#BHEADER**********************************************************************

Copyright (c) 2017, Lawrence Livermore National Security, LLC.

Produced at the Lawrence Livermore National Laboratory.

Written by Ulrike Yang ([email protected]) et al. CODE-LLNL-738-322.

This file is part of AMG. See files COPYRIGHT and README for details.

AMG is free software; you can redistribute it and/or modify it under the

terms of the GNU Lesser General Public License (as published by the Free

Software Foundation) version 2.1 dated February 1999.

This program is distributed in the hope that it will be useful, but WITHOUT

ANY WARRANTY; without even the IMPLIED WARRANTY OF MERCHANTABILITY or

FITNESS FOR A PARTICULAR PURPOSE. See the terms and conditions of the

GNU General Public License for more details.

You should have received a copy of the GNU Lesser General Public License

along with this program; if not, write to the Free Software Foundation,

Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

#EHEADER**********************************************************************

General description:

AMG is a parallel algebraic multigrid solver for linear systems arising from problems on unstructured grids. The driver provided with AMG builds linear systems for various 3-dimensional problems. AMG is written in ISO-C. It is an SPMD code which uses MPI and OpenMP threading within MPI tasks. Parallelism is achieved by data decomposition. The driver provided with AMG achieves this decomposition by simply subdividing driver provided with AMG achieves this decomposition by simply subdividing the grid into logical P x Q x R (in 3D) chunks of equal size. For more information, see the amg.readme file in the docs directory of the distribution. %========================================================================== %==========================================================================

Building the Code

AMG uses a simple Makefile system for building the code. All compiler and link options are set by modifying the file 'AMG/Makefile.include' appropriately.

To build the code, first modify the 'Makefile.include' file appropriately, (it is recommended to use the options -DHYPRE_BIGINT ) then type (in the AMG directory)

make

Other available targets are

make clean (deletes .o files) make veryclean (deletes .o files, libraries, and executables)

To configure the code to run with:

1 - MPI only , add '-DTIMER_USE_MPI' to the 'INCLUDE_CFLAGS' line in the 'Makefile.include' file and use a valid MPI. 2 - OpenMP with MPI, add vendor dependent compilation flag for OMP 3 - to be able to solve problems that are larger than 2^31-1, add '-DHYPRE_BIGINT' 4 - For additional optimizations in MPI add '-DHYPRE_USING_PERSISTENT_COMM' 5 - For additional optimizations in OpenMP add '-DHYPRE_HOPSCOTCH' %========================================================================== %==========================================================================

Figure of Merit (FOM)

For problem 1, there are 2 FOMs printed out at the end of each run: nnz_AP / setup_time nnz_AP * #iterations / solve time Both need to be considered.

For problem 2, one FOM needs to be considered: nnz_AP * (#iterations + time_steps) / time