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

  a                   real*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.

  ia                  integer*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.

  ja                  integer*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.

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

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

  n                   integer*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 CXML
  Reference Manual.