Matt J
Posts:
4,996
Registered:
11/28/09


Re: matrix multiplication with zero dimensions
Posted:
Jan 7, 2013 12:04 AM


"Matt J" wrote in message <kcdjbp$46l$1@newscl01ah.mathworks.com>... > "Roger Stafford" wrote in message <kcdg4j$n70$1@newscl01ah.mathworks.com>... > > > > Think of it this way, Matt. Consider the four multiplications: > > > > M3 = ones(3,3)*ones(3,3); > > M2 = ones(3,2)*ones(2,3); > > M1 = ones(3,1)*ones(1,3); > > M0 = ones(3,0)*ones(0,3); > > > > Each of the elements of 3 x 3 M3 is 3. Each of the elements of 3 x 3 M2 is 2. Each of the elements of 3 x 3 M1 is 1. Therefore by extension of this trend M0 should have 3 x 3 elements and each of them should be 0. > ============= > > OK!
But... I still think these things should be documented somewhere. They don't satisfy the basic definitions of matrix multiplication, PROD, or SUM. They're just extrapolations of them.

