1 | /*
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2 | * Licensed to the Apache Software Foundation (ASF) under one or more
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3 | * contributor license agreements. See the NOTICE file distributed with
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4 | * this work for additional information regarding copyright ownership.
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5 | * The ASF licenses this file to You under the Apache License, Version 2.0
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6 | * (the "License"); you may not use this file except in compliance with
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7 | * the License. You may obtain a copy of the License at
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8 | *
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9 | * http://www.apache.org/licenses/LICENSE-2.0
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10 | *
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11 | * Unless required by applicable law or agreed to in writing, software
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12 | * distributed under the License is distributed on an "AS IS" BASIS,
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13 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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14 | * See the License for the specific language governing permissions and
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15 | * limitations under the License.
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16 | */
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17 | package agents.anac.y2019.harddealer.math3.analysis.interpolation;
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18 |
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19 | import java.util.Arrays;
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20 | import agents.anac.y2019.harddealer.math3.analysis.BivariateFunction;
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21 | import agents.anac.y2019.harddealer.math3.exception.DimensionMismatchException;
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22 | import agents.anac.y2019.harddealer.math3.exception.NoDataException;
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23 | import agents.anac.y2019.harddealer.math3.exception.OutOfRangeException;
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24 | import agents.anac.y2019.harddealer.math3.exception.NonMonotonicSequenceException;
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25 | import agents.anac.y2019.harddealer.math3.util.MathArrays;
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26 |
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27 | /**
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28 | * Function that implements the
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29 | * <a href="http://en.wikipedia.org/wiki/Bicubic_interpolation">
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30 | * bicubic spline interpolation</a>. Due to numerical accuracy issues this should not
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31 | * be used.
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32 | *
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33 | * @since 2.1
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34 | * @deprecated as of 3.4 replaced by
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35 | * {@link agents.anac.y2019.harddealer.math3.analysis.interpolation.PiecewiseBicubicSplineInterpolatingFunction}
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36 | */
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37 | @Deprecated
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38 | public class BicubicSplineInterpolatingFunction
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39 | implements BivariateFunction {
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40 | /** Number of coefficients. */
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41 | private static final int NUM_COEFF = 16;
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42 | /**
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43 | * Matrix to compute the spline coefficients from the function values
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44 | * and function derivatives values
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45 | */
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46 | private static final double[][] AINV = {
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47 | { 1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 },
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48 | { 0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0 },
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49 | { -3,3,0,0,-2,-1,0,0,0,0,0,0,0,0,0,0 },
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50 | { 2,-2,0,0,1,1,0,0,0,0,0,0,0,0,0,0 },
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51 | { 0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0 },
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52 | { 0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0 },
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53 | { 0,0,0,0,0,0,0,0,-3,3,0,0,-2,-1,0,0 },
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54 | { 0,0,0,0,0,0,0,0,2,-2,0,0,1,1,0,0 },
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55 | { -3,0,3,0,0,0,0,0,-2,0,-1,0,0,0,0,0 },
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56 | { 0,0,0,0,-3,0,3,0,0,0,0,0,-2,0,-1,0 },
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57 | { 9,-9,-9,9,6,3,-6,-3,6,-6,3,-3,4,2,2,1 },
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58 | { -6,6,6,-6,-3,-3,3,3,-4,4,-2,2,-2,-2,-1,-1 },
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59 | { 2,0,-2,0,0,0,0,0,1,0,1,0,0,0,0,0 },
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60 | { 0,0,0,0,2,0,-2,0,0,0,0,0,1,0,1,0 },
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61 | { -6,6,6,-6,-4,-2,4,2,-3,3,-3,3,-2,-1,-2,-1 },
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62 | { 4,-4,-4,4,2,2,-2,-2,2,-2,2,-2,1,1,1,1 }
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63 | };
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64 |
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65 | /** Samples x-coordinates */
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66 | private final double[] xval;
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67 | /** Samples y-coordinates */
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68 | private final double[] yval;
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69 | /** Set of cubic splines patching the whole data grid */
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70 | private final BicubicSplineFunction[][] splines;
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71 | /**
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72 | * Partial derivatives.
