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• NVIDIA présente son premier CPU pour PC, fondé sur l'architecture ARM, « Denver » est déjà compatible Windows 8

  NVIDIA présente son premier CPU pour PC Fondé sur l'architecture ARM, « Denver » est déjà compatible Windows 8 NVIDIA vient de présenter, durant la très prolifique conférence du Consumer Electronics Show, une série de coeurs de CPU fondés sur l'architecture ARM et destinés aux PC. Cette présentation survient après celle de Microsoft, qui vient d'annoncer officiellement le virage ARM que prendra Windows. Steve Ballmer a en effet effectué hier la première présentation de Windows 8 sur des puces ARM NV...

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• WWDC : Apple dévoile Metal, une nouvelle bibliothèque graphique pour améliorer les performances de rendu CPU sur les périphériques iOS

  WWDC : Apple dévoile Metal, une nouvelle bibliothèque graphique Son but est d'améliorer les performances de rendu sur CPU pour les périphériques sous iOSDurant la conférence WWDC 2014 (Apple Worldwide Developers Conference), Apple a annoncé une nouvelle bibliothèque graphique bas niveau à l'image de Mantle, appelée Metal. Le but est de drastiquement améliorer les performances de rendu sur CPU, pour les périphériques sous iOS. À cette occasion, Apple a travaillé avec Epic Games afin de produire...

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• Translating EventAggregators usage of SynchronizationContext to VB.Net

  - by Phil Sayers

  Working with a fairly large VB.Net back office winforms application. 1 million+ LOC. Big ball of mud, 90% of all code is in Forms & other UI controls. Slowly introducing better architecture as time & recources allows, We've been using ideas from the EventAggrgator by Jeremy Miller. http://codebetter.com/blogs/jeremy.miller/archive/2008/01/11/build-your-own-cab-extensible-pub-sub-event-aggregator-with-generics.aspx Initially I stripped out the usage of SynchronizationContext. Now I'm trying to introduce it back, and I'm struggling with the translation of the lamda stuff from c# to vb.net. Specifically this line of c# _context.Send(delegate { receiver.Handle(subject); }, null); This is the vb.net I have so far: _context.Send(New SendOrPostCallback(AddressOf listener.Handle(message)), Nothing) The error I'm getting is listener.Handle(message) <-- AddressOf operand must be the name of a method. I'm sure I'm missing something simple, but after staring at this for 2 days, I'm lost.

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• Error // Usage: rails new APP_PATH [options] // when running 'rails server'

  - by madphill

  Background info: I'm using GIT to get a repository of a project with Ruby files in it. The project lives in my SITES folder under home directory on my Mac. I have Ruby: 1.8.7 I have just upgraded Rails to: 3.0.3 All I am trying to accomplish is to be able to render localhost.com:3000 in my browser of the GIT project i've already downloaded so I can work on it locally. I ran the command 'rails server' and was returned the message below:: Usage: rails new APP_PATH [options] Options: [--skip-gemfile] # Don't create a Gemfile -m, [--template=TEMPLATE] # Path to an application template (can be a filesystem path or URL) -d, [--database=DATABASE] # Preconfigure for selected database (options: mysql/oracle/postgresql/sqlite3/frontbase/ibm_db) # Default: sqlite3 -O, [--skip-active-record] # Skip Active Record files -J, [--skip-prototype] # Skip Prototype files -T, [--skip-test-unit] # Skip Test::Unit files [--dev] # Setup the application with Gemfile pointing to your Rails checkout -r, [--ruby=PATH] # Path to the Ruby binary of your choice # Default: /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/bin/ruby -G, [--skip-git] # Skip Git ignores and keeps -b, [--builder=BUILDER] # Path to an application builder (can be a filesystem path or URL) [--edge] # Setup the application with Gemfile pointing to Rails repository Runtime options: -f, [--force] # Overwrite files that already exist -s, [--skip] # Skip files that already exist -p, [--pretend] # Run but do not make any changes -q, [--quiet] # Supress status output Rails options: -h, [--help] # Show this help message and quit -v, [--version] # Show Rails version number and quit Description: The 'rails new' command creates a new Rails application with a default directory structure and configuration at the path you specify. Example: rails new ~/Code/Ruby/weblog This generates a skeletal Rails installation in ~/Code/Ruby/weblog. See the README in the newly created application to get going.

