dpocon.f - Man Page
SRC/dpocon.f
Synopsis
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.
Author
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Referenced By
The man page dpocon(3) is an alias of dpocon.f(3).
Tue Nov 28 2023 12:08:42 Version 3.12.0 LAPACK