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73 | * The value of the first index determines the kind of derivatives:
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74 | * 0 = first partial derivatives wrt x
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75 | * 1 = first partial derivatives wrt y
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76 | * 2 = second partial derivatives wrt x
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77 | * 3 = second partial derivatives wrt y
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78 | * 4 = cross partial derivatives
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79 | */
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80 | private final BivariateFunction[][][] partialDerivatives;
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81 |
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82 | /**
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83 | * @param x Sample values of the x-coordinate, in increasing order.
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84 | * @param y Sample values of the y-coordinate, in increasing order.
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85 | * @param f Values of the function on every grid point.
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86 | * @param dFdX Values of the partial derivative of function with respect
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87 | * to x on every grid point.
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88 | * @param dFdY Values of the partial derivative of function with respect
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89 | * to y on every grid point.
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90 | * @param d2FdXdY Values of the cross partial derivative of function on
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91 | * every grid point.
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92 | * @throws DimensionMismatchException if the various arrays do not contain
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93 | * the expected number of elements.
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94 | * @throws NonMonotonicSequenceException if {@code x} or {@code y} are
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95 | * not strictly increasing.
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96 | * @throws NoDataException if any of the arrays has zero length.
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97 | */
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98 | public BicubicSplineInterpolatingFunction(double[] x,
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99 | double[] y,
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100 | double[][] f,
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101 | double[][] dFdX,
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102 | double[][] dFdY,
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103 | double[][] d2FdXdY)
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104 | throws DimensionMismatchException,
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105 | NoDataException,
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106 | NonMonotonicSequenceException {
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107 | this(x, y, f, dFdX, dFdY, d2FdXdY, false);
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108 | }
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109 |
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110 | /**
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111 | * @param x Sample values of the x-coordinate, in increasing order.
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112 | * @param y Sample values of the y-coordinate, in increasing order.
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113 | * @param f Values of the function on every grid point.
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114 | * @param dFdX Values of the partial derivative of function with respect
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115 | * to x on every grid point.
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116 | * @param dFdY Values of the partial derivative of function with respect
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117 | * to y on every grid point.
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118 | * @param d2FdXdY Values of the cross partial derivative of function on
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119 | * every grid point.
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120 | * @param initializeDerivatives Whether to initialize the internal data
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121 | * needed for calling any of the methods that compute the partial derivatives
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122 | * this function.
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123 | * @throws DimensionMismatchException if the various arrays do not contain
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124 | * the expected number of elements.
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125 | * @throws NonMonotonicSequenceException if {@code x} or {@code y} are
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126 | * not strictly increasing.
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127 | * @throws NoDataException if any of the arrays has zero length.
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128 | *
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129 | * @see #partialDerivativeX(double,double)
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130 | * @see #partialDerivativeY(double,double)
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131 | * @see #partialDerivativeXX(double,double)
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132 | * @see #partialDerivativeYY(double,double)
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133 | * @see #partialDerivativeXY(double,double)
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134 | */
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135 | public BicubicSplineInterpolatingFunction(double[] x,
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136 | double[] y,
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137 | double[][] f,
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138 | double[][] dFdX,
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139 | double[][] dFdY,
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140 | double[][] d2FdXdY,
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141 | boolean initializeDerivatives)
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142 | throws DimensionMismatchException,
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143 | NoDataException,
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144 | NonMonotonicSequenceException {
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145 | final int xLen = x.length;
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146 | final int yLen = y.length;
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147 |
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148 | if (xLen == 0 || yLen == 0 || f.length == 0 || f[0].length == 0) {
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149 | throw new NoDataException();
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150 | }
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151 | if (xLen != f.length) {
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152 | throw new DimensionMismatchException(xLen, f.length);
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153 | }
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154 | if (xLen != dFdX.length) {
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155 | throw new DimensionMismatchException(xLen, dFdX.length);
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156 | }
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157 | if (xLen != dFdY.length) {
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158 | throw new DimensionMismatchException(xLen, dFdY.length);
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159 | }
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160 | if (xLen != d2FdXdY.length) {
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161 | throw new DimensionMismatchException(xLen, d2FdXdY.length);
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162 | }
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163 |
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164 | MathArrays.checkOrder(x);
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165 | MathArrays.checkOrder(y);
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166 |
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167 | xval = x.clone();
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168 | yval = y.clone();
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169 |
