in reply to Inversion on a non square matrix using PDL (or similar?)

You're looking for the Moore-Penrose pseudoinverse. It is defined on MathWorld and is easy to implement for a matrix `A` as `(A^t A)^{-1} A^t` where `A^t` is `A` transposed, `A^t A` is a square matrix, `(A^t A)^{-1}` being its inverse (if it exists).

Hope this helps, -gjb-

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