Search Results

Search found 7324 results on 293 pages for 'operations research'.

Page 186/293 | < Previous Page | 182 183 184 185 186 187 188 189 190 191 192 193  | Next Page >

• Optimality of Binary Search

  - by templatetypedef

  Hello all- This may be a silly question, but does anyone know of a proof that binary search is asymptotically optimal? That is, if we are given a sorted list of elements where the only permitted operation on those objects is a comparison, how do you prove that the search can't be done in o(lg n)? (That's little-o of lg n, by the way.) Note that I'm restricting this to elements where the only operation permitted operation is a comparison, since there are well-known algorithms that can beat O(lg n) on expectation if you're allowed to do more complex operations on the data (see, for example, interpolation search). Thanks so much! This has really been bugging me since it seems like it should be simple but has managed to resist all my best efforts. :-)

  Read the article

• IDL-like parser that turns a document definition into powerful classes?

  - by paniq

  I am looking for an IDL-like (or whatever) translator which turns a DOM- or JSON-like document definition into classes which are accessible from both C++ and Python, within the same application expose document properties as ints, floats, strings, binary blobs and compounds: array, string dict (both nestable) (basically the JSON type feature set) allow changes to be tracked to refresh views of an editing UI provide a change history to enable undo/redo operations can be serialized to and from JSON (can also be some kind of binary format) allow to keep large data chunks on disk, with parts only loaded on demand provide non-blocking thread-safe read/write access to exchange data with realtime threads allow multiple editors in different processes (or even on different machines) to view and modify the document The thing that comes closest so far is the Blender 2.5 DNA/RNA system, but it's not available as a separate library, and badly documented. I'm most of all trying to make sure that such a lib does not exist yet, so I know my time is not wasted when I start to design and write such a thing. It's supposed to provide a great foundation to write editing UI components.

  Read the article

• Reading files with Java

  - by sikas

  I would like to know how can I read a file byte by byte then perform some operation every n bytes. for example: Say I have a file of size = 50 bytes, I want to divide it into blocks each of n bytes. Then each block is sent to a function for some operations to be done on those bytes. The blocks are to be created during the read process and sent to the function when the block reaches n bytes so that I don`t use much memory for storing all blocks. I want the output of the function to be written/appended on a new file. This is what I've reached to read, yet I don't know it it is right: fc = new JFileChooser(); File f = fc.getSelectedFile(); FileInputStream in = new FileInputStream(f); byte[] b = new byte[16]; in.read(b); I haven't done anything yet for the write process.

  Read the article

• Using Selenium 2's IWebDriver to interact with elements on the page

  - by Andreas Grech

  I'm using Selenium's IWebDriver to write Unit Tests in C#. Such is an example: IWebDriver defaultDriver = new InternetExplorerDriver(); var ddl = driver.FindElements(By.TagName("select")); The last line retrieves the select HTML element wrapped in a IWebElement. I need a way to simulate selection to a specific option in that select list but I can't figure out how to do it. Upon some research, I found examples where people are using the ISelenium DefaultSelenium class to accomplish the following, but I am not making use of this class because I'm doing everything with IWebDriver and INavigation (from defaultDriver.Navigate()). I also noticed that ISelenium DefaultSelenium contains a ton of other methods that aren't available in the concrete implementations of IWebDriver. So is there any way I can use IWebDriver and INavigation in conjunction with ISelenium DefaultSelenium ?

  Read the article

• Counting arrays in loop

  - by Ivory Santos

  I have a loop... while($rows=mysql_fetch_array($result)) { $staff[] = $rows['staff']; $a = array_count_values($staff); $b = count($a); echo"$b<br>"; } that output 1 1 1 2 2 2 3 3 4 5 5 on my research, it must be and I wanted the result to be this way 3 (is equal to three 1's) 3 (is equal to three 2's) 2 (is equal to two 3) 1 (is equal to one 4) 2 (is equal to two 5's) any help? what I want is to get the number of same element in an array

  Read the article

• Real time updates in php for a pbbg. (Php, JavaScript, and html)

  - by Darknesschaos

  I am trying to create a PBBG (persistent browser based game) like that of OGame, Space4k, and others. My problem is with the always-updating resource collection and with the building times, as in a time is set when the building, ship, research, and etc completes building and updates the user's profile even if the user is offline. What and/or where should I learn to make this? Should it be a constantly running script in the background Note that I wish to only use PHP, HTML, CSS, JavaScript, and Mysql but will learn something new if needed. Cron jobs or the Windows equivalent seem to be the way, but it doesn't seem right or best to me.c

  Read the article

• Construction an logical expression which will count bits in a byte.

