http://www.cs.sandia.gov/HPCCIT/aztec.html Aztec <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. <category>numerical-linalg </urc>