dpocon.f3
Usage
Functions/Subroutines
subroutine dpocon (uplo, n, a, lda, anorm, rcond, work, iwork, info)
DPOCON
Function/Subroutine Documentation
subroutine dpocon (character uplo, integer n, double precision, dimension( lda, * ) a, integer lda, double precision anorm, double precision rcond, double precision, dimension( * ) work, integer, dimension( * ) iwork, integer info)
DPOCON
Purpose:
!> !> DPOCON estimates the reciprocal of the condition number (in the !> 1-norm) of a real symmetric positive definite matrix using the !> Cholesky factorization A = U**T*U or A = L*L**T computed by DPOTRF. !> !> 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. !>
A
!> A is DOUBLE PRECISION array, dimension (LDA,N) !> The triangular factor U or L from the Cholesky factorization !> A = U**T*U or A = L*L**T, as computed by DPOTRF. !>
LDA
!> LDA is INTEGER !> The leading dimension of the array A. LDA >= max(1,N). !>
ANORM
!> ANORM is DOUBLE PRECISION !> The 1-norm (or infinity-norm) of the symmetric 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 DOUBLE PRECISION array, dimension (3*N) !>
IWORK
!> IWORK is INTEGER 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 119 of file dpocon.f.
Releases
4 releases since Debian 7 (Wheezy); the text changed 3 times.