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• Threads, Sockets, and Designing Low-Latency, High Concurrency Servers

  - by lazyconfabulator

  I've been thinking a lot lately about low-latency, high concurrency servers. Specifically, http servers. http servers (fast ones, anyway) can serve thousands of users simultaneously, with very little latency. So how do they do it? As near as I can tell, they all use events. Cherokee and Lighttpd use libevent. Nginx uses it's own event library performing much the same function of libevent, that is, picking a platform optimal strategy for polling events (like kqueue on *bsd, epoll on linux, /dev/poll on Solaris, etc). They all also seem to employ a strategy of multiprocess or multithread once the connection is made - using worker threads to handle the more cpu intensive tasks while another thread continues to listen and handle connections (via events). This is the extent of my understanding and ability to grok the thousand line sources of these applications. What I really want are finer details about how this all works. In examples of using events I've seen (and written) the events are handling both input and output. To this end, do the workers employ some sort of input/output queue to the event handling thread? Or are these worker threads handling their own input and output? I imagine a fixed amount of worker threads are spawned, and connections are lined up and served on demand, but how does the event thread feed these connections to the workers? I've read about FIFO queues and circular buffers, but I've yet to see any implementations to work from. Are there any? Do any use compare-and-swap instructions to avoid locking or is locking less detrimental to event polling than I think? Or have I misread the design entirely? Ultimately, I'd like to take enough away to improve some of my own event-driven network services. Bonus points to anyone providing solid implementation details (especially for stuff like low-latency queues) in C, as that's the language my network services are written in.

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• S3 Backup Memory Usage in Python

  - by danpalmer

  I currently use WebFaction for my hosting with the basic package that gives us 80MB of RAM. This is more than adequate for our needs at the moment, apart from our backups. We do our own backups to S3 once a day. The backup process is this: dump the database, tar.gz all the files into one backup named with the correct date of the backup, upload to S3 using the python library provided by Amazon. Unfortunately, it appears (although I don't know this for certain) that either my code for reading the file or the S3 code is loading the entire file in to memory. As the file is approximately 320MB (for today's backup) it is using about 320MB just for the backup. This causes WebFaction to quit all our processes meaning the backup doesn't happen and our site goes down. So this is the question: Is there any way to not load the whole file in to memory, or are there any other python S3 libraries that are much better with RAM usage. Ideally it needs to be about 60MB at the most! If this can't be done, how can I split the file and upload separate parts? Thanks for your help. This is the section of code (in my backup script) that caused the processes to be quit: filedata = open(filename, 'rb').read() content_type = mimetypes.guess_type(filename)[0] if not content_type: content_type = 'text/plain' print 'Uploading to S3...' response = connection.put(BUCKET_NAME, 'daily/%s' % filename, S3.S3Object(filedata), {'x-amz-acl': 'public-read', 'Content-Type': content_type})

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• Im Stumped, Why is UIImage\Texture2d memory not being freed

  - by howsyourface

  I've been looking everywhere trying to find a solution to this problem. Nothing seems to help. I've set up this basic test to try to find the cause of why my memory wasn't being freed up: if (texture != nil) { [texture release]; texture = nil; } else { UIImage* ui = [UIImage imageWithContentsOfFile:[[NSBundle mainBundle] pathForResource:@"image" ofType:@"png"]]; texture = [[Texture2D alloc] initWithImage:ui]; } Now i would place this in the touches began and test by monitoring the memory usage using intstruments at the start (normally 11.5 - 12mb) after the first touch, with no object existing the texture is created and memory jumps to 13.5 - 14 However, after the second touch the memory does decrease, but only to around 12.5 - 13. There is a noticeable chunk of memory still occupied. I tested this on a much larger scale, loading 10 of these large textures at a time The memory jumps to over 30 mb and remains there, but on the second touch after releasing the textures it only falls to around 22mb. I tried the test another time loading the images in with [uiimage imagenamed:] but because of the caching this method performs it just means that the full 30mb remains in memory.

