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  • Fastest inline-assembly spinlock

    - by sigvardsen
    I'm writing a multithreaded application in c++, where performance is critical. I need to use a lot of locking while copying small structures between threads, for this I have chosen to use spinlocks. I have done some research and speed testing on this and I found that most implementations are roughly equally fast: Microsofts CRITICAL_SECTION, with SpinCount set to 1000, scores about 140 time units Implementing this algorithm with Microsofts InterlockedCompareExchange scores about 95 time units Ive also tried to use some inline assembly with __asm {} using something like this code and it scores about 70 time units, but I am not sure that a proper memory barrier has been created. Edit: The times given here are the time it takes for 2 threads to lock and unlock the spinlock 1,000,000 times. I know this isn't a lot of difference but as a spinlock is a heavily used object, one would think that programmers would have agreed on the fastest possible way to make a spinlock. Googling it leads to many different approaches however. I would think this aforementioned method would be the fastest if implemented using inline assembly and using the instruction CMPXCHG8B instead of comparing 32bit registers. Furthermore memory barriers must be taken into account, this could be done by LOCK CMPXHG8B (I think?), which guarantees "exclusive rights" to the shared memory between cores. At last [some suggests] that for busy waits should be accompanied by NOP:REP that would enable Hyper-threading processors to switch to another thread, but I am not sure whether this is true or not? From my performance-test of different spinlocks, it is seen that there is not much difference, but for purely academic purpose I would like to know which one is fastest. However as I have extremely limited experience in the assembly-language and with memory barriers, I would be happy if someone could write the assembly code for the last example I provided with LOCK CMPXCHG8B and proper memory barriers in the following template: __asm { spin_lock: ;locking code. spin_unlock: ;unlocking code. }

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  • Question about how to implement a c# host application with a plugin-like architecture

    - by devoured elysium
    I want to have an application that works as a Host to many other small applications. Each one of those applications should work as kind of plugin to this main application. I call them plugins not in the sense they add something to the main application, but because they can only work with this Host application as they depend on some of its services. My idea was to have each of those plugins run in a different app domain. The problem seems to be that my host application should have a set of services that my plugins will want to use and from what is my understanding making data flow in and out from different app domains is not that great of a thing. On one hand I'd like them to behave as stand-alone applications(although, as I said, they need to use lots of times the host application services), but on the other hand I'd like that if any of them crashes, my main application wouldn't suffer from it. What is the best (.NET) approach to this kind of situation? Make them all run on the same AppDomain but each one in a different Thread? Use different AppDomains? One for each "plugin"? How would I make them communicate with the Host Application? Any other way of doing this? Although speed is not an issue here, I wouldn't like for function calls to be that much slower than they are when we're working with just a regular .NET application. Thanks

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  • Efficient Clojure workflow?

    - by Alex B
    I am developing a pet project with Clojure, but wonder if I can speed up my workflow a bit. My current workflow (with Compojure) is: Start Swank with lein swank. Go to Emacs, connect with M-x slime-connect. Load all existing source files one by one. This also starts a Jetty server and an application. Write some code in REPL. When satisfied with experiments, write a full version of a construct I had in mind. Eval (C-c C-c) it. Switch REPL to namespace where this construct resides and test it. Switch to browser and reload browser tab with the affected page. Tweak the code, eval it, check in the browser. Repeat any of the above. There are a number of annoyances with it: I have to switch between Emacs and the browser (or browsers if I am testing things like templating with multiple browsers) all the time. Is there a common idiom to automate this? I used to have a JavaScript bit that reloads the page continuously, but it's of limited utility, obviously, when I have to interact with the page for more than a few seconds. My JVM instance becomes "dirty" when I experiment and write test functions. Basically namespaces become polluted, especially if I'm refactoring and moving the functions between namespaces. This can lead to symbol collisions and I need to restart Swank. Can I undef a symbol? I load all source files one by one (C-c C-k) upon restarting Swank. I suspect I'm doing it all wrong. Switching between the REPL and the file editor can be a bit irritating, especially when I have a lot of Emacs tabs open, alongside the browser(s). I'm looking for ways to improve the above points and the entire workflow in general, so I'd appreciate if you'd share yours. P. S. I have also used Vimclojure before, so Vimclojure-based workflows are welcome too.

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  • What is the best approach to 2D collision detection on the iPhone?

    - by Magic Bullet Dave
    Been working on this problem of collision detection and there appears to be 3 main approaches I could take: Sprite and mask approach. (AND the overlap of the sprites and check for a non-zero number in the resulting sprite pixel data). Bounding circles, rectangles or polygons. (Create one or more shapes that enclose the sprites and do the basic maths to check for overlaps). Use an existing sprite library. The first approach, even though it would have been the way I would have done it in the old days of 16x16 sprite blocks, it appears that there just isn’t an easy way of getting at the individual image pixel data and/or alpha channel within Quartz (or OPENGL for that matter). Detecting the overlap of the bounding box is easy, but then creating a 3rd image from the overlap and then testing it for pixels is complicated and my gut feel is that even if we could get it to work would be slow. Am I missing something neat here? The second approach involves dividing up our sprites into several polygons and testing them for overlaps. The more polygons the more accurate the collision detection. The benefit is that it is fast, and can be accurate. The downside is it makes the sprite creation more complicated. i.e., we have to create the polygons for each sprite. For speed the best approach is to create a tree of polygons. The 3rd approach I’m not sure about as it involves buying code (or using an open source licence). I am not sure what the best library to use is or whether this would make life easier or give us a problem integrating this into our app. So in short I am favouring the polygon and tree approach and would appreciate you views on this before I go and write lots of code. Best regards Dave

