Search Results

Search found 8262 results on 331 pages for 'optimization algorithm'.

Page 131/331 | < Previous Page | 127 128 129 130 131 132 133 134 135 136 137 138  | Next Page >

  • Operations on bytes in C#

    - by Hooch
    Hello. I'm writing application to control LEDS on LPT. I have everything working except this. This is one small function. I have sth like that: I want to build function that will take two argument and return one number: In actual code those binary numers will be in hex. I put them there like that so that it's easier for you to visualize it. Example1: arg1 = 1100 1100 arg2 = 1001 0001 retu = 0100 1100 Example2: arg1 = 1111 1111 arg2 = 0001 0010 retu = 1110 1101 Example3: arg1 = 1111 0000 arg2 = 0010 0010 retu = 1101 0000 I have no idea how this function should look like. I want it to be as fast as possible. I'll call this function 200 times per second.

    Read the article

  • Searching algorithmics: Parsing and processing a request

    - by James P.
    Say you were to create a search engine that can accept a query statement under the form of a String. The statement can be used to retrieve different types of objects with a given set of characteristics and possibly linked to other objects. In plain english or pseudo-code using an OOP approach, how would you go about parsing and processing statements as follows to get the series of desired objects ? get fruit with colour green get variety of apples, pears from Andy get strawberry with colour "deep red" and origin not Spain get total of sales of melons between 2010-10-10 and 2010-12-30 get last deliverydate of bananas from "Pete" and state not sold Hope the question is clear. If not I'll be more than happy to reformulate. P.S: This isn't homework ;)

