Name: Pencil Code school and 2025 user meeting
Start: 2025-10-20T08:30:00+02:00
End: 2025-10-31T18:00:00+01:00
Location: CERN

Pencil Code school and 2025 user meeting

from Monday, 20 October 2025 (08:30) to Friday, 31 October 2025 (18:00)

Monday, 20 October 2025
09:30 Welcome to Pencil Code school - Axel Brandenburg (Nordita) Alberto Roper Pol
Welcome to Pencil Code school
- Axel Brandenburg (Nordita)
- Alberto Roper Pol
09:30 - 10:30
Room: 4/3-006 - TH Conference Room Welcome to the school on Pencil Code! Introduction to the school. History and scientific summary of Pencil Code.
10:30 Introduce yourself - Alberto Roper Pol
Introduce yourself
- Alberto Roper Pol
10:30 - 11:00
Room: 4/3-006 - TH Conference Room Session to introduce yourself! We want to hear about your research interests, background and expectations from the school!
11:00 Coffee break
Coffee break
11:00 - 11:30
Room: 4/2-011 - TH common room
11:30 Basics of Pencil Code - Philippe Bourdin (University of Graz)
Basics of Pencil Code
- Philippe Bourdin (University of Graz)
11:30 - 13:00
Room: 4/3-006 - TH Conference Room
13:00 Lunch break
Lunch break
13:00 - 15:00
15:00 Practice session. Getting familiar with the code - Alberto Roper Pol
Practice session. Getting familiar with the code
- Alberto Roper Pol
15:00 - 16:00
Room: 4/3-006 - TH Conference Room Installation and getting familiar with the code. Running your first sample(s). Go on into the Pencil Code website (https://pencil-code.nordita.org/), download the code and install libraries (you can see the quick starter guide attached here) and documentation available on Pencil Code's website.
16:00 Coffee break
Coffee break
16:00 - 16:30
Room: 4/2-011 - TH common room
16:30 Practice session. Sound and Alfven waves - Deepen Garg (University of Bonn) Antonino Salvino Midiri (Universite de Geneve (CH)) Alberto Roper Pol
Practice session. Sound and Alfven waves
- Deepen Garg (University of Bonn)
- Antonino Salvino Midiri (Universite de Geneve (CH))
- Alberto Roper Pol
16:30 - 17:30
Room: 4/3-006 - TH Conference Room
Tuesday, 21 October 2025
09:30 Numerical schemes for differential equations - Antonino Salvino Midiri (Universite de Geneve (CH)) Philippe Bourdin (University of Graz)
Numerical schemes for differential equations
- Antonino Salvino Midiri (Universite de Geneve (CH))
- Philippe Bourdin (University of Graz)
09:30 - 11:00
Room: 4/3-006 - TH Conference Room
11:00 Coffee break
Coffee break
11:00 - 11:30
Room: 4/2-011 - TH common room
11:30 Numerical schemes for differential equations - Philippe Bourdin (University of Graz)
Numerical schemes for differential equations
- Philippe Bourdin (University of Graz)
11:30 - 12:30
Room: 4/3-006 - TH Conference Room
12:30 Discrete Fourier transform. Power spectra - Isak Stomberg (IFIC Instituto de Física Corpuscular)
Discrete Fourier transform. Power spectra
- Isak Stomberg (IFIC Instituto de Física Corpuscular)
12:30 - 13:00
Room: 4/3-006 - TH Conference Room
13:00 Lunch break
Lunch break
13:00 - 14:00
14:00 Post-processing and visualization - Axel Brandenburg (Nordita) Philippe Bourdin (University of Graz)
Post-processing and visualization
- Axel Brandenburg (Nordita)
- Philippe Bourdin (University of Graz)
14:00 - 15:30
Room: 4/3-006 - TH Conference Room
15:30 Coffee break
Coffee break
15:30 - 16:00
Room: 4/2-011 - TH common room
16:00 Post-processing and visualization - Philippe Bourdin (University of Graz) Simon Candelaresi (University of Augsburg)
Post-processing and visualization
- Philippe Bourdin (University of Graz)
- Simon Candelaresi (University of Augsburg)
16:00 - 16:30
Room: 4/3-006 - TH Conference Room
16:30 Practice session. Forced helical turbulence - Antonino Salvino Midiri (Universite de Geneve (CH)) Alberto Roper Pol Deepen Garg (University of Bonn)
Practice session. Forced helical turbulence
- Antonino Salvino Midiri (Universite de Geneve (CH))
- Alberto Roper Pol
- Deepen Garg (University of Bonn)
16:30 - 17:30
Room: 4/3-006 - TH Conference Room
Wednesday, 22 October 2025
09:30 Running on multiple CPUs. Parallelization - Matthias Rheinhardt (Aalto University)
Running on multiple CPUs. Parallelization
- Matthias Rheinhardt (Aalto University)
09:30 - 10:30
Room: 4/3-006 - TH Conference Room
10:30 Data handling and I/O approaches - Philippe Bourdin (University of Graz)
Data handling and I/O approaches
