1 | /// \ingroup newmat
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2 | ///@{
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3 |
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4 | /// \file newmatnl.cpp
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5 | /// Non-linear optimisation.
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6 |
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7 | // Copyright (C) 1993,4,5,6: R B Davies
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8 |
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9 |
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10 | #define WANT_MATH
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11 | #define WANT_STREAM
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12 |
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13 | #include "newmatap.h"
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14 | #include "newmatnl.h"
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15 |
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16 | #ifdef use_namespace
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17 | namespace NEWMAT {
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18 | #endif
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19 |
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20 |
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21 |
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22 | void FindMaximum2::Fit(ColumnVector& Theta, int n_it)
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23 | {
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24 | Tracer tr("FindMaximum2::Fit");
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25 | enum State {Start, Restart, Continue, Interpolate, Extrapolate,
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26 | Fail, Convergence};
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27 | State TheState = Start;
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28 | Real z,w,x,x2,g,l1,l2,l3,d1,d2=0,d3;
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29 | ColumnVector Theta1, Theta2, Theta3;
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30 | int np = Theta.Nrows();
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31 | ColumnVector H1(np), H3, HP(np), K, K1(np);
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32 | bool oorg, conv;
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33 | int counter = 0;
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34 | Theta1 = Theta; HP = 0.0; g = 0.0;
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35 |
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36 | // This is really a set of gotos and labels, but they do not work
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37 | // correctly in AT&T C++ and Sun 4.01 C++.
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38 |
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39 | for(;;)
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40 | {
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41 | switch (TheState)
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42 | {
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43 | case Start:
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44 | tr.ReName("FindMaximum2::Fit/Start");
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45 | Value(Theta1, true, l1, oorg);
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46 | if (oorg) Throw(ProgramException("invalid starting value\n"));
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47 |
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48 | case Restart:
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49 | tr.ReName("FindMaximum2::Fit/ReStart");
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50 | conv = NextPoint(H1, d1);
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51 | if (conv) { TheState = Convergence; break; }
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52 | if (counter++ > n_it) { TheState = Fail; break; }
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53 |
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54 | z = 1.0 / sqrt(d1);
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55 | H3 = H1 * z; K = (H3 - HP) * g; HP = H3;
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56 | g = 0.0; // de-activate to use curved projection
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57 | if ( g == 0.0 ) K1 = 0.0; else K1 = K * 0.2 + K1 * 0.6;
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58 | // (K - K1) * alpha + K1 * (1 - alpha)
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59 | // = K * alpha + K1 * (1 - 2 * alpha)
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60 | K = K1 * d1; g = z;
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61 |
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62 | case Continue:
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63 | tr.ReName("FindMaximum2::Fit/Continue");
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64 | Theta2 = Theta1 + H1 + K;
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65 | Value(Theta2, false, l2, oorg);
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66 | if (counter++ > n_it) { TheState = Fail; break; }
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67 | if (oorg)
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68 | {
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69 | H1 *= 0.5; K *= 0.25; d1 *= 0.5; g *= 2.0;
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70 | TheState = Continue; break;
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71 | }
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72 | d2 = LastDerivative(H1 + K * 2.0);
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73 |
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74 | case Interpolate:
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75 | tr.ReName("FindMaximum2::Fit/Interpolate");
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76 | z = d1 + d2 - 3.0 * (l2 - l1);
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77 | w = z * z - d1 * d2;
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78 | if (w < 0.0) { TheState = Extrapolate; break; }
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79 | w = z + sqrt(w);
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80 | if (1.5 * w + d1 < 0.0)
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81 | { TheState = Extrapolate; break; }
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82 | if (d2 > 0.0 && l2 > l1 && w > 0.0)
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83 | { TheState = Extrapolate; break; }
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84 | x = d1 / (w + d1); x2 = x * x; g /= x;
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85 | Theta3 = Theta1 + H1 * x + K * x2;
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86 | Value(Theta3, true, l3, oorg);
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87 | if (counter++ > n_it) { TheState = Fail; break; }
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88 | if (oorg)
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89 | {
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90 | if (x <= 1.0)
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91 | { x *= 0.5; x2 = x*x; g *= 2.0; d1 *= x; H1 *= x; K *= x2; }
