The Cactus Team Albert Einstein Institute cactus@cactuscode.org Introduction The Cactus Team Albert Einstein Institute cactus@cactuscode.org

Cactus Plug-In “Thorns” (modules) Core “Flesh” remote steering extensible APIs ANSI C Fortran/C/C++ parameters driver scheduling equations of state Core “Flesh” input/output error handling black holes interpolation make system boundary conditions grid variables SOR solver coordinates wave evolvers multigrid

Cactus Architecture Cactus Thorns Computational Toolkit Toolkit Flesh Configure Make CST Operating Systems SuperUX Irix Linux Unicos HP-UX Solaris AIX OSF NT

Thorn Architecture Thorn Parameter Files Configuration Files and Testsuites Configuration Files ???? Source Code ???? Fortran Routines C Routines C++ Routines Documentation! Make Information

Thorn Collections CactusBase CactusPUGH CactusPUGHIO CactusElliptic +... Cactus Computational Toolkit For organizational convenience, thorns are grouped into arrangements may have related functionality (e.g. IO or Maxwell solvers) may have the same author may contain everything needed for one problem We call a collection of arrangements, a toolkit e.g. Cactus Computational Toolkit Cactus Relativity Toolkit

History Cactus originated in 1997 as a code for numerical relativity, following a long line of codes developed at the NCSA and then the AEI. Numerical Relativity: complicated 3D hyperbolic/elliptic PDEs, dozens of equations, thousands of terms, many people from very different disciplines working together, needing a fast, portable, flexible, easy-to-use, code which can incorporate new technologies without disrupting users. Originally: Paul Walker, Joan Masso, John Shalf, Ed Seidel. Cactus 4.0, August 1999: Total rewrite and redesign of code, learning from experiences with previous versions.

Community Code Designed from the outset to be freely available: Released under the GNU GPL Try to use freely available software options where possible: More choice Can use and develop anywhere Welcome contributions: Bug fixes, feature requests, comments Modules/Thorns Community Mailing Lists Shared modules CVS versioning system

Who Is Using It? Numerical Relativity: Astrophysics: Aerospace: Albert Einstein Institute, Washington University, Penn State University, UT at Texas, UC at Santa Barbara, U. Pittsburg, Southampton University, ... Astrophysics: NCSA (Zeus Code), EU Network (10 institutes) Aerospace: Pilot projects with DLR (German Aviation and Space Center) Application for computer science based projects Grid Application Development Sys (GrADS) European Grid Forum (Egrid) Astrophysics Collaboratory, KDI Gigabit Computing, DFN Looking for new applications ...

Who Is Developing It? Computer scientists at Albert Einstein Institute Konrad-Zuse-Zentrum NCSA NERSC NASA Washington University Rutgers Argonne National Laboratory University of Chicago + others

State of the Art Production runs (using e.g. 512 processors of T3E, 256 processors of Origin 2000) Remote visualization, viewing e.g. IsoSurfaces, flowlines, in real time on a local machine Remote steering, changing parameters for e.g. output Monitoring and interacting with remote runs from a web browser Distributing computing, running a job on coupled remote machines with different architectures Portals for e.g. job submission and management

Numerical Relativity Simulations State of the Art Numerical Relativity Simulations Albert Einstein Institute Washington University Viz: Werner Benger

Support Web site: www.CactusCode.org Users Guide, Thorn Guide HOWTOs Also available with Cactus distributions Still being completed … please complain if something is missing! HOWTOs References for common questions, includes HOWTO-QuickStart Tutorials Help desk cactusmaint@cactuscode.org Bug tracking Mailing lists