/**
* Copyright (C) 2009 - present by OpenGamma Inc. and the OpenGamma group of companies
*
* Please see distribution for license.
*/
package com.opengamma.analytics.math.interpolation;
import java.util.List;
import com.opengamma.analytics.math.function.Function1D;
import com.opengamma.analytics.math.interpolation.data.InterpolatorNDDataBundle;
import com.opengamma.util.tuple.Pair;
/**
*
*/
public class ShepardInterpolatorND extends InterpolatorND {
private final Function1D<Double, Double> _basisFunction;
public ShepardInterpolatorND(final double power) {
_basisFunction = new ShepardNormalizedRadialBasisFunction(power);
}
@Override
public Double interpolate(final InterpolatorNDDataBundle data, final double[] x) {
validateInput(data, x);
final List<Pair<double[], Double>> rawData = data.getData();
final int n = rawData.size();
double sum = 0;
double normSum = 0;
double[] xi;
double yi;
double phi;
double dist;
Pair<double[], Double> temp;
for (int i = 0; i < n; i++) {
temp = rawData.get(i);
xi = temp.getFirst();
yi = temp.getSecond();
dist = DistanceCalculator.getDistance(x, xi);
if (dist == 0.0) {
return yi;
}
phi = _basisFunction.evaluate(dist);
sum += yi * phi;
normSum += phi;
}
return sum / normSum;
}
@Override
public InterpolatorNDDataBundle getDataBundle(final double[] x, final double[] y, final double[] z, final double[] values) {
return new InterpolatorNDDataBundle(transformData(x, y, z, values));
}
@Override
public InterpolatorNDDataBundle getDataBundle(final List<Pair<double[], Double>> data) {
return new InterpolatorNDDataBundle(data);
}
}