Developer Reference

  • 2020.2
  • 07/15/2020
  • Public Content
Contents

cluster_sparse_solver iparm Parameter

The following table describes all individual components of the Parallel Direct Sparse Solver for Clusters Interface
iparm
parameter. Components which are not used must be initialized with 0. Default values are denoted with an asterisk (*).
Component
Description
iparm
(1)
input
Use default values.
0
iparm
(2)
-
iparm
(64)
are filled with default values.
!=0
You must supply all values in components
iparm
(2)
-
iparm
(64)
.
iparm
(2)
input
Fill-in reducing ordering for the input matrix.
2*
The nested dissection algorithm from the METIS package [Karypis98] .
3
The parallel version of the nested dissection algorithm. It can decrease the time of computations on multi-core computers, especially when Phase 1 takes significant time.
10
The MPI version of the nested dissection and symbolic factorization algorithms. The input matrix for the reordering must be distributed among different MPI processes without any intersection. Use
iparm
(41)
and
iparm
(42)
to set the bounds of the domain. During all of Phase 1, the entire matrix is not gathered on any one process, which can decrease computation time (especially when Phase 1 takes significant time) and decrease memory usage for each MPI process on the cluster.
If you set
iparm
(2)
= 10
,
comm
= -1
(MPI communicator), and if there is one MPI process, optimization and full parallelization with the OpenMP version of the nested dissection and symbolic factorization algorithms proceeds. This can decrease computation time on multi-core computers. In this case, set
iparm
(41)
= 1
and
iparm
(42)
=
n
for one-based indexing, or to
0
and
n
- 1
, respectively, for zero-based indexing.
iparm
(3)
Reserved. Set to zero.
iparm(5)
input
User permutation.
This parameter controls whether user supplied fill-in reducing permutation is used instead of the integrated multiple-minimum degree or nested dissection algorithms. Another use of this parameter is to control obtaining the fill-in reducing permutation vector calculated during the reordering stage of
Intel® MKL
PARDISO.
This option is useful for testing reordering algorithms, adapting the code to special applications problems (for instance, to move zero diagonal elements to the end of
P
*
A
*
P
T
), or for using the permutation vector more than once for matrices with identical sparsity structures. For definition of the permutation, see the description of the
perm
parameter.
You can only set one of
iparm
(5)
,
iparm
(31)
, and
iparm
(36)
, so be sure that the
iparm
(31)
(partial solution) and the
iparm
(36)
(Schur complement) parameters are 0 if you set
iparm
(5)
.
0
User permutation in the
perm
array is ignored.
1
Intel® MKL
PARDISO uses the user supplied fill-in reducing permutation from the
perm
array.
iparm
(2)
is ignored.
2
Intel® MKL
PARDISO returns the permutation vector computed at phase 1 in the
perm
array.
iparm
(6)
input
Write solution on
x
.
The array
x
is always used.
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