Fill a nxm matrix with vectorised expression

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Andrea Agosti 2020-10-16

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评论： Konstantin 2020-10-16

采纳的回答： Matt J

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Hi all,

here my doubt: i have a matrix M with dimensions nxm. The matrix is initially initialised with zeros, and i fill each M(i,j) calling another function:

M = zeros(n,m)
for i = 1:n
    for j = 1:m
        M(i,j) = another_function(several_inputs);
    end
end

is it possible to fill the matrix M without the for loops, but instead using a vectorised expression?

Thanks

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Andrea Agosti 2020-10-16

Hi, thanks for your aswer. The inputs of the another_function are different for each i,j.

Thanks

Konstantin 2020-10-16

sometimes it works to vectorize the function itself

matrix = another_function(matrix)

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采纳的回答

Matt J 2020-10-16

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编辑：Matt J 2020-10-16

No, there is no way to vectorize an element-wise function generically, without considering the specifics of the function. You can avoid for-loop syntax by using arrayfun, but this simply hides the loops from view, it doesn't replace them with something more efficient.