Two matrices A and B. B is subset of A(rowwise).I want to check the indexes for which row of B is there in A and do some operation on those indexes of A. I tried like this, works for small matrices but takes time on my matrix.suggest alternative

A=[0 1 2;2 3 4;1 2 3;4 5 6; 9 8 7;3 4 5];
B=[1 2 3;3 4 5;4 5 6 ];
for k=1:length(B)
  for j=1:length(A)
    if(B(k,:)==A(j,:))
      A(j,3)=1;  %operation on superset A,changes 3rd column to 1
    end
  end
end

[Stephen23]

Learn to write vectorized code, as per dpb's answer, and you will find MATLAB code can be quite fast.

http://www.mathworks.com/help/matlab/matlab_prog/vectorization.html

Answer 1

[dpb]

   A(ismember(A,B,'rows'),:)=1;