Who is the author of Zhou Kuai Suan Jing?

According to the written records of Zhou Bi suan Jing, its author should be Fang Rong. Chen Zi's student Fang Rong asked his teacher Chen Zi about the origin of the calendar (calendar data) used to measure "Sunday" in ancient Fuxi. This book began to record that Duke Zhou asked Shang Gao, an astronomical mathematician at the end of Shang Dynasty, for advice on the reason why Fuxi calculated the day of the week. Shang Gao briefly expounded the principle of Fuxi's calculation and correction. Then, Chen Zi told his disciples about the method and principle of Fuxi's calculation of Sunday calendar. Fuxi's astronomical theory is based on the theory of covering the sky. Although the theory of covering the sky was overthrown by later generations, Fuxi's principle and method of calculating the day of the week and making calendars are the source of astronomical calendars and mathematics in later generations. This is consistent with the legend of Fuxi's invention of Yi-ology. It shows that Fuxi first established the Yi-ology of Image Numbers and Yi-ology of Gua in order to calculate the designated calendar of the stars. According to this theory, the earliest calendar "Zhou Li", also known as "Haotian Li" or "Fuxi Li" and "Tai Hao Li", was made by measuring astronomical data with Guiyi. He Tu, Luo Shu and Eight Diagrams (or "Gui Gui", later used for divination, changed to Eight Diagrams, and eight is the initial word of "Gui", which also means that the standard table used by Fuxi is eight feet high) are all key charts and documents of this activity, but the original pictures and documents are not in the present form. This also shows that Fuxi's theory is not completely fictional, and there must be a reason; It also shows how wise and great our ancestors were!