Search Results

Search found 6805 results on 273 pages for 'fast formula'.

Page 234/273 | < Previous Page | 230 231 232 233 234 235 236 237 238 239 240 241  | Next Page >

  • How to write a flexible modular program with good interaction possibilities between modules?

    - by PeterK
    I went through answers on similar topics here on SO but could't find a satisfying answer. Since i know this is a rather large topic, i will try to be more specific. I want to write a program which processes files. The processing is nontrivial, so the best way is to split different phases into standalone modules which then would be used as necessary (since sometimes i will be only interested in the output of module A, sometimes i would need output of five other modules, etc). The thing is, that i need the modules to cooperate, because the output of one might be the input of another. And i need it to be FAST. Moreover i want to avoid doing certain processing more than once (if module A creates some data which then need to be processed by module B and C, i don't want to run module A twice to create the input for modules B,C ). The information the modules need to share would mostly be blocks of binary data and/or offsets into the processed files. The task of the main program would be quite simple - just parse arguments, run required modules (and perhaps give some output, or should this be the task of the modules?). I don't need the modules to be loaded at runtime. It's perfectly fine to have libs with a .h file and recompile the program every time there is a new module or some module is updated. The idea of modules is here mainly because of code readability, maintaining and to be able to have more people working on different modules without the need to have some predefined interface or whatever (on the other hand, some "guidelines" on how to write the modules would be probably required, i know that). We can assume that the file processing is a read-only operation, the original file is not changed. Could someone point me in a good direction on how to do this in C++ ? Any advice is wellcome (links, tutorials, pdf books...).

    Read the article

  • Two radically different queries against 4 mil records execute in the same time - one uses brute force.

    - by IanC
    I'm using SQL Server 2008. I have a table with over 3 million records, which is related to another table with a million records. I have spent a few days experimenting with different ways of querying these tables. I have it down to two radically different queries, both of which take 6s to execute on my laptop. The first query uses a brute force method of evaluating possibly likely matches, and removes incorrect matches via aggregate summation calculations. The second gets all possibly likely matches, then removes incorrect matches via an EXCEPT query that uses two dedicated indexes to find the low and high mismatches. Logically, one would expect the brute force to be slow and the indexes one to be fast. Not so. And I have experimented heavily with indexes until I got the best speed. Further, the brute force query doesn't require as many indexes, which means that technically it would yield better overall system performance. Below are the two execution plans. If you can't see them, please let me know and I'll re-post then in landscape orientation / mail them to you. Brute-force query: Index-based exception query: My question is, based on the execution plans, which one look more efficient? I realize that thing may change as my data grows.

    Read the article

  • Node & Redis: Crucial Design Issues in Production Mode

    - by Ali
    This question is a hybrid one, being both technical and system design related. I'm developing the backend of an application that will handle approx. 4K request per second. We are using Node.js being super fast and in terms of our database struction we are using MongoDB, with Redis being a layer between Node and MongoDB handling volatile operations. I'm quite stressed because we are expecting concurrent requests that we need to handle carefully and we are quite close to launch. However I do not believe I've applied the correct approach on redis. I have a class Student, and they constantly change stages(such as 'active', 'doing homework','in lesson' etc. Thus I created a Redis DB for each state. (1 for being 'active', 2 for being 'doing homework'). Above I have the structure of the 'active' students table; xa5p - JSON stringified object #1 pQrW - JSON stringified object #2 active_student_table - {{studentId:'xa5p'}, {studentId:'pQrW'}} Since there is no 'select all keys method' in Redis, I've been suggested to use a set such that when I run command 'smembers' I receive the keys and later on do 'get' for each id in order to find a specific user (lets say that age older than 15). I've been also suggested that in fact I used never use keys in production mode. My question is, no matter how 'conceptual' it is, what specific things I should avoid doing in Node & Redis in production stage?. Are they any issues related to my design? Students must be objects and I sure can list them in a list but I haven't done yet. Is it that crucial in production stage?

