[计] revised product matrix algorithm
xiū zhèng jǔ zhèn chéng jī suàn fǎ ㄒㄧㄡ ㄓㄥˋ ㄐㄩˇ ㄓㄣˋ ㄔㄥˊ ㄐㄧ ㄙㄨㄢˋ ㄈㄚˇ