Raymond | dee0849 | 2015-04-02 10:43:13 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Licensed to the Apache Software Foundation (ASF) under one or more |
| 3 | * contributor license agreements. See the NOTICE file distributed with |
| 4 | * this work for additional information regarding copyright ownership. |
| 5 | * The ASF licenses this file to You under the Apache License, Version 2.0 |
| 6 | * (the "License"); you may not use this file except in compliance with |
| 7 | * the License. You may obtain a copy of the License at |
| 8 | * |
| 9 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 10 | * |
| 11 | * Unless required by applicable law or agreed to in writing, software |
| 12 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 13 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 14 | * See the License for the specific language governing permissions and |
| 15 | * limitations under the License. |
| 16 | */ |
| 17 | package org.apache.commons.math.analysis.interpolation; |
| 18 | |
| 19 | import org.apache.commons.math.MathException; |
| 20 | import org.apache.commons.math.analysis.MultivariateRealFunction; |
| 21 | import org.apache.commons.math.exception.NotPositiveException; |
| 22 | import org.apache.commons.math.exception.NotStrictlyPositiveException; |
| 23 | import org.apache.commons.math.random.UnitSphereRandomVectorGenerator; |
| 24 | |
| 25 | /** |
| 26 | * Interpolator that implements the algorithm described in |
| 27 | * <em>William Dudziak</em>'s |
| 28 | * <a href="http://www.dudziak.com/microsphere.pdf">MS thesis</a>. |
| 29 | * @since 2.1 |
| 30 | * |
| 31 | * @version $Revision: 980944 $ $Date: 2010-07-30 22:31:11 +0200 (ven. 30 juil. 2010) $ |
| 32 | */ |
| 33 | public class MicrosphereInterpolator |
| 34 | implements MultivariateRealInterpolator { |
| 35 | |
| 36 | /** |
| 37 | * Default number of surface elements that composes the microsphere. |
| 38 | */ |
| 39 | public static final int DEFAULT_MICROSPHERE_ELEMENTS = 2000; |
| 40 | |
| 41 | /** |
| 42 | * Default exponent used the weights calculation. |
| 43 | */ |
| 44 | public static final int DEFAULT_BRIGHTNESS_EXPONENT = 2; |
| 45 | |
| 46 | /** |
| 47 | * Number of surface elements of the microsphere. |
| 48 | */ |
| 49 | private int microsphereElements; |
| 50 | |
| 51 | /** |
| 52 | * Exponent used in the power law that computes the weights of the |
| 53 | * sample data. |
| 54 | */ |
| 55 | private int brightnessExponent; |
| 56 | |
| 57 | /** Create a microsphere interpolator with default settings. |
| 58 | * <p>Calling this constructor is equivalent to call {@link |
| 59 | * #MicrosphereInterpolator(int, int) |
| 60 | * MicrosphereInterpolator(MicrosphereInterpolator.DEFAULT_MICROSPHERE_ELEMENTS, |
| 61 | * MicrosphereInterpolator.DEFAULT_BRIGHTNESS_EXPONENT)}.</p> |
| 62 | */ |
| 63 | public MicrosphereInterpolator() { |
| 64 | this(DEFAULT_MICROSPHERE_ELEMENTS, DEFAULT_BRIGHTNESS_EXPONENT); |
| 65 | } |
| 66 | |
| 67 | /** Create a microsphere interpolator. |
| 68 | * @param microsphereElements number of surface elements of the microsphere. |
| 69 | * @param brightnessExponent exponent used in the power law that computes the |
| 70 | * weights of the sample data. |
| 71 | * @throws NotPositiveException if {@code microsphereElements <= 0} |
| 72 | * or {@code brightnessExponent < 0}. |
| 73 | */ |
| 74 | public MicrosphereInterpolator(final int microsphereElements, |
| 75 | final int brightnessExponent) { |
| 76 | setMicropshereElements(microsphereElements); |
| 77 | setBrightnessExponent(brightnessExponent); |
| 78 | } |
| 79 | |
| 80 | /** |
| 81 | * {@inheritDoc} |
| 82 | */ |
| 83 | public MultivariateRealFunction interpolate(final double[][] xval, |
| 84 | final double[] yval) |
| 85 | throws MathException, IllegalArgumentException { |
| 86 | final UnitSphereRandomVectorGenerator rand |
| 87 | = new UnitSphereRandomVectorGenerator(xval[0].length); |
| 88 | return new MicrosphereInterpolatingFunction(xval, yval, |
| 89 | brightnessExponent, |
| 90 | microsphereElements, |
| 91 | rand); |
| 92 | } |
| 93 | |
| 94 | /** |
| 95 | * Set the brightness exponent. |
| 96 | * @param exponent Exponent for computing the distance dimming |
| 97 | * factor. |
| 98 | * @throws NotPositiveException if {@code exponent < 0}. |
| 99 | */ |
| 100 | public void setBrightnessExponent(final int exponent) { |
| 101 | if (exponent < 0) { |
| 102 | throw new NotPositiveException(exponent); |
| 103 | } |
| 104 | brightnessExponent = exponent; |
| 105 | } |
| 106 | |
| 107 | /** |
| 108 | * Set the number of microsphere elements. |
| 109 | * @param elements Number of surface elements of the microsphere. |
| 110 | * @throws NotStrictlyPositiveException if {@code elements <= 0}. |
| 111 | */ |
| 112 | public void setMicropshereElements(final int elements) { |
| 113 | if (elements <= 0) { |
| 114 | throw new NotStrictlyPositiveException(elements); |
| 115 | } |
| 116 | microsphereElements = elements; |
| 117 | } |
| 118 | } |