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  • combobox with for each loop

    - by Mary
    Hi I am a student do anybody know after populating the combobox with the database values. How to display the same value in the text box. When I select a name in the combobox the same name should be displayed in the text box I am using seleted item. Here is the code. I am getting the error the following error using the foreach loop foreach statement cannot operate on variables of type 'object' because 'object' does not contain a public definition for 'GetEnumerator' using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Linq; using System.Text; using System.Windows.Forms; using System.Data.OleDb; namespace DBExample { public partial class Form1 : Form { private OleDbConnection dbConn; // Connectionn object private OleDbCommand dbCmd; // Command object private OleDbDataReader dbReader;// Data Reader object private Member aMember; private string sConnection; // private TextBox tb1; // private TextBox tb2; private string sql; public Form1() { InitializeComponent(); } private void Form1_Load(object sender, EventArgs e) { try { // Construct an object of the OleDbConnection // class to store the connection string // representing the type of data provider // (database) and the source (actual db) sConnection = "Provider=Microsoft.Jet.OLEDB.4.0;" + "Data Source=c:member.mdb"; dbConn = new OleDbConnection(sConnection); dbConn.Open(); // Construct an object of the OleDbCommand // class to hold the SQL query. Tie the // OleDbCommand object to the OleDbConnection // object sql = "Select * From memberTable Order " + "By LastName , FirstName "; dbCmd = new OleDbCommand(); dbCmd.CommandText = sql; dbCmd.Connection = dbConn; // Create a dbReader object dbReader = dbCmd.ExecuteReader(); while (dbReader.Read()) { aMember = new Member (dbReader["FirstName"].ToString(), dbReader["LastName"].ToString(), dbReader["StudentId"].ToString(), dbReader["PhoneNumber"].ToString()); // tb1.Text = dbReader["FirstName"].ToString(); // tb2.Text = dbReader["LastName"].ToString(); // tb1.Text = aMember.X().ToString(); //tb2.Text = aMember.Y(aMember.ID).ToString(); this.comboBox1.Items.Add(aMember.FirstName.ToString()); // this.listBox1.Items.Add(aMember.ToString()); // MessageBox.Show(aMember.ToString()); // Console.WriteLine(aMember.ToString()); } dbReader.Close(); dbConn.Close(); } catch (System.Exception exc) { MessageBox.Show("show" + exc); } } private void DbGUI_Load(object sender, EventArgs e) { } private void comboBox1_SelectedIndexChanged(object sender, EventArgs e) { this.textBox1.Text = comboBox1.SelectedItem.ToString(); textBox2.Text = string.Empty; foreach (var item in comboBox1.SelectedItem) textBox2.Text += item.ToString(); } private void textBox2_TextChanged(object sender, EventArgs e) { } private void textBox1_TextChanged(object sender, EventArgs e) { } } }

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  • Creating an appropriate index for a frequently used query in SQL Server

    - by Slauma
    In my application I have two queries which will be quite frequently used. The Where clauses of these queries are the following: WHERE FieldA = @P1 AND (FieldB = @P2 OR FieldC = @P2) and WHERE FieldA = @P1 AND FieldB = @P2 P1 and P2 are parameters entered in the UI or coming from external datasources. FieldA is an int and highly on-unique, means: only two, three, four different values in a table with say 20000 rows FieldB is a varchar(20) and is "almost" unique, there will be only very few rows where FieldB might have the same value FieldC is a varchar(15) and also highly distinct, but not as much as FieldB FieldA and FieldB together are unique (but do not form my primary key, which is a simple auto-incrementing identity column with a clustered index) I'm wondering now what's the best way to define an index to speed up specifically these two queries. Shall I define one index with... FieldB (or better FieldC here?) FieldC (or better FieldB here?) FieldA ... or better two indices: FieldB FieldA and FieldC FieldA Or are there even other and better options? What's the best way and why? Thank you for suggestions in advance!

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  • Will Learning C++ Help for Building Fast/No-Additional-Requirements Desktop Applications?

    - by vito
    Will learning C++ help me build native applications with good speed? Will it help me as a programmer, and what are the other benefits? The reason why I want to learn C++ is because I'm disappointed with the UI performances of applications built on top of JVM and .NET. They feel slow, and start slow too. Of course, a really bad programmer can create a slower and sluggish application using C++ too, but I'm not considering that case. One of my favorite Windows utility application is Launchy. And in the Readme.pdf file, the author of the program wrote this: 0.6 This is the first C++ release. As I became frustrated with C#’s large .NET framework requirements and users lack of desire to install it, I decided to switch back to the faster language. I totally agree with the author of Launchy about the .NET framework requirement or even a JRE requirement for desktop applications. Let alone the specific version of them. And some of the best and my favorite desktop applications don't need .NET or Java to run. They just run after installing. Are they mostly built using C++? Is C++ the only option for good and fast GUI based applications? And, I'm also very interested in hearing the other benefits of learning C++.