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170 | final int lastI = xLen - 1;
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171 | final int lastJ = yLen - 1;
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172 | splines = new BicubicSplineFunction[lastI][lastJ];
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173 |
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174 | for (int i = 0; i < lastI; i++) {
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175 | if (f[i].length != yLen) {
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176 | throw new DimensionMismatchException(f[i].length, yLen);
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177 | }
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178 | if (dFdX[i].length != yLen) {
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179 | throw new DimensionMismatchException(dFdX[i].length, yLen);
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180 | }
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181 | if (dFdY[i].length != yLen) {
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182 | throw new DimensionMismatchException(dFdY[i].length, yLen);
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183 | }
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184 | if (d2FdXdY[i].length != yLen) {
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185 | throw new DimensionMismatchException(d2FdXdY[i].length, yLen);
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186 | }
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187 | final int ip1 = i + 1;
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188 | for (int j = 0; j < lastJ; j++) {
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189 | final int jp1 = j + 1;
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190 | final double[] beta = new double[] {
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191 | f[i][j], f[ip1][j], f[i][jp1], f[ip1][jp1],
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192 | dFdX[i][j], dFdX[ip1][j], dFdX[i][jp1], dFdX[ip1][jp1],
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193 | dFdY[i][j], dFdY[ip1][j], dFdY[i][jp1], dFdY[ip1][jp1],
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194 | d2FdXdY[i][j], d2FdXdY[ip1][j], d2FdXdY[i][jp1], d2FdXdY[ip1][jp1]
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195 | };
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196 |
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197 | splines[i][j] = new BicubicSplineFunction(computeSplineCoefficients(beta),
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198 | initializeDerivatives);
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199 | }
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200 | }
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201 |
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202 | if (initializeDerivatives) {
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203 | // Compute all partial derivatives.
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204 | partialDerivatives = new BivariateFunction[5][lastI][lastJ];
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205 |
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206 | for (int i = 0; i < lastI; i++) {
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207 | for (int j = 0; j < lastJ; j++) {
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208 | final BicubicSplineFunction bcs = splines[i][j];
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209 | partialDerivatives[0][i][j] = bcs.partialDerivativeX();
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210 | partialDerivatives[1][i][j] = bcs.partialDerivativeY();
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211 | partialDerivatives[2][i][j] = bcs.partialDerivativeXX();
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212 | partialDerivatives[3][i][j] = bcs.partialDerivativeYY();
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213 | partialDerivatives[4][i][j] = bcs.partialDerivativeXY();
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214 | }
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215 | }
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216 | } else {
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217 | // Partial derivative methods cannot be used.
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218 | partialDerivatives = null;
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219 | }
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220 | }
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221 |
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222 | /**
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223 | * {@inheritDoc}
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224 | */
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225 | public double value(double x, double y)
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226 | throws OutOfRangeException {
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227 | final int i = searchIndex(x, xval);
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228 | final int j = searchIndex(y, yval);
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229 |
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230 | final double xN = (x - xval[i]) / (xval[i + 1] - xval[i]);
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231 | final double yN = (y - yval[j]) / (yval[j + 1] - yval[j]);
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232 |
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233 | return splines[i][j].value(xN, yN);
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234 | }
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235 |
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236 | /**
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237 | * Indicates whether a point is within the interpolation range.
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238 | *
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239 | * @param x First coordinate.
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240 | * @param y Second coordinate.
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241 | * @return {@code true} if (x, y) is a valid point.
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242 | * @since 3.3
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243 | */
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244 | public boolean isValidPoint(double x, double y) {
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245 | if (x < xval[0] ||
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246 | x > xval[xval.length - 1] ||
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247 | y < yval[0] ||
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248 | y > yval[yval.length - 1]) {
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249 | return false;
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250 | } else {
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251 | return true;
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252 | }
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253 | }
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254 |
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255 | /**
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256 | * @param x x-coordinate.
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257 | * @param y y-coordinate.
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258 | * @return the value at point (x, y) of the first partial derivative with
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259 | * respect to x.
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260 | * @throws OutOfRangeException if {@code x} (resp. {@code y}) is outside
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261 | * the range defined by the boundary values of {@code xval} (resp.
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262 | * {@code yval}).
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263 | * @throws NullPointerException if the internal data were not initialized
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264 | * (cf. {@link #BicubicSplineInterpolatingFunction(double[],double[],double[][],
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265 | * double[][],double[][],double[][],boolean) constructor}).
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266 | */
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267 | public double partialDerivativeX(double x, double y)
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268 | throws OutOfRangeException {
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269 | return partialDerivative(0, x, y);
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270 | }
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271 | /**
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272 | * @param x x-coordinate.
