Search Results

Search found 5070 results on 203 pages for 'algorithm'.

Page 121/203 | < Previous Page | 117 118 119 120 121 122 123 124 125 126 127 128  | Next Page >

• How selectorgadget works?

  - by andrisetiawan

  How selectorgadget.com works? Is there any link/page that explain the algorithm behind selectorgadget? thanks

  Read the article

• Computer Vision Website Image Slideshow help

  - by msandbot

  Hi, I'm making an online display of the output of a computer vision algorithm. After running the algorithm I am left with a folder of about 1000 16 bit .tiff files. I need to put those on the website in a list for so that the researchers can click through and find the list. Also there needs to be an image frame with an "animated gif" feel that can be started stopped and played in reverse. Any ideas on the best way to do this? What language to use? I made a simple website in Ruby on Rails but I don't know if it has the capabilities to do what I require.

  Read the article

• Change a Recursive function that has a for loop in it into an iterative function?

  - by Bill

  So I have this function that I'm trying to convert from a recursive algorithm to an iterative algorithm. I'm not even sure if I have the right subproblems but this seems to determined what I need in the correct way, but recursion can't be used you need to use dynamic programming so I need to change it to iterative bottom up or top down dynamic programming. The basic recursive function looks like this: Recursion(i,j) { if(i>j) return 0; else { //This finds the maximum value for all possible subproblems and returns that for this problem for(int x = i; x < j; x++) { if(some subsection i to x plus recursion(x+1,j) is > current max) max = some subsection i to x plus recursion(x+1,j) } } } This is the general idea, but since recursions typically don't have for loops in them I'm not sure exactly how I would convert this to iterative. Does anyone have any ideas?

  Read the article

• How to compute a unicode string which bidirectional representation is specified?

  - by valdo

  Hello, fellows. I have a rather pervert question. Please forgive me :) There's an official algorithm that describes how bidirectional unicode text should be presented. http://www.unicode.org/reports/tr9/tr9-15.html I receive a string (from some 3rd-party source), which contains latin/hebrew characters, as well as digits, white-spaces, punctuation symbols and etc. The problem is that the string that I receive is already in the representation form. I.e. - the sequence of characters that I receive should just be presented from left to right. Now, my goal is to find the unicode string which representation is exactly the same. Means - I need to pass that string to another entity; it would then render this string according to the official algorithm, and the result should be the same. Assuming the following: The default text direction (of the rendering entity) is RTL. I don't want to inject "special unicode characters" that explicitly override the text direction (such as RLO, RLE, etc.) I suspect there may exist several solutions. If so - I'd like to preserve the RTL-looking of the string as much as possible. The string usually consists of hebrew words mostly. I'd like to preserve the correct order of those words, and characters inside those words. Whereas other character sequences may (and should) be transposed. One naive way to solve this is just to swap the whole string (this takes care of the hebrew words), and then swap inside it sequences of non-hebrew characters. This however doesn't always produce correct results, because actual rules of representation are rather complex. The only comprehensive algorithm that I see so far is brute-force check. The string can be divided into sequences of same-class characters. Those sequences may be joined in random order, plus any of them may be reversed. I can check all those combinations to obtain the correct result. Plus this technique may be optimized. For instance the order of hebrew words is known, so we only have to check different combinations of their "joining" sequences. Any better ideas? If you have an idea, not necessarily the whole solution - it's ok. I'll appreciate any idea. Thanks in advance.

  Read the article

• What garbage collection algorithms do all 5 major browsers use?

  - by Martin Wittemann

  I am currently rethinking the object dispose handling of the qooxdoo JavaScript framework. Have a look at the following diagram (A is currently in scope): Let's say we want to delete B. Generally, we cut all reference between all objects. This means we cut connection 1 to 5 in the example. Is this really necessary? As far as I have read hear 1, browsers use the mark-and-sweep algorithm. In that case, we just need to cut reference 1 (connection to the scope) and 5 (connection to the DOM) which could be much faster. But can I be sure that all browsers use the mark-and-sweep algorithm or something similar? 1 http://stackoverflow.com/questions/864516/what-is-javascript-garbage-collection

  Read the article

• Implementation of a distance matrix of a binary tree that is given in the adjacency-list representation

  - by Denise Giubilei

  Given this problem I need an O(n²) implementation of this algorithm: "Let v be an arbitrary leaf in a binary tree T, and w be the only vertex connected to v. If we remove v, we are left with a smaller tree T'. The distance between v and any vertex u in T' is 1 plus the distance between w and u." This is a problem and solution of a Manber's exercise (Exercise 5.12 from U. Manber, Algorithms: A Creative Approach, Addison-Wesley (1989).). The thing is that I can't deal properly with the adjacency-list representation so that the implementation of this algorithm results in a real O(n²) complexity. Any ideas of how the implementation should be? Thanks.