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  • wpf: capturing mouse does not work

    - by amethyste
    hello I am developing an kind of outlook calendar application where I need to make the appointment resizable from mouse. My first try with a thumb did not work properly so I tried another way. What I did is that: 1) on the botton of the appointmennt panel I added a rectangle to figure out the resize zone (the thumb). The appointment panel is put on a grid panel. 2) I intercept down event on the rectangle and send event to this code: private Point startPoint; private void OnResizeElementMouseDown(object sender, MouseButtonEventArgs e) { e.Handled = true; this.MouseMove += new MouseEventHandler(ResizeEndElement_MouseMove); this.MouseLeftButtonUp += new MouseButtonEventHandler(OnResizeElementMouseUp); // some code to perform new height computation Mouse.Capture(this); } where this is the appointment panel that own the thumb. Decreasing height works well. But increasing is more difficult. If I move the mouse very very slowly it's OK, if I speed it up a little bit it tends to leave out the appointment panel and then all MouseMove event are lost. I thought Mouse.Capture() was propose to solve this kind of problem, but in fact not. Does anybody know what is wrong in my code?

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  • Images not showing in ie7 using jquery cycle and jCarouselLite plugin

    - by Geetha
    Hi All, I am using jquery cycle and jCarouselLite plugin to display images as slide. Images are getting displayed in ie7. but working perfect in ie6. Image Property inside the cycle control: Protocol: Not available Type: Not available Address(url): Not available Size: Not available Dimensions: 100X100 but control having the url. if i tried that image url separate it showing the image. Code: $('#slide').cycle({ fx: 'fade', continuous: true, speed: 7500, timeout: 55000, sync: 1 }); Html Code: <div id="slide"> <img src="samp1.jpg" width="664" height="428" border="0" /> <img src="samp2.jpg" width="664" height="428" border="0" /> <img src="samp3.jpg" width="664" height="428" border="0" /> <img src="samp4.jpg" width="664" height="428" border="0" /> <img src="samp5.jpg" width="664" height="428" border="0" /> <img src="samp6.jpg" width="664" height="428" border="0" /> <img src="samp7.jpg" width="664" height="428" border="0" /> <img src="samp8.jpg" width="664" height="428" border="0" /> </div> Geetha.

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  • optimize 2D array in C++

    - by Hristo
    I'm dealing with a 2D array with the following characteristics: const int cols = 500; const int rows = 100; int arr[rows][cols]; I access array arr in the following manner to do some work: for(int k = 0; k < T; ++k) { // for each trainee myscore[k] = 0; for(int i = 0; i < N; ++i) { // for each sample for(int j = 0; j < E[i]; ++j) { // for each expert myscore[k] += delta(i, anotherArray[k][i], arr[j][i]); } } } So I am worried about the array 'arr' and not the other one. I need to make this more cache-friendly and also boost the speed. I was thinking perhaps transposing the array but I wasn't sure how to do that. My implementation turns out to only work for square matrices. How would I make it work for non-square matrices? Also, would mapping the 2D array into a 1D array boost the performance? If so, how would I do that? Finally, any other advice on how else I can optimize this... I've run out of ideas, but I know that arr[j][i] is the place where I need to make changes because I'm accessing columns by columns instead of rows by rows so that is not cache friendly at all. Thanks, Hristo

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  • Value gets changed upon comiting. | CallableStatements

