Search Results

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

Page 110/331 | < Previous Page | 106 107 108 109 110 111 112 113 114 115 116 117  | Next Page >

  • SOM Algorithm Matlab HELP

    - by Tim
    I'm trying to pass a txt file to som_read_data from a GUI......i created a function that takes a txt file from the GUI and then passes it to som_read_data..but i'm getting some errors...here are a list of some of the errors.....any one with ideas? ??? Error using ==> ftell Invalid file identifier. Use fopen to generate a valid file identifier. Error in ==> som_read_data at 169 fpos1 = ftell(fid); c1 = 0; % read first non-comment line Error in ==> prog_som at 3 sD = som_read_data(m);

    Read the article

  • String chunking algorithm with natural language context

    - by Chris Ballance
    I have a arbitrarily large string of text from the user that needs to be split into 10k chunks (potentially adjustable value) and sent off to another system for processing. Chunks cannot be longer than 10k (or other arbitrary value) Text should be broken with natural language context in mind split on punctuation when possible split on spaces if no punction exists break a word as a last resort I'm trying not to re-invent the wheel with this, any suggestions before I roll this from scratch? Using C#.

    Read the article

  • naive bayesian spam filter question

    - by Microkernel
    Hi guys, I am planning to implement spam filter using Naive Bayesian classification model. Online I see a lot of info on Naive Bayesian classification, but the problem is its a lot of mathematical stuff, than clearly stating how its done. And the problem is I am more of a programmer than a mathematician (yes I had learnt Probability and Bayesian theorem back in school, but out of touch for a long long time, and I don't have luxury of learning it now (Have nearly 3 weeks to come-up with a working prototype)). So if someone can explain or point me to location where its explained for programmers than a mathematician, it would be a great help. PS: By the way I have to implement it in C, if you want to know. :( Regards, Microkernel

    Read the article

  • Sparse matrices / arrays in Java

    - by DanM
    I'm working on a project, written in Java, which requires that I build a very large 2-D sparse array. Very sparse, if that makes a difference. Anyway: the most crucial aspect for this application is efficency in terms of time (assume loads of memory, though not nearly so unlimited as to allow me to use a standard 2-D array -- the key range is in the billions in both dimensions). Out of the kajillion cells in the array, there will be several hundred thousand cells which contain an object. I need to be able to modify cell contents VERY quickly. Anyway: Does anyone know a particularly good library for this purpose? It would have to be Berkeley, LGPL or similar license (no GPL, as the product can't be entirely open-sourced). Or if there's just a very simple way to make a homebrew sparse array object, that'd be fine too. I'm considering MTJ, but haven't heard any opinions on its quality. Thanks!! -Dan

    Read the article

  • LinkedIn type friends connection required in php

    - by Akash
    Hi, I am creating a custom social network for one of my clients. In this I am storing the friends of a user in the form of CSV as shown below in the user table uid user_name friends 1 John 2 2 Jack 3,1 3 Gary 2,4 4 Joey 3 In the above scenario if the logged in user is John and if he visits the profile page of Joey, the connection between them should appear as John-Jack-Gary-Joey I am able to establish the connection at level 1 i.e If Jack visits Joey's profile I am able to establish the following : Jack-Gary-Joey But for the 2nd level I need to get into the same routine of for loops which I know is not the right solution + I am not able to implement that as well. So, can someone please help me with this? Thanks in Advance, Akash P:S I am not in a position to change the db architecture :(

    Read the article

  • geofencing algorithm

    - by jose
    i have got a latitude and longitude of a point... i want to get all the readings of latitude and longitude with in a particular radius... is there any methods to calculate all laltitudes and longtiudes with in a radius with respect to a given point?...can u help me

    Read the article

  • Skip List vs. Binary Tree

    - by Claudiu
    I recently came across the data structure known as a Skip list. They seem to have very similar behavior to a binary search tree... my question is - why would you ever want to use a skip list over a binary search tree?

