Question

So we are given with some w and we want to so something like such pseudocode:

u = zeros(size(w));
for o=1:length(size(w))
 for i=1:size(w)(1), 
  for j=1:size(w)(2), 
...
    for k=1:size(w)(length(size(w))),
        u(i, j, ..., k )=1/(exp((-w(i,j, ..., k )))+25);
    end
...
  end
 end
end

is such thing possible with Matlab and how to do it?

Answer 1

@Jonas’s answer is the best option, however for a general-purpose code (one that @Jonas’s ‘matricized’ answer does not apply), you can use a code-generation approach, for example:

fcode = fopen('manyForLoopsScript.m','w');
w = rand(2,3,4);
numLoops = length(size(w));
u = zeros(size(w));

% open the 'for' loops
for m = 1 : numLoops
    fprintf(fcode, 'for a%d = 1:size(w,%d)\n',m,m);
end

% the actuall 'stuff'
indStr = [];
for m = 1 : numLoops
    indStr = [indStr,sprintf('a%d,',m)];
end
indStr = indStr(1:end-1);
fprintf(fcode, ['u(' indStr ') = exp(-w(' indStr '));\n']);

% close the 'for' loops
for m = 1 : numLoops
    fprintf(fcode, 'end\n');
end
fclose(fcode);

manyForLoopsScript