Search Results

Search found 5119 results on 205 pages for 'genetic algorithm'.

Page 168/205 | < Previous Page | 164 165 166 167 168 169 170 171 172 173 174 175  | Next Page >

• Need to get pixel averages of a vector sitting on 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'm not even clear what this type of math is called. I've created a basic image of what I'm trying to capture here: http://imgur.com/Isjip.gif

  Read the article

• Matching a rotated bitmap to a collage image

  - by Dmi

  Hi, My problem is that I have an image of a detailed street map. On this map, there can be a certain small image of a sign (such as a traffic light icon) rotated at any angle, maybe resized. I have this small image in a bitmap. Is there any algorithm or technique by which I can locate this bitmap if a copy of it exists, rotated and maybe resized, in the large collage image? This is similar to the problem with Augmented Reality and locating the marker image, but mine is only 2D with no perspective distortion.

  Read the article

• Is it possible to manipulate the format on a DataGridView that is bound to a Data Source?

  - by Jack Johnstone

  I´m using SQL Server 2005 and Visual Studio 2008, C#. In the data source (the SQL Server data table) I use the date format mm/dd/yyyy, however, in a forms overview (DataGridView) users would like to see a completely other format, with year, week number and day number of week (yyww,d). I´ve created an algorithm for this transformation, but can I populate the affected cells with yyww,d instead of mm/dd/yyyy? And in that case - how would I do it? I guess I need to do it after the cells are populated, but before they are shown. The generic question is - how do I manipulate the format of Data Source bound DataGridView cells.

  Read the article

• How to map a property for HQL usage only (in Hibernate)?

  - by ManBugra

  i have a table like this one: id | name | score mapped to a POJO via XML with Hibernate. The score column i only need in oder by - clauses in HQL. The value for the score column is calculated by an algorithm and updated every 24 hours via SQL batch process (JDBC). So i dont wanna pollute my POJO with properties i dont need at runtime. For a single column that may be not a problem, but i have several different score columns. Is there a way to map a property for HQL use only? For example like this: <property name="score" type="double" ignore="true"/> so that i still can do this: from Pojo p order by p.score but my POJO implementation can look like this: public class Pojo { private long id; private String name; // ... } No Setter for score provided or property added to implementation. using the latest Hibernate version for Java.

  Read the article

• How to reduce the number of points in (x,y) data

  - by Gowtham

  I have a set of data points: (x1, y1) (x2, y2) (x3, y3) ... (xn, yn) The number of sample points can be thousands. I want to represent the same curve as accurately as possible with minimal (lets suppose 30) set of points. I want to capture as many inflection points as possible. However, I have a hard limit on the number of allowed points to represent the data. What is the best algorithm to achieve the same? Is there any free software library that can help? PS: I have tried to implement relative slope difference based point elimination, but this does not always result in the best possible data representation. Thanks for your time. -Gowtham

  Read the article

• Rearrange a python list into n lists, by column

  - by Ben R

  Trying to solve this at this hour has gotten my mind into a tail-spin: I want to rearrange a list l into a list of n lists, where n is the number of columns. e.g., l = [1,2,3,4,5,6,7,8] n = 5 ==> [[1,6][2,7][3,8][4][5]] another example: l = [1,2,3,4,5,6,7,8,9,10] n = 4 ==> [[1,5,9],[2,6,10],[3,7][4,8] Can someone please help me out with an algorithm? Feel free to use any python awesomeness that's available; I'm sure theres some cool mechanism that's a good fit for this, i just can't think of it.

  Read the article

• NASM: Count how many bits in a 32 Bit number are set to 1.

  - by citronas

  I have a 32 Bit number and want to count know how many bits are 1. I'm thinking of this pseudocode: mov eax, [number] while(eax != 0) { div eax, 2 if(edx == 1) { ecx++; } shr eax, 1 } Is there a more efficient way? I'm using NASM on a x86 processor. (I'm just beginning with assembler, so please do not tell me to use code from extern libraries, because I do not even know how to include them ;) ) (I just found http://stackoverflow.com/questions/109023/best-algorithm-to-count-the-number-of-set-bits-in-a-32-bit-integer which also contains my solution. There are other solutions posted, but unfortunatly I can't seem to figure out, how I would write them in assembler)

