dss_reorder

Computes permutation vector that minimizes the fill-in during the factorization phase.

Syntax

dss_reorder(handle, opt, perm)

Fortran:

call dss_reorder(handle, opt, perm)

Include Files

The FORTRAN 77 interface is specified in the mkl_dss.f77 include file, the Fortran 90 interface is specified in the mkl_dss.f90 include file, and the C interface is specified in the mkl_dss.h include file.

Description

If opt contains the option MKL_DSS_AUTO_ORDER, then the routine dss_reorder computes a permutation vector that minimizes the fill-in during the factorization phase. For this option, the perm array is never accessed.

If opt contains the option MKL_DSS_METIS_OPENMP_ORDER, then the routine dss_reorder computes permutation vector using the parallel (OpenMP) nested dissections algorithm to minimize the fill-in during the factorization phase. This option can be used to decrease the time of dss_reorder call on multi-core computers. For this option, the perm array is also never accessed.

If opt contains the option MKL_DSS_MY_ORDER, then the array perm is considered to be a permutation vector supplied by the user. In this case, the array perm is of length nRows, where nRows is the number of rows in the matrix as defined by the previous call to dss_define_structure.

If opt contains the option MKL_DSS_GET_ORDER, then the permutation vector computed during the dss_reorder call is copied to the array perm. In this case the array perm must be allocated by the user beforehand. The permutation vector is computed in the same way as if the option MKL_DSS_AUTO_ORDER is set.

Input Parameters

Name	Type	Description
opt	FORTRAN 77: INTEGER Fortran 90: INTEGER, INTENT(IN) C: _INTEGER_t const*	Parameter to pass the DSS options. The default value for the permutation type is MKL_DSS_AUTO_ORDER.
perm	FORTRAN 77: INTEGER Fortran 90: INTEGER, INTENT(IN) C: _INTEGER_t const*	Array of length `nRows`. Contains a user-defined permutation vector (accessed only if `opt` contains MKL_DSS_MY_ORDER or MKL_DSS_GET_ORDER).

Name

Type

Description

opt

FORTRAN 77: INTEGER

Fortran 90: INTEGER, INTENT(IN)

C: _INTEGER_t const*

Parameter to pass the DSS options. The default value for the permutation type is MKL_DSS_AUTO_ORDER.

perm

FORTRAN 77: INTEGER

Fortran 90: INTEGER, INTENT(IN)

C: _INTEGER_t const*

Array of length nRows. Contains a user-defined permutation vector (accessed only if opt contains MKL_DSS_MY_ORDER or MKL_DSS_GET_ORDER).

Output Parameters

Name	Type	Description
handle	FORTRAN 77: INTEGER8 Fortran 90:* TYPE (MKL_DSS_HANDLE), INTENT(INOUT) C: _MKL_DSS_HANDLE_t*	Pointer to the data structure storing intermediate DSS results (MKL_DSS_HANDLE).

Name

Type

Description

handle

FORTRAN 77: INTEGER*8

Fortran 90: TYPE (MKL_DSS_HANDLE), INTENT(INOUT)

C: _MKL_DSS_HANDLE_t*

Pointer to the data structure storing intermediate DSS results (MKL_DSS_HANDLE).

Return Values

MKL_DSS_SUCCESS

MKL_DSS_STATE_ERR

MKL_DSS_INVALID_OPTION

MKL_DSS_OUT_OF_MEMORY