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  • UIView Controller mysteriously getting deallocated

    - by Dan Ray
    I have a UINavigation scheme with a "welcome" page, a middle page, and a detail page. In the middle page, there's a segmented controller that can swap the main body of that page between a table, a calendar, and a MKMapView, each implemented with their own view controller classes. Today I implemented the MapView and its annotations and all of that. It's nice. And a detail disclosure on each callout takes you to the detail page just the same way as if you'd gotten there via the table. Lovely. I also have a right-button-bar button that pushes in a "search" view. From there you can search the data I'm navigating. When it's done filtering the data (an array of objects I'm keeping in a data singleton), it makes the table reload its data, and calls my annotation-clearer-and-builder methods on the map view, and then pops itself out, so the "middle" page (including whatever view was in the guts of it) is back on the screen. Problem is, if I go back and forth between the map and the search a couple times, any mention of the table view causes us to crash with: *** -[CALayer retain]: message sent to deallocated instance 0x710b810. (I obviously have NSZombies turned on.) I put an NSLog in the dealloc method of my table view controller. That thing's never getting called. I don't know if we're ditching it behind the scenes for memory purposes, or if I'm leaking it and can't get my hands back on it, or what. I'm sort of at a loss about where to look. Any hints?

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  • How do I keep child elements together with parent jQuery sortable.

    - by unknowndomain
    I have a list of items like this... <ol> <li> <span></span> <img src="image.png" /> <p>Image Caption</p> </li> </ol> And I want to be able to sort the LI's but not the sub elements, they should just move with their parent. I am using the jQuery to do that... $('ol li').sortable({ 'cursor': 'move' }); And its working but not moving the whole lot just the element you clicked i.e. the <p>, <img> or <span> I can't figure out how to solve this so I looked about and found an option called 'items': '> li' which was recommended but upon using this nothing drags any more but using firebug + jquery plugin I can see there is a sortable on the <li> still. Not sure what to do, example here: http://clareshilland.unknowndomain.co.uk/ Press ctrl+l to login. Enter the login details: Username: clarePassword: demo Select 'edit' from under then 'image' portion of the menu. The sortables should be those polaroids. Thanks in advance, another one I've been banging my head on the table with.

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  • displaying music current time & duration from AVFoundation

    - by msb
    I have a view-based iphone application that has a single play-pause button that plays an mp3 file. At the time of invoking my doPlayPauseButton() method, I 'd like to show the current time and total duration of this mp3 through the AVAudioPlayer instance I've created, called myAudioPlayer. I have placed two labels at the UI and i'm trying to assign the currentTime and duration properties to these label when the playing begins but my attempts have failed. Here's my play/pause loop, any help would be appreciated: -(IBAction) doPlayPauseButton:(UIButton *)theButton { if(myAudioPlayer.playing) { [myActivityIndicatorView stopAnimating]; myActivityIndicatorView.hidden = YES; //I think I need a myAudioPlayer.currentTime call of some sort for my labels. [myAudioPlayer pause]; [theButton setTitle:@"Play" forState:UIControlStateNormal]; [myTimer invalidate]; } else { [myActivityIndicatorView startAnimating]; myActivityIndicatorView.hidden = NO; myTimer = [NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(doTimer) userInfo:nil repeats:YES]; [myAudioPlayer play]; [theButton setTitle:@"Pause" forState:UIControlStateNormal];

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  • Lightweight development web server with support for PHP v2

