Search Results

Search found 4126 results on 166 pages for 'bitwise operations'.

Page 100/166 | < Previous Page | 96 97 98 99 100 101 102 103 104 105 106 107  | Next Page >

• Where can I find soft-multiply and divide algorithms?

  - by srking

  I'm working on a micro-controller without hardware multiply and divide. I need to cook up software algorithms for these basic operations that are a nice balance of compact size and efficiency. My C compiler port will employ these algos, not the the C developers themselves. My google-fu is so far turning up mostly noise on this topic. Can anyone point me to something informative? I can use add/sub and shift instructions. Table lookup based algos might also work for me, but I'm a bit worried about cramming so much into the compiler's back-end...um, so to speak. Thanks!

  Read the article

• Resetting Objects vs. Constructing New Objects

  - by byronh

  Is it considered better practice and/or more efficient to create a 'reset' function for a particular object that clears/defaults all the necessary member variables to allow for further operations, or to simply construct a new object from outside? I've seen both methods employed a lot, but I can't decide which one is better. Of course, for classes that represent database connections, you'd have to use a reset method rather than constructing a new one resulting in needless connecting/disconnecting, but I'm talking more in terms of abstraction classes. Can anyone give me some real-world examples of when to use each method? In my particular case I'm thinking mostly in terms of ORM or the Model in MVC. For example, if I would want to retrieve a bunch of database objects for display and modify them in one operation.

  Read the article

• Is this an UITableView -beginUpdates documentation error?

  - by mystify

  I can't wrap my head around what they tried to say here in the docs for -beginUpdate: Call this method if you want subsequent insertions, deletion, and selection operations (for example, cellForRowAtIndexPath: and indexPathsForVisibleRows) to be animated simultaneously. Let's see... cellForRowAtIndexPath: and indexPathsForVisibleRows are both GETTER methods. They do not update anything and do not change anything. So why should I call -beginUpdates before calling these? And what's animated regarding these? Well, nothing, huh? Just want to make sure this is really an error in the docs and I didn't miss something.

  Read the article

• IHTMLTxtRange.execCommand("Copy",false,null) fails due to IE settings

  - by srirambalaji-s

  We have a .Net application that is used for editing/rendering customized HTML documents. It is hosted in IE using the AxSHDocVw.AxWebBrowser controls. We proceed with navigating to "about:blank" page initially then we change the Document by writing our custom values into it. The problem we are facing is the call to IHTMLTxtRange.execCommand("Copy",false,null) is failing if we don't enable the IE Security Settings in the Internet Security zone (Scripting-Allow Programmatic Access to Clipboard ). In order to bypass the security setting ,I tried to point to a local html file initially while navigating. But this fails as soon as I modify the Document. I want to use the IHTMLTxtRange.execCommand("Copy",false,null) command so that I can customize our Copy/Paste operations. Is there any other way I can do this. Please share your ideas inorder to overcome this situation. Thanks. Sriram

  Read the article

• Best practice for partial updates in a RESTful service

  - by magiconair

  I am writing a RESTful service for a customer management system and I am trying to find the best practice for updating records partially. For example, I want the caller to be able to read the full record with a GET request. But for updating it only certain operations on the record are allowed, like change the status from ENABLED to DISABLED. (I have more complex scenarios than this) I don't want the caller to submit the entire record with just the updated field for security reasons (it also feels like overkill). Is there a recommended way of constructing the URIs? Do I use GET, POST, PUT or is there no agreed way of doing these kind of things? When reading the REST books RPC style calls seem to be frowned upon. Thanks Frank

  Read the article

• C++ threaded class design from non-threaded class

  - by macs

  I'm working on a library doing audio encoding/decoding. The encoder shall be able to use multiple cores (i.e. multiple threads, using boost library), if available. What i have right now is a class that performs all encoding-relevant operations. The next step i want to take is to make that class threaded. So i'm wondering how to do this. I thought about writing a thread-class, creating n threads for n cores and then calling the encoder with the appropriate arguments. But maybe this is an overkill and there is no need for another class, so i'm going to make use of the "user interface" for thread-creation. I hope there are any suggestions.

