Abstract: Based on the numerical simulated program of 13oltzmann model equation in three dimensional flows, this paper studied the parallel strategy of domain decomposition and supplied the optimization methods in I/O, communication, memory access, etc, which arc applied in the debugging and optimization of the parallel MPI program. Experimental re- sups of large-scale parallel computing of flows around 3-dimensional sphere and spacecraft in rarefied field at high space show that the parallel strategy and the optimization methods are correct and efficient, and the parallel implementation scheme is very useful and can short the computing time explicitly.

Key words: Parallel debugging, Domain decomposition, l3oltzmann model equation, Parallel computing, Performance optimization