    - by David
    In line with this question: http://stackoverflow.com/questions/171655/lightweight-web-app-server-for-php The above question has been asked numerous times and answered exactly the same in all the cases I've found using google. My question is similar to a degree but with a different desired goal: On demand development instances. I have come up with a somewhat questionable solution to host arbitrary directories in my user account for the purpose of development testing. I am not interested in custom vhosts but looking to emulate the behaviour I get when using paster or mongrel for Python & Ruby respectively. Ubuntu 9.10 TOXIC@~/ APACHE_RUN_USER=$USER APACHE_RUN_GROUP=www-data apache2 -d ~/Desktop/ -c "Listen 2990" Is there a better solution, could I do something similar with nginix or lighttpd? Note: The above won't work correctly for stock environments without a copied & altered httpd.conf. Update: The ideal goal is to mimic Paster, Webbrick, and Mongrel for rapid local development hosting. For those light weight servers, it takes less then a minute to get a working instance running ( not factoring any DB support ). Apache2 vhost is great but I've been using Apache2 for over ten years and it would be some sort of abomination hack to setup a new entry in /etc/hosts unless you have your own DNS, in which case a wildcard subdomain setup would probably work great. EXCEPT one more problem, it's pretty easy for me to know what is being hosted ( ex. by paster or mongeral ) just doing a sudo netstat -tulpn while there would be a good possibility of confusion in figure out which vhost is what.

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  • Setting up a multi-site CMS, collecting thoughts about the DB schema

    - by Ben Fransen
    Hello all, I'm collecting some thoughts about creating a multisite CMS. In my opinion there are two major approaches. All data is stored into 1 database, giving me the advantage of single point of updates; Seperated databases, so each client has its own database. Giving me the advantage to measure bandwith. Option 1 gives me the disadvantage of measuring bandwith while option is giving me the disadvantage of a single point of update structure. Are there any generic approaches for creating a sort of update system? So my clients can download a small package (maybe a zip with a conf file to tell the updatescript where to put all the files and how to extend the database??) Do you guys have some thougths about the best solution for a situation like this? I have my own webserver, full access to all resources and I'm developing in PHP with MySQL as DBMS. I hope to hear from you and I surely appreciate any effort you make to help me further! Greets from Holland, Ben Fransen

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  • Software Update Notifications

    - by devio
    I am considering implementing some sort of Software Update Notification for one of the web applications I am developing. There are several questions I came across: Should the update check be executed on the client or on the server? Client-side means, the software retrieves the most current version information, performs its checks, and displays the update information. Server-side check means the software sends its version info to the server, which in turn does the calculations and returns information to the client. My guess is that server-side implementation may turn out to be more flexible and more powerful than client-side, as I can add functionality to the server easily, as long as the client understands it. Where should the update info be displayed? Is it ok to display on the login screen? Should only admins see it? (this is a web app with a database, so updating requires manipulation of db and web, which is only done by admins). What about a little beeping flashing icon which increases in size as the version gets more obsolete every day ;) ? Privacy issues Not everybody likes to have their app usage stats broadcast over the internet. TheOnion question: What do you think?

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  • Trying to use boost lambda, but my code won't compile

    - by hamishmcn
    Hi, I am trying to use boost lambda to avoid having to write trivial functors. For example, I want to use the lambda to access a member of a struct or call a method of a class, eg: #include <vector> #include <utility> #include <algorithm> #include <boost/lambda/lambda.hpp> using namespace std; using namespace boost::lambda; vector< pair<int,int> > vp; vp.push_back( make_pair<int,int>(1,1) ); vp.push_back( make_pair<int,int>(3,2) ); vp.push_back( make_pair<int,int>(2,3) ); sort(vp.begin(), vp.end(), _1.first > _2.first ); When I try and compile this I get the following errors: error C2039: 'first' : is not a member of 'boost::lambda::lambda_functor<T>' with [ T=boost::lambda::placeholder<1> ] error C2039: 'first' : is not a member of 'boost::lambda::lambda_functor<T>' with [ T=boost::lambda::placeholder<2> ] Since vp contains pair<int,int> I thought that _1.first should work. What I am doing wrong?

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  • Setting database-agnostic default column timestamp using Hibernate

    - by unsquared
    I'm working on a java project full of Hibernate (3.3.1) mapping files that have the following sort of declaration for most domain objects. <property name="dateCreated" generated="insert"> <column name="date_created" default="getdate()" /> </property> The problem here is that getdate() is an MSSQL specific function, and when I'm using something like H2 to test subsections of the project, H2 screams that getdate() isn't a recognized function. It's own timestamping function is current_timestamp(). I'd like to be able to keep working with H2 for testing, and wanted to know whether there was a way of telling Hibernate "use this database's own mechanism for retrieving the current timestamp". With H2, I've come up with the following solution. CREATE ALIAS getdate AS $$ java.util.Date now() { return new java.util.Date(); } $$; CALL getdate(); It works, but is obviously H2 specific. I've tried extending H2Dialect and registering the function getdate(), but that doesn't seem to be invoked when Hibernate is creating tables. Is it possible to abstract the idea of a default timestamp away from the specific database engine?

