CURV1 - does set-up for CURV2.

       To use CURV1, load the NCAR Graphics library ngmath.

       Copyright (C) 2000
       University Corporation for Atmospheric Research

       The use of this Software is governed by a License Agreement.

UNIX                                               March 1998                                      CURV1(3NCARG)

       N           (integer,input) The number of input data values. (N > 1)

       X           (real, input) An array containing the abscissae for the input function.

       Y           (real,  input)  An  array  containing the functional values of the input data -- (Y(K) is the
                   functional value at X(K) for K=1,N).

       SLP1        (real, input) A user-specified value for the desired slope at X(1).  See ISLPSW below if  you
                   want to have a value calculated internally.

       SLPN        (real,  input) A user-specified value for the desired slope at X(N).  See ISLPSW below if you
                   want to have a value calculated internally.

       ISLPSW      (integer, input) A switch to indicate  whether  the  slopes  at  the  end  points  should  be
                   calculated internally.

                   = 0 if SLP1 and SLPN are user-specified.
                   = 1 if SLP1 is user-specified, but SLPN is internally calculated.
                   = 2 if SLPN is user-specified, but SLP1 is internally calculated.
                   = 3 if SLP1 and SLPN are internally calculated.

       YP          (real, output) Contains values for the second derivative (CURV1 computes these).

       TEMP        (real, input) Scratch space.

       SIGMA       (real,  input)  Tension factor. Values near zero result in a cubic spline; large values (e.g.
                   50) result in nearly a polygonal line.  A typical value is 1.

       IER         (integer, output) An error return value. If IER  is  returned  as  0,  then  no  errors  were
                   detected.

                   = 1 if N is less than 2.
                   = 2 if X values are not strictly increasing.

       CURV1 - does set-up for CURV2.

       curv2, fitgrid_params.

       Complete documentation for Fitgrid is available at URL
       http://ngwww.ucar.edu/ngdoc/ng/ngmath/fitgrid/fithome.html

       CALL CURV1 (N, X, Y, SLP1, SLPN, ISLPSW, YP, TEMP, SIGMA, IER)