    - by Triztian
    Hello, I having a weird problem with a DAO class and a StoredProcedure, what is happening is that I use a CallableStatement object which takes 15 IN parameters, the value of the field id_color is retrieved correctly from the HTML forms it even is set up how it should in the CallableStatement setter methods, but the moment it is sent to the database the id_color is overwriten by the value 3 here's the "context": I have the following class DAO.CoverDAO which handles the CRUD operations of this table CREATE TABLE `cover_details` ( `refno` int(10) unsigned NOT NULL AUTO_INCREMENT, `shape` tinyint(3) unsigned NOT NULL , `id_color` tinyint(3) unsigned NOT NULL ', `reversefold` bit(1) NOT NULL DEFAULT b'0' , `x` decimal(6,3) unsigned NOT NULL , `y` decimal(6,3) unsigned NOT NULL DEFAULT '0.000', `typecut` varchar(10) NOT NULL, `cornershape` varchar(20) NOT NULL, `z` decimal(6,3) unsigned DEFAULT '0.000' , `othercornerradius` decimal(6,3) unsigned DEFAULT '0.000'', `skirt` decimal(5,3) unsigned NOT NULL DEFAULT '7.000', `foamTaper` varchar(3) NOT NULL, `foamDensity` decimal(2,1) unsigned NOT NULL , `straplocation` char(1) NOT NULL ', `straplength` decimal(6,3) unsigned NOT NULL, `strapinset` decimal(6,3) unsigned NOT NULL, `spayear` varchar(20) DEFAULT 'Not Specified', `spamake` varchar(20) DEFAULT 'Not Specified', `spabrand` varchar(20) DEFAULT 'Not Specified', PRIMARY KEY (`refno`) ) ENGINE=MyISAM AUTO_INCREMENT=143 DEFAULT CHARSET=latin1 $$ The the way covers are being inserted is by a stored procedure, which is the following: CREATE DEFINER=`root`@`%` PROCEDURE `putCover`( IN shape TINYINT, IN color TINYINT(3), IN reverse_fold BIT, IN x DECIMAL(6,3), IN y DECIMAL(6,3), IN type_cut VARCHAR(10), IN corner_shape VARCHAR(10), IN cutsize DECIMAL(6,3), IN corner_radius DECIMAL(6,3), IN skirt DECIMAL(5,3), IN foam_taper VARCHAR(7), IN foam_density DECIMAL(2,1), IN strap_location CHAR(1), IN strap_length DECIMAL(6,3), IN strap_inset DECIMAL(6,3) ) BEGIN INSERT INTO `dbre`.`cover_details` (`dbre`.`cover_details`.`shape`, `dbre`.`cover_details`.`id_color`, `dbre`.`cover_details`.`reversefold`, `dbre`.`cover_details`.`x`, `dbre`.`cover_details`.`y`, `dbre`.`cover_details`.`typecut`, `dbre`.`cover_details`.`cornershape`, `dbre`.`cover_details`.`z`, `dbre`.`cover_details`.`othercornerradius`, `dbre`.`cover_details`.`skirt`, `dbre`.`cover_details`.`foamTaper`, `dbre`.`cover_details`.`foamDensity`, `dbre`.`cover_details`.`strapLocation`, `dbre`.`cover_details`.`strapInset`, `dbre`.`cover_details`.`strapLength` ) VALUES (shape,color,reverse_fold, x,y,type_cut,corner_shape, cutsize,corner_radius,skirt,foam_taper,foam_density, strap_location,strap_inset,strap_length); END As you can see basically it just fills each field, now, the CoverDAO.create(CoverDTO cover) method which creates the cover is like so: public void create(CoverDTO cover) throws DAOException { Connection link = null; CallableStatement query = null; try { link = MySQL.getConnection(); link.setAutoCommit(false); query = link.prepareCall("{CALL putCover(?,?,?,?,?,?,?,?,?,?,?,?,?,?,?)}"); query.setLong(1,cover.getShape()); query.setInt(2,cover.getColor()); query.setBoolean(3, cover.getReverseFold()); query.setBigDecimal(4,cover.getX()); query.setBigDecimal(5,cover.getY()); query.setString(6,cover.getTypeCut()); query.setString(7,cover.getCornerShape()); query.setBigDecimal(8, cover.getZ()); query.setBigDecimal(9, cover.getCornerRadius()); query.setBigDecimal(10, cover.getSkirt()); query.setString(11, cover.getFoamTaper()); query.setBigDecimal(12, cover.getFoamDensity()); query.setString(13, cover.getStrapLocation()); query.setBigDecimal(14, cover.getStrapLength()); query.setBigDecimal(15, cover.getStrapInset()); query.executeUpdate(); link.commit(); } catch (SQLException e) { throw new DAOException(e); } finally { close(link, query); } } The CoverDTO is made of accessesor methods, the MySQL object basically returns the connection from a pool. Here is the pset Query with dummy but appropriate data: putCover(1,10,0,80.000,80.000,'F','Cut',0.000,0,15.000,'4x2',1.5,'A',10.000,5.000) As you can see everything is fine just when I write to the DB instead of 10 in the second parameter a 3 is written. I have done the following: Traced the id_color value to the create method, still got replaced by a 3 Hardcoded the value in the DAO create method, still got replaced by a 3 Called the procedure from the MySQL Workbench, it worked fined so I assume something is happening in the create method, any help is really appreciated.

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  • Fastest Java way to remove the first/top line of a file (like a stack)

    - by christangrant
    I am trying to improve an external sort implementation in java. I have a bunch of BufferedReader objects open for temporary files. I repeatedly remove the top line from each of these files. This pushes the limits of the Java's Heap. I would like a more scalable method of doing this without loosing speed because of a bunch of constructor calls. One solution is to only open files when they are needed, then read the first line and then delete it. But I am afraid that this will be significantly slower. So using Java libraries what is the most efficient method of doing this. --Edit-- For external sort, the usual method is to break a large file up into several chunk files. Sort each of the chunks. And then treat the sorted files like buffers, pop the top item from each file, the smallest of all those is the global minimum. Then continue until for all items. http://en.wikipedia.org/wiki/External_sorting My temporary files (buffers) are basically BufferedReader objects. The operations performed on these files are the same as stack/queue operations (peek and pop, no push needed). I am trying to make these peek and pop operations more efficient. This is because using many BufferedReader objects takes up too much space.

