apply the min index to an array of the same size

Question

hamed amini 2017-4-16

评论： hamed amini 2017-4-16

A and B are arrays with the same size. e.g.

>> size(A) = [2,4,3,5]; % A is a 4 dimensional matrix

>> size(B) = [2,4,3,5]; % B has the same size as A

>> [minA, minAind] = min(A,[ ],4);

size(minA) = [2,4,3]; %min will reduce one of the dimensions

How to extract the elements in B with the same index as minAind?

hamed amini 2017-4-16

I got the idea from a similar post

Answer 1

hamed amini 2017-4-16

I found the answer; here is an example when the min is applied along the 3rd dimension:

>> a=rand(2,3,4,5);

>> [amin, aind] = min(a,[],3);

>> [a1,a2,a4]= ndgrid([1:size(a,1)],[1:size(a,2)],[1:size(a,4)]);

>> allind = sub2ind(size(a), a1, a2,squeeze(aind), a4);

>> a(allind)-amin % ==> this would be all zeros, i.e. allind is the right index.