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• Comet, responseText and memory usage

  - by ithcy

  Is there a way to clear out the responseText of an XHR object without destroying the XHR object? I need to keep a persistent connection open to a web server to feed live data to a browser. The problem is, there is a relatively large amount of data coming through (several hundred K per second constantly), so memory usage is a big problem, because this connection must remain open for at least several minutes. responseText gets very big very quickly, even though the JSON I send back has been crunched as small as it can get. Due to the way the server-side app works, if I use AJAX-style short polling and just destroy the XHR object when I'm done with it, I miss significant amounts of important data even in the few milliseconds it takes to parse the response, create a new XHR and send it out. I do not have the option to use overlapping requests, as the web server only accepts one connection at a time. (Don't ask.) So Comet is exactly the model I need. What I would like to do is parse each JSON chunk as it comes back from the server, and then clear out responseText so that I can keep using the same connection. However, responseText is read-only. It cannot be directly emptied by any method I have found. Is there a part of the picture I am missing here? Does anyone know any tricks I can use to free up responseText when I'm done reading it? Or is there another place the server responses can go? I am not including code because this is really almost a code-agnostic question. The Javascript routines that spawn the XHRs and handle the returned data are very, very simple.

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• Proper Usage of SqlConnection in .NET

  - by Jojo

  Hi guys, I just want an opinion on the proper usage or a proper design with regards to using SqlConnection object. Which of the 2 below is the best use: A data provider class whose methods (each of them) contain SqlConnection object (and disposed when done). Like: IList<Employee> GetAllEmployees() { using (SqlConnection connection = new SqlConnection(this.connectionString)) { // Code goes here... } } Employee GetEmployee(int id) { using (SqlConnection connection = new SqlConnection(this.connectionString)) { // Code goes here... } } or SqlConnection connection; // initialized in constructor IList<Employee> GetAllEmployees() { this.TryOpenConnection(); // tries to open member SqlConnection instance // Code goes here... this.CloseConnection(); // return } Employee GetEmployee(int id) { this.TryOpenConnection(); // tries to open member SqlConnection instance // Code goes here... this.CloseConnection(); // return } Or is there a better approach than this? I have a focused web crawler type of application and this application will crawl 50 or more websites simultaneously (multithreaded) with each website contained in a crawler object and each crawler object has an instance of a data provider class (above). Please advise. Thanks.

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• Dynamic table memory usage

  - by Dan

  I use a dynamic table: <html> <body> <button id="button">Build table</button> <div id="container"> <script type="text/javascript"> window.onload=function(){ var table = null; var row = "<tr><td>111111111111111111111111111111111111111111111111111111</td>" + "<td>222222222222222222222222222222222222222222222222222222</td>" + "<td>333333333333333333333333333333333333333333333333333333</td></tr>"; var data = null; for (var i = 0; i < 2000; i++){ data += row; } var obj = document.getElementById("button"); obj.onclick=function buildTable(){ document.getElementById("container").innerHTML = "<div><table><tbody>" + data + "</tbody></table></div>"; }; }; </script> </body> </html> Using chromes task manager, each time new data is loaded the memory usage increases considerably and doesn't go down, so after some time the app consumes a lot of memory and requires the browser to be closed. Is there any change in the code I can use to solve this or is it a browser side problem?

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• Multiple usage of MenuItems declared once (WPF)

