Adaptive runtime support for direct simulation Monte Carlo methods on distributed memory architectures

In highly adaptive irregular problems such as many Particle-In-Cell (PIC) codes and Direct Sim-ulation Monte Carlo (DSMC) codes, data access patterns may vary from time step to time step. This uctuation may hinder ecient utilization of distributed memory parallel computers because of the resulting overhead for data redistribution and dynamic load balancing. To eciently parallelize such adaptive irregular problems on distributed memory parallel computers, several issues such as eective methods for domain partitioning and fast data transportation must be addressed. This paper presents ecient runtime support methods for such problems. A simple one-dimensional domain partitioning method is implemented and compared with unstructured mesh partitioners such as recursive coordi-nate bisection and recursive inertial bisection. A remapping decision policy has been investigated for dynamic load balancing on 3-dimensional DSMC codes. Performance results are presented.