JuliaLang/julia — pull request #4112 by simonbyrne (2013-08-20 11:20:29+00:00)
Title: add sinpi cospi functions

Adds functions for accurately computing `sin(pi*x)` and `cos(pi*x)` using range reduction: the main benefit is that `sinpi(0.5) == 1.0` and `sinpi(1.0) == 0.0`. Used internally in `sinc` function and several other places.