| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.apache.commons.math.analysis.interpolation; |
| |
| import org.apache.commons.math.MathException; |
| import org.apache.commons.math.analysis.MultivariateRealFunction; |
| import org.apache.commons.math.exception.NotPositiveException; |
| import org.apache.commons.math.exception.NotStrictlyPositiveException; |
| import org.apache.commons.math.random.UnitSphereRandomVectorGenerator; |
| |
| /** |
| * Interpolator that implements the algorithm described in |
| * <em>William Dudziak</em>'s |
| * <a href="http://www.dudziak.com/microsphere.pdf">MS thesis</a>. |
| * @since 2.1 |
| * |
| * @version $Revision: 980944 $ $Date: 2010-07-30 22:31:11 +0200 (ven. 30 juil. 2010) $ |
| */ |
| public class MicrosphereInterpolator |
| implements MultivariateRealInterpolator { |
| |
| /** |
| * Default number of surface elements that composes the microsphere. |
| */ |
| public static final int DEFAULT_MICROSPHERE_ELEMENTS = 2000; |
| |
| /** |
| * Default exponent used the weights calculation. |
| */ |
| public static final int DEFAULT_BRIGHTNESS_EXPONENT = 2; |
| |
| /** |
| * Number of surface elements of the microsphere. |
| */ |
| private int microsphereElements; |
| |
| /** |
| * Exponent used in the power law that computes the weights of the |
| * sample data. |
| */ |
| private int brightnessExponent; |
| |
| /** Create a microsphere interpolator with default settings. |
| * <p>Calling this constructor is equivalent to call {@link |
| * #MicrosphereInterpolator(int, int) |
| * MicrosphereInterpolator(MicrosphereInterpolator.DEFAULT_MICROSPHERE_ELEMENTS, |
| * MicrosphereInterpolator.DEFAULT_BRIGHTNESS_EXPONENT)}.</p> |
| */ |
| public MicrosphereInterpolator() { |
| this(DEFAULT_MICROSPHERE_ELEMENTS, DEFAULT_BRIGHTNESS_EXPONENT); |
| } |
| |
| /** Create a microsphere interpolator. |
| * @param microsphereElements number of surface elements of the microsphere. |
| * @param brightnessExponent exponent used in the power law that computes the |
| * weights of the sample data. |
| * @throws NotPositiveException if {@code microsphereElements <= 0} |
| * or {@code brightnessExponent < 0}. |
| */ |
| public MicrosphereInterpolator(final int microsphereElements, |
| final int brightnessExponent) { |
| setMicropshereElements(microsphereElements); |
| setBrightnessExponent(brightnessExponent); |
| } |
| |
| /** |
| * {@inheritDoc} |
| */ |
| public MultivariateRealFunction interpolate(final double[][] xval, |
| final double[] yval) |
| throws MathException, IllegalArgumentException { |
| final UnitSphereRandomVectorGenerator rand |
| = new UnitSphereRandomVectorGenerator(xval[0].length); |
| return new MicrosphereInterpolatingFunction(xval, yval, |
| brightnessExponent, |
| microsphereElements, |
| rand); |
| } |
| |
| /** |
| * Set the brightness exponent. |
| * @param exponent Exponent for computing the distance dimming |
| * factor. |
| * @throws NotPositiveException if {@code exponent < 0}. |
| */ |
| public void setBrightnessExponent(final int exponent) { |
| if (exponent < 0) { |
| throw new NotPositiveException(exponent); |
| } |
| brightnessExponent = exponent; |
| } |
| |
| /** |
| * Set the number of microsphere elements. |
| * @param elements Number of surface elements of the microsphere. |
| * @throws NotStrictlyPositiveException if {@code elements <= 0}. |
| */ |
| public void setMicropshereElements(final int elements) { |
| if (elements <= 0) { |
| throw new NotStrictlyPositiveException(elements); |
| } |
| microsphereElements = elements; |
| } |
| } |