- Philippe Bourdin (University of Graz)
10:30 - 11:00
Room: 4/3-006 - TH Conference Room
11:00 Coffee break
Coffee break
11:00 - 11:30
Room: 4/2-011 - TH common room
11:30 Contributing to the code. SVN and Github. Pencil Code autotests - Alberto Roper Pol
Contributing to the code. SVN and Github. Pencil Code autotests
- Alberto Roper Pol
11:30 - 12:00
Room: 4/3-006 - TH Conference Room
12:00 Accelerating Pencil Code on GPUs - Matthias Rheinhardt (Aalto University)
Accelerating Pencil Code on GPUs
- Matthias Rheinhardt (Aalto University)
12:00 - 13:00
Room: 4/3-006 - TH Conference Room
13:00 Lunch break
Lunch break
13:00 - 14:00
14:00 TH Colloquium: Dynamos versus magnetogenesis: astrophysics versus cosmology - Axel Brandenburg (Nordita)
TH Colloquium: Dynamos versus magnetogenesis: astrophysics versus cosmology
- Axel Brandenburg (Nordita)
14:00 - 15:30
Room: 4/3-006 - TH Conference Room Magnetic fields occur spontaneously both in astrophysics and in the early universe. Their energy sources are rather different: kinetic energy of the plasma in astrophysics and a variety of other forms of energy including axions, scalar fields, and chiral fermions in the cosmological settings. However, both areas have in common that the magnetic field is amplified by a long wavelength instability. In this colloquium, I will survey astrophysical and cosmological magnetic fields and then present a selection of important recent findings.
15:30 Coffee break
Coffee break
15:30 - 16:00
Room: 4/2-011 - TH common room
16:00 Free hands-on session. Projects definition - Alberto Roper Pol
Free hands-on session. Projects definition
- Alberto Roper Pol
16:00 - 18:30
Room: 4/3-006 - TH Conference Room
19:00 School reception
School reception
19:00 - 20:30
Room: 4/3-006 - TH Conference Room
Thursday, 23 October 2025
09:30 Magnetohydrodynamics in the early Universe - Alberto Roper Pol
Magnetohydrodynamics in the early Universe
- Alberto Roper Pol
09:30 - 11:00
Room: 4/3-006 - TH Conference Room
11:00 Coffee break
Coffee break
11:00 - 11:30
Room: 4/2-011 - TH common room
11:30 Primordial magnetic fields - Alberto Roper Pol Axel Brandenburg
Primordial magnetic fields
- Alberto Roper Pol
- Axel Brandenburg
11:30 - 12:30
Room: 4/3-006 - TH Conference Room
12:30 Chiral MHD - Deepen Garg (University of Bonn)
Chiral MHD
- Deepen Garg (University of Bonn)
12:30 - 13:00
Room: 4/3-006 - TH Conference Room
13:00 Lunch break
Lunch break
13:00 - 14:00
14:00 Gravitational waves - Chiara Caprini (CERN)
Gravitational waves
- Chiara Caprini (CERN)
14:00 - 15:30
Room: 4/3-006 - TH Conference Room
15:30 Coffee break
Coffee break
15:30 - 16:00
Room: 4/2-011 - TH common room
16:00 Inflation - Ramkishor Sharma (University of Hyderabad)
Inflation
- Ramkishor Sharma (University of Hyderabad)
16:00 - 17:30
Room: 4/3-006 - TH Conference Room
Friday, 24 October 2025
09:30 Practice session. Decaying MHD turbulence - Alberto Roper Pol Deepen Garg (University of Bonn) Antonino Salvino Midiri (Universite de Geneve (CH))
Practice session. Decaying MHD turbulence
- Alberto Roper Pol
- Deepen Garg (University of Bonn)
- Antonino Salvino Midiri (Universite de Geneve (CH))
09:30 - 11:00
Room: 4/3-006 - TH Conference Room
11:00 Coffee break
Coffee break
11:00 - 11:30
Room: 4/3-006 - TH Conference Room
11:30 First-order phase transitions - Antonino Salvino Midiri (Universite de Geneve (CH)) Isak Stomberg (IFIC Instituto de Física Corpuscular)
First-order phase transitions
- Antonino Salvino Midiri (Universite de Geneve (CH))
- Isak Stomberg (IFIC Instituto de Física Corpuscular)
11:30 - 13:00
Room: 4/3-006 - TH Conference Room
13:00 Lunch break
Lunch break
13:00 - 14:00
Room: 4/3-006 - TH Conference Room
14:00 Practice session. Gravitational waves - Alberto Roper Pol
Practice session. Gravitational waves
- Alberto Roper Pol
14:00 - 15:00
Room: 4/3-006 - TH Conference Room
15:00 CosmoGW - Alberto Roper Pol
CosmoGW
- Alberto Roper Pol
15:00 - 15:30
Room: 4/3-006 - TH Conference Room
15:30 Coffee break
Coffee break
15:30 - 16:00
Room: 4/3-006 - TH Conference Room
16:00 Open practice session - Alberto Roper Pol
Open practice session
- Alberto Roper Pol
16:00 - 17:30
Room: 4/3-006 - TH Conference Room
17:30 Concluding the school - Alberto Roper Pol
Concluding the school
- Alberto Roper Pol
17:30 - 18:00
Room: 4/3-006 - TH Conference Room
Saturday, 25 October 2025
Sunday, 26 October 2025