    Read the article

  • SQL query optimization

    - by nvtthang
    I have a problem with my SQL query that take time to get all records from database. Any body help me. Below is a sample of database: order(order_id, order_nm) customer(customer_id, customer_nm) orderDetail(orderDetail_id, order_id, orderDate, customer_id, Comment) I want to get latest customer and order detail information. Here is may solution: I've created a function that GetLatestOrderByCustomer(CusID) to get lastest Customer information. CREATE FUNCTION [dbo].[GetLatestOrderByCustomer] ( @cus_id int ) RETURNS varchar(255) AS BEGIN DECLARE @ResultVar varchar(255) SELECT @ResultVar = tmp.comment FROM ( SELECT TOP 1 orderDate, comment FROM orderDetail WHERE orderDetail.customer_id = @cust_id ) tmp -- Return the result of the function RETURN @ResultVar END Below is my SQL query SELECT customer.customer_id , customer.customer_nm , dbo.GetLatestOrderByCustomer(customer.customer_id) FROM Customer LEFT JOIN orderDetail ON orderDetail.customer_id = customer.customer_id It's take time to run the function. Could anybody suggest me any solutions to make it better? Thanks in advance.

    Read the article

  • Convert latitude and longitude into northern and eastings

    - by Rippo
    Hi I have the following UK postcode dy8 3xt and know that the latitude and longitude is:- 52.190108 -2.517266 I also know that the Eastings, Northings for the postcode is:- 389490 283880 However I am struggling to find the equation that converts lat/long to northings and Eastings, I would prefer to have the equation in both in jScript and c# (I am being greedy)! Can anyone help?

    Read the article

  • Genetic Algorithms applied to Curve Fitting

    - by devoured elysium
    Let's imagine I have an unknown function that I want to approximate via Genetic Algorithms. For this case, I'll assume it is y = 2x. I'd have a DNA composed of 5 elements, one y for each x, from x = 0 to x = 4, in which, after a lot of trials and computation and I'd arrive near something of the form: best_adn = [ 0, 2, 4, 6, 8 ] Keep in mind I don't know beforehand if it is a linear function, a polynomial or something way more ugly, Also, my goal is not to infer from the best_adn what is the type of function, I just want those points, so I can use them later. This was just an example problem. In my case, instead of having only 5 points in the DNA, I have something like 50 or 100. What is the best approach with GA to find the best set of points? Generating a population of 100, discard the worse 20% Recombine the remaining 80%? How? Cutting them at a random point and then putting together the first part of ADN of the father with the second part of ADN of the mother? Mutation, how should I define in this kind of problem mutation? Is it worth using Elitism? Any other simple idea worth using around? Thanks

    Read the article

  • Algorithm for finding a rectangle constrained to its parent

    - by Milo
    Basically what I want to do is illustrated here: I start with A and B, then B is conformed to A to create C. The idea is, given TLBR rectangles A, B, make C I also need to know if it produces an empty rectangle (B outside of A case). I tried this but it just isn't doing what I want: if(clipRect.getLeft() > rect.getLeft()) L = clipRect.getLeft(); else L = rect.getLeft(); if(clipRect.getRight() < rect.getRight()) R = clipRect.getRight(); else R = rect.getRight(); if(clipRect.getBottom() > rect.getBottom()) B = clipRect.getBottom(); else B = rect.getBottom(); if(clipRect.getTop() < rect.getTop()) T = clipRect.getTop(); else T = rect.getTop(); if(L < R && B < T) { clipRect = AguiRectangle(0,0,0,0); } else { clipRect = AguiRectangle::fromTLBR(T,L,B,R); } Thanks