    Read the article

  • Stored procedure optimization

    - by George Zacharia
    Hi, i have a stored procedure which takes lot of time to execure .Can any one suggest a better approch so that the same result set is achived. ALTER PROCEDURE [dbo].[spFavoriteRecipesGET] @USERID INT, @PAGENUMBER INT, @PAGESIZE INT, @SORTDIRECTION VARCHAR(4), @SORTORDER VARCHAR(4),@FILTERBY INT AS BEGIN DECLARE @ROW_START INT DECLARE @ROW_END INT SET @ROW_START = (@PageNumber-1)* @PageSize+1 SET @ROW_END = @PageNumber*@PageSize DECLARE @RecipeCount INT DECLARE @RESULT_SET_TABLE TABLE ( Id INT NOT NULL IDENTITY(1,1), FavoriteRecipeId INT, RecipeId INT, DateAdded DATETIME, Title NVARCHAR(255), UrlFriendlyTitle NVARCHAR(250), [Description] NVARCHAR(MAX), AverageRatingId FLOAT, SubmittedById INT, SubmittedBy VARCHAR(250), RecipeStateId INT, RecipeRatingId INT, ReviewCount INT, TweaksCount INT, PhotoCount INT, ImageName NVARCHAR(50) ) INSERT INTO @RESULT_SET_TABLE SELECT FavoriteRecipes.FavoriteRecipeId, Recipes.RecipeId, FavoriteRecipes.DateAdded, Recipes.Title, Recipes.UrlFriendlyTitle, Recipes.[Description], Recipes.AverageRatingId, Recipes.SubmittedById, COALESCE(users.DisplayName,users.UserName,Recipes.SubmittedBy) As SubmittedBy, Recipes.RecipeStateId, RecipeReviews.RecipeRatingId, COUNT(RecipeReviews.Review), COUNT(RecipeTweaks.Tweak), COUNT(Photos.PhotoId), dbo.udfGetRecipePhoto(Recipes.RecipeId) AS ImageName FROM FavoriteRecipes INNER JOIN Recipes ON FavoriteRecipes.RecipeId=Recipes.RecipeId AND Recipes.RecipeStateId <> 3 LEFT OUTER JOIN RecipeReviews ON RecipeReviews.RecipeId=Recipes.RecipeId AND RecipeReviews.ReviewedById=@UserId AND RecipeReviews.RecipeRatingId= ( SELECT MAX(RecipeReviews.RecipeRatingId) FROM RecipeReviews WHERE RecipeReviews.ReviewedById=@UserId AND RecipeReviews.RecipeId=FavoriteRecipes.RecipeId ) OR RecipeReviews.RecipeRatingId IS NULL LEFT OUTER JOIN RecipeTweaks ON RecipeTweaks.RecipeId = Recipes.RecipeId AND RecipeTweaks.TweakedById= @UserId LEFT OUTER JOIN Photos ON Photos.RecipeId = Recipes.RecipeId AND Photos.UploadedById = @UserId AND Photos.RecipeId = FavoriteRecipes.RecipeId AND Photos.PhotoTypeId = 1 LEFT OUTER JOIN users ON Recipes.SubmittedById = users.UserId WHERE FavoriteRecipes.UserId=@UserId GROUP BY FavoriteRecipes.FavoriteRecipeId, Recipes.RecipeId, FavoriteRecipes.DateAdded, Recipes.Title, Recipes.UrlFriendlyTitle, Recipes.[Description], Recipes.AverageRatingId, Recipes.SubmittedById, Recipes.SubmittedBy, Recipes.RecipeStateId, RecipeReviews.RecipeRatingId, users.DisplayName, users.UserName, Recipes.SubmittedBy; WITH SortResults AS ( SELECT ROW_NUMBER() OVER ( ORDER BY CASE WHEN @SORTDIRECTION = 't' AND @SORTORDER='a' THEN TITLE END ASC, CASE WHEN @SORTDIRECTION = 't' AND @SORTORDER='d' THEN TITLE END DESC, CASE WHEN @SORTDIRECTION = 'r' AND @SORTORDER='a' THEN AverageRatingId END ASC, CASE WHEN @SORTDIRECTION = 'r' AND @SORTORDER='d' THEN AverageRatingId END DESC, CASE WHEN @SORTDIRECTION = 'mr' AND @SORTORDER='a' THEN RecipeRatingId END ASC, CASE WHEN @SORTDIRECTION = 'mr' AND @SORTORDER='d' THEN RecipeRatingId END DESC, CASE WHEN @SORTDIRECTION = 'd' AND @SORTORDER='a' THEN DateAdded END ASC, CASE WHEN @SORTDIRECTION = 'd' AND @SORTORDER='d' THEN DateAdded END DESC ) RowNumber, FavoriteRecipeId, RecipeId, DateAdded, Title, UrlFriendlyTitle, [Description], AverageRatingId, SubmittedById, SubmittedBy, RecipeStateId, RecipeRatingId, ReviewCount, TweaksCount, PhotoCount, ImageName FROM @RESULT_SET_TABLE WHERE ((@FILTERBY = 1 AND SubmittedById= @USERID) OR ( @FILTERBY = 2 AND (SubmittedById <> @USERID OR SubmittedById IS NULL)) OR ( @FILTERBY <> 1 AND @FILTERBY <> 2)) ) SELECT RowNumber, FavoriteRecipeId, RecipeId, DateAdded, Title, UrlFriendlyTitle, [Description], AverageRatingId, SubmittedById, SubmittedBy, RecipeStateId, RecipeRatingId, ReviewCount, TweaksCount, PhotoCount, ImageName FROM SortResults WHERE RowNumber BETWEEN @ROW_START AND @ROW_END print @ROW_START print @ROW_END SELECT @RecipeCount=dbo.udfGetFavRecipesCount(@UserId) SELECT @RecipeCount AS RecipeCount SELECT COUNT(Id) as FilterCount FROM @RESULT_SET_TABLE WHERE ((@FILTERBY = 1 AND SubmittedById= @USERID) OR (@FILTERBY = 2 AND (SubmittedById <> @USERID OR SubmittedById IS NULL)) OR (@FILTERBY <> 1 AND @FILTERBY <> 2)) END

