How to find the constant value in a loop for a particular condition?

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Ritesh Chandra Tewari 2021-2-20

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/751134-how-to-find-the-constant-value-in-a-loop-for-a-particular-condition

评论： Ritesh Chandra Tewari 2021-2-20

A = [0.01; 0.03; 0.1; 0.3; 1; 3; 10; 30];
% error = zeros(64,1);
for i= 1:8
    C = A(i);
    for j = 1:8
        sigma = A(j);
        model= svmTrain(X, y, C, @(x1, x2) gaussianKernel(x1, x2, sigma));
        predictions = svmPredict(model, Xval);
        error(i,j) = mean(double(predictions ~= yval));
    end
end
[p,q] = find(error == min(error(:)));

error gives me a 8x8 matrix. when I find minimum value of the matrix , it turns out that [5,3] indices of the matrix gives me the minimum value. Although I can find the corresponding C and sigma value manually as dimension of A is small. but if it is of high dimension then it is hard to find that. I just want to find out corresponding C and sigma value for which I get minimum value in the error matrix automatically.

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Answer 1

KALYAN ACHARJYA 2021-2-20

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https://ww2.mathworks.cn/matlabcentral/answers/751134-how-to-find-the-constant-value-in-a-loop-for-a-particular-condition#answer_628559

编辑：KALYAN ACHARJYA 2021-2-20

在 MATLAB Online 中打开

"I just want to find out corresponding C and sigma value for which I get minimum value in the error matrix automatically"

for i= 1:8
    for j = 1:8
        model= svmTrain(X, y, C, @(x1, x2) gaussianKernel(x1, x2, sigma));
        predictions = svmPredict(model, Xval);
        error(i,j) = mean(double(predictions ~= yval));
    end
end