Chapter 1 parallel sparse solver - freeFEM.org

8 CHAPTER 1. PARALLEL SPARSE SOLVER
example A simple example of calling MUMPS in FreeFem++ with this two methods is given
in the file testsolver MUMPS.edp in the directory examples++-mpi.
1.2.2 SuperLU distributed solver
The package SuperLU DIST [9, 10] solve linear system using LU factorization. It a free scientific
library under BSD license. The web site of this project is http://crd.lbl.gov/∼xiaoye/SuperLU. This
library provide routines to handle square or rectangular matrix in real and complex arithmetics. The
method implemented in SuperLU DIST is a supernodal method [10]. New release of this package
include a parallel symbolic factorization [9]. This scientific library is written in C and using MPI
for communication.
Installation of SuperLU DIST: To used SuperLU DIST in FreeFem++ , you have to install
SuperLU DIST package. We need MPI and ParMetis library to do this compilation. An installation
procedure to obtain this package is given in the file README COMPILE in the directory
src/solver/ of the freefem++ package.
Creating Library of SuperLU DIST interface for FreeFem++ : The FreeFem++ interface
to SuperLU DIST for real (resp. complex) arithmetics is given in file
real SuperLU DIST FreeFem.cpp (resp. complex SuperLU DIST FreeFem.cpp). These files are
in the directory src/solver/. These interfaces are compatible with the release 3.2.1 of SuperLU DIST.
To used SuperLU DIST in FreeFem++ , we need libraries corresponding to these interfaces.
A description to obtain these libraries is given in the file README COMPILE in the directory
src/solver of FreeFem++ . We recall here the procedure. Go to the directory src/solver in
FreeFem++ package. Edit the file makefile-sparsesolver.inc to yours system : comment Section
1, comment line corresponding to libraries BLAS, Metis, ParMetis in Section 2 and comment
in Section 3 the paragraph corresponding to SuperLU DIST solver. And just type make rsludist
(resp. make csludist) in the terminal to obtain the dynamic library of interface for real (resp.
complex) arithmetics.
Now we give a short description of SuperLU DIST parameters before describing the method to
call SuperLU DIST in FreeFem++ .
SuperLU DIST parameters: We describe now some parameters of SuperLU DIST. The SuperLU
DIST library used a 2D-logical process group. This process grid is specifies by nprow
(process row) and npcol (process column) such that Np = nprow npcol where Np is the number of
all process allocated for SuperLU DIST.
The input matrix parameter is controlled by ”matrix= ” in sparams for internal parameter or in the
third line of parameter file. The different value are
matrix = assembled global matrix are available on all process
matrix = distributedglobal the global matrix is distributed among all the process
matrix = distributed the input matrix is distributed (not yet implemented)
The option arguments of SuperLU DIST are describe in the section Users-callable routine of [11].
The parameter Fact and TRANS are specifies in FreeFem++ interfaces to SuperLU DIST during
the different steps. For this reason, the value given by the user for this option is not considered.
The factorization LU is calculated in SuperLU DIST on the matrix Ap.
Ap = Pc Pr Dr A Dc P t c