    Read the article

  • [jquery] multiple resizables acting strange

    - by Noweem
    Hi there everyone, I'm trying to place multiple resizable and draggable div's on one page that move (vertically) inside their own parent div. you can take a look at http://bit.ly/bCutBE However, these div's act really strange when I want to resize them, especially from the north side, they kind of move out of the screen very fast, while they shouldn't be able to get outside the parent div. I only want the div to be able to move and resize vertically inside it's parent, the dragging-part works pretty good, but the resize part give this problem. I can't really describe it better than this, but take a look for yourself and it will be clear immediately when you try to resize one of the coloured div's: move it a little downwards and try to resize it from the north side. the problem seems to be caused by the containment: 'parent', line of the resizable. when I delete this line it works fine, but then the coloured blocks don't stay in their parent, and I want them to stay inside their parent. I hope someone can help me with this... the jquery code I used: $(document).ready(function(){ $(".move") .draggable({ containment: 'parent', grid: [50,50], axis: 'y' }) .resizable({ containment: 'parent', grid: [50,50], handles: 'n, s', minHeight: 50 }); });

    Read the article

  • protocol parsing in c

    - by nomad.alien
    I have been playing around with trying to implement some protocol decoders, but each time I run into a "simple" problem and I feel the way I am solving the problem is not optimal and there must be a better way to do things. I'm using C. Currently I'm using some canned data and reading it in as a file, but later on it would be via TCP or UDP. Here's the problem. I'm currently playing with a binary protocol at work. All fields are 8 bits long. The first field(8bits) is the packet type. So I read in the first 8 bits and using a switch/case I call a function to read in the rest of the packet as I then know the size/structure of it. BUT...some of these packets have nested packets inside them, so when I encounter that specific packet I then have to read another 8-16 bytes have another switch/case to see what the next packet type is and on and on. (Luckily the packets are only nested 2 or 3 deep). Only once I have the whole packet decoded can I handle it over to my state machine for processing. I guess this can be a more general question as well. How much data do you have to read at a time from the socket? As much as possible? As much as what is "similar" in the protocol headers? So even though this protocol is fairly basic, my code is a whole bunch of switch/case statements and I do a lot of reading from the file/socket which I feel is not optimal. My main aim is to make this decoder as fast as possible. To the more experienced people out there, is this the way to go or is there a better way which I just haven't figured out yet? Any elegant solution to this problem?

    Read the article

  • List of Big-O for PHP functions?

    - by Kendall Hopkins
    After using PHP for a while now, I've noticed that not all PHP built in functions as fast as expected. Consider the below two possible implementations of a function that finds if a number is prime using a cached array of primes. //very slow for large $prime_array $prime_array = array( 2, 3, 5, 7, 11, 13, .... 104729, ... ); $result_array = array(); foreach( $array_of_number => $number ) { $result_array[$number] = in_array( $number, $large_prime_array ); } //still decent performance for large $prime_array $prime_array => array( 2 => NULL, 3 => NULL, 5 => NULL, 7 => NULL, 11 => NULL, 13 => NULL, .... 104729 => NULL, ... ); foreach( $array_of_number => $number ) { $result_array[$number] = array_key_exists( $number, $large_prime_array ); } This is because in_array is implemented with a linear search O(n) which will linearly slow down as $prime_array grows. Where the array_key_exists function is implemented with a hash lookup O(1) which will not slow down unless the hash table gets extremely populated (in which case it's only O(logn)). So far I've had to discover the big-O's via trial and error, and occasionally looking at the source code. Now for the question... I was wondering if there was a list of the theoretical (or practical) big O times for all* the PHP built in functions. *or at least the interesting ones For example find it very hard to predict what the big O of functions listed because the possible implementation depends on unknown core data structures of PHP: array_merge, array_merge_recursive, array_reverse, array_intersect, array_combine, str_replace (with array inputs), etc.

