Digital

Name

dcreate_poly_udia − Generate polynomial preconditioner for unsymmetric diagonal storage (Serial and Parallel Versions)

FORMAT

DCREATE_POLY_UDIA (a, ia, ndim, nz, p, n)

Arguments

areal∗8
On entry, a two-dimensional array with dimensions ndim by nz containing the nonzero elements of the matrix A.
On exit, a is unchanged. 

iainteger∗4
On entry, a one-dimensional array of length at least nz,  containing the distances of the diagonals from the main diagonal.
On exit, ia is unchanged. 

ndiminteger∗4
On entry, the leading dimension of array A, as declared in the calling subprogram; ndim >= n.
On exit, ndim is unchanged. 

nzinteger∗4
On entry, the number of diagonals stored in array A.
On exit, nz is unchanged. 

preal∗8
On entry, a one-dimensional array of length at least 3∗n.
On exit, array P contains information for use by the polynomial preconditioner.

ninteger∗4
On entry, the order of the matrix A.
On exit, n is unchanged. 

Description

DCREATE_POLY_UDIA computes the information required by the polynomial preconditioner for a sparse matrix stored using the unsymmetric diagonal storage scheme. The real part of this information is returned in the array P. There is no integer information returned for this preconditioner. Part of the array P is used as workspace during the application of the preconditioner. 

The routine DCREATE_POLY_UDIA is called prior to a call to one of the iterative solver routines with polynomial  preconditioning. 

This routine is available in both serial and parallel versions. The routine names and parameter list are identical for both versions. For information about linking to the serial or to the parallel library, refer to the DXML Reference Manual.