem with calculation, as I can't manipulate with number in string, it doesn't even allow to typecast it into int. How can I fix it? Maybe there is another class or method to type the text over those rectangles? I know about println but it doen't have any x or y coordinates, so I can't work with it. And I think it's only for console programs.

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  • Python Tkinter Tix: How to use ScrolledWindow with grid in Tix NoteBook

    - by Sano98
    Hi guys, I'm adding several widgets to a Frame which is located in a tix.NoteBook. When there are too much widgets to fit in the window, I want to use a scrollbar, so I put tix.ScrolledWindow inside that Frame and add my widgets to this ScrolledWindow instead. The problem is that when using the grid() geometry manager, the scrollbar appears, but it is not working (The drag bar occupies the whole scroll bar). from Tkinter import * import Tix class Window: def __init__(self, root): self.labelList = [] self.notebook = Tix.NoteBook(root, ipadx=3, ipady=3) self.notebook.add('sheet_1', label="Sheet 1", underline=0) self.notebook.add('sheet_2', label="Sheet 2", underline=0) self.notebook.add('sheet_3', label="Sheet 3", underline=0) self.notebook.pack() #self.notebook.grid(row=0, column=0) tab1=self.notebook.sheet_1 tab2=self.notebook.sheet_2 tab3=self.notebook.sheet_3 self.myMainContainer = Frame(tab1) self.myMainContainer.pack() #self.myMainContainer.grid(row=0, column=0) scrwin = Tix.ScrolledWindow(self.myMainContainer, scrollbar='y') scrwin.pack() #scrwin.grid(row=0, column=0) self.win = scrwin.window for i in range (100): self.labelList.append((Label(self.win))) self.labelList[-1].config(text= "Bla", relief = SUNKEN) self.labelList[-1].grid(row=i, column=0, sticky=W+E) root = Tix.Tk() myWindow = Window(root) root.mainloop() Whenever I change at least one of the geometry managers from pack() to grid(), the problem occurs. (Actually, I'd prefer using grid() for all containers.) When I don't use the NoteBook widget, the problem does not occur either. The other examples here all seem to rely on pack(). Any ideas? Many thanks, Sano

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  • Not-quite-JSON string deserialization in Python

    - by cpharmston
    I get the following text as a string from an XML-based REST API 'd':4 'ca':5 'sen':1 'diann':2,6,8 'feinstein':3,7,9 that I'm looking to deserialize into a pretty little Python dictionary: { 'd': [4], 'ca': [5], 'sen': [1], 'diann': [2, 6, 8], 'feinstein': [3, 7, 9] } I'm hoping to avoid using regular expressions or heavy string manipulation, as this format isn't documented and may change. The best I've been able to come up with: members = {} for m in elem.text.split(' '): m = m.split(':') members[m[0].replace("'", '')] = map(int, m[1].split(',')) return members Obviously a terrible approach, but it works, and that's better than anything else I've got right now. Any suggestions on better approaches?

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  • JQuery Validate: only takes the first addMethod?

    - by Neuquino
    Hi, I need to add multiple custom validations to one form. I have 2 definitions of addMethod. But it only takes the first one... here is the code. $(document).ready(function() { $.validator.addMethod("badSelectionB",function(){ var comboValues = []; for(var i=0;i<6;i++){ var id="comision_B_"+(i+1); var comboValue=document.getElementById(id).value; if($.inArray(comboValue,comboValues) != 0){ comboValues.push(comboValue); }else{ return false; } } return true; },"Seleccione una única prioridad por comisión."); $.validator.addMethod("badSelectionA",function(){ var comboValues = []; for(var i=0;i<6;i++){ var id="comision_A_"+(i+1); var comboValue=document.getElementById(id).value; if($.inArray(comboValue,comboValues) != 0){ comboValues.push(comboValue); }else{ return false; } } return true; },"Seleccione una única prioridad por comisión."); $("#inscripcionForm").validate( { rules : { nombre : "required", apellido : "required", dni : { required: true, digits: true, }, mail : { required : true, email : true, }, comision_A_6: { badSelectionA:true, }, comision_B_6: { badSelectionB: true, } }, messages : { nombre : "Ingrese su nombre.", apellido : "Ingrese su apellido.", dni : { required: "Ingrese su dni.", digits: "Ingrese solo números.", }, mail : { required : "Ingrese su correo electrónico.", email: "El correo electrónico ingresado no es válido." } }, }); }); Do you have any clue of what is happening? Thanks in advance,

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  • How do I get a Java to call data from the Internet? Where to even start??