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  • Perl MiniWebserver

    - by snikolov
    hey guys i have config this miniwebserver, however i require the server to download a file in the local directory i am getting a problem can you please fix my issue thanks !/usr/bin/perl use strict; use Socket; use IO::Socket; my $buffer; my $file; my $length; my $output; Simple web server in Perl Serves out .html files, echos form data sub parse_form { my $data = $_[0]; my %data; foreach (split /&/, $data) { my ($key, $val) = split /=/; $val =~ s/+/ /g; $val =~ s/%(..)/chr(hex($1))/eg; $data{$key} = $val;} return %data; } Setup and create socket my $port = shift; defined($port) or die "Usage: $0 portno\n"; my $DOCUMENT_ROOT = $ENV{'HOME'} . "public"; my $server = new IO::Socket::INET(Proto = 'tcp', LocalPort = $port, Listen = SOMAXCONN, Reuse = 1); $server or die "Unable to create server socket: $!" ; Await requests and handle them as they arrive while (my $client = $server-accept()) { $client-autoflush(1); my %request = (); my %data; { -------- Read Request --------------- local $/ = Socket::CRLF; while (<$client>) { chomp; # Main http request if (/\s*(\w+)\s*([^\s]+)\s*HTTP\/(\d.\d)/) { $request{METHOD} = uc $1; $request{URL} = $2; $request{HTTP_VERSION} = $3; } # Standard headers elsif (/:/) { (my $type, my $val) = split /:/, $_, 2; $type =~ s/^\s+//; foreach ($type, $val) { s/^\s+//; s/\s+$//; } $request{lc $type} = $val; } # POST data elsif (/^$/) { read($client, $request{CONTENT}, $request{'content-length'}) if defined $request{'content-length'}; last; } } } -------- SORT OUT METHOD --------------- if ($request{METHOD} eq 'GET') { if ($request{URL} =~ /(.*)\?(.*)/) { $request{URL} = $1; $request{CONTENT} = $2; %data = parse_form($request{CONTENT}); } else { %data = (); } $data{"_method"} = "GET"; } elsif ($request{METHOD} eq 'POST') { %data = parse_form($request{CONTENT}); $data{"_method"} = "POST"; } else { $data{"_method"} = "ERROR"; } ------- Serve file ---------------------- my $localfile = $DOCUMENT_ROOT.$request{URL}; Send Response if (open(FILE, "<$localfile")) { print $client "HTTP/1.0 200 OK", Socket::CRLF; print $client "Content-type: text/html", Socket::CRLF; print $client Socket::CRLF; my $buffer; while (read(FILE, $buffer, 4096)) { print $client $buffer; } $data{"_status"} = "200"; } else { $file = 'a.pl'; open(INFILE, $file); while (<INFILE>) { $output .= $_; ##output of the file } $length = length($output); print $client "'HTTP/1.0 200 OK", Socket::CRLF; print $client "Content-type: application/octet-stream", Socket::CRLF; print $client "Content-Length:".$length, Socket::CRLF; print $client "Accept-Ranges: bytes", Socket::CRLF; print $client 'Content-Disposition: attachment; filename="test.zip"', Socket::CRLF; print $client $output, Socket::CRLF; print $client 'Content-Transfer-Encoding: binary"', Socket::CRLF; print $client "Connection: Keep-Alive", Socket::CRLF; # #$data{"_status"} = "404"; # } close(FILE); Log Request print ($DOCUMENT_ROOT.$request{URL},"\n"); foreach (keys(%data)) { print (" $_ = $data{$_}\n"); } ----------- Close Connection and loop ------------------ close $client; } END

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  • Do you know a date picker to quickly pick one day of the current week?

    - by Murmelschlurmel
    Most date pickers allow you to pick the date from a tine calendar or enter the date by hand. For example http://jqueryui.com/demos/datepicker/ This requires - two clicks (one to display the calendar and one to select the correct date) - good eyesight (usually the pop-up calendar is very small) - and good hand-eye coordination to pick the correct date in the tiny calendar with your mouse. That's no problem for power users, but a hassle for older people and computer beginners. I found a website with a different approach. It seems like their users mostly select dates of the current week. So they listed all the days of the week in a bar together with the weekday. The current day is marked in another color. There is a tiny calender icon on the right hand that opens up a regular date picker. That gives you access to all regular date picker functionality. Here is a screenshot: http://mite.yo.lk/assets/img/tour/de/zeiten-erfassen.png Do you know of any jquery plugin which has a similar feature? If not, do you any other plugin or widget which would help me speed up development ? Thank you!

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  • How to display many SVGs in Java with high performance

    - by Oak
    What I want My goal is to be able to display a large number of SVG images on a single drawing area in Java, each with its own translation/rotation/scale values. I'm looking for the simplest solution allowing this, optionally even using OpenGL to speed things up. What I've Tried My initial naive approach was to use SVGSalamander to draw directly on a JPanel, but the performance was pathetic. I poked around around and learned that I should do something like manually convert each SVG into a BufferedImage created with createCompatibleImage, then do the transformations I want, then draw it using double buffering. I ran into some troubles here, and before I continued I tried looking for frameworks to simplify things. What I've Looked At I've been a bit overwhelmed by the available options, which is why I'm turning to SO for help. I've looked at: Cairo (with Glitz maybe?) Libart - not sure if this actually supports SVGs FengGUI Slick - looks promising but a bit of an overkill But couldn't decide what is best for me to start working with, and I hope someone here as experience with any of these doing similar things.

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  • Serialized NHibernate Configuration objects - detect out of date or rebuild on demand?

