Complexity measures for matrix multiplication algorithms

A new class of algorithms for the computation of bilinear forms has been recently introduced [1, 3]. These algorithms approximate the result with an arbitrarily small error. Such approximate algorithms may have a multiplicative complexity smaller than exact ones. On the other hand any comparison between approximate and exact algorithms has to take into account the complexity-stability relations. In this paper some complexity measures for matrix multiplication algorithms are discussed and applied to the evaluation of exact and approximate algorithms. Multiplicative complexity is shown to remain a valid comparison test and the cost of approximation appears to be only a logarithmic factor.