backSpline
Monotone Inverse Spline
Description
Creates a monotone inverse Spline.
Usage
backSpline(object)
## S3 method for class 'nbSpline':
backSpline(object)
## S3 method for class 'npolySpline':
backSpline(object)
Arguments
| object |
a spline object inheriting from class npolySpline or nbSpline (typically produced by interpSpline). The spline must be monotone.
|
Value
returns an object of class
c("polySpline", "spline") that contains the following two components:
The returned object represents a monotone spline that approximates the inverse function of the input spline.
The first derivatives at its knots are initially set to be the reciprocals of the first derivatives
of the input spline at its knots. Hyman's algorithm is used to alter any of those derivatives
that would cause the spline to be non-monotone.
Differences between Spotfire Enterprise Runtime for R and Open-source R
In open-source R, backSpline uses a different algorithm, (usually) resulting in a slightly different splines.
See Also
Examples
isp <- interpSpline(c(1,2,3,4),c(5,9,11,12))
predict(backSpline(isp))