From: "Scott A. Hutchinson" <sahutch@cs.sandia.gov>
Newsgroups: comp.parallel
Subject: SOFTWARE ANNOUNCEMENT
Date: 19 Oct 1998 17:23:43 GMT
Organization: Sandia National Labs
Approved: bigrigg@cs.cmu.edu
Message-Id: <70fsiv$jpf$1@encore.ece.cmu.edu>
Originator: bigrigg@ece.cmu.edu


			!!!!! NEW SOFTWARE ANNOUNCEMENT !!!!!

        Aztec 2.0: A parallel iterative package for the solving linear
        systems arising in Newton-Krylov Methods, Version 2.0

		http://www.cs.sandia.gov/CRF/aztec1.html

        Authors:	Ray S. Tuminaro, Charles H. Tong, John N. Shadid,
			Scott A. Hutchinson, Lydie Prevost
			Sandia National Laboratories
			Albuquerque, New Mexico, USA


Aztec Version 2.0 Release Notes:

* We have added several new features:
    1) ilut preconditioner
    2) ilu(k), bilu(k), icc(k) for k > 0.
    2) arbitrary overlap in domain decomposition
    3) equation reordering for incomplete factorization based on RCM algorithm
    4) Matrix-free & user-supplied preconditioning interface
    5) Improved flexibility. Solvers can be used as preconditioners.

*****************  IMPORTANT for Aztec 1.1 USERS   ****************

  The following changes must be made to use Aztec 2.0:

    1) references to "params[AZ_fill]" need to be changed to
       "params[AZ_ilut_fill]".

    2) references such as "option[AZ_precond] = xxx;" where xxx is AZ_ilu,
       AZ_ilut, AZ_bilu must be changed to option[AZ_precond] = AZ_dom_decomp;
       options[AZ_subdomain_solve] = xxx;
    3) options[AZ_keep_info] must be set to '1' if previous solver information
       is to be reused.
    4) options[AZ_overlap] = AZ_none' corresponds to 'options[AZ_overlap] = 0'
       and
       options[AZ_overlap] = AZ_full' corresponds to 'options[AZ_overlap] = 1'

       The keywords 'AZ_none' and 'AZ_full' are still recognized however they
       may be phased out some day.

   Finally, Aztec 2.0 may give a somewhat different convergence history than
   Aztec 1.1. The main difference between the two is that RCM reordering is now
   the default when using incomplete factorizations.  If you don't want this
   set
                   options[AZ_reorder] = 0;

*******************************************************************
*******************************************************************
*******************************************************************

* Several new machines have been added to the Makefile including: Cray T3E and
  Linux boxes.

* A new matrix-free sample program has been included with the distribution.

* We have fixed a bug in the MPI communication associated with AZ_transform().

* We have fixed a couple of memory bugs in the domain decomposition.

* Other minor bug fixes.

* IMPORTANT: a few Aztec function parameters have changed. Mostly things like
  using unsigned integers instead of signed integers.  This may generate
  warnings on some compilers unless you explicitly cast the parameters.

* The User's Guide has been updated to reflect these changes.

-------------------------------------------------------------------------------

Aztec is an iterative library that greatly simplifies the parallelization
process when solving the linear systems 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: workstation clusters
(DEC, SGI, SUN, LINUX, etc.), Cray T3E, Intel TeraFlop, Intel Paragon, IBM SP2,
nCUBE 2 as well as other MPI platforms, vector machines or serial machines.

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).

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 on the WWW at:

	http://www.cs.sandia.gov/CRF/aztec1.html

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