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Search found 6324 results on 253 pages for 'nathan fast'.

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  • How to make scrolling through images as fast as Apple's Photos app

    - by clozach
    The Goal — On an iPhone, to browse through several hundred locally-stored jpgs using a UIScrollView. The Problem — Like many others before me, I've tried implementing a scroll view based on Apple's Page Control sample code and found it lacking. The biggest issue I'm currently up against is that the sample code's architecture doesn't seem to scale. With just a few images loaded from disk, everything's fine. Once the number of images gets into the dozens, though, scrolling suffers terribly: the scrollview stutters mid-scroll with each new swipe. The only code I've toyed with that comes even close to being reasonably responsive is Three20, but even there the performance doesn't hold a candle to Photos. For now, I'm just using Three20, but a faster, custom solution would definitely be preferable.

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  • Insert MANY key value pairs fast into berkeley db with hash access

    - by Kungi
    Hi, i'm trying to build a hash with berkeley db, which shall contain many tuples (approx 18GB of key value pairs), but in all my tests the performance of the insert operations degrades drastically over time. I've written this script to test the performance: #include<iostream> #include<db_cxx.h> #include<ctime> #define MILLION 1000000 int main () { long long a = 0; long long b = 0; int passes = 0; int i = 0; u_int32_t flags = DB_CREATE; Db* dbp = new Db(NULL,0); dbp->set_cachesize( 0, 1024 * 1024 * 1024, 1 ); int ret = dbp->open( NULL, "test.db", NULL, DB_HASH, flags, 0); time_t time1 = time(NULL); while ( passes < 100 ) { while( i < MILLION ) { Dbt key( &a, sizeof(long long) ); Dbt data( &b, sizeof(long long) ); dbp->put( NULL, &key, &data, 0); a++; b++; i++; } DbEnv* dbep = dbp->get_env(); int tmp; dbep->memp_trickle( 50, &tmp ); i=0; passes++; std::cout << "Inserted one million --> pass: " << passes << " took: " << time(NULL) - time1 << "sec" << std::endl; time1 = time(NULL); } } Perhaps you can tell me why after some time the "put" operation takes increasingly longer and maybe how to fix this. Thanks for your help, Andreas

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  • Fast CGI, Lighttpd, Ubuntu

    - by Gosh
    Is this log file familiar to someone of UBUNTU users? Lighttpd log file: > 2009-08-30 21:37:45: (log.c.75) server started > 2009-08-30 21:37:45: (mod_fastcgi.c.1029) the fastcgi-backend php5-cgi *failed* to start: > 2009-08-30 21:37:45: (mod_fastcgi.c.1033) *child exited with status 9 php5-cgi* > 2009-08-30 21:37:45: (mod_fastcgi.c.1036) If you're trying to run PHP as a FastCGI backend, make sure you're using the FastCGI-enabled version. > You can find out if it is the right one by executing 'php -v' and it should display '(cgi-fcgi)' in the output, NOT '(cgi)' NOR '(cli)'. > For more information, check http://trac.lighttpd.net/trac/wiki/Docs%3AModFastCGI#preparing-php-as-a-fastcgi-programIf this is PHP on Gentoo, add 'fastcgi' to the USE flags. > 2009-08-30 21:37:45: (mod_fastcgi.c.1340) [ERROR]: *spawning fcgi failed*. > 2009-08-30 21:37:45: (server.c.908) Configuration of plugins failed. Going down. Please open a secret how did you solved fcgi problem and made lighttpd to start, if you did. Thx, Gosh.

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  • Fast 4x4 matrix multiplication in Java with NIO float buffers

    - by kayahr
    I know there are LOT of questions like that but I can't find one specific to my situation. I have 4x4 matrices implemented as NIO float buffers (These matrices are used for OpenGL). Now I want to implement a multiply method which multiplies Matrix A with Matrix B and stores the result in Matrix C. So the code may look like this: class Matrix4f { private FloatBuffer buffer = FloatBuffer.allocate(16); public Matrix4f multiply(Matrix4f matrix2, Matrix4f result) { {{{result = this * matrix2}}} <-- I need this code return result; } } What is the fastest possible code to do this multiplication? Some OpenGL implementations (Like the OpenGL ES stuff in Android) provide native code for this but others doesn't. So I want to provide a generic multiplication method for these implementations.