    Read the article

  • Time complexity of a sorting algorithm

    - by Passonate Learner
    The two programs below get n integers from file and calculates the sum of ath to bth integers q(number of question) times. I think the upper program has worse time complexity than the lower, but I'm having problems calculating the time complexity of these two algorithms. [input sample] 5 3 5 4 3 2 1 2 3 3 4 2 4 [output sample] 7 5 9 Program 1: #include <stdio.h> FILE *in=fopen("input.txt","r"); FILE *out=fopen("output.txt","w"); int n,q,a,b,sum; int data[1000]; int main() int i,j; fscanf(in,"%d%d",&n,&q); for(i=1;i<=n;i++) fscanf(in,"%d",&data[i]); for i=0;i<q;i++) { fscanf(in,"%d%d",&a,&b); sum=0; for(j=a;j<=b;j++) sum+=data[j]; fprintf(out,"%d\n",sum); } return 0; } Program 2: #include <stdio.h> FILE *in=fopen("input.txt","r"); FILE *out=fopen("output.txt","w"); int n,q,a,b; int data[1000]; int sum[1000]; int main() { int i,j; fscanf(in,"%d%d",&n,&q); for(i=1;i<=n;i++) fscanf(in,"%d",&data[i]); for(i=1;i<=n;i++) sum[i]=sum[i-1]+data[i]; for(i=0;i<q;i++) { fscanf(in,"%d%d",&a,&b); fprintf(out,"%d\n",sum[b]-sum[a-1]); } return 0; } The programs below gets n integers from 1 to m and sorts them. Again, I cannot calculate the time complexity. [input sample] 5 5 2 1 3 4 5 [output sample] 1 2 3 4 5 Program: #include <stdio.h> FILE *in=fopen("input.txt","r") FILE *out=fopen("output.txt","w") int n,m; int data[1000]; int count[1000]; int main() { int i,j; fscanf(in,"%d%d",&n,&m); for(i=0;i<n;i++) { fscanf(in,"%d",&data[i]); count[data[i]]++ } for(i=1;i<=m;i++) { for(j=0;j<count[i];j++) fprintf(out,"%d ",i); } return 0; } It's ironic(or not) that I cannot calculate the time complexity of my own algorithms, but I have passions to learn, so please programming gurus, help me!

    Read the article

  • Using base64 encoding as a mechanism to detect changes

    - by Mikos
    Is it possible to detect changes in the base64 encoding of an object to detect the degree of changes in the object. Suppose I send a document attachment to several users and each makes changes to it and emails back to me, can I use the string distance between original base64 and the received base64s to detect which version has the most changes. Would that be a valid metric? If not, would there be any other metrics to quantify the deltas?

    Read the article

  • Most efficient way of creating tree from adjacency list

    - by Jeff Meatball Yang
    I have an adjacency list of objects (rows loaded from SQL database with the key and it's parent key) that I need to use to build an unordered tree. It's guaranteed to not have cycles. This is taking wayyy too long (processed only ~3K out of 870K nodes in about 5 minutes). Running on my workstation Core 2 Duo with plenty of RAM. Any ideas on how to make this faster? public class StampHierarchy { private StampNode _root; private SortedList<int, StampNode> _keyNodeIndex; // takes a list of nodes and builds a tree // starting at _root private void BuildHierarchy(List<StampNode> nodes) { Stack<StampNode> processor = new Stack<StampNode>(); _keyNodeIndex = new SortedList<int, StampNode>(nodes.Count); // find the root _root = nodes.Find(n => n.Parent == 0); // find children... processor.Push(_root); while (processor.Count != 0) { StampNode current = processor.Pop(); // keep a direct link to the node via the key _keyNodeIndex.Add(current.Key, current); // add children current.Children.AddRange(nodes.Where(n => n.Parent == current.Key)); // queue the children foreach (StampNode child in current.Children) { processor.Push(child); nodes.Remove(child); // thought this might help the Where above } } } } public class StampNode { // properties: int Key, int Parent, string Name, List<StampNode> Children }

    Read the article

  • Average function without overflow exception

    - by Ron Klein
    .NET Framework 3.5. I'm trying to calculate the average of some pretty large numbers. For instance: using System; using System.Linq; class Program { static void Main(string[] args) { var items = new long[] { long.MinValue + 100, long.MinValue + 200, long.MinValue + 300 }; try { var avg = items.Average(); Console.WriteLine(avg); } catch (OverflowException ex) { Console.WriteLine("can't calculate that!"); } Console.ReadLine(); } } Obviously, the mathematical result is 9223372036854775607 (long.MaxValue - 200), but I get an exception there. This is because the implementation (on my machine) to the Average extension method, as inspected by .NET Reflector is: public static double Average(this IEnumerable<long> source) { if (source == null) { throw Error.ArgumentNull("source"); } long num = 0L; long num2 = 0L; foreach (long num3 in source) { num += num3; num2 += 1L; } if (num2 <= 0L) { throw Error.NoElements(); } return (((double) num) / ((double) num2)); } I know I can use a BigInt library (yes, I know that it is included in .NET Framework 4.0, but I'm tied to 3.5). But I still wonder if there's a pretty straight forward implementation of calculating the average of integers without an external library. Do you happen to know about such implementation? Thanks!! UPDATE: The previous example, of three large integers, was just an example to illustrate the overflow issue. The question is about calculating an average of any set of numbers which might sum to a large number that exceeds the type's max value. Sorry about this confusion. I also changed the question's title to avoid additional confusion. Thanks all!!

