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• Haskell math performance

  - by Travis Brown

  I'm in the middle of porting David Blei's original C implementation of Latent Dirichlet Allocation to Haskell, and I'm trying to decide whether to leave some of the low-level stuff in C. The following function is one example—it's an approximation of the second derivative of lgamma: double trigamma(double x) { double p; int i; x=x+6; p=1/(x*x); p=(((((0.075757575757576*p-0.033333333333333)*p+0.0238095238095238) *p-0.033333333333333)*p+0.166666666666667)*p+1)/x+0.5*p; for (i=0; i<6 ;i++) { x=x-1; p=1/(x*x)+p; } return(p); } I've translated this into more or less idiomatic Haskell as follows: trigamma :: Double -> Double trigamma x = snd $ last $ take 7 $ iterate next (x' - 1, p') where x' = x + 6 p = 1 / x' ^ 2 p' = p / 2 + c / x' c = foldr1 (\a b -> (a + b * p)) [1, 1/6, -1/30, 1/42, -1/30, 5/66] next (x, p) = (x - 1, 1 / x ^ 2 + p) The problem is that when I run both through Criterion, my Haskell version is six or seven times slower (I'm compiling with -O2 on GHC 6.12.1). Some similar functions are even worse. I know practically nothing about Haskell performance, and I'm not terribly interested in digging through Core or anything like that, since I can always just call the handful of math-intensive C functions through FFI. But I'm curious about whether there's low-hanging fruit that I'm missing—some kind of extension or library or annotation that I could use to speed up this numeric stuff without making it too ugly.

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• need a near 100% uptime third-party web-accesible hosting for static web resources

  - by Jared Henderson

  I hope this makes sense: my business sells a website template, we currently have about 10,000 users. For various reasons that are unimportant to this question, I try to keep the file size of the zipped template we give them as small as possible. Because of this, I have taken a bunch of images and a couple of static files used by the template and moved them to external hosting. They are referenced by absolute URL in the css and markup, instead of shipping all of those images and files with every template. So, basically 10,000+ and growing users are requesting images and files from a third-party host. I don't use my own webhosting for this because I still kind of use a medium-cheap shared hosting for my website, and if it goes down, 10,000+ users are potentially effected. Currently I'm having the template directly access files inside of an open-source google-code project that I created for just this purpose. But, that seems like a bastardization of what a google-code repository is for, and plus, google code (i've found out) often spews 502 bad gateway errors for hours at a time. So, anyway, my question is: where is the right kind of place to host these? Obviously I'm willing to pay. My main needs are speed and uptime, since the images and files are being requested from thousands of different websites every day. Is this something that I should use Amazon S3 for? I'm guessing there's some kind of service exactly for this kind of need, but I'm at a loss to figure out what it is.

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• How to Manage CSS Explosion

  - by Jason

  I have been heavily relying on CSS for a website that I am working on (currently, everything is done as property values within each tag on the website and I'm trying to get away from that to make updates significantly easier). The problem I am running into, is I'm starting to get a bit of "CSS explosion" going on. It is becoming difficult for me to decide how to best organize and abstract data within the CSS file. For example: I am using a large number of div tags within the website (previously it was completely tables based). So I'm starting to get a lot of CSS that looks like this... div.title { background-color: Blue; color: White; text-align: center; } div.footer { /* Stuff Here */ } div.body { /* Stuff Here */ } etc. It's not too bad yet, but since I am learning here, I was wondering if recommendations could be made on how best to organize the various parts of a CSS file. What I don't want to get to is where I have a separate CSS attribute for every single thing on my website (which I have seen happen), and I always want the CSS file to be fairly intuitive. (P.S. I do realize this is a very generic, high-level question. My ultimate goal is to make it easy to use the CSS files and demonstrate their power to increase the speed of web development so other individuals that may work on this site in the future will also get into the practice of using them rather than hard-coding values everywhere.)

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• Self-describing file format for gigapixel images?

  - by Adam Goode

  In medical imaging, there appears to be two ways of storing huge gigapixel images: Use lots of JPEG images (either packed into files or individually) and cook up some bizarre index format to describe what goes where. Tack on some metadata in some other format. Use TIFF's tile and multi-image support to cleanly store the images as a single file, and provide downsampled versions for zooming speed. Then abuse various TIFF tags to store metadata in non-standard ways. Also, store tiles with overlapping boundaries that must be individually translated later. In both cases, the reader must understand the format well enough to understand how to draw things and read the metadata. Is there a better way to store these images? Is TIFF (or BigTIFF) still the right format for this? Does XMP solve the problem of metadata? The main issues are: Storing images in a way that allows for rapid random access (tiling) Storing downsampled images for rapid zooming (pyramid) Handling cases where tiles are overlapping or sparse (scanners often work by moving a camera over a slide in 2D and capturing only where there is something to image) Storing important metadata, including associated images like a slide's label and thumbnail Support for lossy storage What kind of (hopefully non-proprietary) formats do people use to store large aerial photographs or maps? These images have similar properties.

