1 | /// \ingroup newmat
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2 | ///@{
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3 |
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4 | /// \file evalue.cpp
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5 | /// Eigen-value decomposition (Householder method).
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6 |
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7 | // Copyright (C) 1991,2,3,4: R B Davies
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8 |
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9 | #define WANT_MATH
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10 |
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11 | #include "include.h"
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12 | #include "newmatap.h"
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13 | #include "newmatrm.h"
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14 | #include "precisio.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 | #ifdef DO_REPORT
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21 | #define REPORT { static ExeCounter ExeCount(__LINE__,17); ++ExeCount; }
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22 | #else
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23 | #define REPORT {}
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24 | #endif
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25 |
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26 |
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27 |
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28 | static void tred2(const SymmetricMatrix& A, DiagonalMatrix& D,
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29 | DiagonalMatrix& E, Matrix& Z)
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30 | {
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31 | Tracer et("Evalue(tred2)");
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32 | REPORT
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33 | Real tol =
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34 | FloatingPointPrecision::Minimum()/FloatingPointPrecision::Epsilon();
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35 | int n = A.Nrows(); Z.resize(n,n); Z.Inject(A);
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36 | D.resize(n); E.resize(n);
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37 | Real* z = Z.Store(); int i;
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38 |
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39 | for (i=n-1; i > 0; i--) // i=0 is excluded
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40 | {
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41 | Real f = Z.element(i,i-1); Real g = 0.0;
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42 | int k = i-1; Real* zik = z + i*n;
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43 | while (k--) g += square(*zik++);
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44 | Real h = g + square(f);
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45 | if (g <= tol) { REPORT E.element(i) = f; h = 0.0; }
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46 | else
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47 | {
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48 | REPORT
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49 | g = sign(-sqrt(h), f); E.element(i) = g; h -= f*g;
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50 | Z.element(i,i-1) = f-g; f = 0.0;
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51 | Real* zji = z + i; Real* zij = z + i*n; Real* ej = E.Store();
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52 | int j;
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53 | for (j=0; j<i; j++)
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54 | {
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55 | *zji = (*zij++)/h; g = 0.0;
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56 | Real* zjk = z + j*n; zik = z + i*n;
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57 | k = j; while (k--) g += *zjk++ * (*zik++);
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58 | k = i-j;
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59 | if (k) for(;;)
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60 | { g += *zjk * (*zik++); if (!(--k)) break; zjk += n; }
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61 | *ej++ = g/h; f += g * (*zji); zji += n;
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62 | }
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63 | Real hh = f / (h + h); zij = z + i*n; ej = E.Store();
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64 | for (j=0; j<i; j++)
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65 | {
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66 | f = *zij++; g = *ej - hh * f; *ej++ = g;
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67 | Real* zjk = z + j*n; Real* zik = z + i*n;
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68 | Real* ek = E.Store(); k = j+1;
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69 | while (k--) *zjk++ -= ( f*(*ek++) + g*(*zik++) );
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70 | }
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71 | }
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72 | D.element(i) = h;
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73 | }
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74 |
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75 | D.element(0) = 0.0; E.element(0) = 0.0;
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76 | for (i=0; i<n; i++)
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77 | {
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78 | if (D.element(i) != 0.0)
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79 | {
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80 | REPORT
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81 | for (int j=0; j<i; j++)
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82 | {
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83 | Real g = 0.0;
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84 | Real* zik = z + i*n; Real* zkj = z + j;
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85 | int k = i;
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86 | if (k) for (;;)
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87 | { g += *zik++ * (*zkj); if (!(--k)) break; zkj += n; }
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88 | Real* zki = z + i; zkj = z + j;
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89 | k = i;
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90 | if (k) for (;;)
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91 | { *zkj -= g * (*zki); if (!(--k)) break; zkj += n; zki += n; }
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92 | }
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93 | }
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94 | Real* zij = z + i*n; Real* zji = z + i;
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95 | int j = i;
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96 | if (j) for (;;)
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97 | { *zij++ = 0.0; *zji = 0.0; if (!(--j)) break; zji += n; }
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98 | D.element(i) = *zij; *zij = 1.0;
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99 | }
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100 | }
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101 |
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102 | static void tql2(DiagonalMatrix& D, DiagonalMatrix& E, Matrix& Z)
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103 | {
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104 | Tracer et("Evalue(tql2)");
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105 | REPORT
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106 | Real eps = FloatingPointPrecision::Epsilon();
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107 | int n = D.Nrows(); Real* z = Z.Store(); int l;
