org.apache.commons.math.analysis.interpolation
Class MicrosphereInterpolatingFunction

java.lang.Object
  org.apache.commons.math.analysis.interpolation.MicrosphereInterpolatingFunction

All Implemented Interfaces:

MultivariateRealFunction

public class MicrosphereInterpolatingFunction
extends java.lang.Object
implements MultivariateRealFunction

Interpolating function that implements the Microsphere Projection.

Version:

$Revision: 990655 $ $Date: 2010-08-29 23:49:40 +0200 (dim. 29 août 2010) $

Nested Class Summary

private static class

MicrosphereInterpolatingFunction.MicrosphereSurfaceElement Class for storing the accounting data needed to perform the microsphere projection.

Field Summary

private double	brightnessExponent Exponent used in the power law that computes the weights of the sample data.
private int	dimension Space dimension.
private java.util.List<MicrosphereInterpolatingFunction.MicrosphereSurfaceElement>	microsphere Internal accounting data for the interpolation algorithm.
private java.util.Map<RealVector,java.lang.Double>	samples Sample data.

Constructor Summary

MicrosphereInterpolatingFunction(double[][] xval, double[] yval, int brightnessExponent, int microsphereElements, UnitSphereRandomVectorGenerator rand)

Method Summary

private double	cosAngle(RealVector v, RealVector w) Compute the cosine of the angle between 2 vectors.
double	value(double[] point) Compute the value for the function at the given point.

Methods inherited from class java.lang.Object

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

Field Detail

dimension

private final int dimension

Space dimension.

microsphere

private final java.util.List<MicrosphereInterpolatingFunction.MicrosphereSurfaceElement> microsphere

Internal accounting data for the interpolation algorithm. Each element of the list corresponds to one surface element of the microsphere.

brightnessExponent

private final double brightnessExponent

Exponent used in the power law that computes the weights of the sample data.

samples

private final java.util.Map<RealVector,java.lang.Double> samples

Sample data.

Constructor Detail

MicrosphereInterpolatingFunction

public MicrosphereInterpolatingFunction(double[][] xval,
                                        double[] yval,
                                        int brightnessExponent,
                                        int microsphereElements,
                                        UnitSphereRandomVectorGenerator rand)
                                 throws DimensionMismatchException,
                                        NoDataException

Parameters:

xval - the arguments for the interpolation points. xval[i][0] is the first component of interpolation point i, xval[i][1] is the second component, and so on until xval[i][d-1], the last component of that interpolation point (where dimension is thus the dimension of the sampled space).

yval - the values for the interpolation points

brightnessExponent - Brightness dimming factor.

microsphereElements - Number of surface elements of the microsphere.

rand - Unit vector generator for creating the microsphere.

Throws:

DimensionMismatchException - if the lengths of yval and xval (equal to n, the number of interpolation points) do not match, or the the arrays xval[0] ... xval[n], have lengths different from dimension.

NoDataException - if there are no data (xval null or zero length)

Method Detail

value

public double value(double[] point)

Description copied from interface: MultivariateRealFunction

Compute the value for the function at the given point.

Specified by:

value in interface MultivariateRealFunction

Parameters:

point - Interpolation point.

Returns:

the interpolated value.

cosAngle

private double cosAngle(RealVector v,
                        RealVector w)

Compute the cosine of the angle between 2 vectors.

Parameters:

v - Vector.

w - Vector.

Returns:

cosine of the angle