SRC/zppcon.f(3) | Library Functions Manual | SRC/zppcon.f(3) |
NAME
SRC/zppcon.f
SYNOPSIS
Functions/Subroutines
subroutine zppcon (uplo, n, ap, anorm, rcond, work, rwork,
info)
ZPPCON
Function/Subroutine Documentation
subroutine zppcon (character uplo, integer n, complex*16, dimension( * ) ap, double precision anorm, double precision rcond, complex*16, dimension( * ) work, double precision, dimension( * ) rwork, integer info)
ZPPCON
Purpose:
!> !> ZPPCON estimates the reciprocal of the condition number (in the !> 1-norm) of a complex Hermitian positive definite packed matrix using !> the Cholesky factorization A = U**H*U or A = L*L**H computed by !> ZPPTRF. !> !> An estimate is obtained for norm(inv(A)), and the reciprocal of the !> condition number is computed as RCOND = 1 / (ANORM * norm(inv(A))). !>
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 order of the matrix A. N >= 0. !>
AP
!> AP is COMPLEX*16 array, dimension (N*(N+1)/2) !> The triangular factor U or L from the Cholesky factorization !> A = U**H*U or A = L*L**H, packed columnwise in a linear !> array. The j-th column of U or L is stored in the array AP !> as follows: !> if UPLO = 'U', AP(i + (j-1)*j/2) = U(i,j) for 1<=i<=j; !> if UPLO = 'L', AP(i + (j-1)*(2n-j)/2) = L(i,j) for j<=i<=n. !>
ANORM
!> ANORM is DOUBLE PRECISION !> The 1-norm (or infinity-norm) of the Hermitian matrix A. !>
RCOND
!> RCOND is DOUBLE PRECISION !> The reciprocal of the condition number of the matrix A, !> computed as RCOND = 1/(ANORM * AINVNM), where AINVNM is an !> estimate of the 1-norm of inv(A) computed in this routine. !>
WORK
!> WORK is COMPLEX*16 array, dimension (2*N) !>
RWORK
!> RWORK is DOUBLE PRECISION array, dimension (N) !>
INFO
!> INFO is INTEGER !> = 0: successful exit !> < 0: if INFO = -i, the i-th argument had an illegal value !>
Author
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Definition at line 117 of file zppcon.f.
Author
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