MODFLOW-2000, the U. S. Geological Survey modular ground-water model; user guide to the Link-AMG (LMG) package for solving matrix equations using an algebraic multigrid solver

This report describes a computer program that links MODFLOW-2000, the U.S Geological Survey modular three-dimensional finite-difference ground-water model, with an advanced technique for solving matrix equations, the freeware algebraic multigrid (AMG) solver produced by the GMD -German National Research Center for Information Technology. The AMG solver can be downloaded from the Internet URL at http://www.mgnet.org/mgnet/Codes/gmd/amg.tgz, where the version used in this report is identified as AMG1R5. For convenience it is also distributed with MODFLOW-2000. The AMG solver is, however, produced by GMD and, though freely distributed, is subject to restrictions defined by GMD. One of those restrictions is that GMD must be acknowledged in publications for which results were produced using the algebraic multigrid solver. The U.S. Geological Survey encourages users to respect this restriction. While this is the only restriction that will apply to most users, those using the algebraic multigrid solver in any other way should consult with GMD about additional restrictions.