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  • Simple File-based Record Storage with Fast Text Searching for Compact Framework and Silverlight

    - by Eric Farr
    I have a single table with lots of records ( 100k) that I need to be able to index and search on several text fields. The easiest searches will have the first part of the string specified (eg, LIKE 'ABC%' in SQL). The tougher searches will need to search for any substring within the text fields (eg, LIKE '%ABC%' in SQL). I need to run on the Compact Framework. SQL Compact is a memory hog and overkill for my one table. Besides, I'd like to be able to run on Silverlight 4 eventually. The file and indexes can be generated on the full .NET Framework and I only need read capability on the Compact Framework. My records are not especially large and can be expressed in fix length format. I'm looking for some existing code or libraries to avoid having to write a file-based BTree implementation from scratch.

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  • Fast way to set text format for a range of Text using TLF

    - by wezzy
    Hi, i have to set the text format for some tokens in a plain text. I'm trying to use the Text Layout Framework to improve the speed of the operation but i've founded that TLF is far slower (10X in my tests) than the old setTextFormat(). For each token i call this function: public function setTextFormat(format:TextLayoutFormat, begin:int, end:int):void{ var selection:SelectionState = new SelectionState(this._textFlow, begin, end, this._normalFormat); IEditManager(_textFlow.interactionManager).applyLeafFormat(format, selection); } is there any faster and clever way to do this operation ? Thanks

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  • Fast find near users using PostGIS

    - by opedge
    I have 5 tables: - users - information about user with current location_id (fk to geo_location_data) - geo_location_data - information about location, with PostGIS geography(POINT, 4326) column - user_friends - relationships between users. I want to find near friends for current user, but it takes a lot of time of executing select query to know if user is a friend and after that execute select using ST_DWithin.. May be something wrong in domain model or in queries?

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  • ASP.NET - fast Segmented downoad of file through webservice

    - by H4mm3rHead
    Hi, Im doing this project where i need to download files through a webservice (images, videos). The download MUST go through an existing webservice. The existing webservice was made when there were no need to upload and download files but the project has changed and now we need to do It through a webservice. Right now I have implemented the download as a method that returns a byte[], I open a streamreader and resds the entire file into a byte[] and returns it to my method. This is working file on small files <~1Mb, above it takes too long time. I want to show some progress (e.g. when the user downlaods a 20Mb video) which i cannot do right now. And i want to make it download much faster (is a strategy to use multithreading and several threads that downloads a part of the file?). It is within a WPF application i need to do this. Any ideas on how to approach this?

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  • Looking for fast, minimal, preferrably free disc cloning software [closed]

    - by Dave
    We have to test our application installation and functionality on many Windows operating system versions and languages (XP, Vista, Win7; English, Spanish, Portuguese, etc; 32-bit & b4-bit.) While we can do much of this in virtual machines, we have noticed that VM's sometimes hide problems, or raise false bugs. So, we need to do "bare metal" OS installation for much of our testing. I have been using Acronis True Image for the past year, and am not impressed. It often gives random errors which require a reboot, and is really slow. For example, when trying to restore an image, it goes through a "Locking partition" cycle about three times (once after you click OK on each step of the wizard), each of which can take 5 minutes to complete. This all happens BEFORE it actually starts the image copy, which is sometimes quick (3-5 minutes), sometimes long (hours). The size of all of our images are roughly the same, so that is not related. So, anyway, I'm looking to switch to something else: I only need very basic functionality--just creating images of entire discs, and then restoring those images onto the exact same hard drive at a later date. That's it. I'm not opposed to paying for a good piece of software, but if there is something free out there that does the job well, that would be a preference. My OS on which the imaging software would run is Windows Vista, but a bootable media (into a Linux flavor) would be fine also, as long as its quick to use and reliable. Recommendations? (Also, moderators, if this should be a CW, I'll be happy to mark it as such; unclear about the rules there.)

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  • Efficient data structure for fast random access, search, insertion and deletion

    - by Leonel
    I'm looking for a data structure (or structures) that would allow me keep me an ordered list of integers, no duplicates, with indexes and values in the same range. I need four main operations to be efficient, in rough order of importance: taking the value from a given index finding the index of a given value inserting a value at a given index deleting a value at a given index Using an array I have 1 at O(1), but 2 is O(N) and insertion and deletions are expensive (O(N) as well, I believe). A Linked List has O(1) insertion and deletion (once you have the node), but 1 and 2 are O(N) thus negating the gains. I tried keeping two arrays a[index]=value and b[value]=index, which turn 1 and 2 into O(1) but turn 3 and 4 into even more costly operations. Is there a data structure better suited for this?

