sine_integral, an Octave code which evaluates the Cosine Integral and the Sine Integral, by Shanjie Zhang, Jianming Jin;
The Fortran77 source code of this library is copyrighted by Shanjie Zhang and Jianming Jin. However, they give permission to incorporate routines from this library into a user program provided that the copyright is acknowledged.
sine_integral is available in a Fortran90 version and a MATLAB version and an Octave version and a Python version.
cordic, an Octave code which uses the CORDIC method to compute certain elementary functions.
fn, an Octave code which evaluates elementary and special functions, by Wayne Fullerton.
polpak, an Octave code which evaluates certain mathematical functions, especially some recursive polynomial families.
test_values, an Octave code which contains a few test values of many functions.