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273 | * @param y y-coordinate.
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274 | * @return the value at point (x, y) of the first partial derivative with
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275 | * respect to y.
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276 | * @throws OutOfRangeException if {@code x} (resp. {@code y}) is outside
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277 | * the range defined by the boundary values of {@code xval} (resp.
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278 | * {@code yval}).
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279 | * @throws NullPointerException if the internal data were not initialized
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280 | * (cf. {@link #BicubicSplineInterpolatingFunction(double[],double[],double[][],
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281 | * double[][],double[][],double[][],boolean) constructor}).
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282 | */
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283 | public double partialDerivativeY(double x, double y)
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284 | throws OutOfRangeException {
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285 | return partialDerivative(1, x, y);
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286 | }
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287 | /**
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288 | * @param x x-coordinate.
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289 | * @param y y-coordinate.
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290 | * @return the value at point (x, y) of the second partial derivative with
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291 | * respect to x.
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292 | * @throws OutOfRangeException if {@code x} (resp. {@code y}) is outside
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293 | * the range defined by the boundary values of {@code xval} (resp.
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294 | * {@code yval}).
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295 | * @throws NullPointerException if the internal data were not initialized
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296 | * (cf. {@link #BicubicSplineInterpolatingFunction(double[],double[],double[][],
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297 | * double[][],double[][],double[][],boolean) constructor}).
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298 | */
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299 | public double partialDerivativeXX(double x, double y)
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300 | throws OutOfRangeException {
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301 | return partialDerivative(2, x, y);
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302 | }
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303 | /**
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304 | * @param x x-coordinate.
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305 | * @param y y-coordinate.
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306 | * @return the value at point (x, y) of the second partial derivative with
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307 | * respect to y.
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308 | * @throws OutOfRangeException if {@code x} (resp. {@code y}) is outside
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309 | * the range defined by the boundary values of {@code xval} (resp.
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310 | * {@code yval}).
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311 | * @throws NullPointerException if the internal data were not initialized
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312 | * (cf. {@link #BicubicSplineInterpolatingFunction(double[],double[],double[][],
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313 | * double[][],double[][],double[][],boolean) constructor}).
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314 | */
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315 | public double partialDerivativeYY(double x, double y)
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316 | throws OutOfRangeException {
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317 | return partialDerivative(3, x, y);
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318 | }
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319 | /**
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320 | * @param x x-coordinate.
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321 | * @param y y-coordinate.
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322 | * @return the value at point (x, y) of the second partial cross-derivative.
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323 | * @throws OutOfRangeException if {@code x} (resp. {@code y}) is outside
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324 | * the range defined by the boundary values of {@code xval} (resp.
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325 | * {@code yval}).
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326 | * @throws NullPointerException if the internal data were not initialized
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327 | * (cf. {@link #BicubicSplineInterpolatingFunction(double[],double[],double[][],
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328 | * double[][],double[][],double[][],boolean) constructor}).
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329 | */
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330 | public double partialDerivativeXY(double x, double y)
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331 | throws OutOfRangeException {
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332 | return partialDerivative(4, x, y);
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333 | }
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334 |
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335 | /**
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336 | * @param which First index in {@link #partialDerivatives}.
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337 | * @param x x-coordinate.
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338 | * @param y y-coordinate.
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339 | * @return the value at point (x, y) of the selected partial derivative.
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340 | * @throws OutOfRangeException if {@code x} (resp. {@code y}) is outside
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341 | * the range defined by the boundary values of {@code xval} (resp.
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342 | * {@code yval}).
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343 | * @throws NullPointerException if the internal data were not initialized
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344 | * (cf. {@link #BicubicSplineInterpolatingFunction(double[],double[],double[][],
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345 | * double[][],double[][],double[][],boolean) constructor}).
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346 | */
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347 | private double partialDerivative(int which, double x, double y)
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348 | throws OutOfRangeException {
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349 | final int i = searchIndex(x, xval);
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350 | final int j = searchIndex(y, yval);
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351 |
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352 | final double xN = (x - xval[i]) / (xval[i + 1] - xval[i]);
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353 | final double yN = (y - yval[j]) / (yval[j + 1] - yval[j]);
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354 |
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355 | return partialDerivatives[which][i][j].value(xN, yN);
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356 | }
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357 |
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358 | /**
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359 | * @param c Coordinate.