  Read the article

• in java, which is better - three arrays of booleans or 1 array of bytes?

  - by joe_shmoe

  I know the question sounds silly, but consider this: I have an array of items and a labelling algorithm. at any point the item is in one of three states. The current version holds these states in a byte array, where 0, 1 and 2 represent the three states. alternatively, I could have three arrays of boolean - one for each state. which is better (consumes less memory) depends on how jvm (sun's version) stores the arrays - is a boolean represented by 1 bit? (p.s. don't start with all that "this is not the way OO/Java works" - I know, but here performance comes in front. plus the algorithm is simple and perfectly readable even in such form). Thanks a lot

  Read the article

• large test data for knapsack problem

  - by user347918

  i am researcher student. I am searching large data for knapsack problem. I wanted test my algorithm for knapsack problem. But i couldn't find large data. I need data has 1000 item and capacity is no matter. The point is item as much as huge it's good for my algorithm. Is there any huge data available in internet. Does anybody know please guys i need urgent.

  Read the article

• Detecting similar words among n text documents

  - by javanes

  Hi; I have n documents and want to find common words that are included in these documents. For example I want to say (n-3) documents include the word "web". Certainly I can do this by basic data structures but there maybe efficient algorithm or a way to handle same words with different suffix. Is there any algorithm for such purposes? I am unfamiliar with datamining world. In general manner is there a term used for efforts of finding similarities between different documents? If there is then I will make my research easily. Thanks.

  Read the article

• Approaches for Content-based Item Recommendations

  - by PartlyCloudy

  Hello, I'm currently developing an application where I want to group similar items. Items (like videos) can be created by users and also their attributes can be altered or extended later (like new tags). Instead of relying on users' preferences as most collaborative filtering mechanisms do, I want to compare item similarity based on the items' attributes (like similar length, similar colors, similar set of tags, etc.). The computation is necessary for two main purposes: Suggesting x similar items for a given item and for clustering into groups of similar items. My application so far is follows an asynchronous design and I want to decouple this clustering component as far as possible. The creation of new items or the addition of new attributes for an existing item will be advertised by publishing events the component can then consume. Computations can be provided best-effort and "snapshotted", which means that I'm okay with the best result possible at a given point in time, although result quality will eventually increase. So I am now searching for appropriate algorithms to compute both similar items and clusters. At important constraint is scalability. Initially the application has to handle a few thousand items, but later million items might be possible as well. Of course, computations will then be executed on additional nodes, but the algorithm itself should scale. It would also be nice if the algorithm supports some kind of incremental mode on partial changes of the data. My initial thought of comparing each item with each other and storing the numerical similarity sounds a little bit crude. Also, it requires n*(n-1)/2 entries for storing all similarities and any change or new item will eventually cause n similarity computations. Thanks in advance! UPDATE tl;dr To clarify what I want, here is my targeted scenario: User generate entries (think of documents) User edit entry meta data (think of tags) And here is what my system should provide: List of similar entries to a given item as recommendation Clusters of similar entries Both calculations should be based on: The meta data/attributes of entries (i.e. usage of similar tags) Thus, the distance of two entries using appropriate metrics NOT based on user votings, preferences or actions (unlike collaborative filtering). Although users may create entries and change attributes, the computation should only take into account the items and their attributes, and not the users associated with (just like a system where only items and no users exist). Ideally, the algorithm should support: permanent changes of attributes of an entry incrementally compute similar entries/clusters on changes scale something better than a simple distance table, if possible (because of the O(n²) space complexity)

  Read the article

• how to tesselate bezier triangles?

