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  • What is the fastest method to calculate substring

    - by Misha Moroshko
    I have a huge "binary" string, like: 1110 0010 1000 1111 0000 1100 1010 0111.... It's length is 0 modulo 4, and may reach 500,000. I have also a corresponding array: {14, 2, 8, 15, 0, 12, 10, 7, ...} (every number in the array corresponds to 4 bits in the string) Given this string, this array, and a number N, I need to calculate the following substring string.substr(4*N, 4), i.e.: for N=0 the result should be 1110 for N=1 the result should be 0010 I need to perform this task many many times, and my question is what would be the fastest method to calculate this substring ? One method is to calculate the substring straight forward: string.substr(4*N, 4). I'm afraid this one is not efficient for such huge strings. Another method is to use array[N].toString(2) and then wrap the result with zeros if needed. I'm not sure how fast is this. May be you have any other ideas ?

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  • Using nsIZipWriter or other to compress a string as a string?

    - by Daniel
    I need to be able to take a javascript string, compress it using any fast and available means and get back a binary string/blob. Background: The extension I'm developing needs to send various large content to my server. It does this conveniently by dynamically creating a form, adding fields to the form and posting it. Some of these fields are just too big bandwidth wise for multiple use. I'd like to be able to compress them before adding them and then maybe base64'ing them if the characters cause a problem in the message. Any ideas? I could use nsiZipWriter with temporary files on disk but that is quite ugly and probably sluggish.

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  • Python: need to get energies of charge pairs.

    - by Two786
    I am new to python. I have to make a program for a project that takes a PDB format file as input and returns a list of all the intra-chain and inter-chain charge pairs and their energies (using coulomb’s law assuming a dielectric constant of (?) of 40.0). For simplicity, the charged residues for this program are just Arg (CZ), Lys (NZ), Asp (CG) and Glu (CD) with the charge bearing atoms for each indicated in parentheses. The program should report any attractive or repulsive interactions within 8.0 Å. Here is some additional information needed for the program. Eij = energy of interaction between atoms i and j in kilocalories/mole (kcals/mol) qi = charge for atom i (+1 for Lys or Arg, -1 for Glu or Asp) rij = distance between atoms i and j in angstroms using the distance formula The output should adhere to the following format: First residue : Second residue Distance Energy Lys 10 Chain A: ASP 46 Chain A D= 4.76 ang E= -2.32 kcals/mol (For some reason I can't organize the top two rows, but the first row should be lables and below it the corresponding values.) I really have no idea how to tackle this problem, any and all help is greatly appreciated. I hope this is the right place to ask. Thank you in advance. Using python 2.5

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  • VB.Net HTTPWebRequest Speed is slow comparing Python URLOpen

    - by regexhacks
    Hi I am coding a web-crawler which will crawl the websites and selectively parse different sections of a web site. I am a .Net developer so the choice was obvious that I did it in .Net but the speed was very slow which included downloading and parsing of HTMLPages Then I tried to just download the contents first using .Net and then same domains using python but the python was very impressive in downloading data. I have achieved downloading using python but the later part is not that easy to code in python, which obviously i don't want to do. The same batch of domain which took 100 seconds in Python was taking 20 minutes in .Net based crawler I tried http://www.eqlit.com/ to download and in took 8 seconds in Python and same was taking 100 Seconds in .Net crawler Does anyone anyone have any idea why this is slow in .Net but fast in python?

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  • Memory leak in chrome.extension.sendRequest()

    - by jprim
    Chrome Version : 9.0.597.19 (Build 68937) beta & current stable I have simplified my code as far as possible. I ended up with the attached extension: content.js (content script run on every site): setInterval(function() { chrome.extension.sendRequest({ }, function(response) { //Do nothing }); }, 1); background.js (background page script): chrome.extension.onRequest.addListener(function(request, sender, sendResponse) { sendResponse({ }); }); When you install this extension, you can observe it eating up memory extremely fast (I got 90MB in 1 min with 9 tabs opened). You can speed up the process by opening more tabs. Of course, the extension I am actually developing does not send requests every millisecond, but only every 3 seconds. This just slows it down, though. A user who has run it in the background for a long time with many tabs opened has reported 100MB of memory usage, and I can reproduce it to a less extreme extent, too.

