Search Results

Search found 20275 results on 811 pages for 'general performance'.

Page 594/811 | < Previous Page | 590 591 592 593 594 595 596 597 598 599 600 601  | Next Page >

• Element point map for html5 canvas element, need algorithm

  - by Artiom Chilaru

  I'm currently working on a pure html 5 canvas implementation of the "flying tag cloud sphere", which many of you have undoubtedly seen as a flash object in some pages. The tags are drawn fine, and the performance is satisfactory, but there's one thing in the canvas element that's kind of breaking this idea: you can't identify the objects that you've drawn on a canvas, as it's just a simple flat "image".. What I have to do in this case is catch the click event, and try to "guess" which element was clicked. So I have to have some kind of matrix, which stores a link to a tag object for each pixel on the canvas, AND I have to update this matrix on every redraw. Now this sounds incredibly inefficient, and before I even start trying to implement this, I want to ask the community - is there some "well known" algorithm that would help me in this case? Or maybe I'm just missing something, and the answer is right behind the corner? :)

  Read the article

• data between pages: $_SESSION vs. $_GET ?

  - by Haroldo

  Ok, firstly this is not about forms this is about consistent layout as a user explores a site. let me explain: If we imagine a (non-ajax) digital camera online store, say someone was on the DSLR section and specified to view the cameras in Gallery mode and order by price. They then click onto the Compact camera's page. It would be in the users interests if the 'views' they selected we're carried over to this new page. Now, i'd say use a session - am i wrong? are there performance issues i should be aware of for a few small session vars ( ie view=1 , orderby=price) ?

  Read the article

• Code to find nth largest number in an array

  - by user136104

  I have written following code in perl #!/usr/bin/perl @array = (3,6,8,1,2); my $second_largest = 0; my $largest = 0; for (@array) { if($_ > $largest) { $second_largest = $largest; $largest = $_; } if($_ > $second_largest && $_ < $largest) { $second_largest = $_; } } print "Second largest::".$second_largest; print "largest::".$largest; But I need a general code to find out "Nth" largest and smallest number of an array Please help me

  Read the article

• Random number within a range based on a normal distribution

  - by ConfusedAgain

  I'm math challenged today :( I want to generate random numbers with a range (n to m, eg 100 to 150), but instead of purely random I want the results to be based on the normal distribution. By this I mean that in general I want the numbers "clustered" around 125. I've found this random number package that seems to have a lot of what I need: http://beta.codeproject.com/KB/recipes/Random.aspx It supports a variety of random generators (include mersiene twister) and can apply the generator to a distribution. But I'm confused... if I use a normal distribution generator the random numbers are from roughly -6 to +8 (apparently the true range is float.min to float.max). How do a scale that to my required range?

  Read the article

• Best way to test a batch email script

  - by John

  I have a php mail script sitting on a LAMP vps server. The script grabs about 1000 emails and sends them each an html email. I tested the script with about half a dozen of my own test email accounts and things worked fine. But I am concerned something may go wrong when I actually use this script for 1000 emails. Some things I would like to test for are 1) Confirm all 1000 emails were sent and received 2) Test to make sure emails did not end up in people's spam folders 3) Detect any other general failures Does anyone have suggestions on how I can test for the above cases? I would like to read about your experiences building batch email scripts.

  Read the article

• Determine how much can I write into a filehandle; copying data from one FH to the other.

  - by Vi

  How to determine if I can write the given number of bytes to a filehandle (socket actually)? (Alternatively, how to "unread" the data I had read from other filehandle?) I want something like: n = how_much_can_I_write(w_handle); n = read(r_handle, buf, n); assert(n==write(w_handle, buf, n)); Both filehandles (r_handle and w_handle) have received ready status from epoll_wait. I want all data from r_handle to be copied to w_handle without using a "write debt" buffer. In general, how to copy the data from one filehandle to the other simply and reliably?

  Read the article

• Getting pixel averages of a vector sitting atop a bitmap...

