How to create a convolution matrix?

Hello all,

I have a matrix like this

a=[1 2 3]

For convolution I reversed the matrix a=[3 2 1]

Then, to multiply this matrix with another matrix, I should shift the and get like this one

M=[1 0 0; 2 1 0; 3 2 1; 0 3 2; 0 0 3;]

How can I get this matrix ? Please help...

Answer 1

[Image Analyst]

A for loop, and fliplr() and circshift() should get it for you. Give it a try first - it will be a good learning experience. It's not hard. Come back if it's too hard for you and you really really need us to do it 100% for you and it's not homework.

Answer 2

[patricia torres]

M = convmtx(a,length(a));