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360 | * @param val Coordinate samples.
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361 | * @return the index in {@code val} corresponding to the interval
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362 | * containing {@code c}.
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363 | * @throws OutOfRangeException if {@code c} is out of the
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364 | * range defined by the boundary values of {@code val}.
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365 | */
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366 | private int searchIndex(double c, double[] val) {
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367 | final int r = Arrays.binarySearch(val, c);
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368 |
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369 | if (r == -1 ||
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370 | r == -val.length - 1) {
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371 | throw new OutOfRangeException(c, val[0], val[val.length - 1]);
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372 | }
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373 |
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374 | if (r < 0) {
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375 | // "c" in within an interpolation sub-interval: Return the
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376 | // index of the sample at the lower end of the sub-interval.
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377 | return -r - 2;
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378 | }
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379 | final int last = val.length - 1;
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380 | if (r == last) {
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381 | // "c" is the last sample of the range: Return the index
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382 | // of the sample at the lower end of the last sub-interval.
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383 | return last - 1;
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384 | }
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385 |
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386 | // "c" is another sample point.
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387 | return r;
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388 | }
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389 |
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---|
390 | /**
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391 | * Compute the spline coefficients from the list of function values and
|
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392 | * function partial derivatives values at the four corners of a grid
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393 | * element. They must be specified in the following order:
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394 | * <ul>
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395 | * <li>f(0,0)</li>
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---|
396 | * <li>f(1,0)</li>
|
---|
397 | * <li>f(0,1)</li>
|
---|
398 | * <li>f(1,1)</li>
|
---|
399 | * <li>f<sub>x</sub>(0,0)</li>
|
---|
400 | * <li>f<sub>x</sub>(1,0)</li>
|
---|
401 | * <li>f<sub>x</sub>(0,1)</li>
|
---|
402 | * <li>f<sub>x</sub>(1,1)</li>
|
---|
403 | * <li>f<sub>y</sub>(0,0)</li>
|
---|
404 | * <li>f<sub>y</sub>(1,0)</li>
|
---|
405 | * <li>f<sub>y</sub>(0,1)</li>
|
---|
406 | * <li>f<sub>y</sub>(1,1)</li>
|
---|
407 | * <li>f<sub>xy</sub>(0,0)</li>
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408 | * <li>f<sub>xy</sub>(1,0)</li>
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409 | * <li>f<sub>xy</sub>(0,1)</li>
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410 | * <li>f<sub>xy</sub>(1,1)</li>
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411 | * </ul>
|
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412 | * where the subscripts indicate the partial derivative with respect to
|
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413 | * the corresponding variable(s).
|
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414 | *
|
---|
415 | * @param beta List of function values and function partial derivatives
|
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416 | * values.
|
---|
417 | * @return the spline coefficients.
|
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418 | */
|
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419 | private double[] computeSplineCoefficients(double[] beta) {
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420 | final double[] a = new double[NUM_COEFF];
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421 |
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422 | for (int i = 0; i < NUM_COEFF; i++) {
|
---|
423 | double result = 0;
|
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424 | final double[] row = AINV[i];
|
---|
425 | for (int j = 0; j < NUM_COEFF; j++) {
|
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426 | result += row[j] * beta[j];
|
---|
427 | }
|
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428 | a[i] = result;
|
---|
429 | }
|
---|
430 |
|
---|
431 | return a;
|
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432 | }
|
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433 | }
|
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434 |
|
---|
435 | /**
|
---|
436 | * 2D-spline function.
|
---|
437 | *
|
---|
438 | */
|
---|
439 | class BicubicSplineFunction implements BivariateFunction {
|
---|
440 | /** Number of points. */
|
---|
441 | private static final short N = 4;
|
---|
442 | /** Coefficients */
|
---|
443 | private final double[][] a;
|
---|
444 | /** First partial derivative along x. */
|
---|
445 | private final BivariateFunction partialDerivativeX;
|
---|
446 | /** First partial derivative along y. */
|
---|
447 | private final BivariateFunction partialDerivativeY;
|
---|
448 | /** Second partial derivative along x. */
|
---|
449 | private final BivariateFunction partialDerivativeXX;
|
---|
450 | /** Second partial derivative along y. */
|
---|
451 | private final BivariateFunction partialDerivativeYY;
|
---|
452 | /** Second crossed partial derivative. */
|
---|
453 | private final BivariateFunction partialDerivativeXY;
|
---|
454 |
|
---|
455 | /**
|
---|
456 | * Simple constructor.