  - by user346511

  I'm currently involved in a hardware project where I am mapping triangular shaped LED to traditional bitmap images. I'd like to overlay a triangle vector onto an image and get the average pixel data within the bounds of that vector. However, I'm unfamiliar with the math needed to calculate this. Does anyone have an algorithm or a link that could send me in the right direction? (I tagged this as Python, which is preferred, but I'd be happy with the general algorithm!) I've created a basic image of what I'm trying to capture here: http://imgur.com/Isjip.gif

  Read the article

• Hibernate criteria with projection not performing query for @OneToMany mapping

  - by Josh

  I have a domain object, Expense, that has a field called initialFields. It's annotated as so: @OneToMany(fetch = FetchType.EAGER, cascade = { CascadeType.ALL }, orphanRemoval = true) @JoinTable(blah blah) private final List<Field> initialFields; Now I'm trying to use Projections in order to only pull certain fields for performance reasons, but when doing so the initialFields field is always null. It's the only OneToMany field and the only field I am trying to retrieve with the projection that is behaving this way. If I use a regular HQL query initialFields is populated appropriately, but of course I can't limit the fields. Anyone ever seen anything like this?

  Read the article

• Fastest way of converting a quad to a triangle strip?

  - by Tina Brooks

  What is the fastest way of converting a quadrilateral (made up of foyr x,y points) to a triangle strip? I'm well aware of the general triangulation algorithms that exist, but I need a short, well optimized algorithm that deals with quadrilaterals only. My current algorithm does this, which works for most quads but still gets the points mixed up for some: #define fp(f) bounds.p##f /* Sort four points in ascending order by their Y values */ point_sort4_y(&fp(1), &fp(2), &fp(3), &fp(4)); /* Bottom two */ if (fminf(-fp(1).x, -fp(2).x) == -fp(2).x) { out_quad.p1 = fp(2); out_quad.p2 = fp(1); } else { out_quad.p1 = fp(1); out_quad.p2 = fp(2); } /* Top two */ if (fminf(-fp(3).x, -fp(4).x) == -fp(3).x) { out_quad.p3 = fp(3); out_quad.p4 = fp(4); } else { out_quad.p3 = fp(4); out_quad.p4 = fp(3); }

  Read the article

• Backing up locally modified and new source files

  - by eran

  I'm wondering how other programmers are backing up changes that are not under source control yet, be it new files or modified ones. I'm mostly referring to medium size jobs - hardly worth the effort of making a private branch, but taking more than a day to complete. This is not a vendor-specific question - I'd like to see if various products have different solutions to the problem. I'd appreciate answers referring to SVN and distributed SCCs, though. I'm mostly wondering about that latters (Mercurial, GIT etc.) - it's great that you have your own local repo, but do you back it up on a regular basis along with your source files? Note - I'm not asking about a general backup strategy. For that, we have IT. I'm seeking the best way to keep locally modified stuff backed-up before they are checked back into the main repo.

  Read the article

• What is the "task" in twitter Storm parallelism

  - by John Wang

  I'm trying to learn twitter storm by following the great article "Understanding the parallelism of a Storm topology" However I'm a bit confused by the concept of "task". Is a task an running instance of the component(spout or bolt) ? A executor having multiple tasks actually is saying the same component is executed for multiple times by the executor, am I correct ? Moreover in a general parallelism sense, Storm will spawn a dedicated thread(executor) for a spout or bolt, but what is contributed to the parallelism by an executor(thread) having multiple tasks ? I think having multiple tasks in a thread, since a thread executes sequentially, only make the thread a kind of "cached" resource, which avoids spawning new thread for next task run. Am I correct? I may clear those confusion by myself after taking more time to investigate, but you know, we both love stackoverflow ;-) Thanks in advance.

  Read the article

• For what purpose does java have a float primitive type?

  - by Roman

  I heard plenty times different claims about float type in java. The most popular issues typicaly regard to converting float value to double and vice versa. I read (rather long time ago and not sure that it's actual now with new JVM) that float gives much worse performance then double. And it's also not recommended to use float in scientific applications which should have certain accuracy. I also remember that when I worked with AWT and Swing I had some problems with using float or double (like using Point2D.Float or Point2D.Double). So, I see only 2 advantages of float over double: it needs only 4 bytes while double needs 8 bytes JMM garantees that assignment operation is atomic with float variables while it's not atomic with double's. Are there any other cases where float is better then double? Do you use float's in your applications? It seems to me that the only valuable reason java has float is backward compatibility.

  Read the article

• foreign key constraints on primary key columns - issues ?