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  • JQuery: How to perform a "push" slide, not a slide up?

    - by Tedy
    I using the following JQuery: $("#pushSlideDiv").slideDown("fast"); However, this creates a "slide" effect. Meaning, if I do a slidedown, this makes the underlining DIV reveal it's self from a top-to-bottom reveal. I want a "push" effect, where the slidedown instead reveals as though the div is being pushed onto the page ... where you first see the bottom of the div. How can I do this with JQuery? UPDATE: This isn't a great example, but it does show a push effect that I'm trying to accomplish vs a "slide" effect.

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  • building an ASP NET MVC site, should i go with linq to sql?

    - by aspm
    so i'm about to start a new website from scratch and i've spent about a week trying to figure out what technology to go with. i'm sold on ASP NET MVC. i'm 100% sure i'm going to love using that. but what i am not so sure about yet is using LINQ 2 SQL. so far i've gathered some data... 1) stack overflow uses it - can't be that bad 2) can be REALLY slow if you don't take advantage of compiled queries 3) will always be slower than ADO net, but can be almost just as fast if using #2 in the proper places 4) is NOT the preferred MS solution (there was a thread here on SO about dropping support) i'm itching to use it, but just want to make sure it's the best for me. i come from a heavy ADO/stored procedure and traditional asp net background (this will be my first experience with ASP MVC).

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  • How do I find the millionth number in the series: 2 3 4 6 9 13 19 28 42 63 ... ?

    - by HH
    It takes about minute to achieve 3000 in my comp but I need to know the millionth number in the series. The definition is recursive so I cannot see any shortcuts except to calculate everything before the millionth number. How can you fast calculate millionth number in the series? Series Def n_{i+1} = \floor{ 3/2 * n_{i} } and n_{0}=2. Interestingly, only one site list the series according to Google: this one. Too slow Bash code #!/bin/bash function series { n=$( echo "3/2*$n" | bc -l | tr '\n' ' ' | sed -e 's@\\@@g' -e 's@ @@g' ); # bc gives \ at very large numbers, sed-tr for it n=$( echo $n/1 | bc ) #DUMMY FLOOR func } n=2 nth=1 while [ true ]; #$nth -lt 500 ]; do series $n # n gets new value in the function through global value echo $nth $n nth=$( echo $nth + 1 | bc ) #n++ done

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  • Does FastCGI support PHP 5.3.2 centOS?

    - by bn
    I just upgrade the PHP version in my VPS to 5.3.2 I used FastCGI and worker MPM in php 5.1.2 or 5.2.1 I forgot, it worked fine, and it was so fast, I like it. After I upgrade the PHP version, it gives me Internal Server Error 500 on all .php pages. What is wrong? does FCGI support php 5.3.2? If yes, there should be some differences in setting it up? what should I change to get it back working? Thank You

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  • Alternatives to FastDateFormat for efficient date parsing?

    - by Tom Tucker
    Well aware of performance and thread issues with SimpleDateFormat, I decided to go with FastDateFormat, until I realized that FastDateFormat is for formatting only, no parsing! Is there an alternative to FastDateFormat, that is ready to use out of the box and much faster than SimpleDateFormat? I believe FastDateFormat is one of the faster ones, so anything that is about as fast would do. Just curious , any idea why FastDateFormat does not support parsing? Doesn't it seriously limit its use? Thanks! EDIT Holy crap, I just left a comment and that literally REMOVED a good answer! This appears a serious bug on stackoverflow!

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  • Can I replicate some of the optimisations done by the JVM by hand?