  Read the article

• Performance implications of finalizers on JVM

  - by Alexey Romanov

  According to this post, in .Net, Finalizers are actually even worse than that. Besides that they run late (which is indeed a serious problem for many kinds of resources), they are also less powerful because they can only perform a subset of the operations allowed in a destructor (e.g., a finalizer cannot reliably use other objects, whereas a destructor can), and even when writing in that subset finalizers are extremely difficult to write correctly. And collecting finalizable objects is expensive: Each finalizable object, and the potentially huge graph of objects reachable from it, is promoted to the next GC generation, which makes it more expensive to collect by some large multiple. Does this also apply to JVMs in general and to HotSpot in particular?

  Read the article

• Genetic programming in c++, library suggestions?

  - by shuttle87

  I'm looking to add some genetic algorithms to an Operations research project I have been involved in. Currently we have a program that aids in optimizing some scheduling and we want to add in some heuristics in the form of genetic algorithms. Are there any good libraries for generic genetic programming/algorithms in c++? Or would you recommend I just code my own? I should add that while I am not new to c++ I am fairly new to doing this sort of mathematical optimization work in c++ as the group I worked with previously had tended to use a proprietary optimization package. We have a fitness function that is fairly computationally intensive to evaluate and we have a cluster to run this on so parallelized code is highly desirable. So is c++ a good language for this? If not please recommend some other ones as I am willing to learn another language if it makes life easier. thanks!

  Read the article

• R: simple and short if clauses for combind statements

  - by jorgusch

  Hello, TRUE/FALSE if clauses are easily and quickly done in R. However, if the argument gets more complex, it also gets ugly very soon. For instance: I might want to execute different operations for a row(foo) dependent on the value in one cell (foo[1]). Let the intervals be 0:39 and 40:59 and 60:100 Something like does not exit: (if foo[1] "in" 40:60){... In fact, I only see ways of at least two if clauses and two else statements and the action for the first interval somewhere at the bottom of the code. With more intervals(or any other condition) it is getting more complex. Is there a best practice (for this purpose or others) with a simple construction and nice design to read? Thanks a lot!

  Read the article

• Hebbian learning

  - by Bane

  I have asked another question on Hebbian learning before, and I guess I got a good answer which I accepted, but, the problem is that I now realize that I've mistaken about Hebbian learning completely, and that I'm a bit confused. So, could you please explain how it can be useful, and what for? Because the way Wikipedia and some other pages describe it - it doesn't make sense! Why would we want to keep increasing the weight between the input and the output neuron if the fire together? What kind of problems can it be used to solve, because when I simulate it in my head, it certainly can't do the basic AND, OR, and other operations (say you initialize the weights at zero, the output neurons never fire, and the weights are never increased!)

  Read the article

• Time complexity O() of isPalindrome()

  - by Aran

  I have this method, isPalindrome(), and I am trying to find the time complexity of it, and also rewrite the code more efficiently. boolean isPalindrome(String s) { boolean bP = true; for(int i=0; i<s.length(); i++) { if(s.charAt(i) != s.charAt(s.length()-i-1)) { bP = false; } } return bP; } Now I know this code checks the string's characters to see whether it is the same as the one before it and if it is then it doesn't change bP. And I think I know that the operations are s.length(), s.charAt(i) and s.charAt(s.length()-i-!)). Making the time-complexity O(N + 3), I think? This correct, if not what is it and how is that figured out. Also to make this more efficient, would it be good to store the character in temporary strings?

  Read the article

• How does one implement a truly asynchronous java thread

  - by Ritesh M Nayak

  I have a function that needs to perfom two operations, one which finishes fast and one which takes a long time to run. I want to be able to delegate the long running operation to a thread and I dont care when the thread finishes, but the threads needs to complete. I implemented this as shown below , but, my secondoperation never gets done as the function exits after the start() call. How I can ensure that the function returns but the second operation thread finishes its execution as well and is not dependent on the parent thread ? public void someFunction(String data) { smallOperation() Blah a = new Blah(); Thread th = new Thread(a); th.Start(); } class SecondOperation implements Runnable { public void run(){ // doSomething long running } }

  Read the article

• Replicating Active Directory - testing scenarios

  - by Naeem Sarfraz

  Replicating a production server's Active Directory is possible through a number of approaches as mentioned here and here. I'm looking for a simpler approach if one exists. I have a mixed-mode authentication site that I need to test. Quite simply AD users (internal) will have more privilege's than someone who logs in via forms (external). We have a web service that cache's an AD structure (users & groups). I'm thinking of building a module (http handler I guess?) that will pick up my specially formed URL (http://impersonateduser@localhost/mywebapp) and use the bit before the @ as the username. That will be the username I use for any subsequent operations. How does that sound? Has anyone got other proposals for testing scenarios like this?

