MLD2P4  

MultiLevel Domain Decomposition Parallel Preconditioners Package based on PSBLAS (Parallel Sparse BLAS version 3.5)

Salvatore Filippone (Cranfield University, UK) Pasqua D'Ambra (IAC-CNR, Naples, IT) Daniela di Serafino (Univ. of Campania "L. Vanvitelli", Caserta, IT)

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MLD2P4 (MultiLevel Domain Decomposition Parallel Preconditioners Package based on PSBLAS) provides parallel Algebraic MultiGrid (AMG) and Domain Decomposition preconditioners, to be used in the iterative solution of linear systems.

The name of the package comes from its original implementation, containing multilevel additive and hybrid Schwarz preconditioners, as well as one-level additive Schwarz preconditioners. The current version extends the original plan by including multilevel cycles and smoothers widely used in multigrid methods. A purely algebraic approach is applied to generate coarse-level corrections, so that no geometric background is needed concerning the matrix to be preconditioned.

MLD2P4 has been designed to provide scalable and easy-to-use preconditioners in the context of the PSBLAS (Parallel Sparse Basic Linear Algebra Subprograms) computational framework and is used in conjuction with the Krylov solvers available from PSBLAS. The package employs object-oriented design techniques in Fortran 2003, with interfaces to additional third party libraries such as MUMPS, UMFPACK, SuperLU, and SuperLU_Dist, which can be exploited in building multilevel preconditioners. The parallel implementation is based on a Single Program Multiple Data (SPMD) paradigm; the inter-process communication is based on MPI and is managed mainly through PSBLAS.

MAIN REFERENCE:

P. D'Ambra, D. di Serafino, S. Filippone, MLD2P4: a Package of Parallel Algebraic Multilevel Domain Decomposition Preconditioners in Fortran 95, ACM Transactions on Mathematical Software, 37 (3), 2010, art. 30, doi: 10.1145/1824801.1824808.

TO COMPILE

0. Unpack the tar file in a directory of your choice (preferrably outside the main PSBLAS directory).
1. run configure --with-psblas= adding the options for MUMPS, SuperLU, SuperLU_Dist, UMFPACK as desired. See MLD2P4 User's and Reference Guide (Section 3) for details.
2. Tweak Make.inc if you are not satisfied.
3. make;
4. Go into the test subdirectory and build the examples of your choice.
5. (if desired): make install

NOTES

• The single precision version is supported only by MUMPS and SuperLU; thus, even if you specify at configure time to use UMFPACK or SuperLU_Dist, the corresponding preconditioner options will be available only from the double precision version.

• The preconditioners in MLD2P4 extend those of PSBLAS and are meant to be used with the PSBLAS Krylov solvers; so in an existing program you need to modify the type of the preconditioner object and its settings, but the rest of the application needs not be changed.

The MLD2P4 team.

Project lead: Salvatore Filippone

Contributors: Pasqua D'Ambra Daniela di Serafino Ambra Abdullahi Hassan Alfredo Buttari