  - by Cheery

  My concern are quadratic bezier triangles which I'm trying to tesselate for rendering them. I've managed to implement this by subdividing the triangle recursively like described in a wikipedia page. Though I'd like to get more precision to subdivision. The problem is that I'll either get too few subdivisions or too many because the amount of surfaces doubles on every iteration of that algorithm. In particular I would need an adaptive tesselation algorithm that allows me to define the amount of segments at the edges. I'm not sure whether I can get that though so I'd also like to hear about uniform tesselation techniques. Hardest trouble I have trouble with calculating normals for a point in bezier surface, which I'm not sure whether I need, but been trying to solve out.

  Read the article

• I'm trying to implement 2 factor authentication on the cheap. How would I do that?

  - by Biff MaGriff

  Ok so I need 2 of the 3. Something the user knows. Something the user has. Something the user is. I have a system that is exposed to the internet and we need clients to connect in a secure manner to satisfy our security standards. I'm thinking when a user registers to use our system we send them an application that they install on their home system. The application generates a key based on a timed randomness algorithm. Our application server has the same algorithm so when the user submits their credentials with the key we know that they are a legitimate user. Is this a valid method of 2 factor authentication? What is another way of doing this? Are there any pitfalls that I should be aware of? Thanks for your help!

  Read the article

• How to implement HeightMap smoothing using Thrust

  - by igal k

  I'm trying to implement height map smoothing using Thrust. Let's say I have a big array ( around 1 million floats). A known graphics algorithm to implement the above problem is to calculate the average around a given cell. If for example I need to calculate the value at a given cell[i,j] what I will basically do is: cell[i,j] = cell[i-1,j-1] + cell[i-1,j] + cell[i-1,j+1] + cell[i,j-1] + cell[i,j+1] + cell[i+1,j -1] + cell[i+1,j] + cell[i+1,j+1] cell[i,j] /=9 That's the CPU code. Is there a way to implement it using thrust? I know that I could use the transform algorithm. But I'm not sure it's correct to access different cells which are occupied but different threads (banks conflicts and so on).

  Read the article

• Preoblem with Precision floating point operation in C

  - by Microkernel

  Hi Guys, For one of my course project I started implementing "Naive Bayesian classifier" in C. My project is to implement a document classifier application (especially Spam) using huge training data. Now I have problem implementing the algorithm because of the limitations in the C's datatype. ( Algorithm I am using is given here, http://en.wikipedia.org/wiki/Bayesian_spam_filtering ) PROBLEM STATEMENT: The algorithm involves taking each word in a document and calculating probability of it being spam word. If p1, p2 p3 .... pn are probabilities of word-1, 2, 3 ... n. The probability of doc being spam or not is calculated using Here, probability value can be very easily around 0.01. So even if I use datatype "double" my calculation will go for a toss. To confirm this I wrote a sample code given below. #define PROBABILITY_OF_UNLIKELY_SPAM_WORD (0.01) #define PROBABILITY_OF_MOSTLY_SPAM_WORD (0.99) int main() { int index; long double numerator = 1.0; long double denom1 = 1.0, denom2 = 1.0; long double doc_spam_prob; /* Simulating FEW unlikely spam words */ for(index = 0; index < 162; index++) { numerator = numerator*(long double)PROBABILITY_OF_UNLIKELY_SPAM_WORD; denom2 = denom2*(long double)PROBABILITY_OF_UNLIKELY_SPAM_WORD; denom1 = denom1*(long double)(1 - PROBABILITY_OF_UNLIKELY_SPAM_WORD); } /* Simulating lot of mostly definite spam words */ for (index = 0; index < 1000; index++) { numerator = numerator*(long double)PROBABILITY_OF_MOSTLY_SPAM_WORD; denom2 = denom2*(long double)PROBABILITY_OF_MOSTLY_SPAM_WORD; denom1 = denom1*(long double)(1- PROBABILITY_OF_MOSTLY_SPAM_WORD); } doc_spam_prob= (numerator/(denom1+denom2)); return 0; } I tried Float, double and even long double datatypes but still same problem. Hence, say in a 100K words document I am analyzing, if just 162 words are having 1% spam probability and remaining 99838 are conspicuously spam words, then still my app will say it as Not Spam doc because of Precision error (as numerator easily goes to ZERO)!!!. This is the first time I am hitting such issue. So how exactly should this problem be tackled?

