MaPHyS (Massivelly Parallel Hybrid Solver) is a software package whose proptotype was initially developed in the framework of the PhD thesis of Azzam Haidar (CERFACS) and futher consolidated thanks to the ANR-CIS Solstice funding. This parallel linear solver couples direct and iterative approaches. The underlying idea is to apply to general unstructured linear systems domain decomposition ideas developed for the solution of linear systems arising from PDEs. The interface problem, associated with the so called Schur complement system, is solved using a block preconditioner with overlap between the blocks that is referred to as Algebraic Additive Schwarz.
In the framework of the INRIA technologic development actions; 24 man-month engineer (Yohan Lee-Tin-Yien) have been allocated to this software activity for the 2009-2011 period. The initial software prototype has been completly redesigned in order to enable us to easily interface any sparse direct solvers and develop new preconditioning technique. The first public release of the software is planned eraly 2012. The same software effort has been undertaken for interfacing any graph partitioning tools.
The MaPHyS package is very much a first outcome of the research activity described in Section 3.3 . Finally, MaPHyS is a preconditioner that can be used to speed-up the convergence of any Krylov subspace method. We forsee to either embed in MaPHyS some Krylov solvers or to release them as standalone packages, in particular for the block variants that will be some outcome of the studies discussed in Section 3.3 .