PIM 2.0 The Parallel Iterative Methods Package for Systems of Linear Equations User's Guide (Fortran 77 version)

<< This reports is an updated version of 2-94 >> We describe PIM (Parallel Iterative Methods), a collection of Fortran 77 routines to solve systems of linear equations on parallel computers using iterative methods. A number of iterative methods for symmetric and nonsymmetric systems are available, including * Conjugate-Gradients (CG), * Bi-Conjugate-Gradients (Bi-CG), * Conjugate-Gradients squared (CGS), * the stabilised version of Bi-Conjugate-Gradients (Bi-CGSTAB), * the restarted stabilised version of Bi-Conjugate-Gradients (RBi-CGSTAB), * generalised minimal residual (GMRES), * generalised conjugate residual (GCR), * normal equation solvers (CGNR and CGNE), * quasi-minimal residual (QMR) with coupled two-term recurrences, * transpose-free quasi-minimal residual (TFQMR) and * Chebyshev acceleration. The PIM routines can be used with user-supplied preconditioners, and left-, right- or symmetric-preconditioning are supported. Several stopping criteria can be chosen by the user. In this user's guide we present a brief overview of the iterative methods and algorithms available. The use of PIM is introduced via examples. We also present some results obtained with PIM concerning the selection of stopping criteria and parallel scalability. A reference manual can be found at the end of this report with specific details of the routines and parameters.