    Read the article

  • Java - Removing duplicates in an ArrayList

    - by Will
    I'm working on a program that uses an ArrayList to store Strings. The program prompts the user with a menu and allows the user to choose an operation to perform. Such operations are adding Strings to the List, printing the entries etc. What I want to be able to do is create a method called removeDuplicates().This method will search the ArrayList and remove any duplicated values. I want to leave one instance of the duplicated value(s) within the list. I also want this method to return the total number of duplicates removed. I've been trying to use nested loops to accomplish this but I've been running into trouble because when entries get deleted, the indexing of the ArrayList gets altered and things don't work as they should. I know conceptually what I need to do but I'm having trouble implementing this idea in code. Here is some pseudo code: start with first entry; check each subsequent entry in the list and see if it matches the first entry; remove each subsequent entry in the list that matches the first entry; after all entries have been examined, move on to the second entry; check each entry in the list and see if it matches the second entry; remove each entry in the list that matches the second entry; repeat for entry in the list Here's the code I have so far: public int removeDuplicates() { int duplicates = 0; for ( int i = 0; i < strings.size(); i++ ) { for ( int j = 0; j < strings.size(); j++ ) { if ( i == j ) { // i & j refer to same entry so do nothing } else if ( strings.get( j ).equals( strings.get( i ) ) ) { strings.remove( j ); duplicates++; } } } return duplicates; }

    Read the article

  • Make function non-recursive

    - by user69514
    I'm not sure how to make this function non-recursive. Any ideas?: void foo(int a, int b){ while( a < len && arr[a][b] != -1){ if(++a == len){ a = 0; b++; } } if( a == len){ size++; return; } if( a < (len-1)){ arr[a][b] = 1; arr[a][(b+1)] = 1; foo(a, b); arr[a][b] = -1; arr[a][(b+1)] = -1; } if( a < (len-1) && arr[(a+1)][b] == -1){ arr[a][b] = 0; arr[(a+1)][b] = 0; foo(a,b); arr[a][b] = -1; arr[(a+1)][b] = -1; } }

    Read the article

  • Extracting a given number of the highest values in a List

    - by James P.
    I'm seeking to display a fixed number of items on a web page according to their respective weight (represented by an Integer). The List where these items are found can be of virtually any size. The first solution that comes to mind is to do a Collections.sort() and to get the items one by one by going through the List. Is there a more elegant solution though that could be used to prepare, say, the top eight items?

    Read the article

  • Implementing a hilbert map of the internet

    - by Martin
    In the XKCD comic 195 a design for a map of the internet address space is suggested using a hilbert curve so that items from a similar IPs will be clustered together. Given an IP address, how would I calculate the 2D coordinates (in the range zero to one) that this IP is located on such a map?

    Read the article

  • Could I do this blind relative to absolute path conversion (for perforce depot paths) better?

    - by wonderfulthunk
    I need to "blindly" (i.e. without access to the filesystem, in this case the source control server) convert some relative paths to absolute paths. So I'm playing with dotdots and indices. For those that are curious I have a log file produced by someone else's tool that sometimes outputs relative paths, and for performance reasons I don't want to access the source control server where the paths are located to check if they're valid and more easily convert them to their absolute path equivalents. I've gone through a number of (probably foolish) iterations trying to get it to work - mostly a few variations of iterating over the array of folders and trying delete_at(index) and delete_at(index-1) but my index kept incrementing while I was deleting elements of the array out from under myself, which didn't work for cases with multiple dotdots. Any tips on improving it in general or specifically the lack of non-consecutive dotdot support would be welcome. Currently this is working with my limited examples, but I think it could be improved. It can't handle non-consecutive '..' directories, and I am probably doing a lot of wasteful (and error-prone) things that I probably don't need to do because I'm a bit of a hack. I've found a lot of examples of converting other types of relative paths using other languages, but none of them seemed to fit my situation. These are my example paths that I need to convert, from: //depot/foo/../bar/single.c //depot/foo/docs/../../other/double.c //depot/foo/usr/bin/../../../else/more/triple.c to: //depot/bar/single.c //depot/other/double.c //depot/else/more/triple.c And my script: begin paths = File.open(ARGV[0]).readlines puts(paths) new_paths = Array.new paths.each { |path| folders = path.split('/') if ( folders.include?('..') ) num_dotdots = 0 first_dotdot = folders.index('..') last_dotdot = folders.rindex('..') folders.each { |item| if ( item == '..' ) num_dotdots += 1 end } if ( first_dotdot and ( num_dotdots > 0 ) ) # this might be redundant? folders.slice!(first_dotdot - num_dotdots..last_dotdot) # dependent on consecutive dotdots only end end folders.map! { |elem| if ( elem !~ /\n/ ) elem = elem + '/' else elem = elem end } new_paths << folders.to_s } puts(new_paths) end

    Read the article

  • What is the most efficient way to encode an arbitrary GUID into readable ASCII (33-127)?

