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1 /* |
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2 |
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3 Copyright (C) 1996, 1997 John W. Eaton |
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4 |
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5 This file is part of Octave. |
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6 |
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7 Octave is free software; you can redistribute it and/or modify it |
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8 under the terms of the GNU General Public License as published by the |
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9 Free Software Foundation; either version 2, or (at your option) any |
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10 later version. |
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11 |
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12 Octave is distributed in the hope that it will be useful, but WITHOUT |
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13 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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15 for more details. |
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16 |
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17 You should have received a copy of the GNU General Public License |
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18 along with Octave; see the file COPYING. If not, write to the Free |
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19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
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20 |
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21 */ |
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22 |
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23 #ifdef HAVE_CONFIG_H |
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24 #include <config.h> |
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25 #endif |
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26 |
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27 #include "defun-dld.h" |
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28 #include "error.h" |
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29 #include "gripes.h" |
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30 #include "oct-obj.h" |
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31 #include "utils.h" |
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32 |
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33 DEFUN_DLD (inv, args, nargout, |
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34 "-*- texinfo -*-\n\ |
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35 @deftypefn {Loadable Function} {[@var{x}, @var{rcond}] = } inv (@var{a})\n\ |
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36 @deftypefnx {Loadable Function} {[@var{x}, @var{rcond}] = } inverse (@var{a})\n\ |
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37 Compute the inverse of the square matrix @var{a}. Return an estimate\n\ |
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38 of the reciprocal condition number if requested, otherwise warn of an\n\ |
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39 ill-conditioned matrix if the reciprocal condition number is small.\n\ |
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40 @end deftypefn") |
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41 { |
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42 octave_value_list retval; |
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43 |
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44 int nargin = args.length (); |
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45 |
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46 if (nargin != 1) |
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47 { |
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48 print_usage ("inv"); |
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49 return retval; |
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50 } |
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51 |
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52 octave_value arg = args(0); |
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53 |
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54 int nr = arg.rows (); |
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55 int nc = arg.columns (); |
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56 |
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57 int arg_is_empty = empty_arg ("inverse", nr, nc); |
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58 |
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59 if (arg_is_empty < 0) |
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60 return retval; |
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61 else if (arg_is_empty > 0) |
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62 return octave_value (Matrix ()); |
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63 |
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64 if (nr != nc) |
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65 { |
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66 gripe_square_matrix_required ("inverse"); |
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67 return retval; |
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68 } |
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69 |
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70 if (arg.is_real_type ()) |
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71 { |
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72 Matrix m = arg.matrix_value (); |
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73 |
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74 if (! error_state) |
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75 { |
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76 int info; |
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77 double rcond = 0.0; |
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78 |
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79 Matrix result = m.inverse (info, rcond, 1); |
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80 |
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81 if (nargout > 1) |
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82 retval(1) = rcond; |
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83 |
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84 retval(0) = result; |
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85 |
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86 volatile double xrcond = rcond; |
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87 xrcond += 1.0; |
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88 if (nargout < 2 && (info == -1 || xrcond == 1.0)) |
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89 warning ("inverse: matrix singular to machine precision,\ |
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90 rcond = %g", rcond); |
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91 } |
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92 } |
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93 else if (arg.is_complex_type ()) |
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94 { |
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95 ComplexMatrix m = arg.complex_matrix_value (); |
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96 |
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97 if (! error_state) |
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98 { |
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99 int info; |
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100 double rcond = 0.0; |
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101 |
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102 ComplexMatrix result = m.inverse (info, rcond, 1); |
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103 |
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104 if (nargout > 1) |
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105 retval(1) = rcond; |
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106 |
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107 retval(0) = result; |
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108 |
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109 volatile double xrcond = rcond; |
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110 xrcond += 1.0; |
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111 if (nargout < 2 && (info == -1 || xrcond == 1.0)) |
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112 warning ("inverse: matrix singular to machine precision,\ |
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113 rcond = %g", rcond); |
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114 } |
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115 } |
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116 else |
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117 { |
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118 gripe_wrong_type_arg ("inv", arg); |
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119 } |
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120 |
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121 return retval; |
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122 } |
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123 |
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124 // XXX FIXME XXX -- this should really be done with an alias, but |
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125 // alias_builtin() won't do the right thing if we are actually using |
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126 // dynamic linking. |
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127 |
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128 DEFUN_DLD (inverse, args, nargout, |
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129 "-*- texinfo -*-\n\ |
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130 @deftypefn {Loadable Function} {} inverse (@var{a})\n\ |
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131 See inv.\n\ |
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132 @end deftypefn") |
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133 { |
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134 return Finv (args, nargout); |
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135 } |
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136 |
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137 /* |
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138 ;;; Local Variables: *** |
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139 ;;; mode: C++ *** |
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140 ;;; End: *** |
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141 */ |