  - by zzzeek

  What are the pros/cons from a performance/indexing/data management perspective of creating a one-to-one relationship between tables using the primary key on the child as foreign key, versus a pure surrogate primary key on the child? The first approach seems to reduce redundancy and nicely constrains the one-to-one implicitly, while the second approach seems to be favored by DBAs, even though it creates a second index: create table parent ( id integer primary key, data varchar(50) ) create table child ( id integer primary key references parent(id), data varchar(50) ) pure surrogate key: create table parent ( id integer primary key, data varchar(50) ) create table child ( id integer primary key, parent_id integer unique references parent(id), data varchar(50) ) the platforms of interest here are Postgresql, Microsoft SQL Server.

  Read the article

• DataBind and Postback

  - by Michael La Voie

  This is a general how does DataBind work questions... I have a simple page with a GridView that is bound (in the aspx code) to an ObjectDataSource. I can look in the Select() function called by the ObjectDataSource to see that it is called on the initial load and on every post back. I have some logic that happens on post backs that will affect the GridView's data, and I want to call GridView.DataBind() later on in the post back, after I've made some changes. Is there a way to prevent the automatic rebinding that happens on each post back? Does this mean I can't use an ObjectDataSource for this control?

  Read the article

• What is the differnce between "LINQ to Entities", "LINQ to SQL" and "LINQ to Dataset".

  - by Marcel

  Hi all, I'm working for quite a while now with LINQ. However, it remained still a bit of a mystery what are the real differences between the mentioned flavours of LINQ. The successful answer will contain a short differentiation between them. What is the main goal if it, what is the benefit, and is there a performance impact... P.S. I know that there are a lot of information sources out there, but I look for a kind of a "cheat sheet" which instructs a newbie where to head to for a specific goal.

  Read the article

• iPhone write to file (alternative directory)

  - by strider2k

  New to iPhone 3.2, Apple introduced File-Sharing support. Details can be found at https://developer.apple.com/iphone/library/releasenotes/General/WhatsNewIniPhoneOS/Articles/iPhoneOS3_2.html#//apple_ref/doc/uid/TP40009337-SW1 . Now, most examples floating around in the web demonstrates writing to the documents directory. What if I want to write files from my app but I don't want the user to be able to see it via iTunes? I'm looking at the Files and Networking section of the iPhone OS Programming Guide and I'm unsure what would be a good alternative to the documents directory for writing files to hide from the user and not be rejected by Apple's review team.

  Read the article

• how to work with javascript typed arrays without using for

  - by ramesh babu

  var sendBuffer = new ArrayBuffer(4096); var dv = new DataView(sendBuffer); dv.setInt32(0, 1234); var service = svcName; for (var i = 0; i < service.length; i++) { dv.setUint8(i + 4, service.charCodeAt(i)); } ws.send(sendBuffer); how to workout this wihout using for loop. for loop decreasing performance while works with huge amount of data.

  Read the article

• Getting started with learning the Rails source

  - by japancheese

  Hello, I've been using Ruby on Rails for many projects lately, and I thought it would be interesting to take a look at the Rails source and really see how things operate underneath. I think it'd be a great learning experience and would probably enhance the way I code Rails apps all the more. Does anyone have any tips on how to get started? And where within the Rails source does an application begin to be executed? Perhaps if I started there, I could see how everything is loaded and works in general.

  Read the article

• Decoupling into DAL and BLL - my concerns.

  - by novice_man

  Hi, In many posts concerning this topic I come across very simple examples that do not answer my question. Let's say a have a document table and user table. In DAL written in ADO.NET i have a method to retries all documents for some criteria. Now I the UI I have a case where I need to show this list along with the names of the creator. Up to know I have it done with one method in DAL containig JOIN statement. However eveytime I have such a complex method i have to do custom mapping to some object that doesn't mark 1:1 to DB. Should it be put into another layer ? If so then I will have to resing from join query for iteration through results and querying each document author. . . which doen't make sense... (performance) what is the best approach for such scenarios ?

  Read the article

• make: invoke command for multiple targets of multiple files?

