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1 // f-svd.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 "dbleSVD.h" |
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29 #include "CmplxSVD.h" |
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30 |
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31 #include "tree-const.h" |
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32 #include "user-prefs.h" |
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33 #include "gripes.h" |
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34 #include "error.h" |
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35 #include "defun-dld.h" |
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36 |
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37 DEFUN_DLD ("svd", Fsvd, Ssvd, 2, 3, |
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38 "S = svd (X) or [U, S, V] = svd (X [, 0])\n\ |
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39 \n\ |
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40 Compute the singular value decomposition of X. Given a second input\n\ |
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41 argument, an `economy' sized factorization is computed that omits\n\ |
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42 unnecessary rows and columns of U and V") |
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43 { |
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44 Octave_object retval; |
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45 |
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46 int nargin = args.length (); |
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47 |
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48 if (nargin < 2 || nargin > 3 || nargout == 2 || nargout > 3) |
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49 { |
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50 print_usage ("svd"); |
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51 return retval; |
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52 } |
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53 |
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54 tree_constant arg = args(1).make_numeric (); |
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55 |
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56 if (arg.rows () == 0 || arg.columns () == 0) |
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57 { |
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58 int flag = user_pref.propagate_empty_matrices; |
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59 if (flag != 0) |
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60 { |
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61 if (flag < 0) |
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62 gripe_empty_arg ("svd", 0); |
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63 |
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64 Matrix m; |
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65 retval.resize (3); |
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66 retval(0) = m; |
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67 retval(1) = m; |
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68 retval(2) = m; |
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69 } |
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70 else |
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71 gripe_empty_arg ("svd", 1); |
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72 |
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73 return retval; |
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74 } |
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75 |
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76 Matrix tmp; |
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77 ComplexMatrix ctmp; |
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78 switch (arg.const_type ()) |
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79 { |
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80 case tree_constant_rep::scalar_constant: |
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81 tmp.resize (1, 1); |
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82 tmp.elem (0, 0) = arg.double_value (); |
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83 break; |
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84 case tree_constant_rep::matrix_constant: |
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85 tmp = arg.matrix_value (); |
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86 break; |
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87 case tree_constant_rep::complex_scalar_constant: |
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88 ctmp.resize (1, 1); |
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89 ctmp.elem (0, 0) = arg.complex_value (); |
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90 break; |
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91 case tree_constant_rep::complex_matrix_constant: |
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92 ctmp = arg.complex_matrix_value (); |
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93 break; |
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94 default: |
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95 panic_impossible (); |
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96 break; |
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97 } |
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98 |
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99 SVD::type type = (nargin == 3) ? SVD::economy : SVD::std; |
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100 |
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101 switch (arg.const_type ()) |
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102 { |
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103 case tree_constant_rep::scalar_constant: |
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104 case tree_constant_rep::matrix_constant: |
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105 { |
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106 SVD result (tmp, type); |
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107 |
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108 DiagMatrix sigma = result.singular_values (); |
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109 |
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110 if (nargout == 0 || nargout == 1) |
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111 { |
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112 retval.resize (1); |
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113 retval(0) = tree_constant (sigma.diag (), 1); |
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114 } |
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115 else |
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116 { |
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117 retval.resize (3); |
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118 retval(0) = result.left_singular_matrix (); |
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119 retval(1) = sigma; |
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120 retval(2) = result.right_singular_matrix (); |
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121 } |
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122 } |
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123 break; |
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124 case tree_constant_rep::complex_scalar_constant: |
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125 case tree_constant_rep::complex_matrix_constant: |
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126 { |
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127 ComplexSVD result (ctmp, type); |
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128 |
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129 DiagMatrix sigma = result.singular_values (); |
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130 |
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131 if (nargout == 0 || nargout == 1) |
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132 { |
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133 retval.resize (1); |
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134 retval(0) = tree_constant (sigma.diag (), 1); |
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135 } |
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136 else |
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137 { |
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138 retval.resize (3); |
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139 retval(0) = result.left_singular_matrix (); |
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140 retval(1) = sigma; |
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141 retval(2) = result.right_singular_matrix (); |
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142 } |
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143 } |
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144 break; |
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145 default: |
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146 panic_impossible (); |
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147 break; |
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148 } |
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149 |
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150 return retval; |
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151 } |
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152 |
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153 /* |
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154 ;;; Local Variables: *** |
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155 ;;; mode: C++ *** |
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156 ;;; page-delimiter: "^/\\*" *** |
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157 ;;; End: *** |
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158 */ |