  Read the article

• pass php array to jquery with getJSON

  - by robertdd

  i want to pass a php aray to jQuery: $.getimagesarr = function() { $.getJSON('operations.php', {'operation':'getimglist'}, function(data){ var arr = new Array(); arr = data; return arr; }); } var data = $.getimagesarr(); if (data){ jQuery.each(data, function(i, val) { .... }); } it return undefined in php i have this: function getimglist(){ $results = $_SESSION['files']; echo json_encode($results); } it is possible?

  Read the article

• What data is actually stored in a B-tree database in CouchDB?

  - by Andrey Vlasovskikh

  I'm wondering what is actually stored in a CouchDB database B-tree? The CouchDB: The Definitive Guide tells that a database B-tree is used for append-only operations and that a database is stored in a single B-tree (besides per-view B-trees). So I guess the data items that are appended to the database file are revisions of documents, not the whole documents: +---------|### ... | | +------|###|------+ ... ---+ | | | | +------+ +------+ +------+ +------+ | doc1 | | doc2 | | doc1 | ... | doc1 | | rev1 | | rev1 | | rev2 | | rev7 | +------+ +------+ +------+ +------+ Is it true? If it is true, then how the current revision of a document is determined based on such a B-tree? Doesn't it mean, that CouchDB needs a separate "view" database for indexing current revisions of documents to preserve O(log n) access? Wouldn't it lead to race conditions while building such an index? (as far as I know, CouchDB uses no write locks).

  Read the article

• Whats the best data-structure for storing 2-tuple (a, b) which support adding, deleting tuples and c

  - by bhups

  Hi So here is my problem. I want to store 2-tuple (key, val) and want to perform following operations: - keys are strings and values are Integers - multiple keys can have same value - adding new tuples - updating any key with new value (any new value or updated value is greater than the previous one, like timestamps) - fetching all the keys with values less than or greater than given value - deleting tuples. Hash seems to be the obvious choice for updating the key's value but then lookups via values will be going to take longer (O(n)). The other option is balanced binary search tree with key and value switched. So now lookups via values will be fast (O(lg(n))) but updating a key will take (O(n)). So is there any data-structure which can be used to address these issues? Thanks.

  Read the article

• iPhone: One Object, One Thread

  - by GingerBreadMane

  On the iPhone, I would like to do some operations on an image in a separate thread. Rather than dealing with semiphores, locking, etc., I'd like to use the 'One Object, One Thread' method of safely writing this concurrent operation. I'm not sure what is the correct way to copy my object into a new thread so that the object is not accessed in the main thread. Do I use the 'copy' method? If so, do I do this before the thread or inside the thread? ... -(void)someMethod{ UIImage *myImage; [NSThread detachNewThreadSelector:@selector(getRotatedImage:) toTarget:self withObject:myImage]; } -(void)getRotatedImage:(UIImage *)image{ ... ... UIImage *copiedImage = [image copy]; ... ... }

  Read the article

• What's currently the best way to extend Excel using C#?

  - by user169867

  I have the professional versions of VS2008 & VS2010. I wish to add a couple buttons to a toolbar in Excel. When they are clicked I'd like to be able to open a form (either WinForms or WPF is fine) collect a few values from the user in the form and then take that data + read cell values from the current worksheet to perform some database operations. What's currently the best way to do this using C#? I'd greatly appreciate a pointer to any examples / tutorials. My understanding is that VS2010 has improved the process alot but I may have to deal w/ Excel 2003 which I don't think it supports. I get confused between Visual Studio 2008s Extensibility-Shared Addin template and other Office Addin templates I've seen. I'm not sure when which type of solution is appropriate. I'm new to Office development so I'd really appreciate any help to get me going on the right track. Thanks much.

  Read the article

• How to use a object whose copy constructor and copy assignment is private?

  - by coanor

  In reading TCPL, I got a problem, as the title refered, and then 'private' class is: class Unique_handle { private: Unique_handle& operator=(const Unique_handle &rhs); Unique_handle(const Unique_handle &rhs); public: //... }; the using code is: struct Y { //... Unique_handle obj; }; and I want to execute such operations: int main() { Y y1; Y y2 = y1; } although, these code are come from TCPL, but I still can not got the solution... Can anybody help me, appreciate.

