14-17 August 2007
Nordita Building
Europe/Stockholm timezone

The Pencil Code is a multipurpose code for massively parallel computing (especially on the cheaper Linux clusters).

It includes optionally hydrodynamics, magnetic fields, radiation, ionization, multi-species dust dynamics with coagulation, and certain reaction-diffusion equations. It is developed and maintained under the Concurrent Versioning System ( CVS ) by around 25 people with check-in permission and has been downloaded by around 400 registered users (without check-in permission).

The code is tested nightly on several platforms and provides an excellent pedagogical tool for students to implement new code within an organized framework. The purpose of the meeting is to bring the core developers together and to allow others to interact with them and learn more about the code.

How to get here? (this link has a description and a map). The meeting takes place in the Nordita building, just next to the AlbaNova building.

The meeting is sponsored jointly by Nordita and the AstroSim programme. A full report of the meeting is available.

Organizers: Axel Brandenburg, Boris Dintrans, Wolfgang Dobler, Anders Johansen, Petri Käpylä

All presentations are recorded on video; see link to the video page of Alex Agapow. There is also a link to streaming videos.

List of discussion topics:

   Changing from CVS to another Versioning System **
   GPL agreement, going to version 3 **
   Multiauthor paper discussing methods and tests?
      good illustrative problems? (e.g. source terms)
   Do we need a better tracker against breaks of the auto-test?
   pencil_consistency_check: possible overcalculation... pencil del2a (17) **
     Suggestion: switch off by default, on nightly test machines activate
     through global options file:
     - pencil_consistency_check
     - color output
   Strange comments such as "life_support_off?" **
     WARNING: death on error restored occurred at life_support_off
     [Write Bugzilla report, assign to Anders]
   Configuration based on machine multiple names **
     Host name could be set in global .pencil/ directory.

   A clean up of the IDL directory? **
     Make obsolete directory in $PENCIL_HOME/idl and move all files there.
     Make descriptive subdirectories of $PENCIL_HOME/idl and move useful files
     Suggested subroutines read, write, plot, calc.
   State of the manual. What needs to be done?
     more about boundary conditions (to be done) **
     Manual and Wiki: wiki for not so well established stuff **
     Suggestion: add more formulas (derivations and ``how do we get there'')
     Suggestion: equation of state should come before passive scalar, etc.

Technical additions:
   Spherical and cylindrical coordinates
   Upwinding stuff in non-cartesian coordinates: **
     Suggestion: treat partial derivative with upwinding
   Non-reflecting open b.c.s (Wolfgang) **
   Density floors and ceilings
   Radiation transport in shearing boxes
   The shock viscosity (Tobi and Anders)
   Isolated boundary conditions (Chao-Chin Yang)
     James, R.A. 1977, J. Comp. Phys. 25, 71-92.

Next meeting? Where? Elsewhere than Stockholm? How to do it differently?
Tentative time: 26-29 Aug 2008.

Yes. Possibly Leiden.


Tuesday, 9-10:30, 11-12:30
9:00 Axel Brandenburg   Introduction
9:15 Anders Johansen    Dust in self gravitating shearing sheets
Cristina Green          Traveling waves in sheared convection

Tuesday, 14-15:30, 16-17:30
Wolfgang Dobler         CVS, Mercurial or Subversion -- do we need a
Sven Bingert            Field aligned heat conduction in the corona
Marcus Gellert          Hydrodynamic simulations in cylindrical coordinates

Wednesday, 9-10:30, 11-12:30
Miikka Väisälä          Formation of elephant trunks
Tobias Heinemann        Migrating to subversion

Wednesday, 9-10:30, 11-12:30
Steve Berukoff          Plans to implement protostellar disc chemistry
Chao-Chin Yang          Fueling the circumnuclear region of a barred galaxy

Wednesday, 14-15:30, 16-17:30
Petri Käpylä            Hi-res MHD on the Finnish Louhi machine
Anne Liljeström         Reynold stresses in shearing boxes

Thursday, 9-10:30, 11-12:30

Dhrubaditya Mitra     Simulations in spherical coordinates
Nathalie Toque         Turbulent diffusion
Boris Dintrans          I. Global convection; II. Implicit method

Thursday, 14-15:30, 16-17:30

Wladimir Lyra           Global disc simulations
Lars Mattsson           Disc Simulations: Evolving Late-type Galaxies
Mikaela Sundberg        Code comparison projects - A sociological view

Friday, 9-10:30, 11-12:30

Wolfgang Dobler         Multigrid solvers for the Pencil Code
                        different Version Control System (Discussion)

Friday, 14-15:30

Axel Brandenburg        Parallelization in the x-direction (link)

Nordita Building
Nordita Seminar Room
Roslagstullbacken 23
  • Anders Johansen
  • Axel Brandenburg
  • Boris Dintrans
  • Petri Käpylä
  • Wolfgang Dobler