Main
Development
Information
Community
Social media
Other
  1. Manuals
  2. Leap-16.0
  3. lapack-man
  4. DLA_PORPVGRW(3)

Scroll to navigation

/home/abuild/rpmbuild/BUILD/lapack-3.12.0/SRC/dla_porpvgrw.f(3) Library Functions Manual /home/abuild/rpmbuild/BUILD/lapack-3.12.0/SRC/dla_porpvgrw.f(3)

NAME

/home/abuild/rpmbuild/BUILD/lapack-3.12.0/SRC/dla_porpvgrw.f

SYNOPSIS

Functions/Subroutines


double precision function DLA_PORPVGRW (uplo, ncols, a, lda, af, ldaf, work)
DLA_PORPVGRW computes the reciprocal pivot growth factor norm(A)/norm(U) for a symmetric or Hermitian positive-definite matrix.

Function/Subroutine Documentation

double precision function DLA_PORPVGRW (character*1 uplo, integer ncols, double precision, dimension( lda, * ) a, integer lda, double precision, dimension( ldaf, * ) af, integer ldaf, double precision, dimension( * ) work)

DLA_PORPVGRW computes the reciprocal pivot growth factor norm(A)/norm(U) for a symmetric or Hermitian positive-definite matrix.

Purpose:

!>
!>
!> DLA_PORPVGRW 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.
!>

NCOLS

!>          NCOLS is INTEGER
!>     The number of columns of the matrix A. NCOLS >= 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 triangular factor U or L from the Cholesky factorization
!>     A = U**T*U or A = L*L**T, as computed by DPOTRF.
!>

LDAF

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

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 104 of file dla_porpvgrw.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.

Version 3.12.0 LAPACK