    Read the article

  • iPhone OpenGL ES Texture2D Masking

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

    Read the article

  • How to refresh/redraw the screen (not the program window)

    - by mohrphium
    I'm having a bit of a hard time figuring out, how to remove a drawn ellipse after it has been drawn somewhere else. I need a circle to follow my mouse all the time and this is all the program should do. I get the mousepositions and draw my circle but how can I remove the last one? #include <Windows.h> #include <iostream> void drawRect(int a1, int a2){ HDC screenDC = ::GetDC(0); //Draw circle at mouse position ::Ellipse(screenDC, a1, a2+5, a1+9, a2+14); ::ReleaseDC(0, screenDC); //::InvalidateRect(0, NULL, TRUE); //<- I tried that but then everything flickers //Also, the refresh rate is not fast enough... still some circles left } int main(void) { int a1; int a2; bool exit=false; while (exit!=true) { POINT cursorPos; GetCursorPos(&cursorPos); float x = 0; x = cursorPos.x; float y = 0; y = cursorPos.y; a1=(int)cursorPos.x; a2=(int)cursorPos.y; drawRect(a1, a2); } } I am working with graphics and all that stuff for the first time. Im kinda stuck here... once again. Thanks.

    Read the article

  • Java-Eclipse-Spring 3.1 - the fastest way to get familiar with this set

    - by Leron
    I, know almost all of you at some point of your life as a programmer get to the point where you know (more or less) different technologies/languages/IDEs and a times come when you want to get things together and start using them once - more efficient and second - more closely to the real life situation where in fact just knowing Java, or some experience with Eclipse doesn't mean nothing, and what makes you a programmer worth something is the ability to work with the combination of 2 or more combinations. Having this in mind here is my question - what do you think is the optimal way of getting into Java+Eclipse+Spring3.1 world. I've read, and I've read a lot. I started writing real code but almost every step is discovering the wheel again and again, wondering how to do thing you know are some what trivial, but you've missed that one article where this topic was discussed and so on. I don't mind for paying for a good tutorial like for example, after a bit of research I decided that instead of losing a lot of time getting the different parts together I'd rather pay for the videos in http://knpuniversity.com/screencast/starting-in-symfony2-tutorial and save myself a lot of time (I hope) and get as fast as possible to writing a real code instead of wondering what do what and so on. But I find it much more difficult to find such sources of info especially when you want something more specific as me and that's the reason to ask this question. I know a lot of you go through the hard way, and I won't give up if I have to do the same, but to be honest I really hope to get post with good tutorials on the subject (paid or not) because in my situation time is literally money. Thanks Leron

    Read the article

  • What is the IoC / "Springy" way to handle MVP in GWT? (Hint, probably not the Spring Roo 1.1 way)

    - by Ehrann Mehdan
    This is the Spring Roo 1.1 way of doing a factory that returns a GWT Activity (Yes, Spring Framework) public Activity getActivity(ProxyPlace place) { switch (place.getOperation()) { case DETAILS: return new EmployeeDetailsActivity((EntityProxyId<EmployeeProxy>)place.getProxyId(), requests, placeController, ScaffoldApp.isMobile() ? EmployeeMobileDetailsView.instance() : EmployeeDetailsView.instance()); case EDIT: return makeEditActivity(place); case CREATE: return makeCreateActivity(); } throw new IllegalArgumentException("Unknown operation " + place.getOperation()); } It seems to me that we just went back hundred of years if we use a switch case with constants to make a factory. Now this is official auto generated Spring roo 1.1 with GWT / GAE integration, I kid you not I can only assume this is some executives empty announcements because this is definitly not Spring It seems VMWare and Google were too fast to get something out and didn't quite finish it, isn't it? Am I missing something or this is half baked and by far not the way Spring + GWT MVP should work? Do you have a better example of how Spring, GWT (2.1 MVP approach) and GAE should connect? I would hate to do all the plumbing of managing history and activities like this. (no annotations? IOC?) I also would hate to reinvent the wheel and write my own Spring enhancement just to find someone else did the same, or worse, find out that SpringSource and Google will release roo 1.2 soon and make it right

    Read the article

  • Most efficient method of detecting/monitoring DOM changes?

