If you're doing matrix multiplication yourself, you're doing it wrong. Use PDL::Sparse or another library for that.

(Usually sparse matrices are stored a bit different: for every row and every column there's a linked list of non-zero items together with their indexes, so that walking all non-zero elements is fast, ie following the links).

In reply to Re: Sparse Matrix Multiplication Problem by moritz
in thread Sparse Matrix Multiplication Problem by neversaint

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