3D matrix manipulation. FInd values of given positions

Hi there. Pls help me resolve an issue I cant find a solution for: I have a two 3D matrixes with the same dimentions( 288*288*80)off nii files. I want to search for nonzero positions on the first matrix and use thoses positions to go through the second matrix, and do a sum of the values located on those positions . How can I do it? Regards

[SkyRazor]

I think the page as follows will help you.

http://www.mathworks.com/help/matlab/ref/nonzeros.html

Try the functions nonzeros, find and sum to slove your problem.

Answer 1

[lvn]

This should do it:

sum(matrix2(matrix1~=0))