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1 // f-qr.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 "dbleQR.h" |
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29 #include "CmplxQR.h" |
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30 |
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31 #include "dbleQRP.h" |
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32 #include "CmplxQRP.h" |
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33 |
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34 #include "tree-const.h" |
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35 #include "user-prefs.h" |
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36 #include "gripes.h" |
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37 #include "help.h" |
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38 #include "defun-dld.h" |
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39 |
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40 DEFUN_DLD ("qr", Fqr, Sqr, 2, 2, |
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41 "[Q, R] = qr (X): form Q unitary and R upper triangular such\n\ |
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42 that Q * R = X\n\ |
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43 \n\ |
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44 [Q, R] = qr (X, 0): form the economy decomposition such that if X is\n\ |
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45 if X is m by n then only the first n columns of Q\n\ |
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46 are computed.\n\ |
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47 \n\ |
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48 [Q, R, P] = qr (X): form QRP factorization of X where\n\ |
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49 P is a permutation matrix such that\n\ |
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50 A * P = Q * R\n\ |
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51 \n\ |
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52 [Q, R, P] = qr (X, 0): form the economy decomposition with \n\ |
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53 permutation vector P such that Q * R = X (:, P)\n\ |
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54 \n\ |
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55 qr (X) alone returns the output of the LAPACK routine dgeqrf, such\n\ |
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56 that R = triu (qr (X))") |
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57 { |
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58 Octave_object retval; |
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59 |
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60 int nargin = args.length (); |
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61 |
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62 if (nargin != 2 && nargin != 3 || nargout > 3) |
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63 { |
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64 print_usage ("qr"); |
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65 return retval; |
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66 } |
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67 |
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68 tree_constant tmp = args(1).make_numeric (); |
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69 |
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70 if (tmp.rows () == 0 || tmp.columns () == 0) |
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71 { |
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72 int flag = user_pref.propagate_empty_matrices; |
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73 if (flag != 0) |
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74 { |
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75 if (flag < 0) |
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76 gripe_empty_arg ("qr", 0); |
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77 Matrix m; |
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78 retval(2) = m; |
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79 retval(1) = m; |
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80 retval(0) = m; |
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81 } |
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82 else |
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83 gripe_empty_arg ("qr", 1); |
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84 |
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85 return retval; |
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86 } |
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87 |
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88 QR::type type = nargout == 1 ? QR::raw |
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89 : (nargin == 3 ? QR::economy : QR::std); |
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90 |
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91 switch (tmp.const_type ()) |
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92 { |
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93 case tree_constant_rep::matrix_constant: |
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94 { |
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95 Matrix m = tmp.matrix_value (); |
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96 if (nargout < 3) |
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97 { |
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98 QR fact (m, type); |
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99 retval(1) = fact.R (); |
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100 retval(0) = fact.Q (); |
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101 } |
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102 else |
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103 { |
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104 QRP fact (m, type); |
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105 retval(2) = fact.P (); |
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106 retval(1) = fact.R (); |
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107 retval(0) = fact.Q (); |
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108 } |
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109 } |
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110 break; |
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111 case tree_constant_rep::complex_matrix_constant: |
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112 { |
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113 ComplexMatrix m = tmp.complex_matrix_value (); |
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114 if (nargout < 3) |
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115 { |
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116 ComplexQR fact (m, type); |
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117 retval(1) = fact.R (); |
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118 retval(0) = fact.Q (); |
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119 } |
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120 else |
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121 { |
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122 ComplexQRP fact (m, type); |
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123 retval(2) = fact.P (); |
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124 retval(1) = fact.R (); |
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125 retval(0) = fact.Q (); |
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126 } |
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127 } |
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128 break; |
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129 case tree_constant_rep::scalar_constant: |
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130 { |
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131 double d = tmp.double_value (); |
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132 if (nargout == 1) |
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133 retval(0) = d; |
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134 else |
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135 { |
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136 retval(2) = 1.0; |
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137 retval(1) = d; |
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138 retval(0) = 1.0; |
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139 } |
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140 } |
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141 break; |
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142 case tree_constant_rep::complex_scalar_constant: |
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143 { |
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144 Complex c = tmp.complex_value (); |
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145 if (nargout == 1) |
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146 retval(0) = c; |
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147 else |
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148 { |
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149 retval(2) = 1.0; |
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150 retval(1) = c; |
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151 retval(0) = 1.0; |
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152 } |
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153 } |
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154 break; |
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155 default: |
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156 break; |
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157 } |
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158 return retval; |
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159 } |
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160 |
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161 /* |
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162 ;;; Local Variables: *** |
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163 ;;; mode: C++ *** |
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164 ;;; page-delimiter: "^/\\*" *** |
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165 ;;; End: *** |
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166 */ |