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• Link checker ; how to avoid false positives

  - by Burnzy

  I'm working a on a link checker/broken link finder and I am getting many false positives, after double checking I noticed that many error codes were returning webexceptions but they were actually downloadable, but in some other cases the statuscode is 404 and i can access the page from the browse. So here is the code, its pretty ugly, and id like to have something more, id say practical. All the status codes are in that big if are used to filter the ones i dont want to add to brokenlink because they are valid links ( i tested them all ). What i need to fix is the structure (if possible) and how to not get false 404. Thank you! try { HttpWebRequest request = ( HttpWebRequest ) WebRequest.Create ( uri ); request.Method = "Head"; request.MaximumResponseHeadersLength = 32; // FOR IE SLOW SPEED request.AllowAutoRedirect = true; using ( HttpWebResponse response = ( HttpWebResponse ) request.GetResponse() ) { request.Abort(); } /* WebClient wc = new WebClient(); wc.DownloadString( uri ); */ _validlinks.Add ( strUri ); } catch ( WebException wex ) { if ( !wex.Message.Contains ( "The remote name could not be resolved:" ) && wex.Status != WebExceptionStatus.ServerProtocolViolation ) { if ( wex.Status != WebExceptionStatus.Timeout ) { HttpStatusCode code = ( ( HttpWebResponse ) wex.Response ).StatusCode; if ( code != HttpStatusCode.OK && code != HttpStatusCode.BadRequest && code != HttpStatusCode.Accepted && code != HttpStatusCode.InternalServerError && code != HttpStatusCode.Forbidden && code != HttpStatusCode.Redirect && code != HttpStatusCode.Found ) { _brokenlinks.Add ( new Href ( new Uri ( strUri , UriKind.RelativeOrAbsolute ) , UrlType.External ) ); } else _validlinks.Add ( strUri ); } else _brokenlinks.Add ( new Href ( new Uri ( strUri , UriKind.RelativeOrAbsolute ) , UrlType.External ) ); } else _validlinks.Add ( strUri ); }

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• Socket in C: recv overwrite a char[]

  - by Possa

  Hi all, I'm trying to make a little client-server script like many others that I've done in the past. But in this one I have a problem. It is better if I post the code and the output it give me. Code: #include <mysql.h> //not important now #include <stdlib.h> #include <sys/types.h> #include <sys/socket.h> #include <netinet/in.h> #include <arpa/inet.h> #include <netdb.h> #include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <signal.h> #include <string.h> //constant definition #define SERVER_PORT 2121 #define LINESIZE 21 //global var definition char victim_ip[LINESIZE], file_write[LINESIZE], hacker_ip[LINESIZE]; //function void leggi (int); //not use now for debugging purpose //void scriviDB (); //not important now main () { int sock, client_len, fd; struct sockaddr_in server, client; // transport end point if((sock = socket(AF_INET, SOCK_STREAM, 0)) == -1) { perror("system call socket fail"); exit(1); } server.sin_family = AF_INET; server.sin_addr.s_addr = inet_addr("10.10.10.1"); server.sin_port = htons(SERVER_PORT); // binding address at transport end point if (bind(sock, (struct sockaddr *)&server, sizeof server) == -1) { perror("system call bind fail"); exit(1); } //fprintf(stderr, "Server open: listening.\n"); listen(sock, 5); /* managae client connection */ while (1) { client_len = sizeof(client); if ((fd = accept(sock, (struct sockaddr *)&client, &client_len)) < 0) { perror("accepting connection"); exit(1); } strcpy(hacker_ip, inet_ntoa(client.sin_addr)); printf("1 %s\n", hacker_ip); //debugging purpose //leggi(fd); ////////////////////////// //receive client recv(fd, victim_ip, LINESIZE, 0); victim_ip[sizeof(victim_ip)] = '\0'; printf("2 %s\n", hacker_ip); //debugging purpose recv(fd, file_write, LINESIZE, 0); file_write[sizeof(file_write)] = '\0'; printf("3 %s\n", hacker_ip); //debugging purpose printf("%s@%s for %s\n", file_write, victim_ip, hacker_ip); //send to client send(fd, hacker_ip, 40, 0); //now is hacker_ip for debug ///////////////////////// close(fd); }//end while exit(0); } //end main Client send string: ./send -i 10.10.10.4 -f filename.ext so the script send -i (IP) and -f (FILE) at the server. Here's my output server side: 1 10.10.10.6 2 10.10.10.6 3 [email protected] for As you can see the printf(3) and the printf(ip,file,ip) fail. I don't know how and where but someone overwrite my hacker_ip string. Thanks for your help! :)

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• Why so Long time span in creating Session Factory?