  - by marvin2k

  Hi, I looking to optimize an existing Makefile. It's used to create multiple plots (using Octave) for every logfile in a given directory using an scriptfile for every plot which takes a logfilename as an argument. In the Moment, I use one single rule for every kind of plot available, with a handwritten call to Octave, giving the specific scriptfile/logfile as an argument. It would be nice, if every plot has "his" octave-script as a dependency (plus the logfile, of course), so only one plot is regenerated if his script is changed. Since I don't want to type that much, I wonder how I can simplifiy this by using only one general rule to build "a" plot? To make it clearer: Logfile: "$(LOGNAME).log" Scriptfile: "plot$(PLOTNAME).m" creates "$(LOGNAME)_$(PLOTNAME).png" The first thing I had in mind: %1_%2.png: %1.log $(OCTAVE) --eval "plot$<2('$<1')" But this seems not to be allowed. Could someone give me a hint?

  Read the article

• How would MVVM be for games?

  - by Benny Jobigan

  Particularly for 2d games, and particularly silverlight/wpf games. If you think about it, you can divide a game object into its view (the graphic on the screen) and a view-model/model (the state, ai, and other data for the object). In silverlight, it seems common to make each object a user control, putting the model and view into a single object. I suppose the advantage of this is simplicity. But, perhaps it's less clean or has some disadvantages in terms of the underlying "game engine". What are your thoughts on this matter? What are some advantages and disadvantages of using the MVVM pattern for game development? How about performance? All thoughts are welcome.

  Read the article

• Better product to develop for, iPad or Android based tablet in a purely business related application

  - by Caylem

  Hey guys Just wondering what you'd suggest as the best platform for developing a business application for a tablet device. The application needs to be multitouch, have access to a maps API, a database on the device. It will not be going on sale in the app store or Androids market, it is purely for specific business task and not for the general consumer. Obviously the options seem to be iPhone OS and the iPad or Android and an Android tablet device. The form factor for the end product requires something in the region of 8 inch+ screen and enough processing power to provide a good experience for the end user. Any help would be much appreciated. Thanks

  Read the article

• When to release the UIImage ?

  - by ragnarius

  I use the following code to draw a subimage UIImage* subIm = getSubImage( large, rect ); [subIm drawInRect:self.bounds]; where getSubImage is defined as follows UIImage* getSubImage(UIImage* uim, CGRect rc){ CGImageRef imref = CGImageCreateWithImageInRect(uim.CGImage, rc); UIImage* sub = [UIImage imageWithCGImage:imref]; CGImageRelease(imref); NSLog(@"subimage retainCount=%d", [sub retainCount]); // is 1 return sub; }//getSubImage Is the code correct? Is it safe to "CGImageRelease" imref? Has sub "CGImageRetained" imref? Should I release subIm (I get an error if I do)? Is subIm contained in the autorelease-pool, and , if so, how do I know this? In general, can one check if an object is contained in the autorelease pool (for debugging purpose)?

  Read the article

• UNIX-style RegExp Replace running extremely slowly under windows. Help?

  - by John Sullivan

  I'm trying to run a unix regEXP on every log file in a 1.12 GB directory, then replace the matched pattern with ''. Test run on a 4 meg file is took about 10 minutes, but worked. Obviously something is murdering performance by several orders of magnitude. Find: ^(?!.*155[0-2][0-9]{4}\s.*).*$ -- NOTE: match any line NOT starting 152[0-2]NNNN where in is a number 0-9. Replace with: ''. Is there some justifiable reason for my regExp to take this long to replace matching text, or is the program I am using (this is windows / a program called "grepWin") most likely poorly optimized? Thanks.

  Read the article

• Repeating a List in Scala

  - by Ralph

  I am a Scala noob. I have decided to write a spider solitaire solver as a first exercise to learn the language and functional programming in general. I would like to generate a randomly shuffled deck of cards containing 1, 2, or 4 suits. Here is what I came up with: val numberOfSuits = 1 (List["clubs", "diamonds", "hearts", "spades"].take(numberOfSuits) * 4).take(4) which should return List["clubs", "clubs", "clubs", "clubs"] List["clubs", "diamonds", "clubs", "diamonds"] List["clubs", "diamonds", "hearts", "spades"] depending on the value of numberOfSuits, except there is no List "multiply" operation that I can find. Did I miss it? Is there a better way to generate the complete deck before shuffling? BTW, I plan on using an Enumeration for the suits, but it was easier to type my question with strings. I will take the List generated above and using a for comprehension, iterate over the suits and a similar List of card "ranks" to generate a complete deck.

  Read the article

< Previous Page | 590 591 592 593 594 595 596 597 598 599 600 601  | Next Page >