Mahmood Sheikh

 This code is purely for expository purposes, as conv will be preferred always. As a conv tutorial, this does show nicely the basic idea of how one might write a convolution, except one should not (in practice) generate the entire table first, and THEN do the sum. This will be an inefficient and unnecessary use of memory. I can forgive inefficiency for expository purposes, as long as the reader is made aware of the difference. As such, a few comments to that effect would possibly increase my rating.

This code is purely for expository purposes, as conv will be preferred always. As a conv tutorial, this does show nicely the basic idea of how one might write a convolution, except one should not (in practice) generate the entire table first, and THEN do the sum. This will be an inefficient and unnecessary use of memory. I can forgive inefficiency for expository purposes, as long as the reader is made aware of the difference. As such, a few comments to that effect would possibly increase my rating.

It might also be of interest to show the reader a more
efficient version. In some quick tests, with length(a) = 1000 and length(b) = 100, the version below is 8x faster, but with comments it should be as understandable as the doubly looped version.

na = length(a);
nb = length(b);
b=b(:);
result = zeros(na+nb-1,1);
for m = 1:na
  result(m:(m+nb-1)) = result(m:(m+nb-1)) + a(m)*b;
end