Monday, 27 October 2025
10:00 Introduction - Alberto Roper Pol Axel Brandenburg Philippe-André Bourdin
Introduction
- Alberto Roper Pol
- Axel Brandenburg
- Philippe-André Bourdin
10:00 - 11:00
Room: 4/3-006 - TH Conference Room Reports from steering committee (P. Bourdin), scientific usage of Pencil Code (A. Brandenburg), Pencil Code school (A. Roper Pol)
11:00 Coffee break
Coffee break
11:00 - 11:30
Room: 4/3-006 - TH Conference Room
11:30 Discussion session: coding sessions agenda setup - Alberto Roper Pol
Discussion session: coding sessions agenda setup
- Alberto Roper Pol
11:30 - 12:30
Room: 4/3-006 - TH Conference Room Discussion of relevant topics to be addressed during the week, preparation of the agenda and distribution of the coding sessions.
12:30 Lunch break
Lunch break
12:30 - 14:00
Room: 4/3-006 - TH Conference Room
14:00 Coding session: GPU accelerated code - Matthias Rheinhardt
Coding session: GPU accelerated code
- Matthias Rheinhardt
14:00 - 15:30
Room: 4/3-006 - TH Conference Room Checking samples running with GPUs. Stable versions and future applications.
15:30 Coffee break
Coffee break
15:30 - 16:00
Room: 4/3-006 - TH Conference Room
16:00 Coding session: Dark Matter applications - Axel Brandenburg
Coding session: Dark Matter applications
- Axel Brandenburg
16:00 - 17:30
Room: 4/3-006 - TH Conference Room Dark Matter and N-body simulations with expansion. PIC simulations.
18:00 Reception
Reception
18:00 - 19:30
Room: Glassbox
Tuesday, 28 October 2025
10:00 Diffusion and heat conduction in simulations of convection and solar atmosphere - Philippe-André Bourdin
Diffusion and heat conduction in simulations of convection and solar atmosphere
- Philippe-André Bourdin
10:00 - 10:30
Room: 4/3-006 - TH Conference Room
10:30 Primordial magnetic field from chiral plasma instability with sourcing - Murman Gurgenidze
Primordial magnetic field from chiral plasma instability with sourcing
- Murman Gurgenidze
10:30 - 11:00
Room: 4/3-006 - TH Conference Room
11:00 Coffee break
Coffee break
11:00 - 11:30
Room: 4/3-006 - TH Conference Room
11:30 Discussion: documentation of Pencil Code - Illa Rivero Losada
Discussion: documentation of Pencil Code
- Illa Rivero Losada
11:30 - 12:30
Room: 4/3-006 - TH Conference Room
12:30 Lunch break
Lunch break
12:30 - 14:00
Room: 4/3-006 - TH Conference Room
14:00 Discussion: documentation (contd) - Alberto Roper Pol
Discussion: documentation (contd)
- Alberto Roper Pol
14:00 - 15:30
Room: 4/3-006 - TH Conference Room
15:30 Coffee break
Coffee break
15:30 - 16:00
Room: 4/3-006 - TH Conference Room
16:00 Coding session: Python tools + MacOS tests + unique input file - Alberto Roper Pol
Coding session: Python tools + MacOS tests + unique input file
- Alberto Roper Pol
16:00 - 17:30
Room: 4/3-006 - TH Conference Room Part 1: python visualization, unifying Jupyter notebooks, extending documentation, GW turbulence postprocessing in Python, pip installation of Python packages. Part 2: MacOS tests, docker. Part 3: unique input file, restructuring the run directory.
Wednesday, 29 October 2025
10:00 The inverse magnetic cascade from radiation to matter domination - Axel Brandenburg (Nordita)
The inverse magnetic cascade from radiation to matter domination
- Axel Brandenburg (Nordita)
10:00 - 10:30
Room: 4/3-006 - TH Conference Room
10:30 Using the Pencil Code to study Red giant stars - Carolina Ortiz Rodríguez
Using the Pencil Code to study Red giant stars
- Carolina Ortiz Rodríguez
10:30 - 11:00
Room: 4/3-006 - TH Conference Room
11:00 Coffe break
Coffe break
11:00 - 11:30
Room: 4/3-006 - TH Conference Room