    - by fostandy
    I've been using serialized nhibernate configuration objects (also discussed here and here) to speed up my application startup from about 8s to 1s. I also use fluent-nhibernate, so the path is more like ClassMap class definitions in code fluentconfiguration xml nhibernate configuration configuration serialized to disk. The problem from doing this is that one runs the risk of out of date mappings - if I change the mappings but forget to rebuild the serialized configuration, then I end up using the old mappings without realising it. This does not always result in an immediate and obvious error during testing, and several times the misbehaviour has been a real pain to detect and fix. Does anybody have any idea how I would be able to detect if my classmaps have changed, so that I could either issue an immediate warning/error or rebuild it on demand? At the moment I am comparing timestamps on my compiled assembly against the serialized configuration. This will pickup mapping changes, but unfortunately it generates a massive false positive rate as ANY change to the code results in an out of date flag. I can't move the classmaps to another assembly as they are tightly integrated into the business logic. This has been niggling me for a while so I was wondering if anybody had any suggestions?

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  • jQuery weirdness. Div becomes attached to chained element markup?

    - by Scott B
    I've got a div in my app that is displayed each time my theme options panel is "saved". The markup is... <form method="post"> <?php if ( $_REQUEST['saved']) { ?> <div id="message" class="updated fade"><p>Sweet! The settings were saved :)</p></div> <script type="text/javascript"> $('#message').delay(3000).fadeOut(3000);</script> <?php }?> This has the effect of showing the div (which is absolutely positioned to overlay the interface). I'm also using jQuery to fade the message offscreen after 3 seconds. This works fine, however, when I add a bit of script to my jQuery chain (see the commented out block below), the message div is only visible when the jPicker popup appears. $(function() { $("#carousel").jCarouselLite ( { btnNext: ".next", btnPrev: ".prev", visible: 6, speed: 700 } ); $('#carousel').show(); $('#myTheme').change ( function() { var myImage = $('#myTheme :selected').text(); $('.selectedImage img').attr('src','../wp-content/themes/myTheme/styles/'+myImage+'/screenshot.jpg'); } ); $('#carousel ul li').click ( function(e) { var myOption = $(this).children('img').attr('title'); $("#myTheme option[value='"+myOption+"']").attr('selected', 'selected'); $("#myTheme").css('backgroundColor', '#A9A9A9').animate({backgroundColor: "#ffffff"}, 'slow'); } ); $('#carousel ul li').hover ( function(e) { var img_src = $(this).children('img').attr('src'); $('.selectedImage img').attr('src',img_src); } ,function() { $('.selectedImage img').attr('src', '<?php echo $selectedThumb; ?>'); } ); /* $('#myTheme_sidebar_color').jPicker ( {}, function(color) { $(this).val(color.get_Hex()); }, function(color) { $(this).val(color.get_Hex()); } ); */ });

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  • What is different about C++ math.h abs() compared to my abs()

    - by moka
    I am currently writing some glsl like vector math classes in c++, and I just implemented an abs() function like this: template<class T> static inline T abs(T _a) { return _a < 0 ? -_a : _a; } I compared its speed to the default c++ abs from math.h like this: clock_t begin = clock(); for(int i=0; i<10000000; ++i) { float a = abs(-1.25); }; clock_t end = clock(); unsigned long time1 = (unsigned long)((float)(end-begin) / ((float)CLOCKS_PER_SEC/1000.0)); begin = clock(); for(int i=0; i<10000000; ++i) { float a = myMath::abs(-1.25); }; end = clock(); unsigned long time2 = (unsigned long)((float)(end-begin) / ((float)CLOCKS_PER_SEC/1000.0)); std::cout<<time1<<std::endl; std::cout<<time2<<std::endl; Now the default abs takes about 25ms while mine takes 60. I guess there is some low level optimisation going on. Does anybody know how math.h abs works internally? The performance difference is nothing dramatic, but I am just curious!

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  • Proper way to scan a range of IP addresses

    - by Josh G
    Given a range of IP addresses entered by a user (through various means), I want to identify which of these machines have software running that I can talk to. Here's the basic process: Ping these addresses to find available machines Connect to a known socket on the available machines Send a message to the successfully established sockets Compare the response to the expected response Steps 2-4 are straight forward for me. What is the best way to implement the first step in .NET? I'm looking at the System.Net.NetworkInformation.Ping class. Should I ping multiple addresses simultaneously to speed up the process? If I ping one address at a time with a long timeout it could take forever. But with a small timeout, I may miss some machines that are available. Sometimes pings appear to be failing even when I know that the address points to an active machine. Do I need to ping twice in the event of the request getting discarded? To top it all off, when I scan large collections of addresses with the network cable unplugged, Ping throws a NullReferenceException in FreeUnmanagedResources(). !? Any pointers on the best approach to scanning a range of IPs like this?