    - by Subb
    I'm working on a Sudoku solver at school and we're having a little performance contest. Right now, my algorithm is pretty fast on the first run (about 2.5ms), but even faster when I solve the same puzzle 10 000 times (about 0.5ms for each run). Those timing are, of course, depend of the puzzle being solved. I know the JVM do some optimization when a method is called multiple time, and this is what I suspect is happening. I don't think I can further optimize the algorithm itself (though I'll keep looking), so I was wondering if I could replicate some of the optimizations done by the JVM. Note : compiling to native code is not an option Thanks!

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  • Create a string with n characters.

    - by C. Ross
    Is there a way in java to create a string with a specified number of a specified character? In my case I would need to create a string with 10 spaces. My current code is: StringBuffer outputBuffer = new StringBuffer(length); for (int i = 0; i < length; i++){ outputBuffer.append(" "); } return outputBuffer.toString(); Is there a better way to accomplish the same thing. In particular I'd like something that is fast (in terms of execution).

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  • How painful is a django project deployment to a live (staging) site?

    - by Ignacio
    Hi, I've getting quite fast with a small django project of mine, which I'm developing locally, of course. But, as I had never worked with django before, I'm not aware of what it implies to upload it and test it on a production server. And I'm quite curious, since I'm very eager to test an early release live. I know there is this document, which I think it'll be really helpful: http://djangobook.com/en/2.0/chapter12/ But, are there any details I should take into account before, during and after the deployment? Any advice or best practices? Thanks.

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  • How come JFrame window size in Java does not produce the size of window specified?

    - by typoknig
    Hi all, I am just messing around trying to make a game right now, but I have had this problem before too. When I specify a specific window size (1024 x 768 for instance) the window produced is just a little larger than what I specified. Very annoying. Is there a reason for this? How do I correct it so the window created is actually the size I want instead of being just a little bit bigger? Up till now I have always just gone back and manually adjusted the size a few pixels at a time until I got the result I wanted, but that is getting old. If there was even a formula I could use that would tell me how many pixels I needed to add/subtract from my my variable that would be excellent! P.S. I don't know if my OS could be a factor in this, but I am using W7X64. private int windowWidth = 1024; private int windowHeight = 768; public SomeWindow() { this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); this.setSize(windowWidth, windowHeight); this.setResizable(false); this.setLocation(0,0); this.setVisible(true); }

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  • The D Programming Language for Game Development

    - by n2liquid
    Hi all, Recently I've been bothered because I reached a point in which C++ (even 0x) felt very limited, so I started looking for alternatives. Forget Java, C#, Python or Ruby. I still like the low-level nature of C++ and I'm not fond of virtual machines. Further, I'm a game engine developer, so I have to develop core routines which must be really fast, and lately I've been hungry for code expressiveness. C++ is an almost-there language for me, but there are many exceptions on how to use templates, and GCC isn't optimizing stuff as well as I'd hoped it would. So I'm considering to start learning D. Do you think it will suffice my needs as a game developer? I'm weary because I've never heard of D being used for that. Thanks!

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  • How do you deal with the more mundane parts of programming tasks?

    - by Uri
    My experience as a developer is that many projects or tickets are a mix of a short and focused very interesting task (e.g., designing some API or a platform to solve something) and a lot of repetitive and mundane tasks that cannot be automated (such as certain refactorings to use the API or platform, implementation of certain tests, some GUI handling, etc). I believe that this is the nature of our profession, unless we are high-level architects or managements and can delegate this work. The only item in my personal arsenal when dealing with these tasks is to devote some of my attention to radio or audiobooks (preferably not in English as I find it hard to concentrate on two "streams" of English at the same time). I maintain sufficient attention to carry the task and don't lose concentration as fast. I'm wondering how others cope with these and maintain concentration.

