Sollya - a numerical software tool for the semi-automatic implementation of efficient correctly rounding mathematical functions

Christoph Lauter

LIP, ENS Lyon, France

The efficient implementation of mathematical functions, such as exp, sin, log, consists in finding a well-suited compromise between the precision and the speed of tens of floating-point operations. Correct rounding further requires (formally) proving error bounds. Designing an implementation has hence been tedious, manual work at the price of one man-month per function.

Sollya is a tool that combines some aspects of a Computer Algebra System with safe numerical algorithms. Safety is obtained by the use of interval arithmetic. The tool provides a fully integrated and ergonomic tool-chain for the certified development of mathematical functions. It strives for complete automation of the development: a prototype already allows us to implement and certify correctly rounded mathematical functions in about 2 days whilst running through an extended research space.