AZTEC: A parallel iterative package for the solving linear systems

        Authors: Scott A. Hutchinson, John N. Shadid, Ray S. Tuminaro

        Speaker: Scott A. Hutchinson

        MS 1110
        Sandia National Labs
        PO Box 5800
        Albuquerque, NM 87185

We describe a parallel linear system package, AZTEC.  The package 
incorporates a number of parallel iterative methods (e.g.  GMRES, biCGSTAB, 
CGS, TFQMR) and preconditioners (e.g. Jacobi, Gauss-Seidel, polynomial, 
domain decomposition with LU or ILU within subdomains).  Additionally, AZTEC 
allows for the reuse of previous preconditioning factorizations within 
Newton schemes for nonlinear methods.  Currently, a number of different 
users are using this package to solve a variety of PDE applications.

In this talk we emphasize the parallel programming ease and the overall
efficiency of AZTEC. Ease-of-use is attained using the notion of a global 
distributed matrix. The global distributed matrix allows a user to specify
pieces (different rows for different processors) of an application matrix 
exactly as in the serial setting.  Efficiency is achieved by using a 
transformation function which rewrites the user supplied matrix into
one more convenient for efficient distributed memory computing (locally
numbered entries, ghost variables, grouped messages). Additional performance
is attained using efficient dense matrix algorithms for block sparse matrices.

AZTEC can be used on the Intel Paragon, nCUBE 2, IBM SP2, individual
workstations (e.g. SUN and SGI) and uses the MPI message passing system.