  Read the article

• Extracting data points from a matrix and saving them in different matrixes in MATLAB

  - by Hossein

  Hi, I have a 2D Matrix consisting of some coordinates as below(example): Data(X,Y): 45.987543423,5.35000964 52.987544223,5,98765234 Also I have an array consisting of some integers =0 , for example: Cluster(M) 2,0,3,1 each of these numbers in this array corresponds with a row of my 2D Matrix above.For example, it says that row one(coordinate) in the Data Matirx belongs to the cluster 2,second row belongs to cluster 0 and so on. Now I want to have each of the datapoint of each cluster in a separate matrix, for example I want to save datapoints belonging to cluster 1 in a separate matrix, cluster 2 in a separate matrix and so on,.... I can do them manually, but the problem is this has to be an automatic extraction. which means that the number of clusters(range of the numbers in the cluster array varies in each run) so I have to have a general algorithm that does this extraction for me. Can someone help me please? thanks

  Read the article

• Lua: Random: Percentage

  - by jargl

  I'm creating a game and currently have to deal with some math.randomness. As I'm not that strong in Lua, how do you think Can you make an algorithm that uses math.random with a given percentage? I mean a function like this: function randomChance( chance ) -- Magic happens here -- Return either 0 or 1 based on the results of math.random end randomChance( 50 ) -- Like a 50-50 chance of "winning", should result in something like math.random( 1, 2 ) == 1 (?) randomChance(20) -- 20% chance to result in a 1 randomChance(0) -- Result always is 0 However I have no clue how to go on, and I completely suck at algorithms I hope you understood my bad explanation of what I'm trying to accomplish

  Read the article

• saving file name from html form input

  - by user343934

  I am working on python and biopython right now. I have a file upload form and whatever file is uploaded suppose(abc.fasta) then i want to pass same name in execute (abc.fasta) function parameter and display function parameter (abc.aln). Workflow goes like this. ----If submit is not true then display only header and form part --- if submit is true then call execute() and get file name from form input --- Then display the save file result in the same page. File name is same as input. My raw code is here -- http://pastebin.com/FPUgZSSe Any suggestions, changes and algorithm is appreciated Thanks

  Read the article

• PHP: Safe way to store decryptable passwords

  - by Jammer

  I'm making an application in PHP and there is a requirement that it must be possible to decrypt the passwords in order to avoid problems in the future with switching user database to different system. What encryption/decryption algorithm would you suggest? Is it good idea to just store the encrypted value and then compare the future authentication attempts to that value? Are the passwords still as safe as MD5/SHA1 when the private key is not available to the attacker (Hidden in USB drive for example)? I should still use salting, right? What encryption libraries should I use for PHP?

  Read the article

• When to trash hashmap contents to avoid performance degradation?

  - by Jack

  Hello, I'm woking on Java with a large (millions) hashmap that is actually built with a capacity of 10.000.000 and a load factor of .75 and it's used to cache some values since cached values become useless with time (not accessed anymore) but I can't remove useless ones while on the way I would like to entirely empty the cache when its performance starts to degrade. How can I decide when it's good to do it? For example, with 10 millions capacity and .75 should I empty it when it reaches 7.5 millions of elements? Because I tried various threshold values but I would like to have an analytic one. I've already tested the fact that emping it when it's quite full is a boost for perfomance (first 2-3 algorithm iterations after the wipe just fill it back, then it starts running faster than before the wipe) Thanks

  Read the article

• Use CSS selectors to collect HTML elements from a streaming parser (e.g. SAX stream)

  - by Jakub Narebski

  How to parse CSS (CSS3) selector and use it (in jQuery-like way) to collect HTML elements not from DOM (from tree structure), but from stream (e.g. SAX), i.e. using sequential access parser? Are there CSS selectors that need access to DOM (Wikipedia SAX page says that XPath selectors "need to be able to access any node at any time in the parsed XML tree")? I am most inetersted in implementing selector combinators, e.g. 'A B' descendant selector. I prefer solutions describing algorithm, or in Perl.

