SRC/zla_syrpvgrw.f(3) | Library Functions Manual | SRC/zla_syrpvgrw.f(3) |
NAME
SRC/zla_syrpvgrw.f
SYNOPSIS
Functions/Subroutines
double precision function zla_syrpvgrw (uplo, n, info, a,
lda, af, ldaf, ipiv, work)
ZLA_SYRPVGRW computes the reciprocal pivot growth factor
norm(A)/norm(U) for a symmetric indefinite matrix.
Function/Subroutine Documentation
double precision function zla_syrpvgrw (character*1 uplo, integer n, integer info, complex*16, dimension( lda, * ) a, integer lda, complex*16, dimension( ldaf, * ) af, integer ldaf, integer, dimension( * ) ipiv, double precision, dimension( * ) work)
ZLA_SYRPVGRW computes the reciprocal pivot growth factor norm(A)/norm(U) for a symmetric indefinite matrix.
Purpose:
!> !> !> ZLA_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 ZSYTRF, .i.e., the pivot in !> column INFO is exactly 0. !>
A
!> A is COMPLEX*16 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 COMPLEX*16 array, dimension (LDAF,N) !> The block diagonal matrix D and the multipliers used to !> obtain the factor U or L as computed by ZSYTRF. !>
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 ZSYTRF. !>
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 121 of file zla_syrpvgrw.f.
Author
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