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1 // f-eig.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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240
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24 #ifdef HAVE_CONFIG_H |
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25 #include "config.h" |
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26 #endif |
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27 |
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28 #include "EIG.h" |
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29 |
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30 #include "tree-const.h" |
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31 #include "user-prefs.h" |
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32 #include "gripes.h" |
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33 #include "error.h" |
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34 #include "defun-dld.h" |
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35 |
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36 DEFUN_DLD ("eig", Feig, Seig, 2, 1, |
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37 "eig (X) or [V, D] = eig (X): compute eigenvalues and eigenvectors of X") |
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38 { |
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39 Octave_object retval; |
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40 |
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41 int nargin = args.length (); |
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42 |
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43 if (nargin != 2 || nargout > 2) |
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44 { |
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45 print_usage ("eig"); |
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46 return retval; |
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47 } |
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48 |
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49 tree_constant arg = args(1).make_numeric (); |
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50 |
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51 int a_nr = arg.rows (); |
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52 int a_nc = arg.columns (); |
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53 |
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54 if (a_nr == 0 || a_nc == 0) |
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55 { |
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56 int flag = user_pref.propagate_empty_matrices; |
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57 if (flag != 0) |
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58 { |
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59 if (flag < 0) |
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60 gripe_empty_arg ("eig", 0); |
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61 Matrix m; |
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62 retval.resize (2); |
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63 retval(0) = m; |
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64 retval(1) = m; |
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65 } |
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66 else |
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67 gripe_empty_arg ("eig", 1); |
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68 |
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69 return retval; |
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70 } |
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71 |
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72 if (a_nr != a_nc) |
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73 { |
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74 gripe_square_matrix_required ("eig"); |
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75 return retval; |
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76 } |
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77 |
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78 Matrix tmp; |
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79 ComplexMatrix ctmp; |
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80 EIG result; |
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81 switch (arg.const_type ()) |
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82 { |
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83 case tree_constant_rep::scalar_constant: |
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84 tmp.resize (1, 1); |
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85 tmp.elem (0, 0) = arg.double_value (); |
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86 result = EIG (tmp); |
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87 break; |
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88 case tree_constant_rep::matrix_constant: |
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89 tmp = arg.matrix_value (); |
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90 result = EIG (tmp); |
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91 break; |
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92 case tree_constant_rep::complex_scalar_constant: |
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93 ctmp.resize (1, 1); |
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94 ctmp.elem (0, 0) = arg.complex_value (); |
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95 result = EIG (ctmp); |
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96 break; |
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97 case tree_constant_rep::complex_matrix_constant: |
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98 ctmp = arg.complex_matrix_value (); |
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99 result = EIG (ctmp); |
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100 break; |
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101 default: |
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102 panic_impossible (); |
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103 break; |
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104 } |
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105 |
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106 if (nargout == 0 || nargout == 1) |
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107 { |
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108 retval.resize (1); |
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109 retval(0) = result.eigenvalues (), 1; |
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110 } |
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111 else |
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112 { |
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113 // Blame it on Matlab. |
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114 |
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115 ComplexDiagMatrix d (result.eigenvalues ()); |
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116 |
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117 retval.resize (2); |
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118 retval(0) = result.eigenvectors (); |
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119 retval(1) = d; |
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120 } |
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121 |
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122 return retval; |
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123 } |
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124 |
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125 /* |
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126 ;;; Local Variables: *** |
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127 ;;; mode: C++ *** |
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128 ;;; page-delimiter: "^/\\*" *** |
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129 ;;; End: *** |
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130 */ |