  - by vijay.shad

  Hi My project is web application running in the tomcat container. This application is a spring framework based hibernate application. The problem with this is it takes a lot of time when creates session factory. here is the logs 2010-04-15 23:05:28,053 DEBUG [SessionFactoryImpl] Session factory constructed with filter configurations : {} 2010-04-15 23:05:28,053 DEBUG [SessionFactoryImpl] instantiating session factory with properties: {java.vendor=Sun Microsystems Inc., sun.java.launcher=SUN_STANDARD, catalina.base=/usr/local/InstalledPrograms/apache-tomcat-6.0.20, sun.management.compiler=HotSpot Tiered Compilers, catalina.useNaming=true, os.name=Linux, sun.boot.class.path=/usr/java/jdk1.6.0_17/jre/lib/resources.jar:/usr/java/jdk1.6.0_17/jre/lib/rt.jar:/usr/java/jdk1.6.0_17/jre/lib/sunrsasign.jar:/usr/java/jdk1.6.0_17/jre/lib/jsse.jar:/usr/java/jdk1.6.0_17/jre/lib/jce.jar:/usr/java/jdk1.6.0_17/jre/lib/charsets.jar:/usr/java/jdk1.6.0_17/jre/classes, java.util.logging.config.file=/usr/local/InstalledPrograms/apache-tomcat-6.0.20/conf/logging.properties, java.vm.specification.vendor=Sun Microsystems Inc., hibernate.generate_statistics=true, java.runtime.version=1.6.0_17-b04, hibernate.cache.provider_class=org.hibernate.cache.EhCacheProvider, user.name=root, shared.loader=, tomcat.util.buf.StringCache.byte.enabled=true, hibernate.connection.release_mode=auto, user.language=en, java.naming.factory.initial=org.apache.naming.java.javaURLContextFactory, sun.boot.library.path=/usr/java/jdk1.6.0_17/jre/lib/i386, java.version=1.6.0_17, java.util.logging.manager=org.apache.juli.ClassLoaderLogManager, user.timezone=Canada/Pacific, sun.arch.data.model=32, java.endorsed.dirs=/usr/local/InstalledPrograms/apache-tomcat-6.0.20/endorsed, sun.cpu.isalist=, sun.jnu.encoding=UTF-8, file.encoding.pkg=sun.io, package.access=sun.,org.apache.catalina.,org.apache.coyote.,org.apache.tomcat.,org.apache.jasper.,sun.beans., file.separator=/, java.specification.name=Java Platform API Specification, java.class.version=50.0, user.country=US, java.home=/usr/java/jdk1.6.0_17/jre, java.vm.info=mixed mode, os.version=2.6.18-128.el5, path.separator=:, java.vm.version=14.3-b01, hibernate.jdbc.batch_size=25, java.awt.printerjob=sun.print.PSPrinterJob, sun.io.unicode.encoding=UnicodeLittle, package.definition=sun.,java.,org.apache.catalina.,org.apache.coyote.,org.apache.tomcat.,org.apache.jasper., java.naming.factory.url.pkgs=org.apache.naming, sun.rmi.dgc.client.gcInterval=3600000, user.home=/root, java.specification.vendor=Sun Microsystems Inc., java.library.path=/usr/java/jdk1.6.0_17/jre/lib/i386/server:/usr/java/jdk1.6.0_17/jre/lib/i386:/usr/java/jdk1.6.0_17/jre/../lib/i386:/usr/java/packages/lib/i386:/lib:/usr/lib, java.vendor.url=http://java.sun.com/, java.vm.vendor=Sun Microsystems Inc., hibernate.dialect=org.hibernate.dialect.MySQL5InnoDBDialect, sun.rmi.dgc.server.gcInterval=3600000, common.loader=${catalina.home}/lib,${catalina.home}/lib/*.jar, java.runtime.name=Java(TM) SE Runtime Environment, java.class.path=:/usr/local/InstalledPrograms/apache-tomcat-6.0.20/bin/bootstrap.jar, hibernate.bytecode.use_reflection_optimizer=false, java.vm.specification.name=Java Virtual Machine Specification, java.vm.specification.version=1.0, catalina.home=/usr/local/InstalledPrograms/apache-tomcat-6.0.20, sun.cpu.endian=little, sun.os.patch.level=unknown, hibernate.cache.use_query_cache=true, hibernate.connection.provider_class=org.springframework.orm.hibernate3.LocalDataSourceConnectionProvider, java.io.tmpdir=/usr/local/InstalledPrograms/apache-tomcat-6.0.20/temp, java.vendor.url.bug=http://java.sun.com/cgi-bin/bugreport.cgi, server.loader=, os.arch=i386, java.awt.graphicsenv=sun.awt.X11GraphicsEnvironment, java.ext.dirs=/usr/java/jdk1.6.0_17/jre/lib/ext:/usr/java/packages/lib/ext, user.dir=/, line.separator=, java.vm.name=Java HotSpot(TM) Server VM, hibernate.cache.use_second_level_cache=true, file.encoding=UTF-8, java.specification.version=1.6, hibernate.show_sql=true} 2010-04-15 23:08:53,516 DEBUG [AbstractEntityPersister] Static SQL for entity: com.vsd.model.Order There you can see the time delay of more than 3 mins in executing these processes. My database is mysql and database server is running on the local machine only. The container environment is Centos Linux system. I am clueless about why it takes that much of time in executing these process, But when i do the same task from under eclipse it does not take that much of time. Development environment is Windows.

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• How to access C arrays from assembler for Windows x64?

  - by 0xdword32

  I've written an assembler function to speed up a few things for image processing (images are created with CreateDIBSection). For Win32 the assembler code works without problems, but for Win64 I get a crash as soon as I try to access my array data. I put the relevant info in a struct and my assembler function gets a pointer to this struct. The struct pointer is put into ebx/rbx and with indexing I read the data from the struct. Any idea what I am doing wrong? I use nasm together with Visual Studio 2008 and for Win64 I set "default rel". C++ code: struct myData { tUInt32 ulParam1; void* pData; }; CallMyAssemblerFunction(&myData); Assembler Code: Win32: ... push ebp; mov ebp,esp mov ebx, [ebp + 8]; pointer to our struct mov eax, [ebx]; ulParam1 mov esi, [ebx + 4]; pData, 4 byte pointer movd xmm0, [esi]; ... Win64: ... mov rbx, rcx; pointer to our struct mov eax, [rbx]; ulParam1 mov rsi, [rbx + 4]; pData, 8 byte pointer movd xmm0, [rsi]; CRASH! ...