  Read the article

• Problem with Precision floating point operation in C

  - by Microkernel

  Hi Guys, For one of my course project I started implementing "Naive Bayesian classifier" in C. My project is to implement a document classifier application (especially Spam) using huge training data. Now I have problem implementing the algorithm because of the limitations in the C's datatype. ( Algorithm I am using is given here, http://en.wikipedia.org/wiki/Bayesian_spam_filtering ) PROBLEM STATEMENT: The algorithm involves taking each word in a document and calculating probability of it being spam word. If p1, p2 p3 .... pn are probabilities of word-1, 2, 3 ... n. The probability of doc being spam or not is calculated using Here, probability value can be very easily around 0.01. So even if I use datatype "double" my calculation will go for a toss. To confirm this I wrote a sample code given below. #define PROBABILITY_OF_UNLIKELY_SPAM_WORD (0.01) #define PROBABILITY_OF_MOSTLY_SPAM_WORD (0.99) int main() { int index; long double numerator = 1.0; long double denom1 = 1.0, denom2 = 1.0; long double doc_spam_prob; /* Simulating FEW unlikely spam words */ for(index = 0; index < 162; index++) { numerator = numerator*(long double)PROBABILITY_OF_UNLIKELY_SPAM_WORD; denom2 = denom2*(long double)PROBABILITY_OF_UNLIKELY_SPAM_WORD; denom1 = denom1*(long double)(1 - PROBABILITY_OF_UNLIKELY_SPAM_WORD); } /* Simulating lot of mostly definite spam words */ for (index = 0; index < 1000; index++) { numerator = numerator*(long double)PROBABILITY_OF_MOSTLY_SPAM_WORD; denom2 = denom2*(long double)PROBABILITY_OF_MOSTLY_SPAM_WORD; denom1 = denom1*(long double)(1- PROBABILITY_OF_MOSTLY_SPAM_WORD); } doc_spam_prob= (numerator/(denom1+denom2)); return 0; } I tried Float, double and even long double datatypes but still same problem. Hence, say in a 100K words document I am analyzing, if just 162 words are having 1% spam probability and remaining 99838 are conspicuously spam words, then still my app will say it as Not Spam doc because of Precision error (as numerator easily goes to ZERO)!!!. This is the first time I am hitting such issue. So how exactly should this problem be tackled?

  Read the article

• algorithmes with no executable example code

  - by gcc

  [link] http://stackoverflow.com/questions/2932016/parsing-of-mathematical-expressions (problem has been told before) ** program is to create the infix tree for the given math expression.** if the expression is given completely paranthesized then the out put is fine but when there are no paranthesis or some part paranthesized then the out put is wrong. cant get the idea how to solve. my problem is told above. I have some algorithm to solve my problem, but I have no simple code which will be guide for me. Can anyone give me simple code (not working code) so that I will try working to understand.(for a 3 hours ,I have been searching and reading some text to understand algorithm which is told above.Actually,there is no example code investigating how it is working. Can anyone send me example which is written in c not other language.

  Read the article

• Determining if two rays intersect

  - by Faken

  I have two rays on a 2D plane that extend to infinity but both have a starting point. They are both described by a starting point and a vector in the direction of the ray extending to infinity. I want to find out if the two rays intersect but i don't need to know where they intersect (its part of a collision detection algorithm). Everything i have looked at so far describes finding the intersection point of two lines or line segments. Anyone know a fast algorithm to solve this?

  Read the article

• How to protect access to a url?

  - by ibiza

  I would need to create a php file that will do some work on my webserver and that will be called from a program on another server over the internet. Suppose the php file that will do the work is located at www.example.com/work.php What is the best way to protect unsollicited calls to the www.example.com/work.php? What I need is some mechanism so that when the intended program accesses the url (with some query string parameters), the work gets done, but if somebody type www.example.com/work.php in their browser, access will be denied and no work will be done. The way I've thought is to add some 'token' in the querystring that would be constructed by some algorithm from the calling program, a sample result could be to append to the url : ?key=randomKeyAtEachCall&token=SomeHexadecimalResultCalculatedFromTheKey and the key and token would be validated with a reverse algorithm on the php side. Is that safe, Are there any better idea?

