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

SRC/zla_syrpvgrw.f


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.

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.

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Version 3.12.0 LAPACK