BRAINCIRC is a free modelling environment with a few models included.
It is released under the GNU public license. See the file COPYING for
details. See the file INSTALL for building and installation instructions.
Note that included in the directory src/radau5 is the fortran
package RADAU5 produced by Hairer et al, and available at
http://www.unige.ch/~hairer/software.html. This software
is not covered by the GNU public license, but is covered by
a similar license in the file src/radau5/radau/LICENSE
Also included are slightly the public domain memory handling routines
in nrutil.c. Details are at http://www.nr.com/public-domain.html