Search Results

Search found 1889 results on 76 pages for 'evolutionary algorithms'.

Page 55/76 | < Previous Page | 51 52 53 54 55 56 57 58 59 60 61 62  | Next Page >

• Efficient algorithm for finding largest eigenpair of small general complex matrix

  - by mklassen

  I am looking for an efficient algorithm to find the largest eigenpair of a small, general (non-square, non-sparse, non-symmetric), complex matrix, A, of size m x n. By small I mean m and n is typically between 4 and 64 and usually around 16, but with m not equal to n. This problem is straight forward to solve with the general LAPACK SVD algorithms, i.e. gesvd or gesdd. However, as I am solving millions of these problems and only require the largest eigenpair, I am looking for a more efficient algorithm. Additionally, in my application the eigenvectors will generally be similar for all cases. This lead me to investigate Arnoldi iteration based methods, but I have neither found a good library nor algorithm that applies to my small general complex matrix. Is there an appropriate algorithm and/or library?

  Read the article

• Fuzzy Regular Expressions

  - by Thomas Ahle

  In my work I have with great results used approximate string matching algorithms such as Damerau–Levenshtein distance to make my code less vulnerable to spelling mistakes. Now I have a need to match strings against simple regular expressions such TV Schedule for \d\d (Jan|Feb|Mar|...). This means that the string TV Schedule for 10 Jan should return 0 while T Schedule for 10. Jan should return 2. This could be done by generating all strings in the regex (in this case 100x12) and find the best match, but that doesn't seam practical. Do you have any ideas how to do this effectively?

  Read the article

• What are some interesting fringe programming topics that might have hands-on training?

  - by hal10001

  Whenever training topic questions are asked, the answers are fairly typical, and involve a pretty limited subset of topics like OO, design patterns, algorithms, web services, SQL, etc., but I wonder if there are some fringe topics that are still applicable to the programming field and would give me a more rounded approach to development. When I think of "fringe", I think of 2600: The Hacker Quarterly articles that discuss how to use real world (sometimes obscure) exploits, or something like Maker Faire that demonstrates embedded systems programming using Arduino. I have around $1500-2000 to spend, and my job entails Java technologies, but that does not limit my options.

  Read the article

• Red-Black trees - Erasing a node with two non-leaf children

  - by SalamiArmi

  Hi all, I've been implementing my own version of a red-black tree, mostly basing my algorithms from Wikipedia (http://en.wikipedia.org/wiki/Red-black_tree). Its fairly concise for the most part, but there's one part that I would like clarification on. When erasing a node from the tree that has 2 non-leaf (non-NULL) children, it says to move either side's children into the deletable node, and remove that child. I'm a little confused as to which side to remove from, based on that. Do I pick the side randomly, do I alternate betweek sides, or do I stick to the same side for every future deletion?

  Read the article

• How to structure a Genetic Algorithm class hierarchy?

  - by MahlerFive

  I'm doing some work with Genetic Algorithms and want to write my own GA classes. Since a GA can have different ways of doing selection, mutation, cross-over, generating an initial population, calculating fitness, and terminating the algorithm, I need a way to plug in different combinations of these. My initial approach was to have an abstract class that had all of these methods defined as pure virtual, and any concrete class would have to implement them. If I want to try out two GAs that are the same but with different cross-over methods for example, I would have to make an abstract class that inherits from GeneticAlgorithm and implements all the methods except the cross-over method, then two concrete classes that inherit from this class and only implement the cross-over method. The downside to this is that every time I want to swap out a method or two to try out something new I have to make one or more new classes. Is there another approach that might apply better to this problem?

  Read the article

• How to extend WPF hit testing zone for a Path object.

  - by user275587

  Wpf hit testing is pretty good but the only method I found to extend the hit zone is to put a transparent padding area around your object. I can't find any method to add a transparent area arround a Path object. The path is very thin and I would like to enable hit testing if the user clicks near the path. I can't find any method to extend the path object with a transparent area like the image below : I tried to used a partially transparent stroke brush but I ran into the problem described here : http://stackoverflow.com/questions/1412833/how-can-i-draw-a-soft-line-in-wpf-presumably-using-a-lineargradientbrush I also tried to put an adorner over my line but because of WPF anti-aliasing algorithms, the position is way off when I zoom in my canvas and interfere with other objects hit-testing in a bad way. Any suggestion to extend the hit testing zone would be highly appreciated. Thanks, Kumar

  Read the article

• What to learn in my summer holidays?

