etdrk4, a FORTRAN90 code which uses the ETD RK4 method to solve systems of stiff ordinary differential equations (ODE), by Aly-Khan Kassam, Lloyd Trefethen.
The computer code and data files described and made available on this web page are distributed under the GNU LGPL license.
etdrk4 is available in a FORTRAN90 version and a MATLAB version.
fftpack5, a FORTRAN90 code which computes Fast Fourier Transforms (FFTs), by Paul Swarztrauber and Dick Valent;
Aly-Khan Kassam, Lloyd Trefethen; Modifications by John Burkardt.