Sum of defined portion of a 3D matrix

Hello,

I would like to sum different layers of a 3D matrix, but I don't know an easy way of doing it. Basically what I would like to do is this:

matrix1=sum(timematrix(:,:,1:3))

"timematrix" is a 1x1000x5 matrix and I would like to compute the sum of the first 3 layers. Using the following command works:

matrix1=timematrix(:,:,1)+timematrix(:,:,2)+timematrix(:,:,3)

Thanks in advance!

Answer 1

[Walter Roberson]

 matrix1 = sum(timematrix(:,:,1:3), 3);

[Stephen23]

This is explained perfectly in the documentation:

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