  - by Alex Kofman

  Is it possible in WPF to define some menu structure and than use it in multiple contexts? For example I'd like to use a set of menu items from resources in ContextMenu, Window's menu and ToolBar (ToolBar with icons only, without headers). So items order, commands, icons, separators must be defined just once. I look for something like this: Declaration in resources: <MenuItem Command="MyCommands.CloneObject" CommandParameter="{Binding SelectedObject}" Header="Clone"> <MenuItem.Icon> <Image Source="Images\Clone.png" Height="16" Width="16"></Image> </MenuItem.Icon> </MenuItem> <MenuItem Command="MyCommands.RemoveCommand" CommandParameter="{Binding SelectedObject}" Header="Remove"> <MenuItem.Icon> <Image Source="Images\Remove.png" Height="16" Width="16"></Image> </MenuItem.Icon> </MenuItem> <Separator/> <MenuItem Command="MCommands.CreateChild" CommandParameter="{Binding SelectedObject}" Header="Create child"> <MenuItem.Icon> <Image Source="Images\Child.png" Height="16" Width="16"></Image> </MenuItem.Icon> </MenuItem> Usage: <ToolBar MenuItems(?)="{Reference to set of items}" ShowText(?)="false" /> and <ContextMenu MenuItems(?)="{Reference to set of items}" />

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• FileConnection Blackberry memory usage

  - by Dean

  Hello, I'm writing a blackberry application that reads ints and strings out of a database. This is my first time dealing with reading/writing on the blackberry, so forgive me if this is a dumb question. The database file I'm reading is only about 4kB I open the file with the following code fconn = (FileConnection) Connector.open("file_path_here", Connector.READ); if(fconn.exists()==false){fconn.close();return;} is = fconn.openDataInputStream(); while(!eof){ //etc... } is.close(); fconn.close(); The problem is, this code appears to be eating a LOT of memory. Using breakpoints and the "Memory Statistics" view, I determined the following: calling "Connector.open" creates 71 objects and changes "RAM Bytes in use" by 5376 calling "fconn.openDataInputStream();" increases RAM usage by a whopping 75920 Is this normal? Or am I doing something wrong? And how can I fix this? 75MB of RAM is a LOT of memory to waste on a handheld device, especially when the file I'm reading is only 4kB and I haven't even begun reading any data! How is this even possible?

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• Inheritence and usage of dynamic_cast

  - by Mewzer

  Hello, Suppose I have 3 classes as follows (as this is an example, it will not compile!): class Base { public: Base(){} virtual ~Base(){} virtual void DoSomething() = 0; virtual void DoSomethingElse() = 0; }; class Derived1 { public: Derived1(){} virtual ~Derived1(){} virtual void DoSomething(){ ... } virtual void DoSomethingElse(){ ... } virtual void SpecialD1DoSomething{ ... } }; class Derived2 { public: Derived2(){} virtual ~Derived2(){} virtual void DoSomething(){ ... } virtual void DoSomethingElse(){ ... } virtual void SpecialD2DoSomething{ ... } }; I want to create an instance of Derived1 or Derived2 depending on some setting that is not available until run-time. As I cannot determine the derived type until run-time, then do you think the following is bad practice?... class X { public: .... void GetConfigurationValue() { .... // Get configuration setting, I need a "Derived1" b = new Derived1(); // Now I want to call the special DoSomething for Derived1 (dynamic_cast<Derived1*>(b))->SpecialD1DoSomething(); } private: Base* b; }; I have generally read that usage of dynamic_cast is bad, but as I said, I don't know which type to create until run-time. Please help!

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• When are predicates appropriate and what is the best pattern for usage

  - by Maxim Gershkovich

  When are predicates appropriate and what is the best pattern for usage? What are the advantages of predicates? It seems to me like most cases where a predicate can be employed a tight loop would accomplish the same functionality? I don’t see a reusability argument given you will probably only implement a predicate in one method right? They look and feel nice but besides that they seem like you would only employ them when you need a quick hack on the collection classes? UPDATE But why would you be rewriting the tight loop again and again? In my mind/code when it comes to collections I always end up with something like Class Person End Class Class PersonList Inherits List(Of Person) Function FindByName(Name) as Person tight loop.... End Function End Class @Ani By that same logic I could implement the method as such Class PersonList Inherits List(Of Person) Function FindByName(Name) as PersonList End Function Function FindByAge(Age) as PersonList End Function Function FindBySocialSecurityNumber(SocialSecurityNumber) as PersonList End Function End Class And call it as such Dim res as PersonList = MyList.FindByName("Max").FindByAge(25).FindBySocialSecurityNumber(1234) and the result along with the amount of code and its reusability is largely the same, no? I am not arguing just trying to understand.