    - by mark
    Dear ladies and sirs. The standard string representation of GUID takes about 36 characters. Which is very nice, but also really wasteful. I am wondering, how to encode it in the shortest possible way using all the ASCII characters in the range 33-127. The naive implementation produces 22 characters, simply because 128 bits / 6 bits yields 22. Huffman encoding is my second best, the only question is how to choose the codes.... Any more ideas? Thanks. P.S. The encoding must be lossless, of course.

    Read the article

  • How is load balancing in big systems implemented?

    - by uther-lightbringer
    Hello, I'm wondering how is implemented load balancing in realy big applications like google or facebook. I know that in normal scenario there may be machine dedicated to this task, but I would like to know how is it resolved in realy big aplication with hundreds of thousans people accessing it in any given time. I am just wondering how exactly when one types google.com will that request find its way to concrete computer (are there multiple load balancers? and how is it set up and implemented that user's request will find the way to concrete balancer out of many others). I will realy appreciate if someone enlightens me this issue, thank you.

    Read the article

  • How much time should it take to find the sum of all prime numbers less than 2 million?

    - by Shahensha
    I was trying to solve this Project Euler Question. I implemented the sieve of euler as a helper class in java. It works pretty well for the small numbers. But when I input 2 million as the limit it doesn't return the answer. I use Netbeans IDE. I waited for a lot many hours once, but it still didn't print the answer. When I stopped running the code, it gave the following result Java Result: 2147483647 BUILD SUCCESSFUL (total time: 2,097 minutes 43 seconds) This answer is incorrect. Even after waiting for so much time, this isn't correct. While the same code returns correct answers for smaller limits. Sieve of euler has a very simple algo given at the botton of this page. My implementation is this: package support; import java.util.ArrayList; import java.util.List; /** * * @author admin */ public class SieveOfEuler { int upperLimit; List<Integer> primeNumbers; public SieveOfEuler(int upperLimit){ this.upperLimit = upperLimit; primeNumbers = new ArrayList<Integer>(); for(int i = 2 ; i <= upperLimit ; i++) primeNumbers.add(i); generatePrimes(); } private void generatePrimes(){ int currentPrimeIndex = 0; int currentPrime = 2; while(currentPrime <= Math.sqrt(upperLimit)){ ArrayList<Integer> toBeRemoved = new ArrayList<Integer>(); for(int i = currentPrimeIndex ; i < primeNumbers.size() ; i++){ int multiplier = primeNumbers.get(i); toBeRemoved.add(currentPrime * multiplier); } for(Integer i : toBeRemoved){ primeNumbers.remove(i); } currentPrimeIndex++; currentPrime = primeNumbers.get(currentPrimeIndex); } } public List getPrimes(){ return primeNumbers; } public void displayPrimes(){ for(double i : primeNumbers) System.out.println(i); } } I am perplexed! My questions is 1) Why is it taking so much time? Is there something wrong in what I am doing? Please suggest ways for improving my coding style, if you find something wrong.

    Read the article

  • How to optimize this Python code?

    - by RandomVector
    def maxVote(nLabels): count = {} maxList = [] maxCount = 0 for nLabel in nLabels: if nLabel in count: count[nLabel] += 1 else: count[nLabel] = 1 #Check if the count is max if count[nLabel] > maxCount: maxCount = count[nLabel] maxList = [nLabel,] elif count[nLabel]==maxCount: maxList.append(nLabel) return random.choice(maxList) nLabels contains a list of integers. The above function returns the integer with highest frequency, if more than one have same frequency then a randomly selected integer from them is returned. E.g. maxVote([1,3,4,5,5,5,3,12,11]) is 5

    Read the article

  • Sort months ( with strings ) algorithm

    - by Oscar Reyes
    I have this months array: ["January", "March", "December" , "October" ] And I want to have it sorted like this: ["January", "March", "October", "December" ] I'm currently thinking in a "if/else" horrible cascade but I wonder if there is some other way to do this. The bad part is that I need to do this only with "string" ( that is, without using Date object or anything like that ) What would be a good approach?