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  • Hashtable is that fast

    - by Costa
    Hi s[0]*31^(n-1) + s[1]*31^(n-2) + ... + s[n-1]. Is the hash function of the java string, I assume the rest of languages is similar or close to this implementation. If we have hash-Table and a list of 50 elements. each element is 7 chars ABCDEF1, ABCDEF2, ABCDEF3..... ABCDEFn If each bucket of hashtable contains 5 strings (I think this function will make it one string per bucket, but let us assume it is 5). If we call col.Contains("ABCDEFn"); // will do 6 comparisons and discover the difference on the 7th. The hash-table will take around 70 operations (multiplication and additions) to get the hashcode and to compare with 5 strings in bucket. and BANG it found. For list it will take around 300 comparisons to find it. for the case that there is only 10 elements, the list will take around 70 operations but the Hashtable will take around 50 operations. and note that hashtable operations are more time consuming (it is multiplications). I conclude that HybirdDictionary in .Net probably is the best choice for that most cases that require Hashtable with unknown size, because it will let me use a list till the list becomes more than 10 elements. still need something like HashSet rather than a Dictionary of keys and values, I wonder why there is no HybirdSet!! So what do u think? Thanks

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  • Fast serarch of 2 dimensional array

    - by Tim
    I need a method of quickly searching a large 2 dimensional array. I extract the array from Excel, so 1 dimension represents the rows and the second the columns. I wish to obtain a list of the rows where the columns match certain criteria. I need to know the row number (or index of the array). For example, if I extract a range from excel. I may need to find all rows where column A =”dog” and column B = 7 and column J “a”. I only know which columns and which value to find at run time, so I can’t hard code the column index. I could use a simple loop, but is this efficient ? I need to run it several thousand times, searching for different criteria each time. For r As Integer = 0 To UBound(myArray, 0) - 1 match = True For c = 0 To UBound(myArray, 1) - 1 If not doesValueMeetCriteria(myarray(r,c) then match = False Exit For End If Next If match Then addRowToMatchedRows(r) Next The doesValueMeetCriteria function is a simple function that checks the value of the array element against the query requirement. e.g. Column A = dog etc. Is it more effiecent to create a datatable from the array and use the .select method ? Can I use Linq in some way ? Perhaps some form of dictionary or hashtable ? Or is the simple loop the most effiecent ? Your suggestions are most welcome.

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  • Delphi fast large bitmap creation (without clearing)

    - by Ritsaert Hornstra
    When using the TBitmap wrapper for a GDI bitmap from the unit Graphics I noticed it will always clear out the bitmap (using a PatBlt call) when setting up a bitmap with SetSize( w, h ). When I copy in the bits later on (see routine below) it seems ScanLine is the fastest possibility and not SetDIBits. function ToBitmap: TBitmap; var i, N, x: Integer; S, D: PAnsiChar; begin Result := TBitmap.Create(); Result.PixelFormat := pf32bit; Result.SetSize( width, height ); S := Src; D := Result.ScanLine[ 0 ]; x := Integer( Result.ScanLine[ 1 ] ) - Integer( D ); N := width * sizeof( longword ); for i := 0 to height - 1 do begin Move( S^, D^, N ); Inc( S, N ); Inc( D, x ); end; end; The bitmaps I need to work with are quite large (150MB of RGB memory). With these iomages it takes 150ms to simply create an empty bitmap and a further 140ms to overwrite it's contents. Is there a way of initializing a TBitmap with the correct size WITHOUT initializing the pixels itself and leaving the memory of the pixels uninitialized (eg dirty)? Or is there another way to do such a thing. I know we could work on the pixels in place but this still leaves the 150ms of unnessesary initializtion of the pixels.