  - by danatel

  When interviewing new candidates, we usually ask them to write a piece of C code to count the number of bits with value 1 in a given byte variable (e.g. the byte 3 has two 1-bits). I know all the common answers, such as right shifting eight times, or indexing constant table of 256 precomputed results. But, is there a smarter way without using the precomputed table? What is the shortest combination of byte operations (AND, OR, XOR, +, -, binary negation, left and right shift) which computes the number of bites?

  Read the article

• Reranging a uitableview

  - by Nicolay

  Hallo @ All I ran into the same problem as desciped in http://stackoverflow.com/questions/1884491/crashing-while-trying-to-move-uitableview-rows! All I want to do is on specific reranging operations insert a new cell or delet the selected one! Sometimes I get a * Assertion failure in -[_UITableViewUpdateSupport _setupAnimationForReorderingRow], /SourceCache/UIKit/UIKit-963.10/UITableViewSupport.m:295 Attempt to create two animations for cell exception and when I want to reload my data by calling [self.tableView reloadData] I get a * Terminating app due to uncaught exception 'NSRangeException', reason: '* -[NSCFArray objectAtIndex:]: index (0) beyond bounds (0)' This is quiet anoying! Is there anybody out there who knows how to handle this problem? Please help me!

  Read the article

• Iterate attributes and IBOutlets of a UIViewController

  - by Espuz

  I've a generic UIViewController on my app. All the UIViewController on the app inherits from this generic one. I'm trying to automate the deallocation and releasing of attributes and IBOutlets as properties. I'm doing the first (attributes) on dealloc method and the second (IBOutlets as properties) on viewDidUnload. - (void) dealloc { [_att1 release]; _att1 = nil; [_att2 release]; _att2 = nil; // ... } - (void) viewDidUnload { self.att1 = nil; // att1 is an IBOutlet self.att2 = nil; // att2 is an IBOutlet // ... } Is there any way to iterate all my attributes and IBOutlets to simplify this operations? I want to avoid do it for each outlet and attribute and delegate it to the generic UIViewController. Thanks.

  Read the article

• Calling asynchronous methods from wcf service

  - by hima

  In my asp.net application, I am using wcf service to get all the business logic. I am using that service reference in my application to work with that. Now adding that service reference is giving another option Update service reference is giving Generate asynchronous operations. If I check the option and add the service will it generate asynchronous methods for my existing service. If so how do I use the metohd. Let me know the way for that. Thanks, Hima.

  Read the article

• C++ / Java: Toggle boolean statement?

  - by Martijn Courteaux

  Hi, Is there a short way to toggle a boolean? With integers we can do operations like this: int i = 4; i *= 4; // equals 16 /* Which is equivalent to */ i = i * 4; So is there also something for booleans (like the *= operator for ints)? In C++: bool booleanWithAVeryLongName = true; booleanWithAVeryLongName = !booleanWithAVeryLongName; // Can it shorter? booleanWithAVeryLongName !=; // Or something? In Java: boolean booleanWithAVeryLongName = true; booleanWithAVeryLongName = !booleanWithAVeryLongName; // Can it shorter? booleanWithAVeryLongName !=; // Or something?

  Read the article

• g++: Use ZIP files as input

  - by Notinlist

  We have the Boost library in our side. It consists of huge amount of files which are not changing ever and only a tiny portion of it is used. We swap the whole boost directory if we are changing versions. Currently we have the Boost sources in our SVN, file by file which makes the checkout operations very slow, especially on Windows. It would be nice if there were a notation / plugin to address C++ files inside ZIP files, something like: // @ZIPFS ASSIGN 'boost' 'boost.zip/boost' #include <boost/smart_ptr/shared_ptr.hpp> Are there any support for compiler hooks in g++? Are there any effort regarding ZIP support? Other ideas?

  Read the article

• Backbone.js "model" query

  - by Novice coder

  I'm a learning coder trying to understand this code from a sample MVC framework. The below code is from a "model" file. I've done research on Backbone.js, but I'm still confused as to exactly how this code pull information from the app's database. For example, how are base_url, Model.prototype, and Collection.prototype being used to retrieve information from the backend? Any help would be greatly appreciated. exports.definition = { config : { "defaults": { "title": "-", "description": "-" }, "adapter": { "type": "rest", "collection_name": "schools", "base_url" : "/schools/", } }, extendModel: function(Model) { _.extend(Model.prototype, { // Extend, override or implement Backbone.Model urlRoot: '/school/', name:'school', parse: function(response, options) { response.id = response._id; return response; }, }); return Model; }, extendCollection: function(Collection) { _.extend(Collection.prototype, { // Extend, override or implement Backbone.Collection urlRoot: '/schools/', name: 'schools', }); return Collection; } }

  Read the article

• Can Silverlight be linked with a C++ static library ?

