
Multidimensional array product
Posted:
Aug 16, 2009 8:24 PM


I have a question about how to efficiently form multidimensional arrays.
Lets say I have two 2d arrays (i.e. matrices) a and b; a(i,j) sized i=1..M,j=1..N; and b(i,j) sized i=1..K,j=1..L.
How can I form the 4d array w(m,n,k,l)=a(m,n)*b(k,l) which has a unique entry for every m,n,k,l; i.e. there are M*N*K*L unique entries?
I want to form w in a 'vectorized' way without use of loops. A conventional matrix product like a*b doesn't work of course since the inner dimensions of a and b aren't the same. This isn't the same as a Kronecker product since that remains twodimensional.
Thanks for any assistance.
Ed Stein edstein7997@hushmail.com