  Read the article

• C++ - defining static const integer members in class definition

  - by HighCommander4

  My understanding is that C++ allows static const members to be defined inside a class so long as it's an integer type. Why, then, does the following code give me a linker error? #include <algorithm> #include <iostream> class test { public: static const int N = 10; }; int main() { std::cout << test::N << "\n"; std::min(9, test::N); } The error I get is: test.cpp:(.text+0x130): undefined reference to `test::N' collect2: ld returned 1 exit status Interestingly, if I comment out the call to std::min, the code compiles and links just fine (even though test::N is also referenced on the previous line). Any idea as to what's going on? My compiler is gcc 4.4 on Linux.

  Read the article

• How do I restrict the WCF service called by an ASP.NET AJAX page to only allow calls for that page?

  - by NovaJoe

  I have an AjaxControlToolkit DynamicPopulate control that is updated by calls to a WCF service. I know I can check the HttpContext in the service request to see if a user of the page (and thus, the control) is authenticated. However, I don't want anyone clever to be able to call the service directly, even if they're logged in. I want access to the service to be allowed ONLY to requests that are made from the page. Mainly, I don't want anyone to be able to programatically make a large number of calls and then reverse-engineer the algorithm that sits behind the service. Any clever ideas on how this can be done? Maybe I'm over-thinking this? Thanks in advance.

  Read the article

• Generating a beveled edge for a 2D polygon

  - by Metaphile

  I'm trying to programmatically generate beveled edges for geometric polygons. For example, given an array of 4 vertices defining a square, I want to generate something like this. But computing the vertices of the inner shape is baffling me. Simply creating a copy of the original shape and then scaling it down will not produce the desired result most of the time. My algorithm so far involves analyzing adjacent edges (triples of vertices; e.g., the bottom-left, top-left, and top-right vertices of a square). From there, I need to find the angle between them, and then create a vertex somewhere along that angle, depending on how deep I want the bevel to be. And because I don't have much of a math background, that's where I'm stuck. How do I find that center angle? Or is there a much simpler way of attacking this problem?

  Read the article

• 0.20.2 API hadoop version with java 5

  - by abdeslam

  I have started a maven project trying to implement the MapReduce algorithm in java 1.5.0_14. I have chosen the 0.20.2 API hadoop version. In the pom.xml i'm using thus the following dependency: < dependency < groupId>org.apache.hadoop< /groupId> < artifactId>hadoop-core< /artifactId> < version>0.20.2< /version> < /dependency But when I'm using an import to the org.apache.hadoop classes, I get the following error: bad class file: ${HOME_DIR}\repository\org\apache\hadoop\hadoop-core\0.20.2\hadoop-core-0.20.2.jar(org/apache/hadoop/fs/Path.class) class file has wrong version 50.0, should be 49.0. Does someone know how can I solve this issue. Thanks.

  Read the article

• Why is C++ fwrite() producing larger output in release?

  - by waffleShirt

  I recently wrote an implementation of the Canonical Huffman compression algorithm. I have a 500kb test file that can be compressed to about 250kb when running the debug and release builds from within Visual Studio 2008. However when I run the release build straight from the executeable the test file only compresses to about 330kb. I am assuming that something is going wrong when the file is written using fwrite(). I have tested the program and confirmed that uncompressing the files always produces the correct uncompressed file. Does anyone know why this could possibly be? How could the same executeable file be producing different sized outputs based on where it is launched from?

  Read the article

• Run java with highest security setting

  - by Ankiov Spetsnaz

  I'm currently writing an in house coding challenge web application and I am wondering if there is any other security precaution I would need to have other than below java option at runtime. java -Djava.security.manager=default Basically, challenges would be more of single threaded math and algorithm focused. So I would need to enable basic data structure objects and disable any file, sockets, threading or any thing that might be not so important. Based on my quick search turning on security manager as above seems to be a solution but since this is a security related I would like to be sure before it goes alive. Is there anything else I could do more?

  Read the article

• Search pattern in string using regex in obj-c

  - by manileo86

  I'm working on a string pattern match algorithm. I use NSRegularExpression for finding the matches. For ex: I've to find all words starting with '#' in a string.. Currently I use the following regex function: static NSRegularExpression *_searchTagRegularExpression; static inline NSRegularExpression * SearchTagRegularExpression() { if (!_searchTagRegularExpression) { _searchTagRegularExpression = [[NSRegularExpression alloc] initWithPattern:@"(?<!\\w)#([\\w\\._-]+)? options:NSRegularExpressionCaseInsensitive error:nil]; } return _searchTagRegularExpression; } and I use it as below: NSRegularExpression *regexp = SearchTagRegularExpression(); [regexp enumerateMatchesInString:searchString options:0 range:stringRange usingBlock:^(NSTextCheckingResult *result, NSMatchingFlags flags, BOOL *stop) { // comes here for every match with range }]; This works properly. But i just want to know if this is the best way. suggest if there's any better alternative...