    - by cdg
    Hello oh great wizards of all things android. I really need your help. Mostly because my little brain just doesn't know were to start. I am trying to pull data from the internet to make a widget for the home screen. I have the layout built: <?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/Layout" android:layout_width="fill_parent" android:layout_height="fill_parent" android:background="@drawable/widget_bg_normal" android:clipChildren="false" > <TextView android:id="@+id/text_view" android:layout_width="100px" android:layout_height="wrap_content" android:paddingTop="18px" android:layout_centerHorizontal="true" android:textSize="8px" android:text="158x154 Image downloaded from the internet goes here. Needs to be updated every evening at midnight or unless the button below is pressed. Now if I could only figure out exactly how to do this, life would be good." /> <Button android:id="@+id/new_button" android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="Get New" android:layout_below="@+id/scroll_image" android:layout_centerHorizontal="true" android:padding="0px" android:textSize="10px" android:height="8px" android:includeFontPadding="false" /> </RelativeLayout> Got the provider xml bulit: <?xml version="1.0" encoding="utf-8"?> <appwidget-provider xmlns:android="http://schemas.android.com/apk/res/android" android:minWidth="150dip" android:minHeight="150dip" android:updatePeriodMillis="10000" android:initialLayout="@layout/widget" /> The Manifest works great. <?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.dge.myandroid" android:versionCode="1" android:versionName="1.0"> <application android:icon="@drawable/icon" android:label="@string/app_name"> <activity android:name=".myactivty" android:label="@string/app_name"> <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> <!-- Widget --> <receiver android:name=".mywidget" android:label="@string/app_name" > <intent-filter> <action android:name="android.appwidget.action.APPWIDGET_UPDATE" /> </intent-filter> <meta-data android:name="android.appwidget.widgetprovider" android:resource="@xml/widgetprovider" /> </receiver> <!-- Widget End --> </application> <uses-permission android:name="android.permission.INTERNET" /> <uses-sdk android:minSdkVersion="7" /> </manifest> The data it is calling looks something like this when it is called. It basically goes to a website that uses php to random the image: <html><body bgcolor="#000000">center> <a href="http://www.website.com" target="_blank"> <img border="0" src="http://www.webiste.com//0.gif"></a> <img src="http://www.webiste.com" style="border:none;" /> </center></body></html> But here is were I am stuck. I just don't know where to start at all. The java is so far beyond my little head that I don't know what to do. package com.dge.myandroid; import android.appwidget.AppWidgetProvider; public class mywidget extends AppWidgetProvider { } The wiki example just confused me more. I just don't know where to begin. Please help.

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  • Asynchronous pages in the ASP.NET framework - where are the other threads and how is it reattached?

    - by rkrauter
    Sorry for this dumb question on Asynchronous operations. This is how I understand it. IIS has a limited set of worker threads waiting for requests. If one request is a long running operation, it will block that thread. This leads to fewer threads to serve requests. Way to fix this - use asynchronous pages. When a request comes in, the main worker thread is freed and this other thread is created in some other place. The main thread is thus able to serve other requests. When the request completes on this other thread, another thread is picked from the main thread pool and the response is sent back to the client. 1) Where are these other threads located? 2) IF ASP.NET likes creating new threads, why not increase the number of threads in the main worker pool - they are all running on the same machine anyway? 3) If the main thread hands off a request to this other thread, why does the request not get disconnected? It magically hands off the request to another worker thread somewhere else and when the long running process completes, it picks a thread from the main worker pool and sends response to the client. I am amazed...but how does that work?

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  • List of values as keys for a Map

    - by thr
    I have lists of variable length where each item can be one of four unique, that I need to use as keys for another object in a map. Assume that each value can be either 0, 1, 2 or 3 (it's not integer in my real code, but a lot easier to explain this way) so a few examples of key lists could be: [1, 0, 2, 3] [3, 2, 1] [1, 0, 0, 1, 1, 3] [2, 3, 1, 1, 2] [1, 2] So, to re-iterate: each item in the list can be either 0, 1, 2 or 3 and there can be any number of items in a list. My first approach was to try to hash the contents of the array, using the built in GetHashCode() in .NET to combine the hash of each element. But since this would return an int I would have to deal with collisions manually (two equal int values are identical to a Dictionary). So my second approach was to use a quad tree, breaking down each item in the list into a Node that has four pointers (one for each possible value) to the next four possible values (with the root node representing [], an empty list), inserting [1, 0, 2] => Foo, [1, 3] => Bar and [1, 0] => Baz into this tree would look like this: Grey nodes nodes being unused pointers/nodes. Though I worry about the performance of this setup, but there will be no need to deal with hash collisions and the tree won't become to deep (there will mostly be lists with 2-6 items stored, rarely over 6). Is there some other magic way to store items with lists of values as keys that I have missed?

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  • TechDays Canada 2010

    - by guybarrette
    John Oxley announced that TechDays is returning to Canada in more cities then ever in 2010. Vancouver – September 14/15 at the Vancouver Convention Centre Edmonton – October 5/6 at the Shaw Conference Centre Toronto – October 27/28 at the Metro Toronto Convention Centre Halifax – November 2/3 at the World Trade & Convention Centre Ottawa – November 9/10 at the Hampton Inn & Conference Centre Montreal – November 23/24 at the Palais de Congres Winnipeg – December 7/8 at the Winnipeg Convention Centre Calgary – December 14/15 at the Calgary Stampede Get all the info here var addthis_pub="guybarrette";

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  • How to use WeirdX applet instead of X11 for remote connections in Mac OS X?