    Read the article

  • How can I create photo effects in Android?

    - by PaulH
    I'd like to make an Android app that lets a user apply cool effects to photos taken with the camera. There are already a few out there, I know, but I'd like to try my own hand at one. I'm trying to figure out the best way to implement these effects. Here are some examples from the excellent Vignette app (which I own): http://www.flickr.com/groups/vignetteforandroid/pool/ I have been googling and stack-overflowing, but so far I've mostly found some references to published papers or books. I am ordering this one from Amazon presently - Digital Image Processing: An Algorithmic Introduction using Java After some reading, I think I have a basic understanding of manipulating the RGB values for all the pixels in the image. My main question is how do I come up with a transformation that produces cool effects? By cool effects I mean some like those in the Vignette app or IPhone apps: ToyCamera Polarize I already have quite a bit of experience with Java, and I've made my first app for android already. Any ideas? Thanks in advance.

    Read the article

  • Load balancing and scheduling algorithms.

    - by Lukas Šalkauskas
    Hello there, so here is my problem: I have several different configuarion servers. I have different calculations (jobs); I can predict how long approximately each job will take to be caclulated. Also, I have priorities. My question is how to keep all machines loaded 99-100% and schedule the jobs in the best way. Each machine can do several calculations at a time. Jobs are pushed to the machine. The central machine knows the current load of each machine. Also, I would like to to assign some kind of machine learning here, because I will know statistics of each job (started, finished, cpu load etc.). How can I distribute jobs (calculations) in the best possible way, keeping in mind the priorities? Any suggestions, ideas, or algorithms ? FYI: My platform .NET.

    Read the article

  • Priority queue with dynamic item priorities.

    - by sean
    I need to implement a priority queue where the priority of an item in the queue can change and the queue adjusts itself so that items are always removed in the correct order. I have some ideas of how I could implement this but I'm sure this is quite a common data structure so I'm hoping I can use an implementation by someone smarter than me as a base. Can anyone tell me the name of this type of priority queue so I know what to search for or, even better, point me to an implementation?

    Read the article

  • Java algorithm for normalizing audio

    - by Marty Pitt
    I'm trying to normalize an audio file of speech. Specifically, where an audio file contains peaks in volume, I'm trying to level it out, so the quiet sections are louder, and the peaks are quieter. I know very little about audio manipulation, beyond what I've learnt from working on this task. Also, my math is embarrassingly weak. I've done some research, and the Xuggle site provides a sample which shows reducing the volume using the following code: (full version here) @Override public void onAudioSamples(IAudioSamplesEvent event) { // get the raw audio byes and adjust it's value ShortBuffer buffer = event.getAudioSamples().getByteBuffer().asShortBuffer(); for (int i = 0; i < buffer.limit(); ++i) buffer.put(i, (short)(buffer.get(i) * mVolume)); super.onAudioSamples(event); } Here, they modify the bytes in getAudioSamples() by a constant of mVolume. Building on this approach, I've attempted a normalisation modifies the bytes in getAudioSamples() to a normalised value, considering the max/min in the file. (See below for details). I have a simple filter to leave "silence" alone (ie., anything below a value). I'm finding that the output file is very noisy (ie., the quality is seriously degraded). I assume that the error is either in my normalisation algorithim, or the way I manipulate the bytes. However, I'm unsure of where to go next. Here's an abridged version of what I'm currently doing. Step 1: Find peaks in file: Reads the full audio file, and finds this highest and lowest values of buffer.get() for all AudioSamples @Override public void onAudioSamples(IAudioSamplesEvent event) { IAudioSamples audioSamples = event.getAudioSamples(); ShortBuffer buffer = audioSamples.getByteBuffer().asShortBuffer(); short min = Short.MAX_VALUE; short max = Short.MIN_VALUE; for (int i = 0; i < buffer.limit(); ++i) { short value = buffer.get(i); min = (short) Math.min(min, value); max = (short) Math.max(max, value); } // assign of min/max ommitted for brevity. super.onAudioSamples(event); } Step 2: Normalize all values: In a loop similar to step1, replace the buffer with normalized values, calling: buffer.put(i, normalize(buffer.get(i)); public short normalize(short value) { if (isBackgroundNoise(value)) return value; short rawMin = // min from step1 short rawMax = // max from step1 short targetRangeMin = 1000; short targetRangeMax = 8000; int abs = Math.abs(value); double a = (abs - rawMin) * (targetRangeMax - targetRangeMin); double b = (rawMax - rawMin); double result = targetRangeMin + ( a/b ); // Copy the sign of value to result. result = Math.copySign(result,value); return (short) result; } Questions: Is this a valid approach for attempting to normalize an audio file? Is my math in normalize() valid? Why would this cause the file to become noisy, where a similar approach in the demo code doesn't?

