SixTrack Status

Speaker: R. De Maria

Special thanks to: F. Schmidt, E. McIntosh, LHC@Home volunteers.

Developers: A. Aviral, J. Barranco, D. Banfi, L. Deniau, M. Fjellstrom, P. Gargia,M. Fitterer, M. Giovannozzi, M. Javed, A. Mereghetti, A. Mituca, X. Valls Pla,

Y. Papaphilippou, A. Patapenka, T. Pieloni, K. Singh.LHC@Home support: I. Zacharov, P. Jones, N. Oimyr.

Collimation team: R. Assmann, C. Bracco, G. Robert-Demolaize, P. Hermes, L. Lari,D. Mirarchi, V. Previtali, S. Redaelli, A. Rossi, C. Tambasco, T. Weiler.

Former contributors: M. Berz, E. Forest, H. Grote, F. James, K. Koelbig,K. Jeinemann, F. Neri H. Renshall, G. Ripken, M. Vaenttinen, A. Wrulich.

Legal support: N. Ziogas, M. Ayass..

What is SixTrack• SixTrack is an open source single particle tracking code used to simulate

charged particle trajectories in synchrotrons for many turns with or without acceleration

• It contains symplectic models for drift, thick dipole and quadrupoles, thin multipoles and solenoids, accelerating cavities, (frozen) beam-beam interactions, linear and non-linear deflecting cavities and, in addition, scattering routines for absorber interactions.

• It also computes:– Phase space observables from tracking data: Linear and non linear invariants,

Lyapunov analysis, tunes;– Optics functions using 4D, 5D, 6D formalisms;– High order transfer maps, normal forms;

• It supports Linux, Windows, MAC in a numerically portable way.• It originates from RaceTrack and it has been developed at CERN in the

last few decades mainly by F. Schmidt and E. Mcintosh.

How to use SixTrack

Typical use:• Generate a machine description from MadX (or by hand

for simple machines).• Generate simulation control files.• Execute the code on local Pc or cluster.• Post process the data.

For the LHC: the SixDesk LHC Running environment automatizes all the steps including managing remote jobs using CERN Batch system (LSF) and LHC@Home volunteer project (BOINC).

SixDesk and LHC@Home

SixDesk running environment manage LHC (or HL-LHC) simulations:• uses a model of the LHC to generate a set of machine description

from a statistics of imperfections,• generates all SixTrack control files to cover a cylindrical mesh of

the phase space,• submits, checks, resubmits jobs to LSF or BOINC,• post-process the results for DA estimates and other phase space

observables.

LHC@Home provides on average few thousands CPUs just for SixTrack studies thanks to 300k registered volunteers, yielding tens of thousand SixTrack jobs per day.

SixTrack Status• SixTrack and SixDesk needs to evolve to fulfil needs of CERN currents

projects (LHC, HL-LHC, …) by adding:– new or more accurate models of beam line elements,– new or more refined post-processing analysis.

• The code base is large and difficult:– SixTrack and SixDesk contains 70k lines of code each, mainly Fortran or shell script (but also C,

sed, awk, perl, latex, madx, python).

• Support is limited by available man power:– No private branches are supported. No collimation routines support is provided.

• Main efforts:– Maintenance: mainly LHC@Home, new OS and compiler versions.– Documentation for user and developers: essential for reducing developing time.– New features in the code.

• Core team/point of contact:– Custodian (R. De Maria)– SixTrack Release and LHC@Home manager (E. Mcintosh)– Collimation routine manager (A. Rossi)

Development areas• Active code developments by contributing users and dedicated students:

– Beam-beam and FMA: D. Banfi, J. Barranco, T. Pieloni.– Online aperture checks: P. Garcia, P. Hermes.– Dynamic kicks: A. Mereghetti.– Ion tracking: P. Hermes.– Generic RF-Multipoles: E. MacLean.– Quadrupole Fringe fields: B. Dalena.– Wire kick : Y. Papaphilippou, A. Patapenka.– Build system: R. De Maria, A. Mituca, L. Deniau.– LHC@Home/BOINC: E. McInstosh, I. Zacharov, P. Jones, N. Hoimyr, R. De Maria.– SixDesk DB: R. De Maria, M. Fitterer, D. Banfi, X. Valls Pla, M. Javed*.– C tracking maps: R. De Maria, K . Singh*, A. Aviral*.– Numerical reproducibility: E. McIntosh– Documentation: J. Barranco, M. Fjellstrom, X. Valls Plal, A. Mereghetti, R. De Maria.

• Planned developments:– On-line tune evolution, tracking distribution, dipole fringe fields, radiation effects, GPU computing.

• Recent developments:– Exact Drift implementation: M. Fjellstrom.– Open source licensing: R. De Maria, N. Ziogas, M. Ayass.– Polynomial maps, s-dependent integrator, fringe fields: D. Brett.

• Former contributors:– G. Robert-Demolaize , V. Previtali, L. Lari, C. Bracco, S. Redaelli, E. Forest, F. Schimdt, M. Berz, R. Tomas, Y. Sun, Y. Levinsen, , H. Ranshal, F. Neri, H.

Grote, F. James, K. Koelbig, K. Jeinemann, M. Vaenttinen.

* Support by the Google summer of Code program, **volunteer developer

Resources

SixTrack Website (cern.ch/sixtrack) is the single point of information:• Access to code: SVN repository for SixTrack and SixDesk and

code browser.• Documentation:

– User manual: stable but under review– Physics manual: draft in progress but almost complete– Developer Manual: informal live wiki document (if yor read it, please

also contribute with your knowledge!)• Contacts: Support email, Mailing List.

Feedback is welcome!

Conclusion

SixTrack project represents the state of art for:• single particle tracking for LHC-like synchrotons,• distributed volunteer based computing,• numerical portability.

There is a ambitious development plan to:• improve the user and developer experience,• extend the physics model coverage,• extend the computing platform coverage.

You are welcome to join the SixTrack community!