!>
!> DPTCON computes the reciprocal of the condition number (in the
!> 1-norm) of a real symmetric positive definite tridiagonal matrix
!> using the factorization A = L*D*L**T or A = U**T*D*U computed by
!> DPTTRF.
!>
!> Norm(inv(A)) is computed by a direct method, and the reciprocal of
!> the condition number is computed as
!>              RCOND = 1 / (ANORM * norm(inv(A))).
!> 

N

!>          N is INTEGER
!>          The order of the matrix A.  N >= 0.
!> 

D

!>          D is DOUBLE PRECISION array, dimension (N)
!>          The n diagonal elements of the diagonal matrix D from the
!>          factorization of A, as computed by DPTTRF.
!> 

E

!>          E is DOUBLE PRECISION array, dimension (N-1)
!>          The (n-1) off-diagonal elements of the unit bidiagonal factor
!>          U or L from the factorization of A,  as computed by DPTTRF.
!> 

ANORM

!>          ANORM is DOUBLE PRECISION
!>          The 1-norm of the original 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 the
!>          1-norm of inv(A) computed in this routine.
!> 

WORK

!>          WORK 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
!> 

Univ. of Tennessee

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!>
!>  The method used is described in Nicholas J. Higham, , SIAM J. Sci. Stat. Comput., Vol. 7, No. 1, January 1986.
!>