    Read the article

  • Invert a stack, without using extra data structures?

    - by vks
    How would you invert a stack, without using extra data structures, like a second, or temporary, stack. Thus no stack1-stack2 or stack-queue-stack implementation in the answer. You just have access to push/pop feature of a standard stack. I think there is way to do it by keeping a global counter and using pointer manipulation. If I solve it myself, I will post it. If someone else figures it out, please post your solution.

    Read the article

  • fast similarity detection

    - by reinierpost
    I have a large collection of objects and I need to figure out the similarities between them. To be exact: given two objects I can compute their dissimilarity as a number, a metric - higher values mean less similarity and 0 means the objects have identical contents. The cost of computing this number is proportional to the size of the smaller object (each object has a given size). I need the ability to quickly find, given an object, the set of objects similar to it. To be exact: I need to produce a data structure that maps any object o to the set of objects no more dissimilar to o than d, for some dissimilarity value d, such that listing the objects in the set takes no more time than if they were in an array or linked list (and perhaps they actually are). Typically, the set will be very much smaller than the total number of objects, so it is really worthwhile to perform this computation. It's good enough if the data structure assumes a fixed d, but if it works for an arbitrary d, even better. Have you seen this problem before, or something similar to it? What is a good solution? To be exact: a straightforward solution involves computing the dissimilarities between all pairs of objects, but this is slow - O(n2) where n is the number of objects. Is there a general solution with lower complexity?

    Read the article

  • Time complexity for Search and Insert operation in sorted and unsorted arrays that includes duplicat

    - by iecut
    1-)For sorted array I have used Binary Search. We know that the worst case complexity for SEARCH operation in sorted array is O(lg N), if we use Binary Search, where N are the number of items in an array. What is the worst case complexity for the search operation in the array that includes duplicate values, using binary search?? Will it be the be the same O(lg N)?? Please correct me if I am wrong!! Also what is the worst case for INSERT operation in sorted array using binary search?? My guess is O(N).... is that right?? 2-) For unsorted array I have used Linear search. Now we have an unsorted array that also accepts duplicate element/values. What are the best worst case complexity for both SEARCH and INSERT operation. I think that we can use linear search that will give us O(N) worst case time for both search and delete operations. Can we do better than this for unsorted array and does the complexity changes if we accepts duplicates in the array.

    Read the article

  • Visualizing volume of PCM samples

    - by genevincent
    I have several chunks of PCM audio (G.711) in my C++ application. I would like to visualize the different audio volume in each of these chunks. My first attempt was to calculate the average of the sample values for each chunk and use that as an a volume indicator, but this doesn't work well. I do get 0 for chunks with silence and differing values for chunks with audio, but the values only differ slighly and don't seem to resemble the actual volume. What would be a better algorithem calculate the volume ? I hear G.711 audio is logarithmic PCM. How should I take that into account ?

    Read the article

  • Project Euler Question 14 (Collatz Problem)

    - by paradox
    The following iterative sequence is defined for the set of positive integers: n -n/2 (n is even) n -3n + 1 (n is odd) Using the rule above and starting with 13, we generate the following sequence: 13 40 20 10 5 16 8 4 2 1 It can be seen that this sequence (starting at 13 and finishing at 1) contains 10 terms. Although it has not been proved yet (Collatz Problem), it is thought that all starting numbers finish at 1. Which starting number, under one million, produces the longest chain? NOTE: Once the chain starts the terms are allowed to go above one million. I tried coding a solution to this in C using the bruteforce method. However, it seems that my program stalls when trying to calculate 113383. Please advise :) #include <stdio.h> #define LIMIT 1000000 int iteration(int value) { if(value%2==0) return (value/2); else return (3*value+1); } int count_iterations(int value) { int count=1; //printf("%d\n", value); while(value!=1) { value=iteration(value); //printf("%d\n", value); count++; } return count; } int main() { int iteration_count=0, max=0; int i,count; for (i=1; i<LIMIT; i++) { printf("Current iteration : %d\n", i); iteration_count=count_iterations(i); if (iteration_count>max) { max=iteration_count; count=i; } } //iteration_count=count_iterations(113383); printf("Count = %d\ni = %d\n",max,count); }