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  • application packaging

    - by user285825
    The application packaging (software deliverables) is a vague concept to me. I worked in web application before so all I know how to prepare the deliverables ie WAR and then put them into the servlet container and rest of this being taken care of. But when considering other java or c++-based application (.exe or .class) how to prepare the package? What should be considered for preparation of the package and deployment of the application? Like I understand there should be some entries made into the windows registry or some libraries to be put in /usr/bin directory and so on. And during the development phase the execution and testing is done in more informal manner like writing some shell script or so on. But the deployment scenario is a more formal thing. As I said I have only the idea of deploying web applications I am not much knowledgeable in the other areas. Are there any kind of conventions like there are conventions for documentations like javadoc or doxygen/man pages? Application packaging is not that sort of a thing that there are much discussion on books or online materials. This is very disappointing.

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  • How does Java handle ArrayList refrerences and assignments?

    - by Jonathan
    Hey all- I mostly write in C but am using Java for this project. I want to know what Java is doing here under the hood. ArrayList<Integer> prevRow, currRow; currRow = new ArrayList<Integer>(); for(i =0; i < numRows; i++){ prevRow = currRow; currRow.clear(); currRow.addAll(aBunchOfItems); } Is the prevRow = currRow line copying the list or does prevRow now point to the same list as currRow? If prevRow points to the same list as currRow, I should create a new ArrayList instead of clearing.... private ArrayList<Integer> someFunction(ArrayList<Integer> l){ Collections.sort(l); return l; } main(){ ArrayList<Integer> list = new ArrayList<Integer>(Integer(3), Integer(2), Integer(1)); list = someFunction(list); //Option 1 someFunction(list); //Option 2 } In a similar question, do Option 1 and Option 2 do the same thing in the above code? Thanks- Jonathan

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  • What computer science topic am I trying to describe?

    - by ItzWarty
    I've been programming for around... 6-8 years, and I've begun to realize that I don't really know what really happens at the low-ish level when I do something like int i = j%348 The thing is, I know what j%348 does, it divides j by 348 and finds the remainder. What I don't know is HOW the computer does this. Similarly, I know that try { blah(); }catch(Exception e){ blah2(); } will invoke blah and if blah throws, it will invoke blah2... however, I have no idea how the computer does this instead of err... crashing or ending execution. And I figure that in order for me to get "better" at programming, I should probably know what my code is really doing. [This would probably also help me optimize and... err... not do stupid things] I figure that what I'm asking for is probably something huge taught in universities or something, but to be honest, if I could learn a little, I would be happy. The point of the question is: What topic/computer-science-course am I asking about? Because in all honesty, I don't know. Since I don't know what the topic is called, I'm unable to actually find a book or online resource to learn about the topic, so I'm sort of stuck. I'd be eternally thankful if someone helped me =/

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  • Manually Writing the HTML in TWebBrowser Pt. 2

