シュトラッセンのアルゴリズム
そして、以下の七つの行列をつくる。
P 1 = ( A 11 + A 22 ) ( B 11 + B 22 ) {\displaystyle P_{1}=(A_{11}+A_{22})(B_{11}+B_{22})}
P 2 = ( A 21 + A 22 ) B 11 {\displaystyle P_{2}=(A_{21}+A_{22})B_{11}}
P 3 = A 11 ( B 12 − B 22 ) {\displaystyle P_{3}=A_{11}(B_{12}-B_{22})}
P 4 = A 22 ( B 21 − B 11 ) {\displaystyle P_{4}=A_{22}(B_{21}-B_{11})}
P 5 = ( A 11 + A 12 ) B 22 {\displaystyle P_{5}=(A_{11}+A_{12})B_{22}}