spocon()

subroutine spocon	(	character	uplo,
		integer	n,
		real, dimension( lda, * )	a,
		integer	lda,
		real	anorm,
		real	rcond,
		real, dimension( * )	work,
		integer, dimension( * )	iwork,
		integer	info )

SPOCON

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Purpose:

!>
!> SPOCON 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 SPOTRF.
!>
!> 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

[in]	UPLO	!> UPLO is CHARACTER*1 !> = 'U': Upper triangle of A is stored; !> = 'L': Lower triangle of A is stored. !>
[in]	N	!> N is INTEGER !> The order of the matrix A. N >= 0. !>
[in]	A	!> A is REAL 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 SPOTRF. !>
[in]	LDA	!> LDA is INTEGER !> The leading dimension of the array A. LDA >= max(1,N). !>
[in]	ANORM	!> ANORM is REAL !> The 1-norm (or infinity-norm) of the symmetric matrix A. !>
[out]	RCOND	!> RCOND is REAL !> 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. !>
[out]	WORK	!> WORK is REAL array, dimension (3*N) !>
[out]	IWORK	!> IWORK is INTEGER array, dimension (N) !>
[out]	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.