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  • Best .NET Solution for Frequently Changed Database

    - by sestocker
    I am currently architecting a small CRUD applicaton. Their database is a huge mess and will be changing frequently over the course of the next 6 months to a year. What would you recommend for my data layer: 1) ORM (if so, which one?) 2) Linq2Sql 3) Stored Procedures 4) Parametrized Queries I really need a solution that will be dynamic enough (both fast and easy) where I can replace tables and add/delete columns frequently. Note: I do not have much experience with ORM (only a little SubSonic) and generally tend to use stored procedures so maybe that would be the way to go. I would love to learn Ling2Sql or NHibernate if either would allow for the situation I've described above.

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  • Swing invokeLater never shows up, invokeAndWait throws error. What can I do?

    - by Geo
    I have this code: try { SwingUtilities.invokeAndWait(new Runnable() { public void run() { try { dialog.handleDownload(); } catch (IOException io) { io.printStackTrace(); } } }); } catch(Exception io) { io.printStackTrace(); } in the handleDownload I'm reading an inputstream, calculating a progress bar's value, and setting it to that. So, when I click a button, a new JFrame opens up and does all the stuff I wrote above. If I have the dialog.handleDownload by itself ( in no SwingUtilities method ), it freezes until the operation is finished. If I add it in a invokeLater it's closed very fast ( I can't see anything, and the operation is not finished ). If I add it in a invokeAndWait I get the invokeAndWait cannot be called from the event dispatcher thread error. What should I do?

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  • How can I determine the "correct" number of steps in a questionnaire where branching is used?

    - by Mike Kingscott
    I have a potential maths / formula / algorithm question which I would like help on. I've written a questionnaire application in ASP.Net that takes people through a series of pages. I've introduced conditional processing, or branching, so that some pages can be skipped dependent on an answer, e.g. if you're over a certain age, you will skip the page that has Teen Music Choice and go straight to the Golden Oldies page. I wish to display how far along the questionnaire someone is (as a percentage). Let's say I have 10 pages to go through and my first answer takes me straight to page 9. Technically, I'm now 90% of the way through the questionnaire, but the user can think of themselves as being on page 2 of 3: the start page (with the branching question), page 9, then the end page (page 10). How can I show that I'm on 66% and not 90% when I'm on page 9 of 10? For further information, each Page can have a number of questions on that can have one or more conditions on them that will send the user to another page. By default, the next page will be the next one in the collection, but that can be over-ridden (e.g. entire sets of pages can be skipped). Any thoughts? :-s

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  • How to get new logs in an EventLogEntyCollection?

    - by Massimo
    I need to monitor security event logs on very busy domain controllers, which generates hundreds of them each minute. I know how to use EventLog, EventLogEntry and EvenLogEntryCollection to open and read a server's event log, but an EvenLogEntryCollection can contain ~300.000 events, and it wraps around continuously (and very fast), so I can't rely on its index to find new entries. So far, the only thing I was able to come up with is saving the timestamp of the last processed log entry and then iterate above the EventLogEntryCollection until I find an EventLogEntry which TimeGenerated properties is greater than the timestamp I saved; but it's terribly slow to iterate on ~300.000 entries to find the new ones. How can I quickly find the new entries in an big event log?

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  • What are the exact versions of stuff you had to install in order to be able to step-debug a Scala pr

    - by Alex R
    How do YOU debug a Scala program? I mean YOU as in the person posting the Answer :) Please answer only from personal experience, not from stuff you've heard or read on the Internet. You should not believe everything you read on the Internet, especially tales of complex open-source software configurations that actually work :-) The are many Java tools which claim to support Scala in some way or another, but I have so far struck out in trying to get any one of them to actually let me set a breakpoint in Scala code and step through it. These are big, major open-source IDEs I'm talking about here. The main problem in getting a debugger to work seems to be the "version hell" with fast-changing IDEs, Plug-Ins, JDKs, and the Scala language itself. Hence the second part of my question, which is really the most important part: What is the exact version number of the IDE, Plug-In, JDK, Scala, and even Operating System, that you are successfully using? My question is related to this one, but wider in scope: http://stackoverflow.com/questions/2272705/how-to-debug-scala-code-when-outside-of-an-ide Thanks