    - by Graza
    I need an efficient mechanism for detecting changes to the DOM. Preferably cross-browser, but if there's any efficient means which are not cross browser, I can implement these with a fail-safe cross browser method. In particular, I need to detect changes that would affect the text on a page, so any new, removed or modified elements, or changes to inner text (innerHTML) would be required. I don't have control over the changes being made (they could be due to 3rd party javascript includes, etc), so it can't be approached from this angle - I need to "monitor" for changes somehow. Currently I've implemented a "quick'n'dirty" method which checks body.innerHTML.length at intervals. This won't of course detect changes which result in the same length being returned, but in this case is "good enough" - the chances of this happening are extremely slim, and in this project, failing to detect a change won't result in lost data. The problem with body.innerHTML.length is that it's expensive. It can take between 1 and 5 milliseconds on a fast browser, and this can bog things down a lot - I'm also dealing with a large-ish number of iframes and it all adds up. I'm pretty sure the expensiveness of doing this is because the innerHTML text is not stored statically by browsers, and needs to be calculated from the DOM every time it is read. The types of answers I am looking for are anything from the "precise" (for example event) to the "good enough" - perhaps something as "quick'n'dirty" as the innerHTML.length method, but that executes faster.

    Read the article

  • What are some methods to prevent double posting in a form? (PHP)

    - by jpjp
    I want to prevent users from accidentally posting a comment twice. I use the PRG (post redirect get) method, so that I insert the data on another page then redirect the user back to the page which shows the comment. This allows users to refresh as many times as they want. However this doesn't work when the user goes back and clicks submit again or when they click submit 100 times really fast. I don't want 100 of the same comments. I looked at related questions on SO and found that a token is best. But I am having trouble using it. //makerandomtoken(20) returns a random 20 length char. <form method="post" ... > <input type="text" id="comments" name="comments" class="commentbox" /><br/> <input type="hidden" name="_token" value="<?php echo $token=makerandomtoken(20); ?>" /> <input type="submit" value="submit" name="submit" /> </form> if (isset($_POST['submit']) && !empty($comments)) { $comments= mysqli_real_escape_string($dbc,trim($_POST['comments'])); //how do I make the if-statment to check if the token has been already set once? if ( ____________){ //don't insert comment because already clicked submit } else{ //insert the comment into the database } } So I have the token as a hidden value, but how do I use that to prevent multiple clicking of submit. METHODS: someone suggested using sessions. I would set the random token to $_SESSION['_token'] and check if that session token is equal to the $_POST['_token'], but how do I do that? When I tried, it still doesn't check

    Read the article

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

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

    Read the article

  • Which MySQL Fork/Version to Pick??

    - by Drew
    As most of you know, Sun acquired MySQL (and later Oracle acquired Sun), and during these acquisitions, there were a lot of FUD in MySQL community which resulted in creation of various forks. Today we have MySQL from MySQL, Percona (XtraDB) MySQL, OurDelta MySQL, MariaDB, Drizzle to name a few. Which brings us to the source of the problem. We are in the process of upgrading our databases (hardware/software) and I would like to know which one of the forks should I go with. Each has their own set of pros/cons. We are currently using MySQL 5.0.x from MySQL/Linux on an 8-core machine. Our new hardware is a monster with 32 cores and 32GB of memory connecting to a fast NetApp Storage via FC. I would like to stick with MySQL from MySQL but I have heard horror stories on how badly MySQL 5.1 performs on many cores. I have also heard that MySQL 5.4 performs better on multi-core machines but that's still not production ready. In addition, I have also heard a lot of good things about Percona builds. This is what I know so far: MySQL 5.1 from MySQL: Reliable choice, but doesn't scale well on a big machine Percona: Scales well, good backing company. I don't have much experience with it MariaDB: Don't know much about it besides that it was founded by Original MySQL developers (including Monty) OurDelta: Don't know much Drizzle: Mostly optimized for cloud computing I would like to know what's the general notion about this problem. Which build/version should I go with? How are you guys picking your builds/versions? Thanks!