|
---|
457 | *
|
---|
458 | * @param coeff Spline coefficients.
|
---|
459 | */
|
---|
460 | BicubicSplineFunction(double[] coeff) {
|
---|
461 | this(coeff, false);
|
---|
462 | }
|
---|
463 |
|
---|
464 | /**
|
---|
465 | * Simple constructor.
|
---|
466 | *
|
---|
467 | * @param coeff Spline coefficients.
|
---|
468 | * @param initializeDerivatives Whether to initialize the internal data
|
---|
469 | * needed for calling any of the methods that compute the partial derivatives
|
---|
470 | * this function.
|
---|
471 | */
|
---|
472 | BicubicSplineFunction(double[] coeff, boolean initializeDerivatives) {
|
---|
473 | a = new double[N][N];
|
---|
474 | for (int i = 0; i < N; i++) {
|
---|
475 | for (int j = 0; j < N; j++) {
|
---|
476 | a[i][j] = coeff[i * N + j];
|
---|
477 | }
|
---|
478 | }
|
---|
479 |
|
---|
480 | if (initializeDerivatives) {
|
---|
481 | // Compute all partial derivatives functions.
|
---|
482 | final double[][] aX = new double[N][N];
|
---|
483 | final double[][] aY = new double[N][N];
|
---|
484 | final double[][] aXX = new double[N][N];
|
---|
485 | final double[][] aYY = new double[N][N];
|
---|
486 | final double[][] aXY = new double[N][N];
|
---|
487 |
|
---|
488 | for (int i = 0; i < N; i++) {
|
---|
489 | for (int j = 0; j < N; j++) {
|
---|
490 | final double c = a[i][j];
|
---|
491 | aX[i][j] = i * c;
|
---|
492 | aY[i][j] = j * c;
|
---|
493 | aXX[i][j] = (i - 1) * aX[i][j];
|
---|
494 | aYY[i][j] = (j - 1) * aY[i][j];
|
---|
495 | aXY[i][j] = j * aX[i][j];
|
---|
496 | }
|
---|
497 | }
|
---|
498 |
|
---|
499 | partialDerivativeX = new BivariateFunction() {
|
---|
500 | /** {@inheritDoc} */
|
---|
501 | public double value(double x, double y) {
|
---|
502 | final double x2 = x * x;
|
---|
503 | final double[] pX = {0, 1, x, x2};
|
---|
504 |
|
---|
505 | final double y2 = y * y;
|
---|
506 | final double y3 = y2 * y;
|
---|
507 | final double[] pY = {1, y, y2, y3};
|
---|
508 |
|
---|
509 | return apply(pX, pY, aX);
|
---|
510 | }
|
---|
511 | };
|
---|
512 | partialDerivativeY = new BivariateFunction() {
|
---|
513 | /** {@inheritDoc} */
|
---|
514 | public double value(double x, double y) {
|
---|
515 | final double x2 = x * x;
|
---|
516 | final double x3 = x2 * x;
|
---|
517 | final double[] pX = {1, x, x2, x3};
|
---|
518 |
|
---|
519 | final double y2 = y * y;
|
---|
520 | final double[] pY = {0, 1, y, y2};
|
---|
521 |
|
---|
522 | return apply(pX, pY, aY);
|
---|
523 | }
|
---|
524 | };
|
---|
525 | partialDerivativeXX = new BivariateFunction() {
|
---|
526 | /** {@inheritDoc} */
|
---|
527 | public double value(double x, double y) {
|
---|
528 | final double[] pX = {0, 0, 1, x};
|
---|
529 |
|
---|
530 | final double y2 = y * y;
|
---|
531 | final double y3 = y2 * y;
|
---|
532 | final double[] pY = {1, y, y2, y3};
|
---|
533 |
|
---|
534 | return apply(pX, pY, aXX);
|
---|
535 | }
|
---|
536 | };
|
---|
537 | partialDerivativeYY = new BivariateFunction() {
|
---|
538 | /** {@inheritDoc} */
|
---|
539 | public double value(double x, double y) {
|
---|
540 | final double x2 = x * x;
|
---|
541 | final double x3 = x2 * x;
|
---|
542 | final double[] pX = {1, x, x2, x3};
|
---|
543 |
|
---|
544 | final double[] pY = {0, 0, 1, y};
