deal.II copyright and license

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 code.

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: The legally binding license is the GNU Lesser General Public License (LGPL) as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version.

Furthermore, the deal.II distribution comes 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 all people mentioned at the deal.II Authors page.


As a contributor to this project, you agree that any of your contributions be licensed under the same terms and conditions as the license of the deal.II project granted to you.

The deal.II project does not require copyright assignments for contributions. This means that the copyright for code contributions in the deal.II project is held by its respective contributors who have each agreed to release their contributed code under the terms of the LGPL v2.1 or later.

Referencing the library

In addition to the terms imposed by the LGPL v2.1 or later, we ask for the following courtesy:

  • Every publication presenting numerical results obtained with the help of deal.II should state the name of the library and cite the canonical deal.II reference listed at the top of the publications page.

This is the usual, fair way of giving credit to contributors to a scientific result. In addition, it helps us justify our effort in developing deal.II as an academic undertaking.

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

deal.II comes bundled with copies of UMFPACK, Threading Building Blocks, BOOST and muParser. These projects reside in the subdirectory "bundled/". Please note that these projects are copyrighted by others than the deal.II authors and are covered by different licenses. For details, consult the respective webpage.

The libraries listed above are all open source and as such place few restrictions on their use. However, if you want to distribute software developed with deal.II (in source or binary form) and you are using the packages above (with source code in bundled/), then they may impose different terms. Please consult the licenses of these packages for more information.

Alternatively, the configuration process of deal.II allows you to disable the use of all of these bundled libraries. In that case, you can not use their functionality but you also are not restricted by their license.


For further questions regarding licensing and commercial use please contact the deal.II principal developers directly via one of the following mail addresses:

  • Wolfgang Bangerth < >
  • Timo Heister < >
  • Guido Kanschat < >
  • Matthias Maier < >

Full license text

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