smile.math.rbf

Class MultiquadricRadialBasis

java.lang.Object

smile.math.rbf.MultiquadricRadialBasis

All Implemented Interfaces:

Function, RadialBasisFunction

public class MultiquadricRadialBasis
extends Object
implements RadialBasisFunction

Multiquadric RBF. φ(r) = (r² + r²₀)^1/2 where r₀ is a scale factor. Multiquadrics are said to be less sensitive to the choice of r₀ than som other functional forms.

In general, r₀ should be larger than the typical separation of points but smaller than the "outer scale" or feature size of the function to interplate. There can be several orders of magnitude difference between the interpolation accuracy with a good choice for r₀, versus a poor choice, so it is definitely worth some experimentation. One way to experiment is to construct an RBF interpolator omitting one data point at a time and measuring the interpolation error at the omitted point.

Author:

Haifeng Li

Constructor Summary

Constructors

Constructor and Description
MultiquadricRadialBasis() Constructor.
MultiquadricRadialBasis(double scale) Constructor.

Method Summary

Modifier and Type	Method and Description
double	f(double r) Compute the value of the function at x.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

MultiquadricRadialBasis

public MultiquadricRadialBasis()

Constructor.

MultiquadricRadialBasis

public MultiquadricRadialBasis(double scale)

Constructor.

Method Detail

f

public double f(double r)

Description copied from interface: Function

Compute the value of the function at x.

Specified by:

f in interface Function