  Read the article

• ContextSwitchDeadlock Was Detected error in C#

  - by assassin

  Hi, I am running a C# application, and during run-time I get the following error: The CLR has been unable to transition from COM context 0x20e480 to COM context 0x20e5f0 for 60 seconds. The thread that owns the destination context/apartment is most likely either doing a non pumping wait or processing a very long running operation without pumping Windows messages. This situation generally has a negative performance impact and may even lead to the application becoming non responsive or memory usage accumulating continually over time. To avoid this problem, all single threaded apartment (STA) threads should use pumping wait primitives (such as CoWaitForMultipleHandles) and routinely pump messages during long running operations. Can anyone please help me out with the problem here? Thanks a lot.

  Read the article

• Is it possible to compute the minimum of three numbers by using two comparisons at the same time?

  - by Milo Hou

  I've been trying to think up of some way that I could do two comparisons at the same time to find the greatest/least of three numbers. Arithmetic operations on them are considered "free" in this case. That is to say, the classical way of finding the greater of two, and then comparing it to the third number isn't valid in this case because one comparison depends on the result of the other. Is it possible to use two comparisons where this isn't the case? I was thinking maybe comparing the differences of the numbers somehow or their products or something, but came up with nothing. Just to reemphasize, two comparisons are still done, just that neither comparison relies on the result of the other comparison. EDIT: what about: boolA = A^2 + B^2 < C^2 boolB = A > B if boolA then max=C else if boolB then max=A else max=B

  Read the article

• Sql Server 2000 Stored Procedure Prevent Parallelism or something?

  - by user187305

  I have a huge disgusting stored procedure that wasn't slow a couple months ago, but now is. I barely know what this thing does and I am in no way interested in rewriting it. I do know that if I take the body of the stored procedure and then declare/set the values of the parameters and run it in query analyzer that it runs more than 20x faster. From the internet, I've read that this is probably due to a bad cached query plan. So, I've tried running the sp with "WITH RECOMPILE" after the EXEC and I've also tried putting the "WITH RECOMPLE" inside the sp, but neither of those helped even a little bit. When I look at the execution plan of the sp vs the query, the biggest difference is that the sp has "Parallelism" operations all over the place and the query doesn't have any. Can this be the cause of the difference in speeds? Thank you, any ideas would be great... I'm stuck.

  Read the article

• RESTful application validation. Mix of frontend/backend validation. How?

  - by Julian Davchev

  Hi. Using RESTful for all backend persistance and operations. I just pass data from frontend (by frontend I don't mean clientside but the part that is making use of the REST) to rest and data gets back success or no with validation errors if any. Thing is I have stuff that should be validated on frontend too..like csrf tokens, captcha etc. Only reasonable way is I mix validation coming from token/captcha checks and validation errors coming back from REST. Issue with this will be kinda automation as I wouldn't want form field names to map 1:1 with backend field names use by the REST documents. Any pointers ideas are more than welcome.

  Read the article

• Why is forwarding variadic parameters invalid?

  - by awesomeyi

  Consider the variadic function parameter: func foo(bar:Int...) -> () { } Here foo can accept multiple arguments, eg foo(5,4). I am curious about the type of Int... and its supported operations. For example, why is this invalid? func foo2(bar2:Int...) -> () { foo(bar2); } Gives a error: Could not find an overload for '_conversion' that accepts the supplied arguments Why is forwarding variadic parameters invalid? What is the "conversion" the compiler is complaining about?

  Read the article

• How does Ruby's Enumerator object iterate externally over an internal iterator?

  - by Salman Paracha

  As per Ruby's documentation, the Enumerator object uses the each method (to enumerate) if no target method is provided to the to_enum or enum_for methods. Now, let's take the following monkey patch and its enumerator, as an example o = Object.new def o.each yield 1 yield 2 yield 3 end e = o.to_enum loop do puts e.next end Given that the Enumerator object uses the each method to answer when next is called, how do calls to the each method look like, every time next is called? Does the Enumeartor class pre-load all the contents of o.each and creates a local copy for enumeration? Or is there some sort of Ruby magic that hangs the operations at each yield statement until next is called on the enumeartor? If an internal copy is made, is it a deep copy? What about I/O objects that could be used for external enumeration? I'm using Ruby 1.9.2.

  Read the article

< Previous Page | 96 97 98 99 100 101 102 103 104 105 106 107  | Next Page >