ITERATIVE SOLUTION OF BLOCK TRIDIAGONAL SYSTEMS ON THE CRAY T3D AND T3E SUPERCOMPUTERS

Modeling the flow inside multiaquifer systems can be efficiently perfo rmed by the so-called quasi-3D methods, Integrating the model equation s by the finite element method leads to block-tridiagonal systems, Eff iciently solving these systems is an important task for performing sim ulations on large, realistic multiaquifers, In this paper, three highl y parallel iterative procedures are used, The degree of parallelizatio n attainable by these methods is evaluated on two massively parallel c omputers a Gray T3D and a T3E, The speedups obtained when computing th e flow inside a realistic multiaquifer are analyzed and compared, Both a coarse and a finer finite element mesh were used to compare the abi lity of the T3D and T3E machines in handling problems with different g rain size, The higher efficiency of the T3E over the T3D is also measu red.