Multilevel &'ML' & Multi-level hybrid preconditioner (additive on the
Multilevel &\verb|'ML'|& Multi-level hybrid preconditioner (additive on the
same level and multiplicative through the levels),
same level and multiplicative through the levels),
with post-smoothing only. Number of levels: 2;
with post-smoothing only. Number of levels: 2;
post-smoother: block-Jacobi preconditioner, with ILU(0)
post-smoother: block-Jacobi preconditioner with ILU(0)
on the local blocks; coarsest matrix: distributed among the
on the local blocks; coarsest matrix: distributed among the
processors; corase-level solver: 4 sweeps of the
processors; corase-level solver: 4 sweeps of the
block-Jacobi solver, with ILU(0) on the blocks. \\
block-Jacobi solver, with ILU(0) on the blocks. \\
@ -65,9 +69,12 @@ Multilevel &'ML' & Multi-level hybrid preconditioner (additive on the
\subsection{Examples\label{sec:examples}}
\subsection{Examples\label{sec:examples}}
The simple code reported below shows how to set and apply the MLD2P4 default multi-level
The code reported below shows how to set and apply the MLD2P4 default multi-level
preconditioned, i.e.\ the two-level hybrid post-smoothed Schwarz preconditioner, using block-Jacobi with ILU(0) on the blocks as basic preconditioner,
preconditioned, i.e.\ the two-level hybrid post-smoothed Schwarz preconditioner,
a coarse matrix distributed among the processors, and four block-Jacobi sweeps with ILU(0) on the blocks as approximate coarse-level solver. The choice of this preconditioner is made
using block-Jacobi with ILU(0) on the blocks as basic preconditioner,
a coarse matrix distributed among the processors, and four block-Jacobi
sweeps with ILU(0) on the blocks as approximate coarse-level solver.
The choice of this preconditioner is made
by simply specifying \verb|'ML'| as second argument of \verb|mld_precinit|
by simply specifying \verb|'ML'| as second argument of \verb|mld_precinit|
(a call to \verb|mld_precset| is not needed).
(a call to \verb|mld_precset| is not needed).
The preconditioner is applied within the BiCGSTAB solver provided by PSBLAS.
The preconditioner is applied within the BiCGSTAB solver provided by PSBLAS.
@ -93,7 +100,7 @@ For details on the use of the PSBLAS routines, see the PSBLAS User's Guide \cite