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• How to generate a Program template by generating an abstract class

  - by Byron-Lim Timothy Steffan

  i have the following problem. The 1st step is to implement a program, which follows a specific protocol on startup. Therefore, functions as onInit, onConfigRequest, etc. will be necessary. (These are triggered e.g. by incoming message on a TCP Port) My goal is to generate a class for example abstract one, which has abstract functions as onInit(), etc. A programmer should just inherit from this base class and should merely override these abstract functions of the base class. The rest as of the protocol e.g. should be simply handled in the background (using the code of the base class) and should not need to appear in the programmers code. What is the correct design strategy for such tasks? and how do I deal with, that the static main method is not inheritable? What are the key-tags for this problem? (I have problem searching for a solution since I lack clear statements on this problem) Goal is to create some sort of library/class, which - included in ones code - results in executables following the protocol. EDIT (new explanation): Okay let me try to explain more detailled: In this case programs should be clients within a client server architecture. We have a client server connection via TCP/IP. Each program needs to follow a specific protocol upon program start: As soon as my program starts and gets connected to the server it will receive an Init Message (TcpClient), when this happens it should trigger the function onInit(). (Should this be implemented by an event system?) After onInit() a acknowledgement message should be sent to the server. Afterwards there are some other steps as e.g. a config message from the server which triggers an onConfig and so on. Let's concentrate on the onInit function. The idea is, that onInit (and onConfig and so on) should be the only functions the programmer should edit while the overall protocol messaging is hidden for him. Therefore, I thought using an abstract class with the abstract methods onInit(), onConfig() in it should be the right thing. The static Main class I would like to hide, since within it e.g. there will be some part which connects to the tcp port, which reacts on the Init Message and which will call the onInit function. 2 problems here: 1. the static main class cant be inherited, isn it? 2. I cannot call abstract functions from the main class in the abstract master class. Let me give an Pseudo-example for my ideas: public abstract class MasterClass { static void Main(string[] args){ 1. open TCP connection 2. waiting for Init Message from server 3. onInit(); 4. Send Acknowledgement, that Init Routine has ended successfully 5. waiting for Config message from server 6..... } public abstract void onInit(); public abstract void onConfig(); } I hope you get the idea now! The programmer should afterwards inherit from this masterclass and merely need to edit the functions onInit and so on. Is this way possible? How? What else do you recommend for solving this? EDIT: The strategy ideo provided below is a good one! Check out my comment on that.

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• How can I make this method more Scalalicious

  - by Neil Chambers

  I have a function that calculates the left and right node values for some collection of treeNodes given a simple node.id, node.parentId association. It's very simple and works well enough...but, well, I am wondering if there is a more idiomatic approach. Specifically is there a way to track the left/right values without using some externally tracked value but still keep the tasty recursion. /* * A tree node */ case class TreeNode(val id:String, val parentId: String){ var left: Int = 0 var right: Int = 0 } /* * a method to compute the left/right node values */ def walktree(node: TreeNode) = { /* * increment state for the inner function */ var c = 0 /* * A method to set the increment state */ def increment = { c+=1; c } // poo /* * the tasty inner method * treeNodes is a List[TreeNode] */ def walk(node: TreeNode): Unit = { node.left = increment /* * recurse on all direct descendants */ treeNodes filter( _.parentId == node.id) foreach (walk(_)) node.right = increment } walk(node) } walktree(someRootNode) Edit - The list of nodes is taken from a database. Pulling the nodes into a proper tree would take too much time. I am pulling a flat list into memory and all I have is an association via node id's as pertains to parents and children. Adding left/right node values allows me to get a snapshop of all children (and childrens children) with a single SQL query. The calculation needs to run very quickly in order to maintain data integrity should parent-child associations change (which they do very frequently). In addition to using the awesome Scala collections I've also boosted speed by using parallel processing for some pre/post filtering on the tree nodes. I wanted to find a more idiomatic way of tracking the left/right node values. After looking at the answers listed I have settled on this synthesised version: def walktree(node: TreeNode) = { def walk(node: TreeNode, counter: Int): Int = { node.left = counter node.right = treeNodes .filter( _.parentId == node.id) .foldLeft(counter+1) { (counter, curnode) => walk(curnode, counter) + 1 } node.right } walk(node,1) }

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• Can anyone help convert this VB Webservice?

  - by CraigJSte

  I can't figure it out for the life of me.. I'm using SQL DataSet Query to iterate to a Class Object which acts as a Data Model for Flex... Initially I used VB.net but now need to convert to C#.. This conversion is done except for the last section where I create a DataRow arow and then try to add the DataSet Values to the Class (Results Class)... I get an error message.. 'VTResults.Results.Ticker' is inaccessible due to its protection level (this is down at the bottom) using System; using System.Web; using System.Collections; using System.Web.Services; using System.Web.Services.Protocols; using System.Data; using System.Data.SqlClient; using System.Configuration; /// <summary> /// Summary description for VTResults /// </summary> [WebService(Namespace = "http://velocitytrading.net/ResultsVT.aspx")] [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)] public class VTResults : System.Web.Services.WebService { public class Results { string Ticker; string BuyDate; decimal Buy; string SellDate; decimal Sell; string Profit; decimal Period; } [WebMethod] public Results[] GetResults() { string conn = ConfigurationManager.ConnectionStrings["LocalSqlServer"].ConnectionString; SqlConnection myconn = new SqlConnection(conn); SqlCommand mycomm = new SqlCommand(); SqlDataAdapter myda = new SqlDataAdapter(); DataSet myds = new DataSet(); mycomm.CommandType = CommandType.StoredProcedure; mycomm.Connection = myconn; mycomm.CommandText = "dbo.Results"; myconn.Open(); myda.SelectCommand = mycomm; myda.Fill(myds); myconn.Close(); myconn.Dispose(); int i = 0; Results[] dts = new Results[myds.Tables[0].Rows.Count]; foreach(DataRow arow in myds.Tables[0].Rows) { dts[i] = new Results(); dts[i].Ticker = arow["Ticker"]; dts[i].BuyDate = arow["BuyDate"]; dts[1].Buy = arow["Buy"]; dts[i].SellDate = arow["SellDate"]; dts[i].Sell = arow["Sell"]; dts[i].Profit = arow["Profit"]; dts[i].Period = arow["Period"]; i+=1; } return dts; } } The VB.NET WEBSERVICE that runs fine which I am trying to convert to C# is here. Imports System.Web Imports System.Web.Services Imports System.Web.Services.Protocols Imports System.Data Imports System.Data.SqlClient <WebService(Namespace:="http://localhost:2597/Results/ResultsVT.aspx")> _ <WebServiceBinding(ConformsTo:=WsiProfiles.BasicProfile1_1)> _ <Global.Microsoft.VisualBasic.CompilerServices.DesignerGenerated()> _ Public Class VTResults Inherits System.Web.Services.WebService Public Class Results Public Ticker As String Public BuyDate As String Public Buy As Decimal Public SellDate As String Public Sell As Decimal Public Profit As String Public Period As Decimal End Class <WebMethod()> _ Public Function GetResults() As Results() Try Dim conn As String = ConfigurationManager.ConnectionStrings("LocalSqlServer").ConnectionString Dim myconn = New SqlConnection(conn) Dim mycomm As New SqlCommand Dim myda As New SqlDataAdapter Dim myds As New DataSet mycomm.CommandType = CommandType.StoredProcedure mycomm.Connection = myconn mycomm.CommandText = "dbo.Results" myconn.Open() myda.SelectCommand = mycomm myda.Fill(myds) myconn.Close() myconn.Dispose() Dim i As Integer i = 0 Dim dts As Results() = New Results(myds.Tables(0).Rows.Count - 1) {} Dim aRow As DataRow For Each aRow In myds.Tables(0).Rows dts(i) = New Results dts(i).Ticker = aRow("Ticker") dts(i).BuyDate = aRow("BuyDate") dts(i).Buy = aRow("Buy") dts(i).SellDate = aRow("SellDate") dts(i).Sell = aRow("Sell") dts(i).Profit = aRow("Profit") dts(i).Period = aRow("Period") i += 1 Next Return dts Catch ex As DataException Throw ex End Try End Function End Class