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108 | for (l=1; l<n; l++) E.element(l-1) = E.element(l);
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109 | Real b = 0.0; Real f = 0.0; E.element(n-1) = 0.0;
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110 | for (l=0; l<n; l++)
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111 | {
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112 | int i,j;
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113 | Real& dl = D.element(l); Real& el = E.element(l);
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114 | Real h = eps * ( fabs(dl) + fabs(el) );
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115 | if (b < h) { REPORT b = h; }
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116 | int m;
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117 | for (m=l; m<n; m++) if (fabs(E.element(m)) <= b) break;
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118 | bool test = false;
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119 | for (j=0; j<30; j++)
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120 | {
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121 | if (m==l) { REPORT test = true; break; }
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122 | Real& dl1 = D.element(l+1);
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123 | Real g = dl; Real p = (dl1-g) / (2.0*el); Real r = sqrt(p*p + 1.0);
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124 | dl = el / (p < 0.0 ? p-r : p+r); Real h = g - dl; f += h;
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125 | Real* dlx = &dl1; i = n-l-1; while (i--) *dlx++ -= h;
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126 |
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127 | p = D.element(m); Real c = 1.0; Real s = 0.0;
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128 | for (i=m-1; i>=l; i--)
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129 | {
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130 | Real ei = E.element(i); Real di = D.element(i);
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131 | Real& ei1 = E.element(i+1);
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132 | g = c * ei; h = c * p;
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133 | if ( fabs(p) >= fabs(ei))
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134 | {
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135 | REPORT
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136 | c = ei / p; r = sqrt(c*c + 1.0);
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137 | ei1 = s*p*r; s = c/r; c = 1.0/r;
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138 | }
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139 | else
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140 | {
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141 | REPORT
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142 | c = p / ei; r = sqrt(c*c + 1.0);
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143 | ei1 = s * ei * r; s = 1.0/r; c /= r;
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144 | }
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145 | p = c * di - s*g; D.element(i+1) = h + s * (c*g + s*di);
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146 |
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147 | Real* zki = z + i; Real* zki1 = zki + 1; int k = n;
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148 | if (k) for (;;)
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149 | {
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150 | REPORT
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151 | h = *zki1; *zki1 = s*(*zki) + c*h; *zki = c*(*zki) - s*h;
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152 | if (!(--k)) break;
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153 | zki += n; zki1 += n;
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154 | }
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155 | }
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156 | el = s*p; dl = c*p;
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157 | if (fabs(el) <= b) { REPORT; test = true; break; }
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158 | }
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159 | if (!test) Throw ( ConvergenceException(D) );
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160 | dl += f;
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161 | }
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162 | /*
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163 | for (int i=0; i<n; i++)
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164 | {
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165 | int k = i; Real p = D.element(i);
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166 | for (int j=i+1; j<n; j++)
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167 | { if (D.element(j) < p) { k = j; p = D.element(j); } }
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168 | if (k != i)
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169 | {
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170 | D.element(k) = D.element(i); D.element(i) = p; int j = n;
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171 | Real* zji = z + i; Real* zjk = z + k;
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172 | if (j) for(;;)
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173 | {
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174 | p = *zji; *zji = *zjk; *zjk = p;
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175 | if (!(--j)) break;
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176 | zji += n; zjk += n;
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177 | }
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178 | }
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179 | }
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180 | */
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181 | }
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182 |
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183 | static void tred3(const SymmetricMatrix& X, DiagonalMatrix& D,
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184 | DiagonalMatrix& E, SymmetricMatrix& A)
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185 | {
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186 | Tracer et("Evalue(tred3)");
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187 | REPORT
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188 | Real tol =
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189 | FloatingPointPrecision::Minimum()/FloatingPointPrecision::Epsilon();
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190 | int n = X.Nrows(); A = X; D.resize(n); E.resize(n);
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191 | Real* ei = E.Store() + n;
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192 | for (int i = n-1; i >= 0; i--)
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193 | {
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194 | Real h = 0.0; Real f = - FloatingPointPrecision::Maximum();
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195 | Real* d = D.Store(); Real* a = A.Store() + (i*(i+1))/2; int k = i;
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196 | while (k--) { f = *a++; *d++ = f; h += square(f); }
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197 | if (h <= tol) { REPORT *(--ei) = 0.0; h = 0.0; }
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198 | else
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199 | {
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200 | REPORT
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201 | Real g = sign(-sqrt(h), f); *(--ei) = g; h -= f*g;
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202 | f -= g; *(d-1) = f; *(a-1) = f; f = 0.0;
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203 | Real* dj = D.Store(); Real* ej = E.Store(); int j;
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204 | for (j = 0; j < i; j++)
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205 | {
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206 | Real* dk = D.Store(); Real* ak = A.Store()+(j*(j+1))/2;
