Digital

Name

dcreate_diag_genr − Generate diagonal preconditioner for general storage by rows (Serial and Parallel Versions)

FORMAT

DCREATE_DIAG_GENR (a, ia, ja, nz, p, n)

Arguments

areal∗8
On entry, a one-dimensional array of length at least 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 n+1,  containing the starting indices of each row in arrays JA and A.
On exit, ia is unchanged. 

jainteger∗4
On entry, a one-dimensional array of length at least nz, containing the column values of each nonzero element of the  matrix A.
On exit, ja is unchanged. 

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

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

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

Description

DCREATE_DIAG_GENR computes the information required by the diagonal preconditioner for a sparse matrix stored using the general storage by rows scheme.  The real part of this information is returned in the array P. There is no integer information returned for this preconditioner. 

The routine DCREATE_DIAG_GENR is called prior to a call to one of the iterative solver routines with diagonal 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.