NAME¶
CURVD - derivatives for 1D functions.
SYNOPSIS¶
FUNCTION CURVD (T, N, X, Y, YP, SIGMA)
This function calculates a derivative at a specified point using a spline under
tension. CURV1 must be called prior to calling CURVD, and the values thus
obtained used as input to CURVD. The derivative value is returned.
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¶
CURVD returns the derivative value of the interpolated curve at the specified
point T.
ACCESS¶
To use CURVD, load the NCAR Graphics library ngmath.
SEE ALSO¶
curv1, fitgrid_params.
Complete documentation for Fitgrid is available at URL
http://ngwww.ucar.edu/ngdoc/ng/ngmath/fitgrid/fithome.html
COPYRIGHT¶
Copyright (C) 2000
University Corporation for Atmospheric Research
The use of this Software is governed by a License Agreement.