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• Performance degrades for more than 2 threads on Xeon X5355

  - by zoolii

  Hi All, I am writing an application using boost threads and using boost barriers to synchronize the threads. I have two machines to test the application. Machine 1 is a core2 duo (T8300) cpu machine (windows XP professional - 4GB RAM) where I am getting following performance figures : Number of threads :1 , TPS :21 Number of threads :2 , TPS :35 (66 % improvement) further increase in number of threads decreases the TPS but that is understandable as the machine has only two cores. Machine 2 is a 2 quad core ( Xeon X5355) cpu machine (windows 2003 server with 4GB RAM) and has 8 effective cores. Number of threads :1 , TPS :21 Number of threads :2 , TPS :27 (28 % improvement) Number of threads :4 , TPS :25 Number of threads :8 , TPS :24 As you can see, performance is degrading after 2 threads (though it has 8 cores). If the program has some bottle neck , then for 2 thread also it should have degraded. Any idea? , Explanations ? , Does the OS has some role in performance ? - It seems like the Core2duo (2.4GHz) scales better than Xeon X5355 (2.66GHz) though it has better clock speed. Thank you -Zoolii

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• swf listens to XML, AS3

  - by VideoDnd

  My swf listens to XML from a socket and document. How do I get 'my variables' to grab XML from the socket instead of the XML document? PURPOSE My purpose is to control variables with a XML Socket Server. I hope my question is clear, but ask if there's any questions. EXAMPLE Flash File import flash.net.*; import flash.display.*; import flash.events.*; import flash.system.Security; import flash.utils.Timer; import flash.events.TimerEvent; //MY VARIABLES, LINE 8-12 var timer:Timer = new Timer(10); var myString:String = ""; var count:int = 0; var myStg:String = ""; var fcount:int = 0; var xml_s=new XMLSocket(); xml_s.addEventListener(Event.CONNECT, socket_event_catcher);//OnConnect// xml_s.addEventListener(Event.CLOSE, socket_event_catcher);//OnDisconnect// xml_s.addEventListener(IOErrorEvent.IO_ERROR, socket_event_catcher);//Unable To Connect// xml_s.addEventListener(DataEvent.DATA, socket_event_catcher);//OnDisconnect// xml_s.connect("localhost", 1999); function socket_event_catcher(Event):void { switch (Event.type) { case 'ioError' : trace("ioError: " + Event.text);//Unable to Connect :(// break; case 'connect' : trace("Connection Established!");//Connected :)// break; case 'data' : trace("Received Data: " + Event.data); //var myXML:XML=new XML(Event.data); //trace("myXML.body.file: " + myXML.body.file); //var myLoader:String=myXML.body.file; //var urlReq:URLRequest=new URLRequest(myLoader); //trace("file to load URL: " + urlReq); break; case 'close' : trace("Connection Closed!");//OnDisconnect :( // xml_s.close(); break; } } //LOAD XML var myXML:XML; var myLoader:URLLoader = new URLLoader(); myLoader.load(new URLRequest("time.xml")); myLoader.addEventListener(Event.COMPLETE, processXML); //var myXML:XML=new XML(Event.data); //trace("myXML.body.file: " + myXML.body.file); //var DOINK:String=myXML.body.file; //var urlReq:URLRequest=new URLRequest(DOINK); //trace("file to load URL: " + urlReq); //PARSE XML function processXML(e:Event):void { myXML = new XML(e.target.data); trace(myXML.COUNT.text()); //-77777 //grab the data as a string myString = myXML.COUNT.text() //grab the data as an int count = int(myXML.COUNT.text()); //grab the data as a string myString = myXML.COUNT.text() //grab the data as an int count = int(myXML.COUNT.text()); //grab the data as a string myStg = myXML.COUNT.text() //grab the data as an int fcount = int(myXML.COUNT.text()); //grab the data as a string myStg = myXML.COUNT.text() //grab the data as an int fcount = int(myXML.COUNT.text()); trace("String: ", myString); trace("Int: ", count); trace(count - 1); //just to show you that it's a number that you can do math with (-77778) //TEXT var text:TextField = new TextField(); text.text = myString; addChild(text); } Ruby Server 'Snippet' msg1 = {"msg" => {"head" => {"type" => "frctl", "seq_no" => seq_no, "version" => 1.0}, "SESSION" => {"text" => "88888", "timer" => -1000, "count" => 10, "fcount" => "10"}}} XML <?xml version="1.0" encoding="utf-8"?> <SESSION> <TIMER TITLE="speed">100</TIMER> <COUNT TITLE="starting position">88888</COUNT> <FCOUNT TITLE="ramp">1000</FCOUNT> </SESSION> ENVIROMENT AS3 Ruby 186-25 PROBLEM Coding errors "coercion of value"