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  • iPhone OpenGL ES Texture2D Masking

    - by Robert Neagu
    What's the best choice when trying to mask a texture like ColorSplash or other apps like iSteam, etc? I started learning OPENGL ES like... 4 days ago (I'm a total rookie) and tried the following approach: 1) I created a colored texture2D, a grayscale version of the first texture and a third texture2D called mask 2) I also created a texture2D for the brush... which is grayscale and it's opaque (brush = black = 0,0,0,1 and surroundings = white = 1,1,1,1). My intention was to create an antialiased brush with smooth edges but i'm fine with a normal one right now 3) I searched for masking techniques on the internet and found this tutorial ZeusCMD - Design and Development Tutorials : OpenGL ES Programming Tutorials - Masking about masking. The tutorial tells me to use blending to achieve masking... first draw colored, then mask with glBlendFunc(GL_DST_COLOR, GL_ZERO) and then grayscale with glBlendFunc(GL_ONE, GL_ONE) ... and this gives me something close to what i want... but not exactly what i want. The result is masked but it's somehow overbright-ed 4) For drawing to the mask texture i used an extra frame buffer object (FBO) I'm not really happy with the resulting image (overbright-ed picture) nor with the speed achieved with this method. I think the normal way was to draw directly to the grayscale (overlay) texture2D affecting only it's alpha channel in the places where the brush hits. Is there a fast way to achieve this? I have searched a lot and never got an answer that's clear and understandable. Then, in the main draw loop I could only draw the colored texture and then blend the grayscale ontop with glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA). I just want to learn to use OPENGL ES and it's driving me nuts because i can't get it to work properly. An advice, a link to a tutorial would be much appreciated.

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  • Unable to edit a database row from JSF

    - by user1924104
    Hi guys i have a data table in JSF which displays all of the contents of my database table, it displays it fine, i also have a delete function that can successfully delete from the database fine and updates the data table fine however when i try to update the database i get the error java.lang.IllegalArgumentException: Cannot convert richard.test.User@129d62a7 of type class richard.test.User to long below is the code that i have been using to delete the rows in the database that is working fine : public void delete(long userID) { PreparedStatement ps = null; Connection con = null; if (userID != 0) { try { Class.forName("com.mysql.jdbc.Driver"); con = DriverManager.getConnection("jdbc:mysql://localhost:3306/test", "root", "root"); String sql = "DELETE FROM user1 WHERE userId=" + userID; ps = con.prepareStatement(sql); int i = ps.executeUpdate(); if (i > 0) { System.out.println("Row deleted successfully"); } } catch (Exception e) { e.printStackTrace(); } finally { try { con.close(); ps.close(); } catch (Exception e) { e.printStackTrace(); } } } } i simply wanted to edit the above code so it would update the records instead of deleting them so i edited it to look like : public void editData(long userID) { PreparedStatement ps = null; Connection con = null; if (userID != 0) { try { Class.forName("com.mysql.jdbc.Driver"); con = DriverManager.getConnection("jdbc:mysql://localhost:3306/test", "root", "root"); String sql = "UPDATE user1 set name = '"+name+"', email = '"+ email +"', address = '"+address+"' WHERE userId=" + userID; ps = con.prepareStatement(sql); int i = ps.executeUpdate(); if (i > 0) { System.out.println("Row updated successfully"); } } catch (Exception e) { e.printStackTrace(); } finally { try { con.close(); ps.close(); } catch (Exception e) { e.printStackTrace(); } } } } and the xhmtl is : <p:dataTable id="dataTable" var="u" value="#{userBean.getUserList()}" paginator="true" rows="10" editable="true" paginatorTemplate="{CurrentPageReport} {FirstPageLink} {PreviousPageLink} {PageLinks} {NextPageLink} {LastPageLink} {RowsPerPageDropdown}" rowsPerPageTemplate="5,10,15"> <p:column> <f:facet name="header"> User ID </f:facet> #{u.userID} </p:column> <p:column> <f:facet name="header"> Name </f:facet> #{u.name} </p:column> <p:column> <f:facet name="header"> Email </f:facet> #{u.email} </p:column> <p:column> <f:facet name="header"> Address </f:facet> #{u.address} </p:column> <p:column> <f:facet name="header"> Created Date </f:facet> #{u.created_date} </p:column> <p:column> <f:facet name="header"> Delete </f:facet> <h:commandButton value="Delete" action="#{user.delete(u.userID)}" /> </p:column> <p:column> <f:facet name="header"> Delete </f:facet> <h:commandButton value="Edit" action="#{user.editData(u)}" /> </p:column> currently when you press the edit button it will only update it with the same values as i haven't yet managed to get the datatable to be editable with the database, i have seen a few examples with an array list where the data table gets its values from but never a database so if you have any advice on this too it would be great thanks

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  • What is the fastest way to find duplicates in multiple BIG txt files?

    - by user2950750
    I am really in deep water here and I need a lifeline. I have 10 txt files. Each file has up to 100.000.000 lines of data. Each line is simply a number representing something else. Numbers go up to 9 digits. I need to (somehow) scan these 10 files and find the numbers that appear in all 10 files. And here comes the tricky part. I have to do it in less than 2 seconds. I am not a developer, so I need an explanation for dummies. I have done enough research to learn that hash tables and map reduce might be something that I can make use of. But can it really be used to make it this fast, or do I need more advanced solutions? I have also been thinking about cutting up the files into smaller files. To that 1 file with 100.000.000 lines is transformed into 100 files with 1.000.000 lines. But I do not know what is best: 10 files with 100 million lines or 1000 files with 1 million lines? When I try to open the 100 million line file, it takes forever. So I think, maybe, it is just too big to be used. But I don't know if you can write code that will scan it without opening. Speed is the most important factor in this, and I need to know if it can be done as fast as I need it, or if I have to store my data in another way, for example, in a database like mysql or something. Thank you in advance to anybody that can give some good feedback.