    - by nomad311
    As the name suggests this is a continuation (sort of) of http://stackoverflow.com/questions/2784679/manually-writing-the-html-in-twebbrowser This time around I'm trying to add some auto-refresh logic to the HTML I get. I have pieced together an approach from several sources (see below). In short, I am trying to locate the title node and add a meta node after it (in the HTML head node). But, I get an access violation. Here is the source: iHtmlDoc := IHTMLDocument3(WebBrowser1.Document); iHtmlEleTitle := IHTMLElement2(iHtmlDoc.getElementsByName('title').item(0, 0)); iHtmlEle := IHTMLElement2(IHTMLDocument2(iHtmlDoc).createElement(Format('<meta http-equiv="refresh" content="%d">', [1]))); iHtmlEleTitle.insertAdjacentElement('afterEnd', IHTMLElement(iHtmlEle)); And A (technically not functionally) different way of doing it ...casting is slightly different here: IHTMLElement2(IHtmlDocument3(WebBrowser1.Document).getElementsByName('title').item(0, 0)).insertAdjacentElement('afterEnd', IHTMLDocument2(WebBrowser1.Document).createElement(Format('<meta http-equiv="refresh" content="%d">', [VPI_ISSUANCE_AUTO_RELOAD]))); Again all I get from Delphi is a access exception, and I fished through MSDN documentation on it, but now I'm hoping someone out there has gone through the same and has some insight. Any help? Sources (I think this is all of them): http://webdesign.about.com/od/metataglibraries/a/aa080300a.htm (auto-reload) http://delphi.about.com/od/adptips2005/qt/webbrowserhtml.htm (web browser document as an HTML document) http://msdn.microsoft.com/en-us/library/system.windows.forms.htmlelement.insertadjacentelement(VS.80).aspx (GetElementsByName) http://www.experts-exchange.com/Web_Development/Components/ActiveX/Q_26131034.html (insertAdjacentElement) http://www.experts-exchange.com/Programming/Languages/Pascal/Delphi/Q_23407977.html (GetElementsByName)

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  • what data structure should I use for hash lookup as well as binary search?

    - by zebraman
    I am working on a school homework. I have a list of names. I want to be able to perform binary search on these names (find all names between a lower and upper bound) for first name as well as last name, and perform keyword searches as well (this will be accomplished using hashing. For example, if I have the names Garfield Cat Snoopy Dog Captain Crunch Fat Cat then a binary search of first names (C,H) will return Captain Crunch, Fat Cat, and Garfield Cat. A binary search of last names (Cr,D) will return Captain Crunch. A keyword search of 'cat' will return Fat Cat and Garfield Cat. I understand binary search will only work on a sorted list, but since I am planning on searching two different criteria, I will have to sort the list by last name or first name depending on what I'm searching for. I feel like it will be too inefficient to have to resort the list each time I want to perform a new binary search. Would it just be better for me to set up and maintain two sorted lists (one for sorted by first name, one for sorted by last name)? Also, for hashing, will I have to set up a different table of names for that as well? I understand each keyword will hash to some value determined by a hash function, and this value (or key) is a table address where the corresponding names are stored. So I just want to know what would be the best way to solve this problem? Maintaining separate structures, or is there a way to efficiently do everything I want with just one data structure?

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  • WPF and Prism View Overlay

    - by Zaheer
    Hi, I need some help with overlaying views using the prism framework.Its a little more complexed than that so let me explain.I could be over-thinking this as well :D i have shell (wpf window) and i have 2 views(A & B - both usercontrols) in a module. when the shell loads it loads view A. On view A i have a button to "popup" view B for some user input. so naturally i would think to some sort of modal window/control, maybe even a popup. however the problem i face with the popup is that when i move the shell the popup remains fixed and it doesnt block events in view A. I've tried disabling view A to stop events being fired and i've also tried to use a to get the view B move with the shell. Only the canvas works but i now need a way to block it tho'. Is there anyway i can overlay a view on top of another view with prism? or how does everyone else create modal popups with prism & wpf? any advise or pointers would be greatly appreciated.

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  • No feedback from Socket.SendAsync

    - by BowserKingKoopa
    I'm creating a socket and I'm trying to send data through it using SendAsync. My socket isn't connected to anything so I expected to get an error of some sort. However I get nothing. I get no indication that the send didn't work. If I use the synchronous Send method instead of the asynchronous SendAsync method I get an Exception stating that the socket isn't connected to anything. That makes sense to me. When using SendAsync the completed event doesn't ever fire and I get no indication that the send didn't work. So basically my question is how can I tell when SendAsync fails? Socket socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp); SocketAsyncEventArgs args = new SocketAsyncEventArgs(); args.SetBuffer(new byte[0], 0, 0); args.Completed += delegate(object sender, SocketAsyncEventArgs e) { Debug.WriteLine("async send complete"); Debug.WriteLine("SOCKET ERROR: " + e.SocketError); }; bool completedSynchronously = socket.SendAsync(args); if (completedSynchronously) { Debug.WriteLine("sync send complete"); Debug.WriteLine("socket error: " + args.SocketError); }

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  • Collaborative filtering in MySQL ?

