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,y),  ...  ,  (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,y) and  the  value  1.  is  mapped  onto  (x,y)  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