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• Fatal error: Allowed memory size exhausted...

  - by Nano HE

  HI, I upload my php testing script to online vps server just now. The script used to parse a big size XML file(about 4M, 7000Lines). But my IE explorer show the online error message below. Fatal error: Allowed memory size of 16777216 bytes exhausted (tried to allocate 77 bytes) in /var/www/test/result/index.php on line 26 I am sure I already tested the php script on localhost successfully. Is there any configuration need be enable/modify on my VPS? Such as php.ini or some setting for apache server? I just verified there are about 200M memory usage are avaliable for my VPS. How can I fix this? ...... function startElementHandler ($parser,$name,$attrib){ global $usercount; global $userdata; global $state; // Line #26; //Debug //print "name is: ".$name."\n"; switch ($name) { case $name=="_ID" : { $userdata[$usercount]["first"] = $attrib["FIRST"]; $userdata[$usercount]["last"] = $attrib["LAST"]; $userdata[$usercount]["nick"] = $attrib["NICK"]; $userdata[$usercount]["title"] = $attrib["TITLE"]; break; } ...... default : {$state=$name;break;} } }

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• php memory how much is too much

  - by Rob

  I'm currently re-writing my site using my own framework (it's very simple and does exactly what I need, i've no need for something like Zend or Cake PHP). I've done alot of work in making sure everything is cached properly, caching pages in files so avoid sql queries and generally limiting the number of sql queries. Overall it looks like it's very speedy. The average time taken for the front page (taken over 100 times) is 0.046152 microseconds. But one thing i'm not sure about is whether i've done enough to reduce php memory usage. The only time i've ever encountered problems with it is when uploading large files. Using memory_get_peak_usage(TRUE), which I THINK returns the highest amount of memory used whilst the script has been running, the average (taken over 100 times) is 1572864 bytes. Is that good? I realise you don't know what it is i'm doing (it's rather simple, get the 10 latest articles, the comment count for each, get the user controls, popular tags in the sidebar etc). But would you be at all worried with a script using that sort of memory getting hit 50,000 times a day? Or once every second at peak times? I realise that this is a very open ended question. Hopefully you can understand that it's a bit of a stab in the dark and i'm really just looking for some re-assurance that it's not going to die horribly come re-launch day.

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• Incorrect usage of UPDATE and ORDER BY

  - by nico55555

  I have written some code to update certain rows of a table with a decreasing sequence of numbers. To select the correct rows I have to JOIN two tables. The last row in the table needs to have a value of 0, the second last -1 and so on. To achieve this I use ORDER BY DESC. Unfortunately my code brings up the following error: Incorrect usage of UPDATE and ORDER BY My reading suggests that I can't use UPDATE, JOIN and ORDER BY together. I've read that maybe subqueries might help? I don't really have any idea how to change my code to do this. Perhaps someone could post a modified version that will work? while($row = mysql_fetch_array( $result )) { $products_id = $row['products_id']; $products_stock_attributes = $row['products_stock_attributes']; mysql_query("SET @i = 0"); $result2 = mysql_query("UPDATE orders_products op, orders ord SET op.stock_when_purchased = (@i:=(@i - op.products_quantity)) WHERE op.orders_id = ord.orders_id AND op.products_id = '$products_id' AND op.products_stock_attributes = '$products_stock_attributes' AND op.stock_when_purchased < 0 AND ord.orders_status = 2 ORDER BY orders_products_id DESC") or die(mysql_error()); }

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• Javascript dynamic table memory usage

  - by Dan

  I use a dynamic table: <html> <body> <button id="button">Build table</button> <div id="container"> <script type="text/javascript"> window.onload=function(){ var table = null; var row = "<tr><td>111111111111111111111111111111111111111111111111111111</td>" + "<td>222222222222222222222222222222222222222222222222222222</td>" + "<td>333333333333333333333333333333333333333333333333333333</td></tr>"; var data = null; for (var i = 0; i < 2000; i++){ data += row; } var obj = document.getElementById("button"); obj.onclick=function buildTable(){ document.getElementById("container").innerHTML = "<div><table><tbody>" + data + "</tbody></table></div>"; }; }; </script> </body> </html> Using chromes task manager, each time new data is loaded the memory usage increases considerably and doesn't go down, so after some time the app consumes a lot of memory and requires the browser to be closed. Is there any change in the code I can use to solve this or is it a browser side problem?