    - by user281434
    Hi I'm trying to develop a site that recommends items(fx. books) to users based on their preferences. So far, I've read O'Reilly's "Collective Intelligence" and numerous other online articles. They all, however, seem to deal with single instances of recommendation, for example if you like book A then you might like book B. What I'm trying to do is to create a set of 'preference-nodes' for each user on my site. Let's say a user likes book A,B and C. Then, when they add book D, I don't want the system to recommend other books based solely other users experience with book D. I wan't the system to look up similar 'preference-nodes' and recommend books based on that. Here's an example of 4 nodes: User1: 'book A'->'book B'->'book C' User2: 'book A'->'book B'->'book C'->'book D' user3: 'book X'->'book Y'->'book C'->'book Z' user4: 'book W'->'book Q'->'book C'->'book Z' So a recommendation system, as described in the material I've read, would recommend book Z to User 1, because there are two people who recommends Z in conjuction with liking C (ie. Z weighs more than D), even though a user with a similar 'preference-node', User2, would be more qualified to recommend book D because he has a more similar interest-pattern. So does any of you have any experience with this sort of thing? Is there some things I should try to read or does there exist any open source systems for this? Thanks for your time! Small edit: I think last.fm's algorithm is doing exactly what I my system to do. Using the preference-trees of people to recommmend music more personally to people. Instead of just saying "you might like B because you liked A"

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  • weighted matching algorithm in Perl

    - by srk
    Problem : We have equal number of men and women.each men has a preference score toward each woman. So do the woman for each man. each of the men and women have certain interests. Based on the interest we calculate the preference scores. So initially we have an input in a file having x columns. First column is the person(men/woman) id. id are nothing but 0.. n numbers.(first half are men and next half woman) the remaining x-1 columns will have the interests. these are integers too. now using this n by x-1 matrix... we have come up with a n by n/2 matrix. the new matrix has all men and woman as their rows and scores for opposite sex in columns. We have to sort the scores in descending order, also we need to know the id of person related to the scores after sorting. So here i wanted to use hash table. once we get the scores we need to make up pairs.. for which we need to follow some rules. My trouble is with the second matrix of n by n/2 that needs to give information of which man/woman has how much preference on a woman/man. I need these scores sorted so that i know who is the first preferred woman/man, 2nd preferred and so on for a man/woman. I hope to get good suggestions on the data structures i use.. I prefer php or perl. Thank you in advance

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  • PHP Performance Metrics

    - by bigstylee
    I am currently developing a PHP MVC Framework for a personal project. While I am developing the framework I am interested to see any notable performance by implementing different techniques for optimization. I have implemented a crude BenchMark class that logs mircotime. The problem is I have no frame of reference for execution times. I am very near the beginnig of this project with a database connection and a few queries but no output (bar some debugging text and BenchMark log). I have a current execution time of 0.01917 seconds. I was expecting this to be lower but as I said before I have no frame of reference. I appreciate there are many variables to take into account when juding performance but I am hoping to find some sort of metric to a) techniques to measure performance for example requests per second and b) compare results for example; how a "moderately" sized PHP application on a "standard" webserver will perform. I appreciate "moderately" and "standard" are very subjective words so perhaps a table of known execution times for a particular application (eg StackOverFlow's executing time). What are other techniques of measuring performance are there other than execution time? When looking at MVC Framework Performance Comparisom it talks about Requests Per Second (RPS). How is this calculated? I am guessing with my current execution time of 0.01917 seconds can handle 52 RPS (= 1 / 0.01917 ). This seems to be significantly lower than that quoted on the graph especially when you consider my current limited funcitonality.