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92 | else
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93 | {
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94 | x = 0.5 * (x-1.0); x2 = x*x; Theta1 = Theta2;
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95 | H1 = (H1 + K * 2.0) * x;
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96 | K *= x2; g = 0.0; d1 = x * d2; l1 = l2;
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97 | }
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98 | TheState = Continue; break;
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99 | }
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100 |
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101 | if (l3 >= l1 && l3 >= l2)
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102 | { Theta1 = Theta3; l1 = l3; TheState = Restart; break; }
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103 |
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104 | d3 = LastDerivative(H1 + K * 2.0);
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105 | if (l1 > l2)
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106 | { H1 *= x; K *= x2; Theta2 = Theta3; d1 *= x; d2 = d3*x; }
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107 | else
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108 | {
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109 | Theta1 = Theta2; Theta2 = Theta3;
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110 | x -= 1.0; x2 = x*x; g = 0.0; H1 = (H1 + K * 2.0) * x;
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111 | K *= x2; l1 = l2; l2 = l3; d1 = x*d2; d2 = x*d3;
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112 | if (d1 <= 0.0) { TheState = Start; break; }
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113 | }
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114 | TheState = Interpolate; break;
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115 |
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116 | case Extrapolate:
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117 | tr.ReName("FindMaximum2::Fit/Extrapolate");
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118 | Theta1 = Theta2; g = 0.0; K *= 4.0; H1 = (H1 * 2.0 + K);
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119 | d1 = 2.0 * d2; l1 = l2;
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120 | TheState = Continue; break;
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121 |
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122 | case Fail:
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123 | Throw(ConvergenceException(Theta));
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124 |
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125 | case Convergence:
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126 | Theta = Theta1; return;
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127 | }
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128 | }
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129 | }
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130 |
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131 |
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132 |
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133 | void NonLinearLeastSquares::Value
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134 | (const ColumnVector& Parameters, bool, Real& v, bool& oorg)
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135 | {
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136 | Tracer tr("NonLinearLeastSquares::Value");
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137 | Y.resize(n_obs); X.resize(n_obs,n_param);
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138 | // put the fitted values in Y, the derivatives in X.
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139 | Pred.Set(Parameters);
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140 | if (!Pred.IsValid()) { oorg=true; return; }
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141 | for (int i=1; i<=n_obs; i++)
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142 | {
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143 | Y(i) = Pred(i);
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144 | X.Row(i) = Pred.Derivatives();
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145 | }
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146 | if (!Pred.IsValid()) { oorg=true; return; } // check afterwards as well
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147 | Y = *DataPointer - Y; Real ssq = Y.SumSquare();
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148 | errorvar = ssq / (n_obs - n_param);
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149 | cout << endl;
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150 | cout << setw(15) << setprecision(10) << " " << errorvar;
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151 | Derivs = Y.t() * X; // get the derivative and stash it
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152 | oorg = false; v = -0.5 * ssq;
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153 | }
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154 |
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155 | bool NonLinearLeastSquares::NextPoint(ColumnVector& Adj, Real& test)
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156 | {
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157 | Tracer tr("NonLinearLeastSquares::NextPoint");
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158 | QRZ(X, U); QRZ(X, Y, M); // do the QR decomposition
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159 | test = M.SumSquare();
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160 | cout << " " << setw(15) << setprecision(10)
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161 | << test << " " << Y.SumSquare() / (n_obs - n_param);
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162 | Adj = U.i() * M;
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163 | if (test < errorvar * criterion) return true;
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164 | else return false;
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165 | }
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166 |
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167 | Real NonLinearLeastSquares::LastDerivative(const ColumnVector& H)
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168 | { return (Derivs * H).AsScalar(); }
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169 |
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170 | void NonLinearLeastSquares::Fit(const ColumnVector& Data,
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171 | ColumnVector& Parameters)
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172 | {
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173 | Tracer tr("NonLinearLeastSquares::Fit");
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174 | n_param = Parameters.Nrows(); n_obs = Data.Nrows();
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175 | DataPointer = &Data;
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176 | FindMaximum2::Fit(Parameters, Lim);
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177 | cout << "\nConverged" << endl;
