Error analysis of matrix multiplication with narrow range floating-point arithmetic
Résumé
High-performance computing hardware now supports many different floating-point
formats, from 64 bits to only 4 bits. While the effects of reducing precision in numerical linear
algebra computations have been extensively studied, some of these low precision formats also possess
a very narrow range of representable values, meaning underflow and overflow are very likely. The
goal of this article is to analyze the consequences of this narrow range on the accuracy of matrix
multiplication. We describe a simple scaling that can prevent overflow while minimizing underflow.
We carry out an error analysis to bound the underflow errors and show that they should remain
dominated by the rounding errors in most practical scenarios. We also show that this conclusion
remains true when multiword arithmetic is used. We perform extensive numerical experiments that
confirm that the narrow range of low precision arithmetics should not significantly affect the accuracy
of matrix multiplication—provided a suitable scaling is used.
Origine | Fichiers produits par l'(les) auteur(s) |
---|