Berkeley Elementary Functions Test Suite

A suite of programs is presented to test how accurately the elementary transcendental functions exp, log, sin, cos and atan have been implemented in a computer’s run-time library. The suite is written in the language C and designed to run on any computer with binary floating-point arithmetic rounded in a reasonable way. The suite makes no appeal to extra-precise arithmetic; the tests use only whatever arithmetic capabilities are present in the environment where the transcendental functions are to be used. Despite this limitation, the tests run fast and deliver indication of accuracy to within a small fraction of an ULP (Unit in the Last Place) of the functions under test. This account includes the proofs of the test suite’s claims to accuracy.