Fill the array after each loop iteration

Question

Ali Jaber 2016-4-24

0
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https://ww2.mathworks.cn/matlabcentral/answers/280676-fill-the-array-after-each-loop-iteration

编辑： Ali Jaber 2016-4-24

my Problem is that I want the array to be filled each time the loop iterate, for example here, cosTheta is my array, I want after each iteration to add the new value to it as an element. This is what I wrote:

for k=1:10     
    r(k) = (dot(a,b)/(norm(a)*norm(b)));
end
    cosTheta = [r(1) r(2) r(3) r(4) r(5) r(6) r(7) r(8) r(9) r(10)];
But I think this is not a good idea if I want a larger number of iteration.. for example if k will go from 1 to 50, this not an ideal way to do that, can you help me plz

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Answer 1

Stefan Raab 2016-4-24

1
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Hello,

why use the r at all? Try

n_iter = 10;
cosTheta = zeros(1,n_iter); % Memory preallocation
for k=1:n_iter     
  a = trainZ(k,:);
  b = testZ;
  cosTheta(k) = (dot(a,b)/(norm(a)*norm(b)));
end

Kind regards, Stefan