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  • Quick help refactoring Ruby Class

    - by mplacona
    I've written this class that returns feed updates, but am thinking it can be further improved. It's not glitchy or anything, but as a new ruby developer, I reckon it's always good to improve :-) class FeedManager attr_accessor :feed_object, :update, :new_entries require 'feedtosis' def initialize(feed_url) @feed_object = Feedtosis::Client.new(feed_url) fetch end def fetch @feed_object.fetch end def update @updates = fetch end def updated? @updates.new_entries.count > 0 ? true : false end def new_entries @updates.new_entries end end As you can see, it's quite simple, but the things I'm seeing that aren't quite right are: Whenever I call fetch via terminal, it prints a list with the updates, when it's really supposed return an object. So as an example, in the terminal if I do something like: client = Feedtosis::Client.new('http://stackoverflow.com/feeds') result = client.fetch I then get: <Curl::Easy http://stackoverflow.com/feeds> Which is exactly what I'd expect. However, when doing the same thing with "inniting" class with: FeedManager.new("http://stackoverflow.com/feeds") I'm getting the object returning as an array with all the items on the feed. Sure I'm doing something wrong, so any help refactoring this class will he greatly appreciated. Also, I'd like to see comments about my implementation, as well as any sort of comment to make it better would be welcome. Thanks in advance

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  • Tailing 'Jobs' with Perl under mod_perl

    - by Matthew
    Hi everyone, I've got this project running under mod_perl shows some information on a host. On this page is a text box with a dropdown that allows users to ping/nslookup/traceroute the host. The output is shown in the text box like a tail -f. It works great under CGI. When the user requests a ping it would make an AJAX call to the server, where it essentially starts the ping with the output going to a temp file. Then subsequent ajax calls would 'tail' the file so that the output was updated until the ping finished. Once the job finished, the temp file would be removed. However, under mod_perl no matter what I do I can's stop it from creating zombie processes. I've tried everything, double forking, using IPC::Run etc. In the end, system calls are not encouraged under mod_perl. So my question is, maybe there's a better way to do this? Is there a CPAN module available for creating command line jobs and tailing output that will work under mod_perl? I'm just looking for some suggestions. I know I could probably create some sort of 'job' daemon that I signal with details and get updates from. It would run the commands and keep track of their status etc. But is there a simpler way? Thanks in advance.

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  • Where can I find a quick reference for standard Basic?

    - by Steve314
    The reason? Pure nostalgia. Anyway, there was a standard for Basic that was published in the late 80s or early 90s. It was probably ISO/IEC 10279:1991, but I don't have access to that and cannot be sure. Whatever this standard was, some of the syntax made its way into Borlands Turbo Basic and Microsofts Visual Basic. I never learned any significant amount of VB, but Turbo Basic is one of those things I played with in my mis-spent youth. At one time, my main reference was an article published in one of the main programming periodicals - maybe Personal Computer World, maybe Byte. A scan of that article (if anyone can even identify it) would be great, but all I really want is a few pages quick reference of that standard syntax. Must be free (I'm not that nostalgic), but it must describe the standard syntax - the whole point is to sort out what is standard as opposed to VB or whatever. EDIT The more I think about this, the more convinced I am that this standard was available around 1987 or 1988. Maybe it was the earlier non-full version of the standard above, or maybe it was pre-acceptance of the standard.

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  • Can memory be cleaned up?

    - by Tom
    I am working in Delphi 5 (with FastMM installed) on a Win32 project, and have recently been trying to drastically reduce the memory usage in this application. So far, I have cut the usage nearly in half, but noticed something when working on a separate task. When I minimized the application, the memory usage shrunk from 45 megs down to 1 meg, which I attributed to it paging out to disk. When I restored it and restarted working, the memory went up only to 15 megs. As I continued working, the memory usage slowly went up again, and a minimize and restore flushed it back down to 15 megs. So to my thinking, when my code tells the system to release the memory, it is still being held on to according to Windows, and the actual garbage collection doesn't kick in until a lot later. Can anyone confirm/deny this sort of behavior? Is it possible to get the memory cleaned up programatically? If I keep using the program without doing this manual flush, I get an out of memory error after a while, and would like to eliminate that. Thanks.

