The Pencil Code is a high-order finite-difference code for compressible hydrodynamic flows with magnetic fields and particles. It is highly modular and can easily be adapted to different types of problems. The code runs efficiently under MPI on massively parallel shared- or distributed-memory computers.

The Pencil Code is available from pencil-code.org and is mirrored to GitHub. It was previously hosted at Google Code.

In order to checkout the code with read-write premissions Subversion, use the command

svn checkout https://pencil-code.org/svn/trunk pencil-code --username=<your-username>

where <your-username> is your GitHub username that you should use identically to register on account.pencil-code.org for write access to the code repository.

For read-only access via SVN, a username is not required:

svn checkout https://pencil-code.org/svn/trunk pencil-code

To get started, run one of the samples:

unix>  cd pencil-code
unix>  source sourceme.sh
unix>  cd samples/conv-slab
unix>  mkdir data

To set up the symbolic links and compile the code:

unix>  pc_setupsrc
unix>  pc_build  [ -f /path/to/config/file.conf ]

To create the initial condition and run the code:

unix>  pc_start  [ -f /path/to/config/file.conf ]
unix>  pc_run    [ -f /path/to/config/file.conf ]

See pencil-code/config/hosts/*/*.conf for sample config files. For more details, see the manual in the doc/ directory (also available here).

If you are using bash and you do not want to "source sourceme.sh" on each session, you can insert the following into your .bashrc and/or .bash_profile:

export PENCIL_HOME=$HOME/pencil-code  [or wherever you have the code]
_sourceme_quiet=1; . $PENCIL_HOME/sourceme.sh; unset _sourceme_quiet

• A new documentation webpage has been created with the goal of gather all the documentation together and create auto-documentation for the code: Pencil Code documentation.
• The manual is the main source of information.
• There is also a quick start to help getting started.
• Information about Python with the Pencil Code and the Python Coding Style can be found on the wiki.
• Updates to the community are provided through the newsletter.
• Talk to use during the Pencil Code Office Hours every second Friday of the month at 13:00 CET via zoom (641-599-5185). You may also want to inspect the activity of Pencil Code Steering Committee. Please contact them with your ideas.
• The Pencil Code User Meeting will be held every year. The 2023 meeting will be organized in Austria by Vartika Pandey and Johannes Tschernitz: Pencil Code User Meeting 2023.
• See the Scientific Usage of the Pencil Code for papers using or discussing the code.

• Around 100 people have contributed to various extent during the nearly 20 years of Pencil Code history.
• The current list of contributors shows the temporal check-in activity of the those who stayed connected with the code over the various host changes (Nordita 2001-2007, Google Code 2007-2015, and Github since 2015). Some additional contributors are also listed in the manual.

• For all changes to the code, make sure the auto-test still runs

• If you have write access: check in your changes and make sure you can fix possible problems emerging on travis-ci.com as well as the minutely, hourly, and daily auto-tests.

• If you have only read access: fork this repository and use pull requests to contribute.

• The Pencil Code community adheres to the Contributor Covenant Code of Conduct. Please familiarize yourself with its details.

• The Pencil Code is under the GNU public license agreement.