SAMG SOLVER
GMS now has the support for SAMG mulitgrid solver for MODFLOW. SAMG is the most efficient solver available for use with MODFLOW. Depending on the application and problem size, the computational cost can be reduced by one to two magnitudes.
SAMG (Algebraic Multigrid Methods for Systems) developed by the Fraunhofer Institute for Algorithms and Scientific Computing (FhG-SCAI), is a library of subroutines for the highly efficient solution of large linear systems of equations with sparse matrices. Such systems of equations form the numerical basis of most simulation software packages. Usually, the numerical solution of these linear systems of equations needs most of the computational expense of the whole simulation compared to classical methods (e.g., the ILU-preconditioned conjugate gradient method). SAMG has the advantage of being almost unconditionally numerically scalable. This means that the computational cost using SAMG depends linearly on the number of unknowns.
The algebraic multigrid solution was developed by generalizing the method of "geometric" multigrid for the solution of partial differential equations in such a way, that it can be applied directly to linear systems of equations without using geometric information. For this reason, algebraic multigrid methods are particularly suitable for the solution of differential equations resulting from unstructured two or three dimensional problems, and also for the solution of structurally similar problems. The solution to the MODLFOW system of equations is an excellent application for the SAMG solver.
For more information on the SAMG solver please visit the SAMG page on the Fraunhofer web site including a link to a paper discussing the applications of the SAMG solver with MODFLOW.
Fraunhofer: SAMG Solver and MODFLOW
For more detailed information on the SAMG SOLVER model in GMS visit the GMS wiki at:
www.xmswiki.com/...Solver_Packages