    Read the article

  • Play Multiple iPod Library Songs On iPhone At The Same Time With Pitch Bending & Other Effects

    - by Dino
    Hi, I have been going at this for the past two weeks and it is driving me crazy. I asked this question a couple of days ago (Extract iPod Library raw PCM samples and play with sound effects) and whilst the answer got me half way there I am still stuck. Basically what I am trying to achieve is load up multiple songs from the iPod library for playback with effects such as pitch bend, eq effects etc... I have gone down the route of AVPlayer and AVAudioPlayer which are too simple. The only framework I've seen that can play audio with these effects is OpenAL. I have tried a few objective c wrappers (Finch and ObjectAL) Finch does not play compressed audio whilst ObjectAL will only convert it for me if I pass in a URL for the file (which is something I cannot do because I only have an incompatible iPod library URL). An example of an app that does what I want beautifilly is Tap DJ. It can load up songs from the iPod library fast (unlike TouchDJ and it plays them with all sorts of effects. Any help would be much appreciated.

    Read the article

  • PHP OOP singleton doesn't return object

    - by Misiur
    Weird trouble. I've used singleton multiple times but this particular case just doesn't want to work. Dump says that instance is null. define('ROOT', "/"); define('INC', 'includes/'); define('CLS', 'classes/'); require_once(CLS.'Core/Core.class.php'); $core = Core::getInstance(); var_dump($core->instance); $core->settings(INC.'config.php'); $core->go(); Core class class Core { static $instance; public $db; public $created = false; private function __construct() { $this->created = true; } static function getInstance() { if(!self::$instance) { self::$instance = new Core(); } else { return self::$instance; } } public function settings($path = null) { ... } public function go() { ... } } Error code Fatal error: Call to a member function settings() on a non-object in path It's possibly some stupid typo, but I don't have any errors in my editor. Thanks for the fast responses as always.

    Read the article

  • ListView causing OutOfMemory Error

    - by Michael
    So I am not really given a reason to the right of this error message. I am not exactly sure why this is happening but my guess though is that it has to do with the fact that there are around ~50 good quality drawables. Upon scrolling really fast, the app crashes. I feel as if I am mitigating most common issues with ListView and crashing such as using View Holders as well as only initiating the inflater once. Process: com.example.michael.myandroidappactivity, PID: 20103 java.lang.OutOfMemoryError at android.graphics.BitmapFactory.nativeDecodeAsset(Native Method) Here is the code public class ImageAdapter extends BaseAdapter { private Context context; private ArrayList<Integer> imageIds; private static LayoutInflater inflater; public ImageAdapter(Context _context, ArrayList<Integer> _imageIds) { context = _context; imageIds = _imageIds; } @Override public int getCount() { return imageIds.size(); } @Override public Object getItem(int position) { return null; } @Override public long getItemId(int position) { return 0; } static class ViewHolder{ ImageView img; } @Override public View getView(int position, View convertView, ViewGroup parent) { ViewHolder holder = null; View rowView = null; if(rowView==null) { LayoutInflater inflater = (LayoutInflater) context .getSystemService(Context.LAYOUT_INFLATER_SERVICE); rowView = inflater.inflate(R.layout.listview_layout, parent, false); holder = new ViewHolder(); holder.img = (ImageView) rowView.findViewById(R.id.flag); rowView.setTag(holder); } else { holder = (ViewHolder) rowView.getTag(); } holder.img.setImageResource(imageIds.get(position)); return rowView; } }

    Read the article

  • Configuring PHP in IIS with Tomcat

    - by Silent Walker
    I have my Java site running under IIS 7. I need to install wordpress blog in it. I've installed and configured PHP in IIS. I have tested the PHP handler by creating a separate site, everything works fine, phpinfo() gives the desired output. However, I'm having problem running the PHP files inside my Java web application. I've put my test PHP file inside a folder called blog. When I access this folder in the browser as /mysite/blog I get a 404 page from my Java application. When I try to invoke the php page directly, http://mysite/blog/index.php, I get an unprocessed php page. I'm using isapi_handler for the reidrects. How do I tell my isapi_handler to ignore /blog folder? In my IIS handler mapping, *.php is mapped with Fast CGI. I'm not sure how to approach this problem and any help on this would be much appreciated. Thanks in advance.