  - by rgksugan

  I am finishing my graduate and i am into a sotware company. I am a fresher and have some knowledge in Java and JEE. I can program servlets and JSP and have also developed some Swing applications. I dont have that much knowledge in web frameworks. I want to use my holidays usefully at the same time i dont want to spend a lot of time into programming. What can i learn. Suggest me something usefull. I prefer learning some programming tips/algorithms.

  Read the article

• Concurrency Problem in Java ...

  - by Tara Singh

  I am designing a client-server chat application in Java. This is a secure application where the messages are exchanged using cryptographic algorithms. I have one server and it can support many clients. My problem is that when one client logs on the server it works fine, but when another user logs into the system, the server starts giving me bad padding exceptions for the encrypted text. I am not able to figure out the problem, according to my logic, when new connection request to server is made, the server creates a thread for listening to the client. Is it possible that once the instance of thread class is created, it does all the processing correctly for the first client, but not for the second client because the variables in server listener thread class already have some previous value, and thus the encrypted text is not decrypted properly? Please advise how I can make this process more robust so that the number of clients does not affect how well the server functions.

  Read the article

• Computing orientation of a square and displaying an object with the same orientation

  - by Robin

  Hi, I wrote an application which detects a square within an image. To give you a good understanding of how such an image containing such a square, in this case a marker, could look like: What I get, after the detection, are the coordinates of the four corners of my marker. Now I don't know how to display an object on my marker. The object should have the same rotation/angle/direction as the marker. Are there any papers on how to achieve that, any algorithms that I can use that proofed to be pretty solid/working? It doesn't need to be a working solution, it could be a simple description on how to achieve that or something similar. If you point me at a library or something, it should work under linux, windows is not needed but would be great in case I need to port the application at some point. I already looked at the ARToolkit but they you camera parameter files and more complex matrices while I only got the four corner points and a single image instead of a whole video / camera stream.

  Read the article

• How to spot empty parking spaces?

  - by mithila

  I want to do a final year B.Sc project on parking space detection. Can anybody give me some link related to it? Any text-book, tutorial or anything? What would be prerequisite for this project? What type of skills(programming/math) are needed? What are the initial steps to do? What type of readings(algorithms of image processing) are needed? Detail added in comments: i'm going to use camera, not infrared. i would like to use still images, or one camera which captures images from a parking lot. i think reak-time processing will be tough, at this moment i just need to start the project. so still images will work fine. but later it may b a real-time project

  Read the article

• Static Evaluation Function for Checkers

  - by Kamikaze

  Hi all! I'm trying to write an evaluation function for a game of checkers that I'm developing but I can't find the right documentation. I've read several documents on the web witch describe different techniques for either writing one or letting the computer find it(using genetic algorithms or Bayesian learning) but they're too complicated for a novice like me. All documents pointed a reference to "Some studies in machine learning using the game of checkers" by A.L.Samuel but I couldn't get my hands on it yet :(. I've only read the follow up "Some studies in machine learning using the game of checkers -II" and found some good info there, but it doesn't explain what the eval parameters mean (I think I don't have the whole article). Thanks for your help!

  Read the article

• Is regex too slow? Real life examples where simple non-regex alternative is better

  - by polygenelubricants

  I've seen people here made comments like "regex is too slow!", or "why would you do something so simple using regex!" (and then present a 10+ lines alternative instead), etc. I haven't really used regex in industrial setting, so I'm curious if there are applications where regex is demonstratably just too slow, AND where a simple non-regex alternative exists that performs significantly (maybe even asymptotically!) better. Obviously many highly-specialized string manipulations with sophisticated string algorithms will outperform regex easily, but I'm talking about cases where a simple solution exists and significantly outperforms regex. What counts as simple is subjective, of course, but I think a reasonable standard is that if it uses only String, StringBuilder, etc, then it's probably simple.

  Read the article

• Handling User Authentication in C#.NET?