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  • Fast parsing of PHP in C#

    - by Jessica Shea
    Hello there, I've got a requirement for parsing PHP files in C#. We essentially require some of the devs in another country to upload PHP files and once uploaded we need to check the php files and get a list of all the methods and classes/functions etc. I thought of using a regex but I can't workout if a function belongs to a class etc, so I was wondering if theres already something 'out there' that will parse out PHP files and spit out its functions (I'm trying to avoid writing a full blow AST implementation). Does anyone have any idea? I looked at Coco/R but I couldn't find a PHP grammar file. I'm using .NET 2.0 and C#.

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  • Programming language for fast calculations with big integers

    - by sub
    I'm doing Project Euler problems at the moment and I can solve most of them using my own programming language which uses direct C++ integers (so they are bound to 2^32 on my machine). However, at times there are problems which require me to work with very high numbers, I can't do that with native integers. So I implemented a BigInt library in my language which unfortunately gets extremely slow at times. Is there a programming language suitable for very efficient handling of big numbers? I mean that I want to do the things I could do in other programming languages with it (variables, loops, etc.), but in a faster way. If you have got tips for workarounds of the 2^32 limit in my language/C++/other languages, please tell me too!

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  • Optimizing Mysql to avoid redundancy but still have fast access to calculable data

    - by diglettpotato
    An example for the sake of the question: I have a database which contains users, questions, and answers. Each user has a score which can be calculated using the data from the questions and answers tables. Therefore if I had a score field in the users table, it would be redundant. However, if I don't use a score field, then calculating the score every time would significantly slow down the website. My current solution is to put it in a score field, and then have a cron running every few hours which recalculates everybody's score, and updates the field. Is there a better way to handle this?

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  • How fast should an interpreted language be today?

    - by Tarbal
    Is speed of the (main/only viable) implementation of an interpreted programming language a criteria today? What would be the optimal balance between speed and abstraction? Should scripting languages completely ignore all thoughts about performance and just follow the concepts of rapid development, readability, etc.? I'm asking this because I'm currently designing some experimental languages and interpreters

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  • Fast read of certain bytes of multiple files in C/C++

    - by Alejandro Cámara
    I've been searching in the web about this question and although there are many similar questions about read/write in C/C++, I haven't found about this specific task. I want to be able to read from multiple files (256x256 files) only sizeof(double) bytes located in a certain position of each file. Right now my solution is, for each file: Open the file (read, binary mode): fstream fTest("current_file", ios_base::out | ios_base::binary); Seek the position I want to read: fTest.seekg(position*sizeof(test_value), ios_base::beg); Read the bytes: fTest.read((char *) &(output[i][j]), sizeof(test_value)); And close the file: fTest.close(); This takes about 350 ms to run inside a for{ for {} } structure with 256x256 iterations (one for each file). Q: Do you think there is a better way to implement this operation? How would you do it?

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  • Fast exchange of data between unmanaged code and managed code

    - by vizcaynot
    Hello: Without using p/invoke, from a C++/CLI I have succeeded in integrating various methods of a DLL library from a third party built in C. One of these methods retrieves information from a database and stores it in different structures. The C++/CLI program I wrote reads those structures and stores them in a List<, which is then returned to the corresponding reading and use of an application programmed completely in C#. I understand that the double handling of data (first, filling in several structures and then, filling all of these structures into a list<) may generate an unnecessary overload, at which point I wish C++/CLI had the keyword "yield". Depending on the above scenario, do you have recommendations to avoid or reduce this overload? Thanks.

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  • App is fast on 3GS but slow on 3G

    - by Anthony Chan
    Hi all, I'm new to computer coding and have just finished coding an app and tested it on both 3G and 3GS. On 3GS, it worked as normal as on the simulator. However, when I tried to run it on 3G, the app becomes extremely slow. I'm not sure what's the reason and I hope someone could shed some light on me. Generally, my app has a couple of view controller classes, with one of them being the title page, one being the main page, one is setting, etc. I used a dissolve to transition from the title page to the main page. But even this simple transition shows un-smooth performance on a 3G! My other part of the app involves zooming in to some images by scaling up the images, switching images by push or dissolve upon receiving touch events, saving photos into photo library and storing and retrieving some photos in a folder and some data in a SQlite database, each showing un-smooth actions. Compared with some heavy graphic or heavy maths app, I think mine is pretty simple. I totally have no clue why the app would behave so slow and un-smooth that it is barely useful on a 3G. Any help/ direction would be much appreciated. Thanks for helping out.

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