SYNOPSIS

FUNCTION CURV2 (T, N, X, Y, YP, SIGMA)

This function interpolates a value at a specified point using a spline under tension. CURV1 must be called prior to calling CURV2, and the values thus obtained used as input to CURV2. CURV2 returns the interpolated function value at the X-coordinate specified.

DESCRIPTION

T

(real, input) The abscissa for which an interpolated function value is desired.

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.

YP

(real, input) Contains values for the second derivative (as calculated by CURV1).

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.

RETURN VALUE

CURV2 returns the interpolated value at the specified point T.

ACCESS

To use CURV2, load the NCAR Graphics library ngmath.

COPYRIGHT

Copyright (C) 2000
University Corporation for Atmospheric Research

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