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1 // f-qzval.cc -*- C++ -*- |
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2 /* |
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3 |
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4 Copyright (C) 1993, 1994 John W. Eaton |
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5 |
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6 This file is part of Octave. |
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7 |
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8 Octave is free software; you can redistribute it and/or modify it |
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9 under the terms of the GNU General Public License as published by the |
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10 Free Software Foundation; either version 2, or (at your option) any |
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11 later version. |
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12 |
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13 Octave is distributed in the hope that it will be useful, but WITHOUT |
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14 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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16 for more details. |
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17 |
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18 You should have received a copy of the GNU General Public License |
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19 along with Octave; see the file COPYING. If not, write to the Free |
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20 Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. |
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21 |
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22 */ |
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23 |
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24 // Written by A. S. Hodel <scotte@eng.auburn.edu> |
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25 |
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26 #ifdef HAVE_CONFIG_H |
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27 #include "config.h" |
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28 #endif |
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29 |
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30 #include <float.h> |
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31 |
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32 #include "dMatrix.h" |
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33 #include "dColVector.h" |
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34 #include "CColVector.h" |
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35 #include "f77-uscore.h" |
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36 |
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37 #include "tree-const.h" |
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38 #include "user-prefs.h" |
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39 #include "gripes.h" |
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40 #include "error.h" |
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41 #include "help.h" |
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42 #include "defun-dld.h" |
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43 |
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44 extern "C" |
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45 { |
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46 int F77_FCN (qzhes) (const int*, const int*, double*, double*, const |
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47 long*, double*); |
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48 |
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49 int F77_FCN (qzit) (const int*, const int*, double*, double*, const |
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50 double*, const long*, double*, int*); |
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51 |
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52 int F77_FCN (qzval) (const int*, const int*, double*, double*, |
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53 double*, double*, double*, const long*, double*); |
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54 } |
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55 |
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56 DEFUN_DLD ("qzvalue", Fqzvalue, Sqzvalue, 3, 1, |
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57 "X = qzval (A, B)\n\ |
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58 \n\ |
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59 compute generalized eigenvalues of the matrix pencil (A - lambda B).\n\ |
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60 A and B must be real matrices.") |
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61 { |
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62 Octave_object retval; |
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63 |
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64 int nargin = args.length (); |
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65 |
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66 if (nargin != 3 || nargout > 1) |
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67 { |
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68 print_usage ("qzvalue"); |
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69 return retval; |
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70 } |
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71 |
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72 tree_constant arga = args(1).make_numeric (); |
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73 tree_constant argb = args(2).make_numeric(); |
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74 |
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75 if (arga.is_empty () || argb.is_empty ()) |
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76 retval = vector_of_empties (nargout, "qzvalue"); |
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77 else |
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78 { |
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79 |
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80 // Arguments are not empty, so check for correct dimensions. |
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81 |
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82 int a_rows = arga.rows(); |
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83 int a_cols = arga.columns(); |
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84 int b_rows = argb.rows(); |
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85 int b_cols = argb.columns(); |
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86 |
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87 if ((a_rows != a_cols) || (b_rows != b_cols)) |
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88 { |
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89 gripe_square_matrix_required ("qzvalue: first two parameters:"); |
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90 return retval; |
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91 } |
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92 else if (a_rows != b_rows) |
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93 { |
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94 gripe_nonconformant (); |
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95 return retval; |
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96 } |
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97 |
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98 // Dimensions look o.k., let's solve the problem. |
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99 |
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100 retval.resize (nargout ? nargout : 1); |
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101 |
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102 if (arga.is_complex_type () || argb.is_complex_type ()) |
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103 error ("qzvalue: cannot yet do complex matrix arguments\n"); |
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104 else |
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105 { |
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106 |
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107 // Do everything in real arithmetic. |
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108 |
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109 Matrix jnk (a_rows, a_rows, 0.0); |
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110 |
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111 ColumnVector alfr (a_rows); |
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112 ColumnVector alfi (a_rows); |
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113 ColumnVector beta (a_rows); |
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114 |
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115 long matz = 0; |
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116 int info; |
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117 |
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118 // XXX FIXME ??? XXX |
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119 double eps = DBL_EPSILON; |
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120 |
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121 Matrix ca = arga.matrix_value (); |
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122 Matrix cb = argb.matrix_value (); |
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123 |
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124 // Use EISPACK qz functions. |
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125 |
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126 F77_FCN (qzhes) (&a_rows, &a_rows, ca.fortran_vec (), |
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127 cb.fortran_vec (), &matz, jnk.fortran_vec ()); |
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128 |
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129 F77_FCN (qzit) (&a_rows, &a_rows, ca.fortran_vec (), |
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130 cb.fortran_vec (), &eps, &matz, |
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131 jnk.fortran_vec (), &info); |
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132 |
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133 if (info) |
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134 error ("qzvalue: trouble in qzit, info = %d", info); |
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135 |
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136 F77_FCN (qzval) (&a_rows, &a_rows, ca.fortran_vec (), |
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137 cb.fortran_vec (), alfr.fortran_vec (), |
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138 alfi.fortran_vec (), beta.fortran_vec (), |
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139 &matz, jnk.fortran_vec ()); |
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140 |
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141 // Count and extract finite generalized eigenvalues. |
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142 |
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143 int i, cnt; |
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144 Complex Im (0, 1); |
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145 for (i = 0, cnt = 0; i < a_rows; i++) |
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146 if (beta (i) != 0) |
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147 cnt++; |
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148 |
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149 ComplexColumnVector cx (cnt, 0.0); |
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150 |
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151 for (i = 0; i < a_rows; i++) |
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152 { |
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153 if (beta (i) != 0) |
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154 { |
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155 |
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156 // Finite generalized eigenvalue. |
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157 |
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158 cnt--; |
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159 cx (cnt) = (alfr (i) + Im * alfi (i)) / beta (i); |
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160 } |
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161 } |
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162 retval(0) = cx; |
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163 } |
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164 } |
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165 return retval; |
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166 } |
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167 |
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168 /* |
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169 ;;; Local Variables: *** |
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170 ;;; mode: C++ *** |
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171 ;;; page-delimiter: "^/\\*" *** |
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172 ;;; End: *** |
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173 */ |
