ZTPCON  -  estimate the reciprocal of the condition number
       of a packed triangular matrix A, in either the  1-norm  or
       the infinity-norm


SYNOPSIS

       SUBROUTINE ZTPCON( NORM,  UPLO,  DIAG, N, AP, RCOND, WORK,
                          RWORK, INFO )

           CHARACTER      DIAG, NORM, UPLO

           INTEGER        INFO, N

           DOUBLE         PRECISION RCOND

           DOUBLE         PRECISION RWORK( * )

           COMPLEX*16     AP( * ), WORK( * )


PURPOSE

       ZTPCON 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)) ).


ARGUMENTS

       NORM    (input) 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    (input) CHARACTER*1
               = 'U':  A is upper triangular;
               = 'L':  A is lower triangular.

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

       N       (input) INTEGER
               The order of the matrix A.  N >= 0.

       AP      (input) COMPLEX*16 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.

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

       WORK    (workspace) COMPLEX*16 array, dimension (2*N)

       RWORK   (workspace) DOUBLE PRECISION array, dimension (N)

       INFO    (output) INTEGER
               = 0:  successful exit
               < 0:  if INFO = -i, the i-th argument had an ille­
               gal value


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