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• Dependency between operations in scala actors

  - by paradigmatic

  I am trying to parallelise a code using scala actors. That is my first real code with actors, but I have some experience with Java Mulithreading and MPI in C. However I am completely lost. The workflow I want to realise is a circular pipeline and can be described as the following: Each worker actor has a reference to another one, thus forming a circle There is a coordinator actor which can trigger a computation by sending a StartWork() message When a worker receives a StartWork() message, it process some stuff locally and sends DoWork(...) message to its neighbour in the circle. The neighbours do some other stuff and sends in turn a DoWork(...) message to its own neighbour. This continues until the initial worker receives a DoWork() message. The coordinator can send a GetResult() message to the initial worker and wait for a reply. The point is that the coordinator should only receive a result when data is ready. How can a worker wait that the job returned to it before answering the GetResult() message ? To speed up computation, any worker can receive a StartWork() at any time. Here is my first try pseudo-implementation of the worker: class Worker( neighbor: Worker, numWorkers: Int ) { var ready = Foo() def act() { case StartWork() => { val someData = doStuff() neighbor ! DoWork( someData, numWorkers-1 ) } case DoWork( resultData, remaining ) => if( remaining == 0 ) { ready = resultData } else { val someOtherData = doOtherStuff( resultData ) neighbor ! DoWork( someOtherData, remaining-1 ) } case GetResult() => reply( ready ) } } On the coordinator side: worker ! StartWork() val result = worker !? GetResult() // should wait

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• is mysql index useful on column 'state' when only doing bit-operations on the column?

  - by Geert-Jan

  I have a lot of domain entities (stored in mysql) which undergo lots of different operations. Each operation is executed from a different program. I need to keep (flow)-state for these entities which I implemented in as a long field 'flowstate' used as a bitset. to query mysql for entities which have undergone a certain operation I do something like: select * from entities where state >> 7 & 1 = 1 Indicating bit 7 (cooresponding to operation 7) has run. (<-- simplified) Anyway, I really didn't pay attention to the performance implications of this setup in the beginning, and I think I'm in a bit of trouble since queries as the above run pretty slow. What I'd like to know: Does an mysql index on 'flowstate' help at all? After all it's not a single value Mysql can quickly find using a binary sort or whatever. If it doesn't, are there any other things I could do to speed things up? . Are there special 'mask-indices' for fields with use-cases as the above? TIA, Geert-jan

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• Use a vector to index a matrix without linear index

  - by David_G

  G'day, I'm trying to find a way to use a vector of [x,y] points to index from a large matrix in MATLAB. Usually, I would convert the subscript points to the linear index of the matrix.(for eg. Use a vector as an index to a matrix in MATLab) However, the matrix is 4-dimensional, and I want to take all of the elements of the 3rd and 4th dimensions that have the same 1st and 2nd dimension. Let me hopefully demonstrate with an example: Matrix = nan(4,4,2,2); % where the dimensions are (x,y,depth,time) Matrix(1,2,:,:) = 999; % note that this value could change in depth (3rd dim) and time (4th time) Matrix(3,4,:,:) = 888; % note that this value could change in depth (3rd dim) and time (4th time) Matrix(4,4,:,:) = 124; Now, I want to be able to index with the subscripts (1,2) and (3,4), etc and return not only the 999 and 888 which exist in Matrix(:,:,1,1) but the contents which exist at Matrix(:,:,1,2),Matrix(:,:,2,1) and Matrix(:,:,2,2), and so on (IRL, the dimensions of Matrix might be more like size(Matrix) = (300 250 30 200) I don't want to use linear indices because I would like the results to be in a similar vector fashion. For example, I would like a result which is something like: ans(time=1) 999 888 124 999 888 124 ans(time=2) etc etc etc etc etc etc I'd also like to add that due to the size of the matrix I'm dealing with, speed is an issue here - thus why I'd like to use subscript indices to index to the data. I should also mention that (unlike this question: Accessing values using subscripts without using sub2ind) since I want all the information stored in the extra dimensions, 3 and 4, of the i and jth indices, I don't think that a slightly faster version of sub2ind still would not cut it..

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• ConcurrentLinkedQueue$Node remains in heap after remove()

  - by action8

  I have a multithreaded app writing and reading a ConcurrentLinkedQueue, which is conceptually used to back entries in a list/table. I originally used a ConcurrentHashMap for this, which worked well. A new requirement required tracking the order entries came in, so they could be removed in oldest first order, depending on some conditions. ConcurrentLinkedQueue appeared to be a good choice, and functionally it works well. A configurable amount of entries are held in memory, and when a new entry is offered when the limit is reached, the queue is searched in oldest-first order for one that can be removed. Certain entries are not to be removed by the system and wait for client interaction. What appears to be happening is I have an entry at the front of the queue that occurred, say 100K entries ago. The queue appears to have the limited number of configured entries (size() == 100), but when profiling, I found that there were ~100K ConcurrentLinkedQueue$Node objects in memory. This appears to be by design, just glancing at the source for ConcurrentLinkedQueue, a remove merely removes the reference to the object being stored but leaves the linked list in place for iteration. Finally my question: Is there a "better" lazy way to handle a collection of this nature? I love the speed of the ConcurrentLinkedQueue, I just cant afford the unbounded leak that appears to be possible in this case. If not, it seems like I'd have to create a second structure to track order and may have the same issues, plus a synchronization concern.

