1. * ProC: Galaxy Collisions AstroGrid-D Meeting, Garching

2. 2 AstroGrid-D Meeting, Garching 2006-11-15 H.-M. Adorf, MPA The science case Given an observation of a galaxy...... explain its formation history estimate initial physical parameters generate a movie ProC: galaxy collisions

3. 3 AstroGrid-D Meeting, Garching 2006-11-15 H.-M. Adorf, MPA Antennae galaxy collision

4. 4 AstroGrid-D Meeting, Garching 2006-11-15 H.-M. Adorf, MPA The science case Given an observation of a galaxy...... explain its formation history estimate initial physical parameters generate a movie Galaxy collisions: astrophysics

5. 5 AstroGrid-D Meeting, Garching 2006-11-15 H.-M. Adorf, MPA Problems faced Cannot compute backwards in time Need forward simulations Solution approach Guess (sample) initial physical parameters Simulate colliding galaxies & store snapshots Project 3D-snapshots to 2D-images & compare with 2D- observation Iterate (optimize) as long as necessary Problems and solutions

6. 6 AstroGrid-D Meeting, Garching 2006-11-15 H.-M. Adorf, MPA Forward simulations are demanding 8 to 10-dim parameter space: huge # of samples 1 simulation WF per physical parameter set (sample) >5 snapshots per simulation WF Many iterations for optimized projection per snapshot Computational demands

7. 7 AstroGrid-D Meeting, Garching 2006-11-15 H.-M. Adorf, MPA The curse of dimensionality

8. 8 AstroGrid-D Meeting, Garching 2006-11-15 H.-M. Adorf, MPA Three islands drifting to form a continent #1 ProC galaxy merger and matching workflow Simulation sub-workflow for galaxy collisions Projection sub-workflow comparing multiple simulated 3D- snapshots with observed 2D-image #2 ProC sampler control element Efficient sampling of high-dimensional parameter spaces Pluggable sampling algorithms (SA, MCMC, SparseGrid,...) #3 ProC workflow submission... Via GAT to queue mgrs. (SGE) & grid middleware (GT4) Three islands...

9. 9 AstroGrid-D Meeting, Garching 2006-11-15 H.-M. Adorf, MPA ProC workflows

10. 10 AstroGrid-D Meeting, Garching 2006-11-15 H.-M. Adorf, MPA ProC galaxy collision workflow

11. 11 AstroGrid-D Meeting, Garching 2006-11-15 H.-M. Adorf, MPA ProC projection workflow

12. 12 AstroGrid-D Meeting, Garching 2006-11-15 H.-M. Adorf, MPA Observed galaxy (simulated)

13. 13 AstroGrid-D Meeting, Garching 2006-11-15 H.-M. Adorf, MPA Simulated galaxy #6 (projected)

14. 14 AstroGrid-D Meeting, Garching 2006-11-15 H.-M. Adorf, MPA Simulated galaxy #5 (projected)

15. 15 AstroGrid-D Meeting, Garching 2006-11-15 H.-M. Adorf, MPA Simulated galaxy #1 (projected)

16. 16 AstroGrid-D Meeting, Garching 2006-11-15 H.-M. Adorf, MPA Status Island #1: galaxy collision Gadget incorporated into ProC Galaxy simulation and projection workflows are production-ready; were used in master thesis (Ilya Saverchenko, TUM/MPA) Production runs via GAT with queue manager (SGE) Island #2: ProC sampler ProC sampler control element ready for serial workflows Sparse grid sampling algorithm (exploration and optimization) Island #3: ProC job submission via GAT to Globus Toolkit 4 Workaround implemented for missing exit status problem Successful ProC-tests by Alexander Beck-Ratzka, AEI ProC: galaxy collisions

17. 17 AstroGrid-D Meeting, Garching 2006-11-15 H.-M. Adorf, MPA Grid technology employed Gridified workflow manager (ProC) Grid Application Toolkit (GAT): Java implementation CoG-Kit (inside GAT, and as GT4 client) Distributed job execution via queue manager (SGE) Grid technology

18. 18 AstroGrid-D Meeting, Garching 2006-11-15 H.-M. Adorf, MPA Future work Island #1: galaxy collision Use sampler control element with sparse grid sampling algorithm in optimization mode for estimating initial physical parameters, and projection parameters (snapshot time and angle) Island #2: ProC sampler Implement parallel execution of trivially parallelizable workflows Island #3: GT4 workflow execution Deploy Gadget and post-processing software at LRZ Submit galaxy collision jobs & workflows via GAT to GT4 at LRZ Generate a movie of galaxy collision and merger history ProC: galaxy collisions