A Software Tool for Load Balanced Adaptive Multiple Grids on Distributed Memory Computers

T h e solut ion of partial dif ferential equations on twodimensional domains can benefit f r o m the use of irregular grids. In t he case of multigrid solut ion techniques, a hierarchy of nested grids is used. W e imp lemen ted a n adaptive mult iple grid generat ion method and relaxat ion schemes on the iPSC/2 hypercube, based on a general software tool f o r t he man ipu la t ion of dataparallel applications characterized by a n arbitrary and varying topology. T h i s tool takes care of t he data exchanges needed t o ensure t h e consistency of t h e distributed data s tructure and controls t he load balanced execution of t he application by redistributing the data among t h e processors of t h e distributed m e m o r y parallel computer . Remapp ing is done af ter each grid ref inement . In a mult igrid context, a n appropriate choice of data s tructures allows t o coordinate t h e migrat ion of pieces of t h e grids on diflerent levels, so as t o l im i t inter-grid communicat ion.