  Read the article

• R: how to make a unique set of names from a vector of strings?

  - by Mike Dewar

  Hi, I have a vector of strings. Check out my vector, it's awesome: > awesome [1] "a" "b" "c" "d" "d" "e" "f" "f" I'd like to make a new vector that is the same length as awesome but where, if necessary, the strings have been uniqueified. For example, a valid output of my desired function would be > awesome.uniqueified [1] "a" "b" "c" "d.1" "d.2" "e" "f.1" "f.2" Is there an easy, R-thonic and beautiful way to do this? I should say my list in real life (it's not called awesome) contains 25000ish mircoarray probeset identifiers. I'm always nervous when I embark on writing little generic functions (which I'm sure I could do) as I'm sure some R guru has come across this problem in the past, nailed it with some incredible algorithm that doesn't even have to store more than half an element in the vector. I'm just not sure what they might have called it. Probably not uniqueify.

  Read the article

• Alternative to latex / a way to typeset good looking documents from Java to PDF

  - by drasto

  I'm working on application in Java that will maintain database of song lyrics in plain text and print out some songbooks/chordbooks(that is create PDF file from selected songs). I was planing that the Java application will generate source code for pdflatex and after compiling this source user will get PDF file. Lately I've run into a lot of problems because of latex limitation: fixed memory size (some pictures will also be drawn to PDF) - error when exceeded, no way to query end of line or and of page dynamically, it's very hard to override latex placement algorithm in a complex way,... see also some my other questions regarding latex. I come to conclusion that latex is not good option for automated PDF generation. So I need replacement. I need to be able to typeset: Chords over lyrics when the lyrics are in variable char width so I need to be able to measure text width Chord diagrams that means I'll have to draw quite complex pictures Each song on separate double page Different fonts etc. Thanks for all answers

  Read the article

• UML and Documenting Simple Diagrams

  - by Jason

  As part of a rewrite of an old Java application into C#, I'm writing an actual Software Design Specification. A problem I run into is when a method is too simple to bother with a Sequence Diagram (it doesn't interact with other objects). As an example, I have a simple POJO called Item, containing the following method: public String getCategoryKey() { StringBuffer value = new StringBuffer("s-"); value.append(this.getModelID()); value.append("-c"); return value; } The purpose and the algorithm for the method needs to be documented. However, a sequence diagram is overkill. How would others document it? (I take no credit/blame for the given method, it's very old code and the author "forgot" to put their name in the Javadoc).

  Read the article

• k-means clustering in R on very large, sparse matrix?

  - by movingabout

  Hello, I am trying to do some k-means clustering on a very large matrix. The matrix is approximately 500000 rows x 4000 cols yet very sparse (only a couple of "1" values per row). The whole thing does not fit into memory, so I converted it into a sparse ARFF file. But R obviously can't read the sparse ARFF file format. I also have the data as a plain CSV file. Is there any package available in R for loading such sparse matrices efficiently? I'd then use the regular k-means algorithm from the cluster package to proceed. Many thanks

  Read the article

• How to test Text Search accuracy and efficiency?

  - by DEN

  I have created a web application. One of the feature is text search which perform the boolean operator ( NOT, AND, OR) as well. However, I have no idea on calculating the search's accuracy and efficiency. For example: 1 . Probe identification system for a measurement instrument 2 . Pulse-based impedance measurement instrument 3 . Millimeter with filtered measurement mode when the user key in will return the result as below input :measurement instrument Result: 1,2 input : measurement OR instrument NOT milimeter Result: 1,2,3 so, i have no idea on what issue and what algorithm to calculate on the accuracy and efficiency of the text search.. anyone have any idea on that?

  Read the article

< Previous Page | 164 165 166 167 168 169 170 171 172 173 174 175  | Next Page >