i4lib, a Fortran90 code which contains many utility routines for I4 or "single precision integer" arithmetic.
The information on this web page is distributed under the MIT license.
i4lib is available in a C version and a C++ version and a Fortran90 version and a MATLAB version and an Octave version and a Python version.
c8lib, a Fortran90 code which implements certain elementary functions for "C8" or double precision complex variables;
r8lib, a Fortran90 code which contains many utility routines, using "R8" or "double precision real" arithmetic.
subpak, a Fortran90 code which contains many utility routines;