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• linux new/delete, malloc/free large memory blocks

  - by brian_mk

  Hi folks, We have a linux system (kubuntu 7.10) that runs a number of CORBA Server processes. The server software uses glibc libraries for memory allocation. The linux PC has 4G physical memory. Swap is disabled for speed reasons. Upon receiving a request to process data, one of the server processes allocates a large data buffer (using the standard C++ operator 'new'). The buffer size varies depening upon a number of parameters but is typically around 1.2G Bytes. It can be up to about 1.9G Bytes. When the request has completed, the buffer is released using 'delete'. This works fine for several consecutive requests that allocate buffers of the same size or if the request allocates a smaller size than the previous. The memory appears to be free'd ok - otherwise buffer allocation attempts would eventually fail after just a couple of requests. In any case, we can see the buffer memory being allocated and freed for each request using tools such as KSysGuard etc. The problem arises when a request requires a buffer larger than the previous. In this case, operator 'new' throws an exception. It's as if the memory that has been free'd from the first allocation cannot be re-allocated even though there is sufficient free physical memory available. If I kill and restart the server process after the first operation, then the second request for a larger buffer size succeeds. i.e. killing the process appears to fully release the freed memory back to the system. Can anyone offer an explanation as to what might be going on here? Could it be some kind of fragmentation or mapping table size issue? I am thinking of replacing new/delete with malloc/free and use mallopt to tune the way the memory is being released to the system. BTW - I'm not sure if it's relevant to our problem, but the server uses Pthreads that get created and destroyed on each processing request. Cheers, Brian.

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• making check boxes clickable once in javascript?

  - by OVERTONE

  Sorry but im an absolute noob with javascript. Ive made a form for a simple quiz but cant figure out how to make radio's only click once. I can select two or three buttons as my answer. i want to change this. <form name = "Beginners Quiz"> <p>Film speed refers to:</p> <p><input type="radio" name="Answer 1" id="Answer1" value = "a" onclick = "recordAnswer(1,this.value"/>How long it takes to develop film. <br/> <p><input type="radio" name="Answer 2" id="Answer2" value = "b" onclick = "recordAnswer(1,this.value"/>How fast film moves through film-transport system. <br/> <p><input type="radio" name="Answer 3" id="Answer3" value = "c" onclick = "recordAnswer(1,this.value"/> How sensitive the film is to light. <br/> <p><input type="radio" name="Answer 4" id="Answer4" value = "d" onclick = "recordAnswer(1,this.value"/> None of these makes sense. <br/> ive been rooting around w3shcools tutorials to no avail. can someone shed some light?

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• Slow Databinding setup time in C# .NET 4.0

  - by Svisstack

  Hello, I have got a problem. I have windows forms application with dynamic generated layout, but i have a problem in performance. In this form i use DataBinding from .NET 4.0 and databinding after setup works fine, but he binding setup time for ONE control blocking my application on approx 0.7 second. I have some controls and time of binging setuping is around 2 minutes. I trying all possible solutions, I dont have any ideas without write self binding class. Why is wrong with my code? case "Boolean": { Binding b = new Binding("Checked", __bindingsource, __ep.Name); CheckBox cb = new CheckBox(); /* * HERE is the problem */ cb.DataBindings.Add(b); /* * HERE is the end of problem */ __flp.Controls.Add(cb); __bindingcontrol.AddBinding(b); break; } Without problem code lines all works fast and without binding ;-( but i want binding turn on in normal speed. PS1. I have suspended layout in generation time. PS2. I have same problem with binding TextBox'es, PictureBoxe's, CheckBox is only example. How to do that?

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• fastest SCM tool available for Embedded software development

  - by wrapperm

  Hi All, In my company, presently we are using Rational clearcase as the Software Configuration Management tool for our Embedded software development. The software is basically for Automobiles, to be specific for Engines (I dont think these information really matters). But I find Clearcase to be very slow is performing any the activities (accesing files, branching and labelling), in addition to which there are various other limitations. We have recently decided to research on some free & open source, distributed version control system which could be able to handle our large projects with speed and efficiency. This tool should be a full-fledged repository with complete history and full revision tracking capabilities, not dependent on network access or a central server. Branching and merging are fast and easy to do. It should have multisite development facility. With these above mentioned requirement, we have come up with some of the tools that are presently available in the market: GIT, Mercurial, Bazaar, Subversion, CVS, Perforce, and Visual SourceSafe. I need everybody's help in finding me an approrpiate SCM tool for me which meets the above mentioned requirements. Thanking you in Advance, Rahamath.