  Read the article

• Minimum number of training examples for Find-S/Candidate Elimination algorithms?

  - by Rich

  Consider the instance space consisting of integer points in the x, y plane, where 0 = x, y = 10, and the set of hypotheses consisting of rectangles (i.e. being of the form (a = x = b, c = y = d), where 0 = a, b, c, d = 10). What is the smallest number of training examples one needs to provide so that the Find-S algorithm perfectly learns a particular target concept (e.g. (2 = x = 4, 6 = y = 9))? When can we say that the target concept is exactly learned in the case of the Find-S algorithm, and what is the optimal query strategy? I'd also like to know the answer w.r.t Candidate Elimination. Thanks in advance.

  Read the article

• Scalling connected lines

  - by Hristo

  Hello, I have some kind of a shape consisting of vertical, horizontal and diagonal lines. I have starting X,Y and ending X,Y (this is my input - just 2 points defining a line) of each line and I would like to make the whole shape scalable (just by changing the value of a scale ratio variable), so that I can still preserve the proper connection of the lines and the proportions as well. Just for getting a better idea of what I mean: it'd be as if I had the same lines in a vector editor. Would that be possible with an algorithm, and could you please, give me another possible solution if there is no such algorithm ? Thank you very much in advance!

  Read the article

• Can I replicate some of the optimisations done by the JVM by hand?

  - by Subb

  I'm working on a Sudoku solver at school and we're having a little performance contest. Right now, my algorithm is pretty fast on the first run (about 2.5ms), but even faster when I solve the same puzzle 10 000 times (about 0.5ms for each run). Those timing are, of course, depend of the puzzle being solved. I know the JVM do some optimization when a method is called multiple time, and this is what I suspect is happening. I don't think I can further optimize the algorithm itself (though I'll keep looking), so I was wondering if I could replicate some of the optimizations done by the JVM. Note : compiling to native code is not an option Thanks!

  Read the article

• Garbage collection implementation

  - by Suresh S

  In which language garbage collection algorithm is implemented for java.i think c, please confirm?

  Read the article

• How can I call an executable to run on a separate machine within a program on my own machine (win xp

  - by Mr. H.

  My objective is to write a program which will call another executable on a separate computer(all with win xp) with parameters determined at run-time, then repeat for several more computers, and then collect the results. In short, I'm working on a grid-computing project. The algorithm itself being used is already coded in FORTRAN, but we are looking for an efficient way to run it on many computers at once. I suppose one way to accomplish this would be to upload a script to each computer and then run said script on each computer, all automatically and dependent on my own parameters. But how can I write a program which will write to, upload, and run a script on a separate computer? I had considered GridGain, but the algorithm is already coded and in a different language, so that is ruled out. My current guess at accomplishing this task is using Expect (wiki/Expect), but I have no knowledge of the tool. Any advice appreciated.

  Read the article

• i need help to designe code in c++

  - by user344987

  ) Design and implement a Graph data structure. Use adjacency matrix to implement the unweighted graph edges. The Graph must support the following operations: 1.Constructor 2.Destructor 3.Copy constructor 4.A function to add an edge between two nodes in the graph 5.A display function that outputs all the edges of the graph 6.A function edge that accepts two nodes, the function returns true if there is an edge between the passed nodes, and returns false otherwise. B.(100 points) Depth first search and Breadth first search functions. C.(100 points) A function to output a spanning tree of the graph, use any algorithm you find appropriate, also, make the necessary changes on the data structure in A to implement your algorithm.

  Read the article

• How do C++ header files work?

  - by PulpFiction

  Hi all. When I include some function from a header file in a C++ program, does the entire header file code get copied to the final executable or only the machine code for the specific function is generated. For example, if I call std::sort from the <algorithm> header in C++, is the machine code generated only for the sort() function or for the entire <algorithm> header file. I think that a similar question exists somewhere on Stack Overflow, but I have tried my best to find it (I glanced over it once, but lost the link). If you can point me to that, it would be wonderful.

  Read the article

< Previous Page | 117 118 119 120 121 122 123 124 125 126 127 128  | Next Page >