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Topic: matrix multiplication with zero dimensions
Replies: 11   Last Post: Jan 7, 2013 10:20 AM

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Matt J

Posts: 4,997
Registered: 11/28/09
Re: matrix multiplication with zero dimensions
Posted: Jan 7, 2013 12:04 AM
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"Matt J" wrote in message <kcdjbp$46l$>...
> "Roger Stafford" wrote in message <kcdg4j$n70$>...
> >
> > 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.

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