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• Android - I can't make a widget clickable to launch an intent

  - by Daniele

  Hi all. I am new to Android development. I have developed a very simple widget that was meant to interact with the user via an ImageButton. What I am trying to do now is as follows. When a user taps the button (after adding the widget to their home screen), I want the phone to dial a certain telephone number. A sort of speed dial for your home screen. Unfortunately when I tap the button nothing happens. This is the body of my SpeedDialAppWidgetProvider.onUpdate method: Log.d("", "beginning of onUpdate"); final int N = appWidgetIds.length; for (int i=0; i<N; i++) { int appWidgetId = appWidgetIds[i]; Log.d("", "dealing with appWidgetId: " + appWidgetId); // Create an Intent to launch ExampleActivity Intent dialIntent = new Intent(Intent.ACTION_CALL, Uri.parse("tel:1234567")); PendingIntent pendingIntent = PendingIntent.getActivity(context, 0, dialIntent, 0); Log.d("", "pendingIntent classname " + pendingIntent.getClass().getName()); // Get the layout for the App Widget and attach an on-click listener to the button RemoteViews remoteViews = new RemoteViews(context.getPackageName(), R.layout.speed_dial_appwidget); remoteViews.setOnClickPendingIntent(R.id.dial_icon, pendingIntent); Log.d("", "remoteViews classname " + remoteViews.getClass().getName()); // Tell the AppWidgetManager to perform an update on the current App Widget appWidgetManager.updateAppWidget(appWidgetId, remoteViews); Log.d("", "end of onUpdate"); I can see the method is called and the result of the logging makes sense. The speed_dial_appwidget.xml file is like this: <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" androidrientation="vertical" android:layout_width="wrap_content" android:layout_height="wrap_content" > <ImageButton id="@+id/dial_icon" android:src="@drawable/speed_dial" android:layout_width="wrap_content" android:layout_height="wrap_content"/> </LinearLayout> Can you please help me with this? Thanks in advance, Dan

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• What are some typing patterns using a standard QWERTY keyboard that work well for you as a programme

  - by OrbMan

  After hunting and pecking for about 35 years, I have decided to learn to type. I am learning QWERTY and have learned about 2/3 of the letters so far. While learning, I have noticed how asymmeterical the keyboard is, which really bothers me. (I will probably switch to a symmetrical keyboard eventually, but for now am trying to do everything as standard and "correct" as possible.) Although I am not there yet in my lessons, it seems that many of the keys I am going to use as a C# web developer are supposed to be typed by the pinky of my right hand. Are there any typing patterns you have developed that are more ergonomic (or faster) when typing large volumes of code rife with braces, colons, semi-colons and quotes? Or, should I just accept the fact that every other key is going to be hit with my right pinky? It is not that speed is such a huge concern, as much as that it seems so inefficient to rely on one finger so much... As an example, some of the conventions I use as a hunt and pecker, like typing open and close braces right away with my index and middle finger, and then hitting the left arrow key to fill in the inner content, don't seem to work as well with just a pinky. What are some typing patterns using a standard QWERTY keyboard that work really well for you as a programmer? Update: US layout and I use home row Update 2: Despite my best efforts to the contrary, people are interpreting this questionas "how do I learn to type" or "what keyboard should I use". Take it as a given, that I will learn to type, and that I will be doing so on a standard QWERTY layout keyboard, not DVORAK. I am interested in aquiring a skill that will be useful wherever I go.

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• Perl Regex - Condensing groups of find/replace

  - by brydgesk

  I'm using Perl to perform some file cleansing, and am running into some performance issues. One of the major parts of my code involves standardizing name fields. I have several sections that look like this: sub substitute_titles { my ($inStr) = @_; ${$inStr} =~ s/ PHD./ PHD /; ${$inStr} =~ s/ P H D / PHD /; ${$inStr} =~ s/ PROF./ PROF /; ${$inStr} =~ s/ P R O F / PROF /; ${$inStr} =~ s/ DR./ DR /; ${$inStr} =~ s/ D.R./ DR /; ${$inStr} =~ s/ HON./ HON /; ${$inStr} =~ s/ H O N / HON /; ${$inStr} =~ s/ MR./ MR /; ${$inStr} =~ s/ MRS./ MRS /; ${$inStr} =~ s/ M R S / MRS /; ${$inStr} =~ s/ MS./ MS /; ${$inStr} =~ s/ MISS./ MISS /; } I'm passing by reference to try and get at least a little speed, but I fear that running so many (literally hundreds) of specific string replaces on tens of thousands (likely hundreds of thousands eventually) of records is going to hurt the performance. Is there a better way to implement this kind of logic than what I'm doing currently? Thanks Edit: Quick note, not all the replace functions are just removing periods and spaces. There are string deletions, soundex groups, etc.

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• General Address Parser for Freeform Text

  - by Daemonic

  We have a program that displays map data (think Google Maps, but with much more interactivity and custom layers for our clients). We allow navigation via a set of combo boxes that prefill certain fields with a bunch of data (ie: Country: Canada, the Province field is filled in. Select Ontario, and a list of Counties/Regions is filled in. Select a county/region, and a city is filled in, etc...). While this guarantees accurate addresses, it's a pain for the users if they don't know where a street address or a city are located (ie, which county/region is kitchener in?). So we are looking at trying to do an address parser with a freeform text field. The user could enter something like this (similar to Google Maps, Bing Maps, etc...): 22 Main St, Kitchener, On And we could compartmentalize it into sections and do lookups on the data and get to the point they are looking for (or suggest alternatives). The problem with this is that how do we properly compartmentalize information? How do we break up the sections and find possible matches? I'm guessing we wouldn't be guaranteed that the user would enter data in a format we always expected (obviously). A follow up to this would be how to present the data if we don't find an exact match (or find multiple exact matches... two cities with the same street name in different counties, for example). We have a ton of data available in the mapping data (mapinfo tab format mostly). So we can do quick scans of street names, cities, states, etc. But I'm not sure about the best way to go about approaching this problem. Sure, using Google Maps would be nice, bue most of our clients are in closed in networks where outside access is not usually allowed and most aren't willing to rely on google maps (since it doesn't contain as much information as they need, such as custom map layers). They could, obviously, go to google and get the proper location then move to our software, but this would time consuming and speed of the process can be quite important.

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