how to generalize a nested for-loop?

Question

Mnr 2015-11-2

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/252217-how-to-generalize-a-nested-for-loop

评论： Mnr 2015-11-2

采纳的回答： per isakson

Hello all,

Per my earlier question in http://www.mathworks.com/matlabcentral/answers/252008-a-simpler-way-of-doing-a-nested-loop

Is there a way to generalize that nested loop so that it works for any sizes of V? Thank you.

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Answer 1

per isakson 2015-11-2

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/252217-how-to-generalize-a-nested-for-loop#answer_198112

编辑：per isakson 2015-11-2

在 MATLAB Online 中打开

Try

>> tic, for ii = 1:5000, h1 = cssm( 4 ); end, toc
Elapsed time is 0.279794 seconds.
>> tic, for ii = 1:5000, h1 = cssm( 6 ); end, toc
Elapsed time is 0.950556 seconds.

where

function    h1 = cssm( N )
    % V = [1+1i, 1-1i, -1+1i, -1-1i];
    V = rand(1,N)+1i*rand(1,N);
    n = length(V);
    h1 = zeros(n, n, n, n);
    for m1 = 1:n
        c = 0.3 * V(m1);
        for m2 = 1:n
            c = c + 0.2 * V(m2);
            for m3 = 1:n
                c = c + 0.5 * V(m3);
                for m4 = 1:n
                    h1(m1,m2,m3,m4) = c + 0.8 * V(m4);
                end
            end
        end
    end
end