SRC/dla_syrpvgrw.f(3)      Library Functions Manual      SRC/dla_syrpvgrw.f(3)

NAME
       SRC/dla_syrpvgrw.f

SYNOPSIS
   Functions/Subroutines
       double precision function dla_syrpvgrw (uplo, n, info, a, lda, af,
           ldaf, ipiv, work)
           DLA_SYRPVGRW computes the reciprocal pivot growth factor
           norm(A)/norm(U) for a symmetric indefinite matrix.

Function/Subroutine Documentation
   double precision function dla_syrpvgrw (character*1 uplo, integer n,
       integer info, double precision, dimension( lda, * ) a, integer lda,
       double precision, dimension( ldaf, * ) af, integer ldaf, integer,
       dimension( * ) ipiv, double precision, dimension( * ) work)
       DLA_SYRPVGRW computes the reciprocal pivot growth factor
       norm(A)/norm(U) for a symmetric indefinite matrix.

       Purpose:


            DLA_SYRPVGRW computes the reciprocal pivot growth factor
            norm(A)/norm(U). The 'max absolute element' norm is used. If this is
            much less than 1, the stability of the LU factorization of the
            (equilibrated) matrix A could be poor. This also means that the
            solution X, estimated condition numbers, and error bounds could be
            unreliable.

       Parameters
           UPLO

                     UPLO is CHARACTER*1
                  = 'U':  Upper triangle of A is stored;
                  = 'L':  Lower triangle of A is stored.

           N

                     N is INTEGER
                The number of linear equations, i.e., the order of the
                matrix A.  N >= 0.

           INFO

                     INFO is INTEGER
                The value of INFO returned from DSYTRF, .i.e., the pivot in
                column INFO is exactly 0.

           A

                     A is DOUBLE PRECISION array, dimension (LDA,N)
                On entry, the N-by-N matrix A.

           LDA

                     LDA is INTEGER
                The leading dimension of the array A.  LDA >= max(1,N).

           AF

                     AF is DOUBLE PRECISION array, dimension (LDAF,N)
                The block diagonal matrix D and the multipliers used to
                obtain the factor U or L as computed by DSYTRF.

           LDAF

                     LDAF is INTEGER
                The leading dimension of the array AF.  LDAF >= max(1,N).

           IPIV

                     IPIV is INTEGER array, dimension (N)
                Details of the interchanges and the block structure of D
                as determined by DSYTRF.

           WORK

                     WORK is DOUBLE PRECISION array, dimension (2*N)

       Author
           Univ. of Tennessee

           Univ. of California Berkeley

           Univ. of Colorado Denver

           NAG Ltd.

       Definition at line 120 of file dla_syrpvgrw.f.

Author
       Generated automatically by Doxygen for LAPACK from the source code.

LAPACK                          Version 3.12.0           SRC/dla_syrpvgrw.f(3)