IMPLEMENTATION OF A MONTE-CARLO CODE ON A PARALLEL COMPUTER-SYSTEM

This paper reports the implementation of the EGS4 (Electron Gamma Show er version 4) Monte Carlo code system on a multiple-transputer system, the Edinburgh Concurrent Supercomputer (ECS). Basic aspects of runnin g Monte Carlo calculations on parallel computer are described includin g distribution of random number seeds to the individual processes. Bas ed on an independent task farm topology, an existing EGS4 usercode, DO SIMETER, which can be used to calculate the absorbed dose in cylindric al dosimeters placed in cubic phantoms, has been re-written for runnin g on the ECS. The parallelised code consists of three sequential progr ammes: (1) a 'control' process to generate tasks; (2) a number of 'sim ulation' processes to consume tasks and to generate results; and (3) a n 'analysis' process to collect and to analyse results. A linear incre ase in computing speed has been achieved with the number of 'simulatio n' transputers used on the ECS. The basic techniques used in this work are also suitable for the implementation of the Monte Carlo code on o ther parallel computer systems which have similar operational structur es as the ECS.