    Read the article

  • Full-text search in C++

    - by Jen
    I have a database of many (though relatively short) HTML documents. I want users to be able to search this database by entering one or more search words in a C++ desktop application. Hence, I’m looking for a fast full-text search solution. Ideally, it should: Skip common words, such as the, of, and, etc. Support stemming, i.e. search for run also finds documents containing runner, running and ran. Be able to update its index in the background as new documents are added to the database. Be able to provide search word suggestions (like Google Suggest) To illustrate, assume the database has just two documents: Document 1: This is a test of text search. Document 2: Testing is fun. The following words should be in the index: fun, search, test, testing, text. If the user types t in the search box, I want the application to be able to suggest test, testing and text (Ideally, the application should be able to query the search engine for the 10 most common search words starting with t). A search for testing should return both documents. Can you suggest a C or C++ based solution? (I’ve briefly reviewed CLucene and Xapian, but I’m not sure if either will address my needs, especially querying the search word indexes for the suggest feature).

    Read the article

  • How to seek to a specific time in a RTP stream?

    - by Cipi
    I am streaming a prerecorded H264 video that has the following structure: [I] [x] [x] [x] [I] [x] [x] [x] [I]... In between the IDR (I-s in my structure) I have 32 (only 3 presented here) other frames (all other stuff that is not IDR like SEI, SPS, PPS... X-es) Now, let assume that the timing of my frames is such: TIME: 1 2 3 4 5 6 7 8 9 FRAME: [I] [x] [x] [x] [I] [x] [x] [x] [I]... Now i want to seek to the time 4. If I seek to that frame, and send it, the picture gets messed up because the decoder needs a IDR to decode it properly, so I resorted to finding the appropriate IDR (in this case one with the time 1) and sending it as the frame with the time 4. So now the picture is decoded properly, all is well... but... If my GOV is 32, and I need to send the non IDR frame that has the index 31, and if the time span between it and the corresponding IDR is 3 seconds, I actually get 3 seconds earlier then the time I want. Now, this is not precise, because I cannot seek to the half of the GOV time span. Also, I cant set smaller GOV, so I want other ideas... My other idea was to send the last known IDR, and then send all other non IDR frames that come before the one I want, only I would set for all of them RTP-TIME to be the same as the corresponding IDR. In this case the picture gets decoded perfectly, but now in the above case, 3 seconds that follow non IDR frame with the wanted time get fast paced in the decoder/player (there is no instantaneous seek)... Any ideas? Or I can only seek to IDR-s and not the frames in between?

    Read the article

  • How to use MySQL geospatial extensions with spherical geometries

    - by Joshua
    Hi Everyone, I would like to store thousands of latitude/longitude points in a MySQL db. I was successful at setting up the tables and adding the data using the geospatial extensions where the column 'coord' is a Point(lat, lng). Problem: I want to quickly find the 'N' closest entries to latitude 'X' degrees and longitude 'Y' degrees. Since the Distance() function has not yet been implemented, I used GLength() function to calculate the distance between (X,Y) and each of the entries, sorting by ascending distance, and limiting to 'N' results. The problem is that this is not calculating shortest distance with spherical geometry. Which means if Y = 179.9 degrees, the list of closest entries will only include longitudes of starting at 179.9 and decreasing even though closer entries exist with longitudes increasing from -179.9. How does one typically handle the discontinuity in longitude when working with spherical geometries in databases? There has to be an easy solution to this, but I must just be searching for the wrong thing because I have not found anything helpful. Should I just forget the GLength() function and create my own function for calculating angular separation? If I do this, will it still be fast and take advantage of the geospatial extensions? Thanks! josh UPDATE: This is exactly what I am describing above. However, it is only for SQL Server. Apparently SQL Server has a Geometry and Geography datatypes. The geography does exactly what I need. Is there something similar in MySQL?