  - by Niklaos

  Hi, I'm currently doing research to start a new project. This project will be in 2 parts a light Client (probably console) and an heavy one using silverlight. The light client must be cross-platform. However, they will both use the same Core (by the way, the core will need to use the sockets). I'd like to use C++ to build the light client but given that the core is common to both applications, it would be much appreciated if it's could be the same code. So the question is quite simple : Can Silverlight be compilated with a C++ static library ? And if it's possible, what about cross-platform issues (with moonlight) ? If it's not possible. Which language can i use to work with silverlight while being cross-platform ? Because of performance, a compilated language will be better ! Thanks for your expertise :)

  Read the article

• Should I denormalize a has_many has_many?

  - by Cameron

  I have this: class User < ActiveRecord::Base has_many :serials has_many :sites, :through => :series end class Serial < ActiveRecord::Base belongs_to :user belongs_to :site has_many :episodes end class Site < ActiveRecord::Base has_many :serials has_many :users, :through => :serials end class Episode < ActiveRecord::Base belongs_to :serial end I would like to do some operations on User.serials.episodes but I know this would mean all sorts of clever tricks. I could in theory just put all the episode data into serial (denormalize) and then group_by Site when needed. If I have a lot of episodes that I need to query on would this be a bad idea? thanks

  Read the article

• Precision problems of real numbers in Fortran

  - by saladoil

  I've been trying to use Fortran for my research project, with the GNU Fortran compiler (gfortran), latest version, but I've been encountering some problems in the way it processes real numbers. If you have for example the code: program test implicit none real :: y = 23.234, z z = y * 100000 write(*,*) y, z end program You'll get as output: 23.23999 2323400.0. I find this really strange. Can someone tell me what's exactly happening here? Looking at z I can see that y does retain its precision, so for calculations that shouldn't be a problem I suppose. But why is the output of y not exactly the same as the value that I've specified, and what can I do to make it exactly the same?

  Read the article

• Right-click on a Listbox in a Silverlight 4 app.

  - by AngryHacker

  I am trying to implement what I used to take for granted in Winforms applications. I am a Silverlight noob, so hopefully all this is elementary. I have a listbox in a Silverlight 4 app. I'd like to do the following: Right-click on the listbox Have the item under the location where I click highlight itself I'd like a context menu to popup (with my own items in the context menu) From my research so far, it appears that there is no ContextMenu construct in Silverlight, instead we have to build up a Grid/Canvas structure and attach it to a Popup object, which is what is then popped up. My questions are as follows: To accomplish #2, I need some kind of hit test on the listbox. I can't figure out how to do that and my google-fu isn't helping. Once I do identify the index under the mouse, how do I actually select the item? Is there a reusable Context menu component somewhere that I can use? Extra credit if the component allows arbitrary sub-menus.

  Read the article

• python parallel computing: split keyspace to give each node a range to work on

  - by MatToufoutu

  My question is rather complicated for me to explain, as i'm not really good at maths, but i'll try to be as clear as possible. I'm trying to code a cluster in python, which will generate words given a charset (i.e. with lowercase: aaaa, aaab, aaac, ..., zzzz) and make various operations on them. I'm searching how to calculate, given the charset and the number of nodes, what range each node should work on (i.e.: node1: aaaa-azzz, node2: baaa-czzz, node3: daaa-ezzz, ...). Is it possible to make an algorithm that could compute this, and if it is, how could i implement this in python? I really don't know how to do that, so any help would be much appreciated

  Read the article

• powerpoint macro timer

  - by mustafabattal

  Hi, I have to complete a timer on powerpoint, it countsdown for a specificed amount of time when a shape on particular slide is clicked. I heard macros could be a way to do this, but I have very little knowledge about them. With my research I was able to add a macro and pop out a message box when a shape is clicked*. How can I implement a timer with this? VB syntax is pretty unfamiliar to me. What happens after timer finishes is another question though. *with macro in module: sub hello_world() MsgBox( 'hello world!') end sub

  Read the article

• In game programming are global variables bad?