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• Will high reputation in Programmers help to get a good job?

  - by Lorenzo

  In reference to this question, do you think that having a high reputation on this site will help to get a good job? Aside silly and humorous questions, on Programmers we can see a lot of high quality theory questions. I think that, if Stack Overflow will eventually evolve in "strictly programming related" (which usually is "strictly coding related"), the questions on Programmers will be much more interesting and meaningful ("Stack Overflow" = "I have this specific coding/implementation issue"; "Programmers" = "Best practices, team shaping, paradigms, CS theory"). So could high reputation on this site help (or at least be a good reference)? And then, more o less than Stack Overflow?

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• implementing a high level function in a script to call a low level function in the game engine

  - by eat_a_lemon

  In my 2d game engine I have a function that does pathfinding, find_shortest_path. It executes for each time step in the game loop and calculates the next coordinate pair in the series of coordinates to reach the destination object. Now I want to call this function in a scripting language and have it only return the last coordinate pair result. I want the game engine to go about the business of rendering the incremental steps but I don't want the high level script to care about the rendering. The high level script is only for ai game logic. Now I know how to bind a method from C to python but how can I signal and coordinate the wait time between the incremental steps without the high level function returning until its time for the last step?

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• Language+IDE for teaching high school students?

  - by daveagp

  I'm investigating languages and IDEs for a project involving teaching high-school students (around grade 11). It will teach basics of programming as an introduction to computer science (e.g., including how numbers/strings/characters are represented, using procedures and arrays, control flow, a little bit of algorithms, only very basic I/O). The non-negotiable requirements for this project are: a free up-to-date cross-platform IDE (Win & Mac incl. 64-bit) with debug a compiler where it's easy to learn from your mistakes together with the IDE, a gentle installation+learning curve So far, the best options I see are the following. Are there others I should know about? I am giving a short explanation with each one to generally show what I am looking for. In order from most to least promising: Pascal + FreePascal IDE (it seems a little buggy but actively developed?) Python + Eclipse + PyDev (good but features are overwhelming/hard to navigate) Groovy + Eclipse ('') Python + IDLE (looks unnatural to do debugging, to me) Pascal + Lazarus (IDE overwhelming, e.g. not obvious how to "start from scratch") Preferably, as a rule of thumb, the language should be direct enough that you don't need to wrap every program in a class, don't need to reference a System object to println, etc. I tried a little bit to see if there is something in JavaScript or (non-Visual) Basic along the lines of what I want, but found nothing so far. I would say that C/C++/C#, Java, Ruby, Lisp, VB do not fit my criteria for languages for this project. To reiterate my questions: are any of those 5 options really awesome or un-awesome? Are there other options which are even MORE awesome? Anything for Basic or JavaScript which meets all of the criteria? Thanks!

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• java distributed cache for low latency, high availability

  - by Shahbaz

  I've never used distributed caches/DHTs like memcached, jboss cache, ehcache, etc. I'm wondering which, if any, is appropriate for my use. First, I'm not doing web applications (as most of these project seem to be geared towards web apps). I write servers (Order Management Systems actually) for financial trading firms. The servers themselves are not too complicated. They need to receive information (market data, orders, executions, etc.) rout them to their destination while possibly transforming some of these messages. I am looking at these products to solve the following problems: * Safe repository of the state of the server. I'd rather build the logic of my application as a bunch of transformers (similar to Apache Camel) and store the state in a 'safe' place * This repository should be distributed: in case one of these data stores crashes, one or two more should be up and I should be able to switch to them seamlessly * This repository should be fast. Single digits milliseconds count here, in other words, systems which consume/process this data are automated systems, not humans clicking on links. This system needs to have high-throughput and low latency. By sending my data outside the process, I am necessarily slowing performance, but I am trying to balance absolute raw speed and absolute protection of data. * This repository should be safe. Similar to the point about several on-line backups, this system needs to write data to disk (potentially more than one disk). I'd really like to stop writing my own 'transaction servers.' Am I correct to be looking into projects such as jboss cache, ehcache, etc.? Thanks