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207 | Real g = 0.0; k = j;
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208 | while (k--) g += *ak++ * *dk++;
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209 | k = i-j; int l = j;
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210 | if (k) for (;;) { g += *ak * *dk++; if (!(--k)) break; ak += ++l; }
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211 | g /= h; *ej++ = g; f += g * *dj++;
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212 | }
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213 | Real hh = f / (2 * h); Real* ak = A.Store();
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214 | dj = D.Store(); ej = E.Store();
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215 | for (j = 0; j < i; j++)
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216 | {
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217 | f = *dj++; g = *ej - hh * f; *ej++ = g;
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218 | Real* dk = D.Store(); Real* ek = E.Store(); k = j+1;
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219 | while (k--) { *ak++ -= (f * *ek++ + g * *dk++); }
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220 | }
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221 | }
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222 | *d = *a; *a = h;
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223 | }
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224 | }
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225 |
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226 | static void tql1(DiagonalMatrix& D, DiagonalMatrix& E)
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227 | {
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228 | Tracer et("Evalue(tql1)");
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229 | REPORT
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230 | Real eps = FloatingPointPrecision::Epsilon();
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231 | int n = D.Nrows(); int l;
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232 | for (l=1; l<n; l++) E.element(l-1) = E.element(l);
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233 | Real b = 0.0; Real f = 0.0; E.element(n-1) = 0.0;
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234 | for (l=0; l<n; l++)
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235 | {
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236 | int i,j;
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237 | Real& dl = D.element(l); Real& el = E.element(l);
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238 | Real h = eps * ( fabs(dl) + fabs(el) );
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239 | if (b < h) b = h;
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240 | int m;
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241 | for (m=l; m<n; m++) if (fabs(E.element(m)) <= b) break;
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242 | bool test = false;
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243 | for (j=0; j<30; j++)
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244 | {
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245 | if (m==l) { REPORT test = true; break; }
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246 | Real& dl1 = D.element(l+1);
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247 | Real g = dl; Real p = (dl1-g) / (2.0*el); Real r = sqrt(p*p + 1.0);
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248 | dl = el / (p < 0.0 ? p-r : p+r); Real h = g - dl; f += h;
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249 | Real* dlx = &dl1; i = n-l-1; while (i--) *dlx++ -= h;
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250 |
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251 | p = D.element(m); Real c = 1.0; Real s = 0.0;
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252 | for (i=m-1; i>=l; i--)
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253 | {
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254 | Real ei = E.element(i); Real di = D.element(i);
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255 | Real& ei1 = E.element(i+1);
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256 | g = c * ei; h = c * p;
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257 | if ( fabs(p) >= fabs(ei))
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258 | {
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259 | REPORT
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260 | c = ei / p; r = sqrt(c*c + 1.0);
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261 | ei1 = s*p*r; s = c/r; c = 1.0/r;
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262 | }
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263 | else
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264 | {
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265 | REPORT
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266 | c = p / ei; r = sqrt(c*c + 1.0);
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267 | ei1 = s * ei * r; s = 1.0/r; c /= r;
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268 | }
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269 | p = c * di - s*g; D.element(i+1) = h + s * (c*g + s*di);
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270 | }
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271 | el = s*p; dl = c*p;
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272 | if (fabs(el) <= b) { REPORT test = true; break; }
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273 | }
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274 | if (!test) Throw ( ConvergenceException(D) );
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275 | Real p = dl + f;
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276 | test = false;
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277 | for (i=l; i>0; i--)
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278 | {
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279 | if (p < D.element(i-1)) { REPORT D.element(i) = D.element(i-1); }
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280 | else { REPORT test = true; break; }
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281 | }
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282 | if (!test) i=0;
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283 | D.element(i) = p;
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284 | }
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285 | }
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286 |
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287 | void eigenvalues(const SymmetricMatrix& A, DiagonalMatrix& D, Matrix& Z)
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288 | { REPORT DiagonalMatrix E; tred2(A, D, E, Z); tql2(D, E, Z); SortSV(D,Z,true); }
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289 |
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290 | void eigenvalues(const SymmetricMatrix& X, DiagonalMatrix& D)
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291 | { REPORT DiagonalMatrix E; SymmetricMatrix A; tred3(X,D,E,A); tql1(D,E); }
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292 |
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293 | void eigenvalues(const SymmetricMatrix& X, DiagonalMatrix& D,
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294 | SymmetricMatrix& A)
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295 | { REPORT DiagonalMatrix E; tred3(X,D,E,A); tql1(D,E); }
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296 |
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297 |
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298 | #ifdef use_namespace
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299 | }
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300 | #endif
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301 |
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302 | ///@}
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303 |
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