The two main numerical libraries in Fortran 90 are . NAG Numerical Libraries for Fortran 90 Users . IMSL Fortran 90 MP Library Both of these offer both a modified version of the Fortran 77 library, recompiled for Fortran 90, and a completely new library, using all the new facilities of Fortran 90. ... On the Sun using Sun OS 4.2.1 we also got completely wrong results when using library functions in single precision, since the C system on Sun converted all function calls into double precision. ...