On Why and How to Minimize the Arithmetic Complexity of Fast Matrix Multiplication Algorithms

Paul Stankovski Wagner
Naively multiplying two $2 \times 2$ matri- ces requires eight multiplications and four additions. Strassen showed how to perform the same computation using seven multiplications and 18 additions. By chang- ing basis, Karstadt and Schwartz lowered the number of additions to 12, which they showed to be optimal within this generalized Karstadt-Schwartz (KS) framework. We present improved methods for optimizing the number of additions in Strassen-type matrix multipli- cation schemes for larger mat