11:30 Discussion: distribution version control (Git and SVN), branches and breaking autotests
Discussion: distribution version control (Git and SVN), branches and breaking autotests
11:30 - 13:30
Room: 4/3-006 - TH Conference Room

13:30 Lunch break
Lunch break
13:30 - 15:30
Room: 4/3-006 - TH Conference Room
15:30 Relativistic magnetohydrodynamics in the early Universe - Antonino Salvino Midiri (Universite de Geneve (CH))
Relativistic magnetohydrodynamics in the early Universe
- Antonino Salvino Midiri (Universite de Geneve (CH))
15:30 - 16:15
Room: 4/3-006 - TH Conference Room
16:15 Coding session: Relativistic hydrodynamics and high frequency problem - Alberto Roper Pol
Coding session: Relativistic hydrodynamics and high frequency problem
- Alberto Roper Pol
16:15 - 17:30
Room: 4/3-006 - TH Conference Room
17:30 Coding session: AI applications for sub-grid modeling of non-linear physics + missing slices in Dardel - Matthias Rheinhardt
Coding session: AI applications for sub-grid modeling of non-linear physics + missing slices in Dardel
- Matthias Rheinhardt
17:30 - 19:00
Room: 4/3-006 - TH Conference Room
Thursday, 30 October 2025
10:00 Discussion session: output of relevant papers for developments of Pencil Code when compiling the code - Axel Brandenburg (Nordita)
Discussion session: output of relevant papers for developments of Pencil Code when compiling the code
- Axel Brandenburg (Nordita)
10:00 - 10:50
Room: 4/3-006 - TH Conference Room
10:50 Coffee break
Coffee break
10:50 - 11:20
Room: 4/3-006 - TH Conference Room
11:20 Discussion: Minimizing data load of huge simulations - Matthias Rheinhardt
Discussion: Minimizing data load of huge simulations
- Matthias Rheinhardt
11:20 - 11:50
Room: 4/3-006 - TH Conference Room
11:50 Discussion session: coding standards - Philippe-André Bourdin
Discussion session: coding standards
- Philippe-André Bourdin
11:50 - 13:00
Room: 4/3-006 - TH Conference Room
13:00 Lunch break
Lunch break
13:00 - 14:00
Room: 4/3-006 - TH Conference Room

14:00 Coding session: reheating simulations and issue on gaussian noise initial conditions + scalar-induced GWs
Coding session: reheating simulations and issue on gaussian noise initial conditions + scalar-induced GWs
14:00 - 15:30
Room: 4/3-006 - TH Conference Room Reheating simulations and issue on gaussian noise initial conditions for the logarithm of density. Scalar-induced gravitational waves, studying scalar perturbations.

15:30 Coffee break
Coffee break
15:30 - 16:00
Room: 4/3-006 - TH Conference Room

16:00 Coding session: Special modules + Initialization from external file
Coding session: Special modules + Initialization from external file
16:00 - 17:30
Room: 4/3-006 - TH Conference Room Dealing with multiple special modules: rename special by the name, fix the input list, rename variables. Initialization of fields from an external file (e. g. with hdf5 external file).
Friday, 31 October 2025
10:00 Axion-USR model - Alireza Talebian Ashkezari
Axion-USR model
- Alireza Talebian Ashkezari
10:00 - 10:30
Room: 4/3-006 - TH Conference Room
11:00 Coffee break
Coffee break
11:00 - 11:30
Room: 4/3-006 - TH Conference Room
11:30 Discussion: Numerical Dissipation in the Pencil Code - Simon Candelaresi
Discussion: Numerical Dissipation in the Pencil Code
- Simon Candelaresi
11:30 - 12:30
Room: 4/3-006 - TH Conference Room
12:30 Lunch break
Lunch break
12:30 - 14:00
Room: 4/3-006 - TH Conference Room

14:00 Coding session: merging backreact_infl and klein_gordon modules + adding scalar/fluid coupling
Coding session: merging backreact_infl and klein_gordon modules + adding scalar/fluid coupling
14:00 - 15:30
Room: 4/3-006 - TH Conference Room

15:30 Coffee break
Coffee break
15:30 - 16:00
Room: 4/3-006 - TH Conference Room
16:00 PCUM25 closure - Alberto Roper Pol
PCUM25 closure
- Alberto Roper Pol
16:00 - 17:00
Room: 4/3-006 - TH Conference Room