Quicker function than repmat to multiplay matrices with vectors?

I've recognised that in my programm the most time-consuming parts are the parts where I use repmat, most of the times when I want to multiply a large Matrix with a vector. Is there an easier way?

The main problem was to vectorize the code instead of using loops all the time, but now, since I replicate a lot of data to get matrix-operations running, the program ist not really quicker...Are there better alternatives?

E.g.: LargeMatr=[ 1 2 3; 4 5 6; 7 8 9] %in reality around 40000 x 1000 elements

Vector=[ 1 3 4]'; % One column/ In reality with 40000 elements x 1 element

Result= LargeMatr.*Vector % is not possible, so I have to do this:

Result= LargeMatr.*repmat(Vector,1,3);

Is this already the most efficient way? Or would a loop even be quicker?

Thanks a lot!

Answer 1

[per isakson]

Try to use bsxfun, Apply element-by-element binary operation to two arrays with singleton expansion enabled

There is an example in the documentation of bsxfun that applies to your problem.

[Tim]

Thanks a lot! That really improves the performance!