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  • Running [R] on a Netbook

    - by Thomas
    I am interested in purchasing a netbook to do field research in another country. My hardware specifications for the nebtook are fairly basic: Be rugged enough to survive a bit of wear and tear Fairly fast processing (the ability to upgrade from 1GB of RAM to 2GB) A battery life of longer than 6 hours At least a 10 inch screen A decent camera for Skyping However, I am mainly concerned about being able to do basic statistical analysis in conjunction with R Be able run a Spreadsheet program to do basic data input (like Excel or Open Office) Use R to do basic data analysis (Regression, some simulation (nothing crazy), data cleaning, and some of the functionality) Word Processing (Word or Open Office) Do you have any suggestions on which models or brands my fit my needs? Some of the models I am considering: Samsung NB-30 Toshiba NB 305 Asus Eee PC 1005HA Lenovo S10-2 Does anyone use R on a netbook, and if so do you have any recommendations on how best to optimize it? This article from Lifehacker mentions some OS. Anybody use these in conjunction with R? Any help would be much appreciated.

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  • What is the absolute fastest way to implement a concurrent queue with ONLY one consumer and one producer?

    - by JohnPristine
    java.util.concurrent.ConcurrentLinkedQueue comes to mind, but is it really optimum for this two-thread scenario? I am looking for the minimum latency possible on both sides (producer and consumer). If the queue is empty you can immediately return null AND if the queue is full you can immediately discard the entry you are offering. Does ConcurrentLinkedQueue use super fast and light locks (AtomicBoolean) ? Has anyone benchmarked ConcurrentLinkedQueue or knows about the ultimate fastest way of doing that? Additional Details: I imagine the queue should be a fair one, meaning the consumer should not make the consumer wait any longer than it needs (by front-running it) and vice-versa.

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  • How to determine the best "framerate" (setInterval delay) to use in a JavaScript animation loop?

    - by Ricket
    When writing a JavaScript animation, you of course make a loop using setInterval (or repeated setTimeout). But what is the best delay to use in the setInterval/setTimeout call(s)? In the jQuery API page for the .animate() function, the user "fbogner" says: Just if anyone is interested: Animations are "rendered" using a setInterval with a time out of 13ms. This is quite fast! Chrome's fastest possible interval is about 10ms. All other browsers "sample" at about 20-30ms. Any idea how jQuery determined to use this specific number?

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  • model.matrix() with na.action=NULL?

    - by Vincent
    I have a formula and a data frame, and I want to extract the model.matrix(). However, I need the resulting matrix to include the NAs that were found in the original dataset. If I were to use model.frame() to do this, I would simply pass it na.action=NULL. However, the output I need is of the model.matrix() format. Specifically, I need only the right-hand side variables, I need the output to be a matrix (not a data frame), and I need factors to be converted to a series of dummy variables. I'm sure I could hack something together using loops or something, but I was wondering if anyone could suggest a cleaner and more efficient workaround. Thanks a lot for your time! And here's an example: dat <- data.frame(matrix(rnorm(20),5,4), gl(5,2)) dat[3,5] <- NA names(dat) <- c(letters[1:4], 'fact') ff <- a ~ b + fact # This omits the row with a missing observation on the factor model.matrix(ff, dat) # This keeps the NA, but it gives me a data frame and does not dichotomize the factor model.frame(ff, dat, na.action=NULL) Here is what I would like to obtain: (Intercept) b fact2 fact3 fact4 fact5 1 1 0.7266086 0 0 0 0 2 1 -0.6088697 0 0 0 0 3 NA 0.4643360 NA NA NA NA 4 1 -1.1666248 1 0 0 0 5 1 -0.7577394 0 1 0 0 6 1 0.7266086 0 1 0 0 7 1 -0.6088697 0 0 1 0 8 1 0.4643360 0 0 1 0 9 1 -1.1666248 0 0 0 1 10 1 -0.7577394 0 0 0 1

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