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  • "variable tracking" is eating my compile time!

    - by wowus
    I have an auto-generated file which looks something like this... static void do_SomeFunc1(void* parameter) { // Do stuff. } // Continues on for another 4000 functions... void dispatch(int id, void* parameter) { switch(id) { case ::SomeClass1::id: return do_SomeFunc1(parameter); case ::SomeClass2::id: return do_SomeFunc2(parameter); // This continues for the next 4000 cases... } } When I build it like this, the build time is enormous. If I inline all the functions automagically into their respective cases using my script, the build time is cut in half. GCC 4.5.0 says ~50% of the build time is being taken up by "variable tracking" when I use -ftime-report. What does this mean and how can I speed compilation while still maintaining the superior cache locality of pulling out the functions from the switch? EDIT: Interestingly enough, the build time has exploded only on debug builds, as per the following profiling information of the whole project (which isn't just the file in question, but still a good metric; the file in question takes the most time to build): Debug: 8 minutes 50 seconds Release: 4 minutes, 25 seconds

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  • wordpress generating slow mysql queries - is it index problem?

    - by tash
    Hello Stack Overflow I've got very slow Mysql queries coming up from my wordpress site. It's making everything slow and I think this is eating up CPU usage. I've pasted the Explain results for the two most frequently problematic queries below. This is a typical result - although very occasionally teh queries do seem to be performed at a more normal speed. I have the usual wordpress indexes on the database tables. You will see that one of the queries is generated from wordpress core code, and not from anything specific - like the theme - for my site. I have a vague feeling that the database is not always using the indexes/is not using them properly... Is this right? Does anyone know how to fix it? Or is it a different problem entirely? Many thanks in advance for any help anyone can offer - it is hugely appreciated Query: [wp-blog-header.php(14): wp()] SELECT SQL_CALC_FOUND_ROWS wp_posts.* FROM wp_posts WHERE 1=1 AND wp_posts.post_type = 'post' AND (wp_posts.post_status = 'publish' OR wp_posts.post_status = 'private') ORDER BY wp_posts.post_date DESC LIMIT 0, 6 id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE wp_posts ref type_status_date type_status_date 63 const 427 Using where; Using filesort Query time: 34.2829 (ms) 9) Query: [wp-content/themes/LMHR/index.php(40): query_posts()] SELECT SQL_CALC_FOUND_ROWS wp_posts.* FROM wp_posts WHERE 1=1 AND wp_posts.ID NOT IN ( SELECT tr.object_id FROM wp_term_relationships AS tr INNER JOIN wp_term_taxonomy AS tt ON tr.term_taxonomy_id = tt.term_taxonomy_id WHERE tt.taxonomy = 'category' AND tt.term_id IN ('217', '218', '223', '224') ) AND wp_posts.post_type = 'post' AND (wp_posts.post_status = 'publish' OR wp_posts.post_status = 'private') ORDER BY wp_posts.post_date DESC LIMIT 0, 6 id select_type table type possible_keys key key_len ref rows Extra 1 PRIMARY wp_posts ref type_status_date type_status_date 63 const 427 Using where; Using filesort 2 DEPENDENT SUBQUERY tr ref PRIMARY,term_taxonomy_id PRIMARY 8 func 1 Using index 2 DEPENDENT SUBQUERY tt eq_ref PRIMARY,term_id_taxonomy,taxonomy PRIMARY 8 antin1_lovemusic2010.tr.term_taxonomy_id 1 Using where Query time: 70.3900 (ms)

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  • How can I improve the performance of LinqToSql queries that use EntitySet properties?

    - by DanM
    I'm using LinqToSql to query a small, simple SQL Server CE database. I've noticed that any operations involving sub-properties are disappointingly slow. For example, if I have a Customer table that is referenced by an Order table, LinqToSql will automatically create an EntitySet<Order> property. This is a nice convenience, allowing me to do things like Customer.Order.Where(o => o.ProductName = "Stopwatch"), but for some reason, SQL Server CE hangs up pretty bad when I try to do stuff like this. One of my queries, which isn't really that complicated takes 3-4 seconds to complete. I can get the speed up to acceptable, even fast, if I just grab the two tables individually and convert them to List<Customer> and List<Order>, then join then manually with my own query, but this is throwing out a lot of what makes LinqToSql so appealing. So, I'm wondering if I can somehow get the whole database into RAM and just query that way, then occasionally save it. Is this possible? How? If not, is there anything else I can do to boost the performance besides resorting to doing all the joins manually? Note: My database in its initial state is about 250K and I don't expect it to grow to more than 1-2Mb. So, loading the data into RAM certainly wouldn't be a problem from a memory point of view. Update Here are the table definitions for the example I used in my question: create table Order ( Id int identity(1, 1) primary key, ProductName ntext null ) create table Customer ( Id int identity(1, 1) primary key, OrderId int null references Order (Id) )

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