NHSE Software Catalog

Aztec

url

http://www.cs.sandia.gov/HPCCIT/aztec.html

title_line

a parallel iterative package for solving linear systems
arising in Newton-Krylov methods

author

Ray S. Tuminaro, John N. Shadid, Scott A. Hutchinson
Sandia National Laboratories
Albuquerque, New Mexico, USA

abstract

Aztec is an iterative library that greatly simplifies the
parallelization process when solving a sparse linear system of
equations Ax = b where A is a user supplied nxn sparse matrix, b is a
user supplied vector of length n and x is a vector of length n to be
computed. Aztec is intended as a software tool for users who want to
avoid cumbersome parallel programming details but who have large
sparse linear systems which require an efficiently utilized parallel
processing system. A collection of data transformation tools are
provided that allow for easy creation of distributed sparse
unstructured matrices for parallel solution. Once the distributed
matrix is created, computation can be performed on any of the parallel
machines running Aztec: nCUBE 2, IBM SP2 and Intel Paragon, MPI
platforms as well as standard serial and vector platforms.

Aztec includes a number of Krylov iterative methods such as conjugate
gradient (CG), generalized minimum residual (GMRES) and stabilized
biconjugate gradient (BiCGSTAB) to solve systems of equations. These
Krylov methods are used in conjunction with various preconditioners
such as polynomial or domain decomposition methods using LU or
incomplete LU factorizations within subdomains. Although the matrix A
can be general, the package has been designed for matrices arising
from the approximation of partial differential equations (PDEs).

Also, Aztec supports two different sparse matrix notations - either a
point-entry modified sparse row (MSR) format or a block-entry variable
block row (VBR) format. These two formats have been generalized for
parallel implementation and the library includes highly optimized
matrix-vector multiply kernels and preconditioners for both types of
data structures.

contact

Ray S. Tuminaro
tuminaro@cs.sandia.gov
(505) 845-7298

John N. Shadid
jnshadi@cs.sandia.gov
(505) 845-7876

Scott A. Hutchinson
sahutch@cs.sandia.gov
(505) 845-7996

comment

Aztec is publicly available through a research license. The code is
distributed along with technical documentation, example C and Fortran
driver routines and sample input files via the internet.