    Read the article

  • CakePHP Routes: Messing With The MVC

    - by thesunneversets
    So we have a real-estate-related site that has controller/action pairs like "homes/view", "realtors/edit", and so forth. From on high it has been deemed a good idea to refactor the site so that URLS are now in the format "/realtorname/homes/view/id", and perhaps also "/admin/homes/view/id" and/or "/region/..." As a mere CakePHP novice I'm finding it difficult to achieve this in routes.php. I can do the likes of: Router::connect('/:filter/h/:id', array('controller'=>'homes','action'=>'view')); Router::connect('/admin/:controller/:action/:id'); But I'm finding that the id is no longer being passed simply and elegantly to the actions, now that controller and action do not directly follow the domain. Therefore, questions: Is it a stupid idea to play fast and loose with the /controller/action format in this way? Is there a better way of stating these routes so that things don't break egregiously? Would we be better off going back to subdomains (the initial method of achieving this type of functionality, shot down on potentially spurious SEO-related grounds)? Many thanks for any advice! I'm sorry that I'm such a newbie that I don't know whether I'm asking stupid questions or not....

    Read the article

  • Recursive problem...

    - by Chronos
    Guys, I'm new to java and multithreading..... and I have a following problem: I have two classes running in two different threads. Class A and Class B. Class A has the method "onNewEvent()". Once that method is invoked, it will ask class B to do some work. As soon as B finishes the work it invokes onJobDone() method of the class A. Now... here comes the problem... what I want is to create new job within onJobDone() method and to send it again to B. here is what I do (pseudo code) ... in the sequence of execution A.onNewEvent(){ //create job //ask B to do it B.do() } B.do{ // Do some stuff A.jobDone() } A.onJobDOne(){ B.do() //doItAgain // print message "Thank you for doing it" } The problem is... that message "Thank you for doing it" never gets printed... in fact, when onJobDone() method is invoked, it invokes B.do()... because B.do() is very fast, it invokes onJobDone() immediatly... so execution flow never comes to PRINT MESSAGE part of code... I suppose this is one of the nasty multithreading problems.... any help would be appreciated.

    Read the article

  • Why does multiple sessions started on the same page gets the same session id?

    - by Calmarius
    I tryed the following: <?php session_name('user'); session_start(); // sets an 'user' cookie with session id. // This session stores the user's login data. // Its an ordinary session. $USERSESSION=$_SESSION; // saving this session $userSessId=session_id(); session_write_close(); //closing this session session_name('chatroom'); session_start(); // set a 'chatroom' cookie but contains the same session id and points to the same data :( . // This session would be used to store the chat text. This session would be // shared between all users joined in this chat room by setting the same session id for all members. // by calling session_regenerate_id would make a diffent session id for every user and it won't be a chat room anymore. ?> So I want to do a chat like thing with sessions. On the client side it would be done with ajax that polls this php page in every 5-10 seconds. Sessions may be cached in the server's memory so it can be accessible fast. I can store the chat in the database but my service runs on a free webhost which is limited, only 4 mysql connections allowed at a time which is almost nothing. I try to touch my database as least times as possible.

    Read the article

  • Database structure for ecommerce site

    - by imanc
    Hey Guys, I have been tasked with designing an ecommerce solution. The aspect that is causing me the most problems is the database. Currently the site consists of 10+ country based shops each with their own database (all residing on the same mysql instance). For the new site I'd rather all these shop databases be merged into one database so that all tables (products, orders, customers etc.) have a shop_id field. From a programming perspective this seems to make the most sense as we won't have to manage data across multiple databases. Currently the entire site generates about 120k orders a year, but is experiencing fairly heavy growth and we need to design a solution that will scale. In 5 years there may be more than a million orders per year and a database that contains 5 years order history (archiving maybe a solution here). The question is - do we use a single database, or do we keep the database-per-shop structure? I am currently trying to find supporting evidence for either avenue. The company I am designing the solution for prefer the per-shop database structure because they believe it will allow the sites to scale. But my argument is that the shop's database probably won't get that busy over the next few years that they exceed the capacity of a mysql database and a "no expenses spared" hardware set-up. I am wondering if anyone has any advice either way? Does anyone have experience with websites / ecommerce sites that have tables containing millions of records? I know there is probably not a clear answer here, but at what stage do we have too many records or too large table files to have a fast loading site? Also, if anyone has any advice on sources of information - books, websites, etc. where I can do further research, it would be highly appreciated! Cheers, imanc

    Read the article

< Previous Page | 230 231 232 233 234 235 236 237 238 239 240 241  | Next Page >