  - by Daniel

  I am new to .NET, and don't have much experience in programming. What is the standard way of handling user authentication in .NET in the following situation? 1.In Process A, User inputs ID/Password 2.Process A sends the ID/Password to Process B over a nonsecure public channel. 3.Process B authenticates the user with the recieved ID/Password what are some of the standard cryptographic algorithms I can use in above model? The users(customers that bought my company's software) will be running the software(Process A) locally in their computer(connected to internet). I need to authenticate the users so that only registered users can run the program. Thank You!

  Read the article

• Graph Algorithm To Find All Paths Between N Arbitrary Vertices

  - by russtbarnacle

  I have an graph with the following attributes: Undirected Not weighted Each vertex has a minimum of 2 and maximum of 6 edges connected to it. Vertex count will be < 100 I'm looking for paths between a random subset of the vertices (at least 2). The paths should simple paths that only go through any vertex once. My end goal is to have a set of routes so that you can start at one of the subset vertices and reach any of the other subset vertices. Its not necessary to pass through all the subset nodes when following a route. All of the algorithms I've found (Dijkstra,Depth first search etc.) seem to be dealing with paths between two vertices and shortest paths. Is there a known algorithm that will give me all the paths (I suppose these are subgraphs) that connect these subset of vertices?

  Read the article

• Interpolation of scattered data: What could I do?

  - by Simon

  Hi! I need your help. I'm working on a 3D chart in Java using Java 3D. It should be able to display a bunch of measured values. As measured, the data I get is scattered. This means I will have to interpolate the missing points in order to get my surface plotted nicely. I didn't study all that 3D-Geometry stuff yet and I don't know where to start. My idea is to triangulate the points to a surface and then, based on the triangulation, interpolate the missing points. (see this to have a rough idea of what I want to achieve) Does someone have experiences with the interpolation of scattered data? Is my approach the right one? If yes, what kind of data structures and algorithms will I need in order to triangulate my points cloud?

  Read the article

• Functional data structures in C++

  - by drg

  Does anyone know of a C++ data structure library providing functional (a.k.a. immutable, or "persistent" in the FP sense) equivalents of the familiar STL structures? By "functional" I mean that the objects themselves are immutable, while modifications to those objects return new objects sharing the same internals as the parent object where appropriate. Ideally, such a library would resemble STL, and would work well with Boost.Phoenix (caveat- I haven't actually used Phoenix, but as far as I can tell it provides many algorithms but no data structures, unless a lazily-computed change to an existing data structure counts - does it?)

  Read the article

• Plain-English tutorial on artificial neural networks?

  - by Stuart

  I've Googled, StackOverflowed, everything, and I cannot seem to find a tutorial I can understand. I understand the concept of genetic algorithms, and how to implement them, (Though I haven't tried) but I cannot grasp the concept of neural networks. I know vaguely how they work... And that's about it. Could someone direct me to a tutorial that could help someone who has not even graduated middle school yet? Sure, I'm several years ahead of the majority of people my grade, but I don't understand summation, (which I apparently need if I don't want a simple binary output) vectors, and other things that I apparently should know. Is there a simple, bare-bones tutorial for neural networks? After I learn the basics, I'll proceed to more difficult ones. Preferably, they would be in Java. Thanks!

  Read the article

• Which OOD approach should I take?

  - by Sorush Rabiee

  According to Niklaus Wirth, Algorithms + Data Structures = Programs. So I use this as a start point to object-oriented modeling and inheritance design: in a way that I separate the 'Objects' from 'Operations'. then look for patterns and inheritance hierarchy. But now after practice I guess it's not a good idea for every modeling problem, because sometimes it's not effective. (I mean there is no possibility of developing (or is very hard to develop) codes of Turing-Completed languages based on this paradigm.) What is your viewpoint for designing an OOD structure as an experienced programmer?

  Read the article

• What should every programmer know about security ?

  - by M.H

  I am an IT student and I am now in the 3rd year in university,until now we are studing a lot of subjects related to computer in general (Programming,Algorithms,Computer architecture,maths....etc). But there is a whole world called security we are very far from it ,I mean here security in general(Computers Security,Interner Security,Networks Security,hacking,cracking...etc). I am very sure that nobody can learn every thing about security but sure there is a "minimum" knowledge every programmer or IT student should know about it and my question is what is this minimum knowledge ? can you suggest some E-books or courses or any thing can help to start with this road ?

