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  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)