libctl is copyright © 1998—2019, Steven G. Johnson.

libctl is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this library; if not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. You can also find it on the GNU web site:

http://www.gnu.org/copyleft/gpl.html

Many of the files in libctl are individually licensed under the terms of the GNU Lesser General Public License; either version 2 of the License, or (at your option) any later version. This is indicated by the licensing comments at the top of each file. There are a few files in libctl that we place in the public domain, which are not restricted by the terms of the GPL or LGPL; these files explicitly indicate this fact at the top of the file. All files fall under the GPL unless they expressly say otherwise.

The files src/integrator.c and src/cintegrator.c contain multi-dimensional numeric integration code that was adapted in part from HIntLib by Rudolf Schuerer and from the GNU Scientific Library by Brian Gough. Both of these libraries are licensed under the GNU GPL, version 2 or later.