replace random data with dataset

Question

Pablo Villarreal 2019-4-10

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/455617-replace-random-data-with-dataset

回答： the cyclist 2019-4-16

I have this code and I´ve been trying to use a dataset I have instead random numbers, but everytime I try it messes with the code.

k = 5;
numP = 100;
xMax = 50;
yMax = 50;
data = load('data.txt');
xP = data(:, 1);
yP = data(:, 2);
%xP = xMax * rand(1,numP);
%yP = yMax * rand(1,numP);
points = [xP; yP];
[cluster, centr] = kmeans(k, points);

Heres kmeans.m

function [ cluster, centr ] = kmeans( k, P )
numP = size(P,2);
dimP = size(P,1);
randIdx = randperm(numP,k);
centr = P(:,randIdx);
cluster = zeros(1,numP);
clusterPrev = cluster;
iterations = 0;
stop = false;
while stop == false
    
    for idxP = 1:numP
        dist = zeros(1,k);
        for idxC=1:k
            dist(idxC) = norm(P(:,idxP)-centr(:,idxC));
        end
        [~, clusterP] = min(dist);
        cluster(idxP) = clusterP;
    end
    
    centr = zeros(dimP,k);
    for idxC = 1:k
        centr(:,idxC) = mean(P(:,cluster==idxC),2);
    end
    
    if clusterPrev==cluster
        stop = true;
    end
    clusterPrev = cluster;
    
    iterations = iterations + 1;
    
end
end

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Image Analyst 2019-4-10

编辑：Image Analyst 2019-4-10

Are you sure it's running your code? There is a built-in kmeans() function if you have the Statistics and Machine Learning Toolbox. Call your function something different, like pablokmeans().

Also explain how your script "messes with the code". I don't see it opening your m-file and doing anything with it so how does the script mess up the code?

Also attach 'data.txt' with the paper clip icon.

Pablo Villarreal 2019-4-16

在 MATLAB Online 中打开

Oh, sorry, the fuction kmeans was me translating it, while in spanish, it didnt call the built in function.

Well, it messes with the code when I change it to read xp and yp from a file dataset. The code wasnt made for it and I cant figure a way to change kmeans.m for it to process the dataset instead of random made numbers. The dataset looks like this:

4,10;
5,3;
10,1;
2,2;
9,2;
6,7;
.
.
.

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Answer 1

the cyclist 2019-4-16

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/455617-replace-random-data-with-dataset#answer_370929

My best guess at your error is that your randomly generated data consists of two [1 x numP] row vectors, but when you read your data in from file, they are two [numP x 1] column vectors. So the algorithm thinks there are only two observations with numP dimensions.