MATLAB: Sum of defined portion of a 3D matrix

3d matrixindexingsum

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!

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

I am a little confused, do you mean like this:

Y = reshape(1:18,6,3)  % A manageable dimension.
Y_1 = sum(Y,2)

So in your case it would be

Y_1 = sum(Y,2).';

Or do you mean, more like this:

Y = 1:18
Y_1 = sum(reshape(Y,3,6))

So in your case it would be

Y_1 = sum(reshape(Y,320,467))

sum(bsxfun(@times,A,b),3)