    Read the article

  • Trend analysis using iterative value increments

    - by Dave Jarvis
    We have configured iReport to generate the following graph: The real data points are in blue, the trend line is green. The problems include: Too many data points for the trend line Trend line does not follow a Bezier curve (spline) The source of the problem is with the incrementer class. The incrementer is provided with the data points iteratively. There does not appear to be a way to get the set of data. The code that calculates the trend line looks as follows: import java.math.BigDecimal; import net.sf.jasperreports.engine.fill.*; /** * Used by an iReport variable to increment its average. */ public class MovingAverageIncrementer implements JRIncrementer { private BigDecimal average; private int incr = 0; /** * Instantiated by the MovingAverageIncrementerFactory class. */ public MovingAverageIncrementer() { } /** * Returns the newly incremented value, which is calculated by averaging * the previous value from the previous call to this method. * * @param jrFillVariable Unused. * @param object New data point to average. * @param abstractValueProvider Unused. * @return The newly incremented value. */ public Object increment( JRFillVariable jrFillVariable, Object object, AbstractValueProvider abstractValueProvider ) { BigDecimal value = new BigDecimal( ( ( Number )object ).doubleValue() ); // Average every 10 data points // if( incr % 10 == 0 ) { setAverage( ( value.add( getAverage() ).doubleValue() / 2.0 ) ); } incr++; return getAverage(); } /** * Changes the value that is the moving average. * @param average The new moving average value. */ private void setAverage( BigDecimal average ) { this.average = average; } /** * Returns the current moving average average. * @return Value used for plotting on a report. */ protected BigDecimal getAverage() { if( this.average == null ) { this.average = new BigDecimal( 0 ); } return this.average; } /** Helper method. */ private void setAverage( double d ) { setAverage( new BigDecimal( d ) ); } } How would you create a smoother and more accurate representation of the trend line?

    Read the article

  • C# searching for new Tool for the tool box, how to template this code

    - by Nix
    All i have something i have been trying to do for a while and have yet to find a good strategy to do it, i am not sure C# can even support what i am trying to do. Example imagine a template like this, repeated in manager code overarching cocept function Returns a result consisting of a success flag and error list. public Result<Boolean> RemoveLocation(LocationKey key) { List<Error> errorList = new List<Error>(); Boolean result = null; try{ result = locationDAO.RemoveLocation(key); }catch(UpdateException ue){ //Error happened less pass this back to the user! errorList = ue.ErrorList; } return new Result<Boolean>(result, errorList); } Looking to turn it into a template like the below where Do Something is some call (preferably not static) that returns a Boolean. I know i could do this in a stack sense, but i am really looking for a way to do it via object reference. public Result<Boolean> RemoveLocation(LocationKey key) { var magic = locationDAO.RemoveLocation(key); return ProtectedDAOCall(magic); } public Result<Boolean> CreateLocation(LocationKey key) { var magic = locationDAO.CreateLocation(key); return ProtectedDAOCall(magic); } public Result<Boolean> ProtectedDAOCall(Func<..., bool> doSomething) { List<Error> errorList = new List<Error>(); Boolean result = null; try{ result = doSomething(); }catch(UpdateException ue){ //Error happened less pass this back to the user! errorList = ue.ErrorList; } return new Result<Boolean>(result, errorList); } If there is any more information you may need let me know. I am interested to see what someone else can come up with. Marc solution applied to the code above public Result<Boolean> CreateLocation(LocationKey key) { LocationDAO locationDAO = new LocationDAO(); return WrapMethod(() => locationDAO.CreateLocation(key)); } public Result<Boolean> RemoveLocation(LocationKey key) { LocationDAO locationDAO = new LocationDAO(); return WrapMethod(() => locationDAO.RemoveLocation(key)); } static Result<T> WrapMethod<T>(Func<Result<T>> func) { try { return func(); } catch (UpdateException ue) { return new Result<T>(default(T), ue.Errors); } }

    Read the article

< Previous Page | 106 107 108 109 110 111 112 113 114 115 116 117  | Next Page >