  - by Joe.F

  I know my gut reaction to global variables is "badd!" but in the two game development courses I've taken at my college globals were used extensively, and now in the DirectX 9 game programming tutorial I am using (www.directxtutorial.com) I'm being told globals are okay in game programming ...? The site also recommends using only structs if you can when doing game programming to help keep things simple. I'm really confused on this issue, and all the research I've been trying to do is very confusing. I realize there are issues when using global variables (threading issues, they make code harder to maintain, the state of them is hard to track etc) but also there is a cost associated with not using globals, I'd have to pass a loooot of information around very often which can be confusing and I imagine time-costing, although I guess pointers would speed the process up (this is my first time writing a game in C++.) Anyway, I realize there is probably no "right" or "wrong" answer here since both ways work, but I want my code to be as proper as I can so any input would be good, thank you very much!

  Read the article

• Cross-referencing UML models in VS 2010

  - by cheaster

  I am just starting to explore/use the UML modeling support in Visual Studio 2010 Umltimate. I have created two model projects within a single solution. Let's call them Model A and Model B. I have some data types (classes) defined in Model B. I want to use them as return types for operations in Model A. However, I cannot figure out how to make the types defined in Model B show up in Model A when attempting to set return type on an operation. Any help/suggestions would be greatly appreciated! Thanks!

  Read the article

• Combining XSLT transforms

  - by Flynn1179

  Is there a way to combine two XSLT documents into a single XSLT document that does the same as transforming using the original two in sequence? i.e. Combining XSLTA and XSLTB into XSLTC such that XSLTB( XSLTA( xml )) == XSLTC( xml )? There's three reasons I'd like to be able to do this: Simplifies development; some operations need sequential transforms, and although I can generate a combined one by hand, it's a lot more difficult to maintain that two much simpler, separate transforms. Speed; one transform is in most cases hopefully faster than two. I'm currently working on a program that literally just transforms a data file in XML into an XHTML page capable of editing it using one XSLT, and a second XSLT that transforms the XHTML page back into the data file when it's saved. One test I hope to be able to do is to combine the two, and easily confirm that the 'combined' XSLT should leave the data unchanged.

  Read the article

• Are spinlocks a good choice for a memory allocator?

  - by dsimcha

  I've suggested to the maintainers of the D programming language runtime a few times that the memory allocator/garbage collector should use spinlocks instead of regular OS critical sections. This hasn't really caught on. Here are the reasons I think spinlocks would be better: At least in synthetic benchmarks that I did, it's several times faster than OS critical sections when there's contention for the memory allocator/GC lock. Edit: Empirically, using spinlocks didn't even have measurable overhead in a single-core environment, probably because locks need to be held for such a short period of time in a memory allocator. Memory allocations and similar operations usually take a small fraction of a timeslice, and even a small fraction of the time a context switch takes, making it silly to context switch in the case of contention. A garbage collection in the implementation in question stops the world anyhow. There won't be any spinning during a collection. Are there any good reasons not to use spinlocks in a memory allocator/garbage collector implementation?

  Read the article

• How to detect if breaking an edge will make a graph disjoint?

  - by the_graph_guy

  I have a graph that starts off with a single, root node. Nodes are added one by one to the graph. At node creation time, they have to be linked either to the root node, or to another node, by a single edge. Edges can also be created and deleted (one by one, between any two nodes). Nodes can be deleted one at a time. Node and edge creation, deletion operations can happen in any arbitrary order. OK, so here's my question: When an edge is deleted, is it possible do determine, in constant time (i.e. with an O(1) algorithm), if doing this will divide the graph into two disjoint subgraphs? If it will, then which side of the edge will the root node belong? I'm willing to maintain, within reasonable limits, any additional data structure that can facilitate the derivation of this information. Maybe it is not possible to do it in O(1), if so any pointers to literature will be appreciated.

  Read the article

• Nesting a SharePoint Webpart inside of a User Control

  - by jlech

  I know it's usually the other way around, but I have some extenuating requirements that must be met (read as "No one bothered to do the research and now I have to bail them out") I have a standard user control (ascx) that is to be imported into a SharePoint 2007 website. Due to a design constraint, a sharepoint web part that is also needed has to be nested inside of this user control. So in other words, the user control would have to look something like this: <%@ Control Language="C#" AutoEventWireup="true" CodeFile="foo.ascx.cs" Inherits="foo" %> <div id="container"> ...snipped... <!-- SharePoint web part goes here --> ...snipped... </div> Any help would be appreciated. Thanks!

  Read the article

< Previous Page | 182 183 184 185 186 187 188 189 190 191 192 193  | Next Page >