  Read the article

• Discrete and Continuous Classifier on Sparse Data

  - by Chris S

  I'm trying to classify an example, which contains discrete and continuous features. Also, the example represents sparse data, so even though the system may have been trained on 100 features, the example may only have 12. What would be the best classifier algorithm to use to accomplish this? I've been looking at Bayes, Maxent, Decision Tree, and KNN, but I'm not sure any fit the bill exactly. The biggest sticking point I've found is that most implementations don't support sparse data sets and both discrete and continuous features. Can anyone recommend an algorithm and implementation (preferably in Python) that fits these criteria? Libraries I've looked at so far include: Orange (Mostly academic. Implementations not terribly efficient or practical.) NLTK (Also academic, although has a good Maxent implementation, but doesn't handle continuous features.) Weka (Still researching this. Seems to support a broad range of algorithms, but has poor documentation, so it's unclear what each implementation supports.)

  Read the article

• Java - Collections.binarySearch with PriorityQueue?

  - by msr

  Hello, Can I use Collections.binarySearch() method to search elements in a PriorityQueue? Otherwise, how can I apply search algorithms to a PriorityQueue? I have this (class Evento implements Comparable): public class PriorityQueueCAP extends PriorityQueue<Evento>{ // (...) public void removeEventos(Evento evento){ Collections.binarySearch(this, evento); // ERROR! } } And I got this error: "The method binarySearch(List, T) in the type Collections is not applicable for the arguments (PriorityQueueCAP, Evento)" Why? Thanks in advance!

  Read the article

• Evenly select N elems from array

  - by ninuhadida

  Hi, I need to evenly select n elements from an array. I guess the best way to explain is by example. say I have: array [0,1,2,3,4] and I need to select 3 numbers.. 0,3,4. of course, if the array length <= n, I just need to return the whole array. I'm pretty sure there's a defined algorithm for this, been trying to search, and I took a look at Introduction to algorithms but couldn't find anything that met my needs (probably overlooked it) The problem I'm having is that I can't figure out a way to scale this up to any array [ p..q ], selecting N evenly elements. note: I can't just select the even elements from the example above.. A couple other examples; array[0,1,2,3,4,5,6], 3 elements ; I need to get 0,3,6 array[0,1,2,3,4,5], 3 elements ; I need to get 0, either 2 or 3, and 5

  Read the article

• Storing old previous year data in Rails?

  - by Millisami

  Hi, I'm developing an app which has massive data entries. Its like Campaign which has attrs like rate_per_sq_feet, start_date, end_date. i.e it will have max date of around 30 days. Once the campaign is finished, its done and another starts. Now I'm confused that how to store those campaigns as reports so that its not accessed regurlarly. What I mean is to store in such a way that it will act like report on later years to come? Its something like fiscal year on accounts where the previous year reports are stored with all the calculations done so that when retrieved later, all the algorithms and calculations shouldn't be performed. Something like frozen data??

  Read the article

• Good "Modelling & Simulation" book recommendations for programmers?

  - by Harry

  I'm a programmer, and have completely forgotten all the advanced engineering Math I studied ~20 years ago at school. I now have an urgent need to learn about Modelling and Simulation. Though the present context is Disease Modelling, I'm not sure if there's such a thing as 'general' modelling and simulation... with concepts / techniques / algorithms that could be used in just about any domain (and not just limited to biology, finance, trade, economic, weather, etc.) Would you have any recommendations that are easy to read by a semi-Math-literate programmer? Basically, I cannot afford to drown myself in too much Math and theory behind M & S, hence this post. Tia...

  Read the article

• How to perform FST (Finite State Transducer) composition

  - by Tasbeer

  Consider the following FSTs : T1 0 1 a : b 0 2 b : b 2 3 b : b 0 0 a : a 1 3 b : a T2 0 1 b : a 1 2 b : a 1 1 a : d 1 2 a : c How do I perform the composition operation on these two FSTs (i.e. T1 o T2) I saw some algorithms but couldn't understand much. If anyone could explain it in a easy way it would be a major help. Please note that this is NOT a homework. The example is taken from the lecture slides where the solution is given but I couldn't figure out how to get to it.

  Read the article

< Previous Page | 51 52 53 54 55 56 57 58 59 60 61 62  | Next Page >