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178 | }
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179 |
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180 | void NonLinearLeastSquares::MakeCovariance()
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181 | {
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182 | if (Covariance.Nrows()==0)
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183 | {
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184 | UpperTriangularMatrix UI = U.i();
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185 | Covariance << UI * UI.t() * errorvar;
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186 | SE << Covariance; // get diagonals
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187 | for (int i = 1; i<=n_param; i++) SE(i) = sqrt(SE(i));
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188 | }
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189 | }
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190 |
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191 | void NonLinearLeastSquares::GetStandardErrors(ColumnVector& SEX)
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192 | { MakeCovariance(); SEX = SE.AsColumn(); }
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193 |
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194 | void NonLinearLeastSquares::GetCorrelations(SymmetricMatrix& Corr)
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195 | { MakeCovariance(); Corr << SE.i() * Covariance * SE.i(); }
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196 |
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197 | void NonLinearLeastSquares::GetHatDiagonal(DiagonalMatrix& Hat) const
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198 | {
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199 | Hat.resize(n_obs);
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200 | for (int i = 1; i<=n_obs; i++) Hat(i) = X.Row(i).SumSquare();
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201 | }
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202 |
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203 |
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204 | // the MLE_D_FI routines
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205 |
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206 | void MLE_D_FI::Value
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207 | (const ColumnVector& Parameters, bool wg, Real& v, bool& oorg)
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208 | {
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209 | Tracer tr("MLE_D_FI::Value");
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210 | if (!LL.IsValid(Parameters,wg)) { oorg=true; return; }
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211 | v = LL.LogLikelihood();
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212 | if (!LL.IsValid()) { oorg=true; return; } // check validity again
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213 | cout << endl;
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214 | cout << setw(20) << setprecision(10) << v;
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215 | oorg = false;
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216 | Derivs = LL.Derivatives(); // Get derivatives
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217 | }
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218 |
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219 | bool MLE_D_FI::NextPoint(ColumnVector& Adj, Real& test)
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220 | {
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221 | Tracer tr("MLE_D_FI::NextPoint");
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222 | SymmetricMatrix FI = LL.FI();
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223 | LT = Cholesky(FI);
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224 | ColumnVector Adj1 = LT.i() * Derivs;
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225 | Adj = LT.t().i() * Adj1;
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226 | test = SumSquare(Adj1);
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227 | cout << " " << setw(20) << setprecision(10) << test;
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228 | return (test < Criterion);
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229 | }
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230 |
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231 | Real MLE_D_FI::LastDerivative(const ColumnVector& H)
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232 | { return (Derivs.t() * H).AsScalar(); }
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233 |
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234 | void MLE_D_FI::Fit(ColumnVector& Parameters)
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235 | {
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236 | Tracer tr("MLE_D_FI::Fit");
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237 | FindMaximum2::Fit(Parameters,Lim);
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238 | cout << "\nConverged" << endl;
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239 | }
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240 |
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241 | void MLE_D_FI::MakeCovariance()
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242 | {
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243 | if (Covariance.Nrows()==0)
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244 | {
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245 | LowerTriangularMatrix LTI = LT.i();
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246 | Covariance << LTI.t() * LTI;
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247 | SE << Covariance; // get diagonal
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248 | int n = Covariance.Nrows();
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249 | for (int i=1; i <= n; i++) SE(i) = sqrt(SE(i));
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250 | }
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251 | }
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252 |
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253 | void MLE_D_FI::GetStandardErrors(ColumnVector& SEX)
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254 | { MakeCovariance(); SEX = SE.AsColumn(); }
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255 |
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256 | void MLE_D_FI::GetCorrelations(SymmetricMatrix& Corr)
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257 | { MakeCovariance(); Corr << SE.i() * Covariance * SE.i(); }
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258 |
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259 |
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260 |
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261 | #ifdef use_namespace
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262 | }
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263 | #endif
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264 |
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265 |
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266 | ///@}
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