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  • Are there some cases where Python threads can safely manipulate shared state?

    - by erikg
    Some discussion in another question has encouraged me to to better understand cases where locking is required in multithreaded Python programs. Per this article on threading in Python, I have several solid, testable examples of pitfalls that can occur when multiple threads access shared state. The example race condition provided on this page involves races between threads reading and manipulating a shared variable stored in a dictionary. I think the case for a race here is very obvious, and fortunately is eminently testable. However, I have been unable to evoke a race condition with atomic operations such as list appends or variable increments. This test exhaustively attempts to demonstrate such a race: from threading import Thread, Lock import operator def contains_all_ints(l, n): l.sort() for i in xrange(0, n): if l[i] != i: return False return True def test(ntests): results = [] threads = [] def lockless_append(i): results.append(i) for i in xrange(0, ntests): threads.append(Thread(target=lockless_append, args=(i,))) threads[i].start() for i in xrange(0, ntests): threads[i].join() if len(results) != ntests or not contains_all_ints(results, ntests): return False else: return True for i in range(0,100): if test(100000): print "OK", i else: print "appending to a list without locks *is* unsafe" exit() I have run the test above without failure (100x 100k multithreaded appends). Can anyone get it to fail? Is there another class of object which can be made to misbehave via atomic, incremental, modification by threads? Do these implicitly 'atomic' semantics apply to other operations in Python? Is this directly related to the GIL?

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  • Neural Network settings for fast training

    - by danpalmer
    I am creating a tool for predicting the time and cost of software projects based on past data. The tool uses a neural network to do this and so far, the results are promising, but I think I can do a lot more optimisation just by changing the properties of the network. There don't seem to be any rules or even many best-practices when it comes to these settings so if anyone with experience could help me I would greatly appreciate it. The input data is made up of a series of integers that could go up as high as the user wants to go, but most will be under 100,000 I would have thought. Some will be as low as 1. They are details like number of people on a project and the cost of a project, as well as details about database entities and use cases. There are 10 inputs in total and 2 outputs (the time and cost). I am using Resilient Propagation to train the network. Currently it has: 10 input nodes, 1 hidden layer with 5 nodes and 2 output nodes. I am training to get under a 5% error rate. The algorithm must run on a webserver so I have put in a measure to stop training when it looks like it isn't going anywhere. This is set to 10,000 training iterations. Currently, when I try to train it with some data that is a bit varied, but well within the limits of what we expect users to put into it, it takes a long time to train, hitting the 10,000 iteration limit over and over again. This is the first time I have used a neural network and I don't really know what to expect. If you could give me some hints on what sort of settings I should be using for the network and for the iteration limit I would greatly appreciate it. Thank you!

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  • SeriesInterpolate - removing data at start of array

    - by Allan Jardine
    Hello all, I've been experimenting with Flex Charts (in Flash Builder 4) recently, but have run into one area which didn't quite work as I was expecting. Specifically, when adding and removing a data point from an array, with SeriesInterpolate set. I've put up three examples, as I expect these will make a lot more sense than me trying to explain it with words only!: http://sprymedia.co.uk/media/misc/flex/linechart/LineChart-Add.swf - Clicking the button in the top right adds a new data point to the end of the data array, and the chart is smoothly updated (almost smoothly there is a 1px shift when animating which is odd...) http://sprymedia.co.uk/media/misc/flex/linechart/LineChart-Delete.swf - Clicking the button (which is now labelled incorrectly) will remove the item at the start of the data array - but the chart draws this as if it were removing the end element. http://sprymedia.co.uk/media/misc/flex/linechart/LineChart-AddDelete.swf - This is sort of what I'm eventually aiming for - a smooth side scroll chart, where new data is added at the end and the old data is sifted off the front. However the delete behaviour makes this look a bit odd. Does anyone know if there is a way to get the smooth transition I'm looking with SeriesInterpolate? Or is it possible to implement a custom transition? Many thanks, Allan

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