    - by penyuan
    When I am away, I've got an Apple PowerBook set up to use X11 forwarding with SSH to connect to a remote iMac in my room. Whenever I start X client programs on the client iMac, X11 would start on my PowerBook, which is OK. Question: Is it possible to change my settings so that the WeirdX applet I have on my PowerBook will take care of the X client programs instead of the default X11? Is there a config file I can edit to chance the $DISPLAY variable, and what should I set it to? Is this even the issue? Thank you very much.

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  • Managing EntityConnection lifetime

    - by kervin
    There have been many question on managing EntityContext lifetime, e.g. http://stackoverflow.com/questions/813457/instantiating-a-context-in-linq-to-entities I've come to the conclusion that the entity context should be considered a unit-of-work and therefore not reused. Great. But while doing some research for speeding up my database access, I ran into this blog post... Improving Entity Framework Performance The post argues that EFs poor performance compared to other frameworks is often due to the EntityConnection object being created each time a new EntityContext object is needed. To test this I manually created a static EntityConnection in Global.asax.cs Application_Start(). I then converted all my context using statements to using( MyObjContext currContext = new MyObjeContext(globalStaticEFConnection) { .... } This seems to have sped things up a bit without any errors so far as far as I can tell. But is this safe? Does using a applicationwide static EntityConnection introduce race conditions? Best regards, Kervin

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  • How to develop JSP/Servlets Web App using MVC pattern?

    - by A.S al-shammari
    I'm developing a JSP/Servlets web app (no frameworks). I want to use MVC pattern. I designed my project like this : Controller :a servlet that reads a request, extracts the values,communicates with model objects and gives information to a JSP page. View : JSP Pages. Model : Java Classes / Java Beans .. etc . The problem : Index.jsp is the starting point (default page) in my web site. So, the Index.jsp becomes the controller to parse the request! .For example , the following request : index.jsp?section=article&id=10 parsed in index.jsp as following : <div class="midcol"> <!-- Which section? --> <%String fileName = request.getParameter("section"); if (fileName == null) { fileName = "WEB-INF/jspf/frontpage.jsp"; } else { fileName = "WEB-INF/jspf/" + fileName + ".jsp"; } %> <jsp:include page='<%= fileName%>' /> </div> Here, I can't force the servlet to be a controller .. because the index.jsp is the controller here since it's the starting point! Is there any solution to forward the request from index.jsp to the servlet and then go back to index.jsp ? Or any solution that achieves the MVC goal - the servlet should be the controller - ? I'm thinking of making a FrontPageController servlet as default page instead of index.jsp ! but I don't know if it's a perfect idea ?!

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  • emacs debugger: how can I step-out, step-over ?

    - by Cheeso
    I don't know why I'm having so much trouble groking the documentation for the elisp debugger. I see it has a commands to "step-into" (d). But for the life of me, I cannot see a step-out or step-over. Can anyone help? If I have this in the Backtrace buffer: Debugger entered--returning value: 5047 line-beginning-position() * c-parse-state() * byte-code("...") * c-guess-basic-syntax() c-show-syntactic-information(nil) call-interactively(c-show-syntactic-information) ...where do I put the cursor, and what key do I type, to step out of the parse-state() fn ? by that I mean, run until that fn returns, and then stop in the debugger again.

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  • JQuery Validate: only takes the last addMethod?

    - by Neuquino
    Hi, I need to add multiple custom validations to one form. I have 2 definitions of addMethod. But it only takes the last one... here is the code. $(document).ready(function() { $.validator.addMethod("badSelectionB",function(){ var comboValues = []; for(var i=0;i<6;i++){ var id="comision_B_"+(i+1); var comboValue=document.getElementById(id).value; if($.inArray(comboValue,comboValues) == -1){ comboValues.push(comboValue); }else{ return false; } } return true; },"Seleccione una única prioridad por comisión."); $.validator.addMethod("badSelectionA",function(){ var comboValues = []; for(var i=0;i<6;i++){ var id="comision_A_"+(i+1); var comboValue=document.getElementById(id).value; if($.inArray(comboValue,comboValues) == -1){ comboValues.push(comboValue); }else{ return false; } } return true; },"Seleccione una única prioridad por comisión."); $("#inscripcionForm").validate( { rules : { nombre : "required", apellido : "required", dni : { required: true, digits: true, }, mail : { required : true, email : true, }, comision_A_6: { badSelectionA:true, }, comision_B_6: { badSelectionB: true, } }, messages : { nombre : "Ingrese su nombre.", apellido : "Ingrese su apellido.", dni : { required: "Ingrese su dni.", digits: "Ingrese solo números.", }, mail : { required : "Ingrese su correo electrónico.", email: "El correo electrónico ingresado no es válido." } }, }); }); Do you have any clue of what is happening? Thanks in advance,

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  • Link User32 with gcc

    - by Tim Cooper
    I have a C program which has a function call that is defined in windows.h (which I have included), however, when I try and compile it with gcc, I get the error: warning: implicit declaration of function `LockWorkStation' I looked at the MSDN documentation and I see that this function is the User32 library file, and I was wondering how I would go about linking that to my file.

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