We present a non-commutative algorithm for the product of 3 × 5 by 5 × 5 matrices using 58 multiplications. This algorithm allows to construct a non-commutative algorithm for multiplying 5 × 5 (resp. 10 × 10, 15 × 15) matrices using 98 (resp. 686, 2088) multiplications. Furthermore, we describe an approximate algorithm that requires 89 multiplications and computes this product with an arbitrary small error.
CCS CONCEPTS• Computing methodologies → Exact arithmetic algorithms; Linear algebra algorithms.