1. 1 Simulation of complex structures using massive parallel processing Peter Ballo and Eva Vitkovska Slovak University of Technology Bratislava peter.ballo@stuba.sk

2. 2 Our aim: is to simulate and optimize complex structures

3. 3 Our experiences in the past: Grain boundary simulation BALLO, P., KIOUSSIS, N., LU, G.Materials Research Society Proceedings, Vol.634. : MRS, 2001, s. B3.14.1-7.Boston. USA, 27.11.-1.12.2000. BALLO, P., KIOUSSIS, M., LU, G. Phys. Rev. B, 64, 024104 (2001). BALLO, P., SLUGEN, V. Phys. Rev. B, 65, 012107 (2002). BALLO, P., SLUGEN, V. Computational Materials Science, 33, 491 (2005). BALLO, P., DEGMOVÁ, J., SLUGEN, V.:Phys. Rev. B, 72, 064118 (2005). BALLO, P., HARMATHA, L. Phys. Rev. B, 68,153201 (2003). P.Ballo, D. Donoval, and L.Harmatha, IWCE 11, Vienna 2006 Electronic structure of defect in silicon

4. 4 What we need before we begin

5. 5 1. Well formulated problem-Size -Shape -Material -Surface/grain boundary -Temperature 2. Well chosen approximation-Structure -Interaction -Dynamics 3. Numerical technique-Molecular dynamics -Simulated annealing -Genetic algorithm -ab initio technique

6. 6 what we have improved

7. 7 GB More complex structures From simple and ideal structures To large and more realistic structures Benefit: The possibility to describe more realistic structures

8. 8 New kind of interaction between atoms From simple empirical interactionTo more complex ab initio interaction Benefit: ab initio interaction enables to describe new effect in the structure

9. 9 New effects on surfaces or grain boundaries

10. 10 From simulated annealingTo genetic algorithm Numerical methodology Profit: genetic algorithm is more efficient for large systems and gives benefit as parallel

11. 11 New computational facilities From small and inefficient system Gigabit internal network To large and efficient system Infinity internal network Benefit: New kinds of parallel computation We are going to increase the number of CPUs up to several hundreds

12. 12 Parallel Genetic Algorithm Structure Optimization Simulator A new kind of massive parallel structure optimization simulator based on Genetic Algorithm We are working on

13. 13 Multi Scale Modeling on reactor steels application for project ALEGRO (a Gas-Cooled Fast Reactor Demonstrator) MPS Massive Parallel System LAMMPS An application... Output from post computing

14. 14 LAMMPS Barkhausen Noise Parallel Genetic Algorithm Structure Optimization Simulator PAS