The deal.II library has been placed under an Open Source license, in the sense advocated by the Open Source Initiative. You are thus free to copy and use it, and you have free access to all source codes. However, deal.II is not in the public domain, it is property of and copyrighted by the deal.II authors, and there are restrictions on its use. We will give some hints on license issues first. The legally binding license is the Q Public License (QPL) at the bottom of this page. Furthermore, deal.II distributions come bundled with some third party software for which the deal.II authors do not own the copyright. The licenses of these parts are discussed below.
In this document, as well as in the program files, the terms authors of deal.II and deal.II authors generally refer to the principal authors of the library. These are Wolfgang Bangerth, Timo Heister, and Guido Kanschat.
deal.II is distributed under the Open Source license called the Q Public License (or "QPL") listed in full below. Essentially, an interpretation of this license is that you can use the library free of charge for developing your own programs. However, if you plan to distribute these programs to others, certain restrictions are imposed by the QPL.
In non-legal terms, the license stipulates that if you want to give your program to someone else in whatever form (including as a binary executable), you have to make the entire source code of your own program and all modifications to the deal.II library available free of charge as well.
We recognize that giving away the source code may be an unacceptable restriction in a commercial setting. As the owners of the sources, we are able to grant you a differently licensed version of the deal.II library that does not contain this requirement, and we are very much willing to negotiate the terms of such a license. Please contact the authors of the library if you are interested in commercial use of deal.II.
In addition to the terms imposed by the QPL, we ask for the following courtesy:
We keep a list of publications
using deal.II. Feel free to let us know about your publications.
Parts of the deal.II distribution under a separate license
Some of the files in the contrib/ subdirectory are by
other people, and are distributed under separate licenses. These
files are not part of the deal.II library, but
they are part of our distribution. They are generally available for
use in non-commercial academic settings. For commercial use and if
you want to distribute your codes, please consult the licenses of
these parts of the deal.II distribution. We made sure that those parts of the
distribution for which the license is not entirely free for all uses can be
disabled upon configuration of deal.II without
unduly restricting the functionality of the rest of the
library.
In particular, these are libraries that we distribute in the
contrib/ subdirectory, courtesy of their authors:
deal.II can interface with a number of other packages that you have to install yourself. They are, of course, covered by their own licenses.
The QPL was originally developed by Troll Tech for their Qt program library, but has since gained some support by other library authors as well. For more information on the QPL, please follow this link.
The intent of this license is to establish freedom to share and change the software regulated by this license under the open source model.
This license applies to any software containing a notice placed by the copyright holder saying that it may be distributed under the terms of the Q Public License version 1.0. Such software is herein referred to as the Software. This license covers modification and distribution of the Software, use of third-party application programs based on the Software, and development of free software which uses the Software.
1. You are granted the non-exclusive rights set forth in this license provided you agree to and comply with any and all conditions in this license. Whole or partial distribution of the Software, or software items that link with the Software, in any form signifies acceptance of this license.
2. You may copy and distribute the Software in unmodified form provided that the entire package, including - but not restricted to - copyright, trademark notices and disclaimers, as released by the initial developer of the Software, is distributed.
3. You may make modifications to the Software and distribute your modifications, in a form that is separate from the Software, such as patches. The following restrictions apply to modifications:
a. Modifications must not alter or remove any copyright notices in the Software.
b. When modifications to the Software are released under this license, a non-exclusive royalty-free right is granted to the initial developer of the Software to distribute your modification in future versions of the Software provided such versions remain available under these terms in addition to any other license(s) of the initial developer.
4. You may distribute machine-executable forms of the Software or machine-executable forms of modified versions of the Software, provided that you meet these restrictions:
a. You must include this license document in the distribution.
b. You must ensure that all recipients of the machine-executable forms are also able to receive the complete machine-readable source code to the distributed Software, including all modifications, without any charge beyond the costs of data transfer, and place prominent notices in the distribution explaining this.
c. You must ensure that all modifications included in the machine-executable forms are available under the terms of this license.
5. You may use the original or modified versions of the Software to compile, link and run application programs legally developed by you or by others.
6. You may develop application programs, reusable components and other software items that link with the original or modified versions of the Software. These items, when distributed, are subject to the following requirements:
a. You must ensure that all recipients of machine-executable forms of these items are also able to receive and use the complete machine-readable source code to the items without any charge beyond the costs of data transfer.
b. You must explicitly license all recipients of your items to use and re-distribute original and modified versions of the items in both machine-executable and source code forms. The recipients must be able to do so without any charges whatsoever, and they must be able to re-distribute to anyone they choose.
c. If the items are not available to the general public, and the initial developer of the Software requests a copy of the items, then you must supply one.
The Software and this license document are provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
This license is governed by the Laws of Germany. Disputes shall be settled by Amtsgericht Heidelberg.