NAME

       dtpcon.f -

SYNOPSIS

   Functions/Subroutines
       subroutine dtpcon (NORM, UPLO, DIAG, N, AP, RCOND, WORK, IWORK, INFO)
           DTPCON

Function/Subroutine Documentation

   subroutine dtpcon (characterNORM, characterUPLO, characterDIAG, integerN, double precision,
       dimension( * )AP, double precisionRCOND, double precision, dimension( * )WORK, integer,
       dimension( * )IWORK, integerINFO)
       DTPCON

       Purpose:

            DTPCON estimates the reciprocal of the condition number of a packed
            triangular matrix A, in either the 1-norm or the infinity-norm.

            The norm of A is computed and an estimate is obtained for
            norm(inv(A)), then the reciprocal of the condition number is
            computed as
               RCOND = 1 / ( norm(A) * norm(inv(A)) ).

       Parameters:
           NORM

                     NORM is CHARACTER*1
                     Specifies whether the 1-norm condition number or the
                     infinity-norm condition number is required:
                     = '1' or 'O':  1-norm;
                     = 'I':         Infinity-norm.

           UPLO

                     UPLO is CHARACTER*1
                     = 'U':  A is upper triangular;
                     = 'L':  A is lower triangular.

           DIAG

                     DIAG is CHARACTER*1
                     = 'N':  A is non-unit triangular;
                     = 'U':  A is unit triangular.

           N

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

           AP

                     AP is DOUBLE PRECISION array, dimension (N*(N+1)/2)
                     The upper or lower triangular matrix A, packed columnwise in
                     a linear array.  The j-th column of A is stored in the array
                     AP as follows:
                     if UPLO = 'U', AP(i + (j-1)*j/2) = A(i,j) for 1<=i<=j;
                     if UPLO = 'L', AP(i + (j-1)*(2n-j)/2) = A(i,j) for j<=i<=n.
                     If DIAG = 'U', the diagonal elements of A are not referenced
                     and are assumed to be 1.

           RCOND

                     RCOND is DOUBLE PRECISION
                     The reciprocal of the condition number of the matrix A,
                     computed as RCOND = 1/(norm(A) * norm(inv(A))).

           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.

       Date:
           November 2011

       Definition at line 130 of file dtpcon.f.

Author

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