So you want to compute an outer product? For two 1-dimensional terms (i.e. vectors) you have: 
[a1...an]' * [b1...bn] = [a1*b1 ... a1*bn; ...; an*b1 ... an*bn]

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which can be written "a_i * b_j" using physicists' tensor notation. For two 2-dimensional terms (i.e. matrices) you have a tensor product like "a_ij * b_kl", and you can generalize this to any rank (and to other operations besides "*"). I think PDL can compute outer products for low ranks, but you'll probably need to create an iterator or some such to avoid running out of memory with higher ranks.

In reply to Re: Obtaining terms in an expansion by educated_foo
in thread Obtaining terms in an expansion by randyk

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