c_ftcurvpi - calculate integrals for periodic functions

       To use c_ftcurvpi, 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                                 c_ftcurvpi(3NCARG)

       xl          The lower limit of the integration.

       xr          The upper limit of the integration.

       p           The period of the function; p must not be less than xi[n-1] - xi[0].

       m           The number of input data points. (N > 1)

       xi          An array containing the abscissae for the input function.

       yi          An array containing the functional values of the input function (y(k) is the functional value
                   at x(k) for k=0,n).

       integral    The integral of the function from xl to xr is given by *integral.

       int c_ftcurvpi (float, float, float, int, float [], float [], float *);

       c_ftcurvpi - calculate integrals for periodic functions

       c_ftcurvpi returns an error value as per:

       = 0 -- no error.
       = 1 -- if n is less than 2.
       = 2 -- if the period is strictly less than the span of the abscissae.

       fitgrid_params, c_ftseti, c_ftsetr, c_ftsetc.

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

       int c_ftcurvpi (xl, xr, p, m, xi, yi, integral);

       c_ftcurvpi  is  called  after  all  of  the desired values for control parameters have been set using the
       procedures c_ftseti, c_ftsetr, c_ftsetc.  Control parameters that apply to c_ftcurvpi are: sig.