The paper describes the development and performance of parallel algorithms for the discrete element method (DEM) software. Spatial domain decomposition strategy and message passing inter-processor communication have been implemented in the DEMMAT code for simulation of visco-elastic frictional granular media. The novel algorithm combining link-cells for contact detection, the static domain decomposition for parallelization and MPI data transfer for processors exchanging particles has been developed for distributed memory PC clusters. The parallel software DEMMAT_PAR has been applied to model compacting of spherical particles in the rectangular box. Two benchmark problems with different numbers of particles have been solved in order to measure parallel efficiency of the code. The inter-processor communication has been examined in order to improve domain decomposition topology and to achieve better load balancing. The speed-up equal to 11 has been obtained on 16 processors. The parallel performance study has been performed on the PC cluster VILKAS of Vilnius Gediminas Technical University, Lithuania.

The paper describes the development and performance of parallel algorithms for the discrete element method (DEM) software. Spatial domain decomposition strategy and message passing inter-processor communication have been implemented in the DEMMAT code for simulation of visco-elastic frictional granular media. The novel algorithm combining link-cells for contact detection, the static domain decomposition for parallelization and MPI data transfer for processors exchanging particles has been developed for distributed memory PC clusters. The parallel software DEMMAT_PAR has been applied to model compacting of spherical particles in the rectangular box. Two benchmark problems with different numbers of particles have been solved in order to measure parallel efficiency of the code. The inter-processor communication has been examined in order to improve domain decomposition topology and to achieve better load balancing. The speed-up equal to 11 has been obtained on 16 processors. The parallel performance study has been performed on the PC cluster VILKAS of Vilnius Gediminas Technical University, Lithuania.

1 Notions from logic 1 Denote the set of positive integers {1, 2, 3, ...} by Z + , and the set {0, ..., n − 1} by n. By the natural numbers we mean the set Z + {0}. If A is a set, then card A is the cardinality of the set. Denote the set of k-tuples < a 1 , ..., a k > of members of A by A k .

1 Notions from logic 1 Denote the set of positive integers {1, 2, 3, ...} by Z + , and the set {0, ..., n − 1} by n. By the natural numbers we mean the set Z + {0}. If A is a set, then card A is the cardinality of the set. Denote the set of k-tuples < a 1 , ..., a k > of members of A by A k .

The paper describes application of the discrete element method (DEM) to the compacting simulation of visco-elastic granular media. Parallel DEM code employ the static spatial-decomposition algorithm. The basic version of discrete element method, numerical time-integration and parallel algorithm are developed and implemented into DEMMATP code. The performance of parallel computations, the speed-up and the efficiency have been measured on the Beowulf PC cluster.