    Read the article

  • Is there "good" PRNG generating values without hidden state?

    - by actual
    I need some good pseudo random number generator that can be computed like a pure function from its previous output without any state hiding. Under "good" I mean: I must be able to parametrize generator in such way that running it for 2^n iterations with any parameters should cover all or almost all values between 0 and 2^n - 1, where n is the number of bits in output value. Combined generator output of n + p bits must cover all or almost all values between 0 and 2^(n + p) - 1 if I run it for 2^n iterations for every possible combination of its parameters, where p is the number of bits in parameters. For example, LCG can be computed like a pure function and it can meet first condition, but it can not meet second one. Say, we have 32-bit generator, m = 2^32 and it is constant, our p = 64 (two 32-bit parameters a and c), n + p = 96, so we must peek data by three ints from output to meet second condition. Unfortunately, condition can not be meet because of strictly alternating sequence of odd and even ints in output. To overcome this, hidden state must be introduced, but that makes function not pure and breaks first condition (period become much longer). Am I wanting too much?

    Read the article

  • Quick way to do data lookup in PHP

    - by Ghostrider
    I have a data table with 600,000 records that is around 25 megabytes large. It is indexed by a 4 byte key. Is there a way to find a row in such dataset quickly with PHP without resorting to MySQL? The website in question is mostly static with minor PHP code and no database dependencies and therefore fast. I would like to add this data without having to use MySQL if possible. In C++ I would memory map the file and do a binary search in it. Is there a way to do something similar in PHP?

    Read the article

  • Efficient algorithm to distribute work?

    - by Zwei Steinen
    It's a bit complicated to explain but here we go. We have problems like this (code is pseudo-code, and is only for illustrating the problem. Sorry it's in java. If you don't understand, I'd be glad to explain.). class Problem { final Set<Integer> allSectionIds = { 1,2,4,6,7,8,10 }; final Data data = //Some data } And a subproblem is: class SubProblem { final Set<Integer> targetedSectionIds; final Data data; SubProblem(Set<Integer> targetedSectionsIds, Data data){ this.targetedSectionIds = targetedSectionIds; this.data = data; } } Work will look like this, then. class Work implements Runnable { final Set<Section> subSections; final Data data; final Result result; Work(Set<Section> subSections, Data data) { this.sections = SubSections; this.data = data; } @Override public void run(){ for(Section section : subSections){ result.addUp(compute(data, section)); } } } Now we have instances of 'Worker', that have their own state sections I have. class Worker implements ExecutorService { final Map<Integer,Section> sectionsIHave; { sectionsIHave = {1:section1, 5:section5, 8:section8 }; } final ExecutorService executor = //some executor. @Override public void execute(SubProblem problem){ Set<Section> sectionsNeeded = fetchSections(problem.targetedSectionIds); super.execute(new Work(sectionsNeeded, problem.data); } } phew. So, we have a lot of Problems and Workers are constantly asking for more SubProblems. My task is to break up Problems into SubProblem and give it to them. The difficulty is however, that I have to later collect all the results for the SubProblems and merge (reduce) them into a Result for the whole Problem. This is however, costly, so I want to give the workers "chunks" that are as big as possible (has as many targetedSections as possible). It doesn't have to be perfect (mathematically as efficient as possible or something). I mean, I guess that it is impossible to have a perfect solution, because you can't predict how long each computation will take, etc.. But is there a good heuristic solution for this? Or maybe some resources I can read up before I go into designing? Any advice is highly appreciated!

    Read the article

< Previous Page | 127 128 129 130 131 132 133 134 135 136 137 138  | Next Page >