SRC/dppcon.f(3)            Library Functions Manual            SRC/dppcon.f(3)

NAME
       SRC/dppcon.f

SYNOPSIS
   Functions/Subroutines
       subroutine dppcon (uplo, n, ap, anorm, rcond, work, iwork, info)
           DPPCON

Function/Subroutine Documentation
   subroutine dppcon (character uplo, integer n, double precision, dimension(
       * ) ap, double precision anorm, double precision rcond, double
       precision, dimension( * ) work, integer, dimension( * ) iwork, integer
       info)
       DPPCON

       Purpose:


            DPPCON estimates the reciprocal of the condition number (in the
            1-norm) of a real symmetric positive definite packed matrix using
            the Cholesky factorization A = U**T*U or A = L*L**T computed by
            DPPTRF.

            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 DOUBLE PRECISION array, dimension (N*(N+1)/2)
                     The triangular factor U or L from the Cholesky factorization
                     A = U**T*U or A = L*L**T, 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 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 117 of file dppcon.f.

Author
       Generated automatically by Doxygen for LAPACK from the source code.

LAPACK                          Version 3.12.0                 SRC/dppcon.f(3)