Provided by: libncarg-dev_6.3.0-6build1_amd64

NAME

```       c_ftkurvp - interpolation for closed parametric curves

```

FUNCTIONPROTOTYPE

```       int c_ftkurvp (int, float [], float [], int, float [], float [], float []);

```

SYNOPSIS

```       int c_ftkurvp (n, xi, yi, m, t, xo, yo);

```

DESCRIPTION

```       n           The number of input data values. (n > 1)

xi          An array containing the abscissae for the input function.

yi          An  array  containing  the  functional values (y[k] is the functional value at
x[k] for k=0,n-1).

m           The number of desired interpolated values.

t           Contains an array of values for the parameter mapping  onto  the  interpolated
curve. Any interval [tt,tt+1.] maps onto the entire curve.

xo          An  array  containing  the X values for the interpolated points.  t[k] maps to
(xo[k],yo[k]) for k=0,m-1.

yo          An array containing the Y values for the interpolated points.   t[k]  maps  to
(xo[k],yo[k]) for k=0,m-1.

```

RETURNVALUE

```       c_ftkurvp returns an error value as per:

= 0 -- no error.
= 1 -- if n is less than 2.
= 2 -- if adjacent coordinate pairs coincide.

```

USAGE

```       This  procedure  calculates  an  interpolatory  spline under tension through a sequence of
points in the plane forming a closed curve.

Given a sequence of distinct input  points  (  (x[0],y[0]),  ...  ,  (x[n-1],y[n-1]),  the
interpolated  curve  is  parameterized  by mapping points in the interval [0.,1.] onto the
interpolated curve. The resulting curve has a  parametric  representation  both  of  whose
components  are splines under tension and functions of the polygonal arc length. The value
0. is mapped onto (x[0],y[0]) and  the  value  1.  is  mapped  onto  (x[0],y[0])  as  well
(completing the closed curve).

c_ftkurvp  is  called after all of the desired values for control parameters have been set
using the procedures c_ftseti, c_ftsetr, c_ftsetc. The only control parameter that applies
to c_ftkurvp is: sig.

The value for the parameter sig specifies the 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. (the default).

```

ACCESS

```       To use c_ftkurvp, load the NCAR Graphics library ngmath.

```

SEEALSO

```       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

```

```       Copyright (C) 2000