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• Which linear programming package should I use for high numbers of constraints and "warm starts"

  - by davidsd

  I have a "continuous" linear programming problem that involves maximizing a linear function over a curved convex space. In typical LP problems, the convex space is a polytope, but in this case the convex space is piecewise curved -- that is, it has faces, edges, and vertices, but the edges aren't straight and the faces aren't flat. Instead of being specified by a finite number of linear inequalities, I have a continuously infinite number. I'm currently dealing with this by approximating the surface by a polytope, which means discretizing the continuously infinite constraints into a very large finite number of constraints. I'm also in the situation where I'd like to know how the answer changes under small perturbations to the underlying problem. Thus, I'd like to be able to supply an initial condition to the solver based on a nearby solution. I believe this capability is called a "warm start." Can someone help me distinguish between the various LP packages out there? I'm not so concerned with user-friendliness as speed (for large numbers of constraints), high-precision arithmetic, and warm starts. Thanks!

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• Alternatives to LINQ To SQL on high loaded pages

  - by Alex

  To begin with, I LOVE LINQ TO SQL. It's so much easier to use than direct querying. But, there's one great problem: it doesn't work well on high loaded requests. I have some actions in my ASP.NET MVC project, that are called hundreds times every minute. I used to have LINQ to SQL there, but since the amount of requests is gigantic, LINQ TO SQL almost always returned "Row not found or changed" or "X of X updates failed". And it's understandable. For instance, I have to increase some value by one with every request. var stat = DB.Stats.First(); stat.Visits++; // .... DB.SubmitChanges(); But while ASP.NET was working on those //... instructions, the stats.Visits value stored in the table got changed. I found a solution, I created a stored procedure UPDATE Stats SET Visits=Visits+1 It works well. Unfortunately now I'm getting more and more moments like that. And it sucks to create stored procedures for all cases. So my question is, how to solve this problem? Are there any alternatives that can work here? I hear that Stackoverflow works with LINQ to SQL. And it's more loaded than my site.

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• How to convert string with double high/wide characters to normal string [VC++6]

  - by Shaitan00

  My application typically recieves a string in the following format: " Item $5.69 " Some contants I always expect: - the LENGHT always 20 characters - the start index of the text always [5] - and most importantly the index of the DECIMAL for the price always [14] In order to identify this string correctly I validate all the expected contants listed above .... Some of my clients have now started sending the string with Doube-High / Double-Wide values (pair of characters which represent a single readable character) similar to the following: " Item $x80x90.x81x91x82x92 " For testing I simply scan the string character-by-character, compare char[i] and char[i+1] and replace these pairs with their corresponding single character when a match is found (works fine) as follows: [Code] for (int i=0; i < sData.length(); i++) { char ch = sData[i] & 0xFF; char ch2 = sData[i+1] & 0xFF; if (ch == '\x80' && ch2 == '\x90') zData.replace("\x80\x90", "0"); else if (ch == '\x81' && ch2 == '\x91') zData.replace("\x81\x91", "1"); else if (ch == '\x82' && ch2 == '\x92') zData.replace("\x82\x92", "2"); ... ... ... } [/Code] But the result is something like this: " Item $5.69 " Notice how this no longer matches my expectation: the lenght is now 17 (instead of 20) due to the 3 conversions and the decimal is now at index 13 (instead of 14) due to the conversion of the "5" before the decimal point. Ideally I would like to convert the string to a normal readable format keeping the constants (length, index of text, index of decimal) at the same place (so the rest of my application is re-usable) ... or any other suggestion (I'm pretty much stuck with this)... Is there a STANDARD way of dealing with these type of characters? Any help would be greatly appreciated, I've been stuck on this for a while now ... Thanks,

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