|
---|
545 |
|
---|
546 | return apply(pX, pY, aYY);
|
---|
547 | }
|
---|
548 | };
|
---|
549 | partialDerivativeXY = new BivariateFunction() {
|
---|
550 | /** {@inheritDoc} */
|
---|
551 | public double value(double x, double y) {
|
---|
552 | final double x2 = x * x;
|
---|
553 | final double[] pX = {0, 1, x, x2};
|
---|
554 |
|
---|
555 | final double y2 = y * y;
|
---|
556 | final double[] pY = {0, 1, y, y2};
|
---|
557 |
|
---|
558 | return apply(pX, pY, aXY);
|
---|
559 | }
|
---|
560 | };
|
---|
561 | } else {
|
---|
562 | partialDerivativeX = null;
|
---|
563 | partialDerivativeY = null;
|
---|
564 | partialDerivativeXX = null;
|
---|
565 | partialDerivativeYY = null;
|
---|
566 | partialDerivativeXY = null;
|
---|
567 | }
|
---|
568 | }
|
---|
569 |
|
---|
570 | /**
|
---|
571 | * {@inheritDoc}
|
---|
572 | */
|
---|
573 | public double value(double x, double y) {
|
---|
574 | if (x < 0 || x > 1) {
|
---|
575 | throw new OutOfRangeException(x, 0, 1);
|
---|
576 | }
|
---|
577 | if (y < 0 || y > 1) {
|
---|
578 | throw new OutOfRangeException(y, 0, 1);
|
---|
579 | }
|
---|
580 |
|
---|
581 | final double x2 = x * x;
|
---|
582 | final double x3 = x2 * x;
|
---|
583 | final double[] pX = {1, x, x2, x3};
|
---|
584 |
|
---|
585 | final double y2 = y * y;
|
---|
586 | final double y3 = y2 * y;
|
---|
587 | final double[] pY = {1, y, y2, y3};
|
---|
588 |
|
---|
589 | return apply(pX, pY, a);
|
---|
590 | }
|
---|
591 |
|
---|
592 | /**
|
---|
593 | * Compute the value of the bicubic polynomial.
|
---|
594 | *
|
---|
595 | * @param pX Powers of the x-coordinate.
|
---|
596 | * @param pY Powers of the y-coordinate.
|
---|
597 | * @param coeff Spline coefficients.
|
---|
598 | * @return the interpolated value.
|
---|
599 | */
|
---|
600 | private double apply(double[] pX, double[] pY, double[][] coeff) {
|
---|
601 | double result = 0;
|
---|
602 | for (int i = 0; i < N; i++) {
|
---|
603 | for (int j = 0; j < N; j++) {
|
---|
604 | result += coeff[i][j] * pX[i] * pY[j];
|
---|
605 | }
|
---|
606 | }
|
---|
607 |
|
---|
608 | return result;
|
---|
609 | }
|
---|
610 |
|
---|
611 | /**
|
---|
612 | * @return the partial derivative wrt {@code x}.
|
---|
613 | */
|
---|
614 | public BivariateFunction partialDerivativeX() {
|
---|
615 | return partialDerivativeX;
|
---|
616 | }
|
---|
617 | /**
|
---|
618 | * @return the partial derivative wrt {@code y}.
|
---|
619 | */
|
---|
620 | public BivariateFunction partialDerivativeY() {
|
---|
621 | return partialDerivativeY;
|
---|
622 | }
|
---|
623 | /**
|
---|
624 | * @return the second partial derivative wrt {@code x}.
|
---|
625 | */
|
---|
626 | public BivariateFunction partialDerivativeXX() {
|
---|
627 | return partialDerivativeXX;
|
---|
628 | }
|
---|
629 | /**
|
---|
630 | * @return the second partial derivative wrt {@code y}.
|
---|
631 | */
|
---|
632 | public BivariateFunction partialDerivativeYY() {
|
---|
633 | return partialDerivativeYY;
|
---|
634 | }
|
---|
635 | /**
|
---|
636 | * @return the second partial cross-derivative.
|
---|
637 | */
|
---|
638 | public BivariateFunction partialDerivativeXY() {
|
---|
639 | return partialDerivativeXY;
|
---|
640 | }
|
---|
641 | }
|
---|