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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 // Originally written by A. S. Hodel <scotte@eng.auburn.edu> |
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24 |
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25 #ifdef HAVE_CONFIG_H |
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26 #include <config.h> |
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27 #endif |
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28 |
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29 #include "defun-dld.h" |
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30 #include "error.h" |
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31 #include "help.h" |
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32 #include "oct-obj.h" |
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33 |
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34 DEFUN_DLD (givens, args, nargout, |
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35 "G = givens (X, Y)\n\ |
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36 \n\ |
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37 compute orthogonal matrix G = [c s; -conj (s) c]\n\ |
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38 such that G [x; y] = [*; 0] (x, y scalars)\n\ |
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39 \n\ |
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40 [c, s] = givens (x, y) returns the (c, s) values themselves.") |
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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 != 2 || nargout > 2) |
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47 { |
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48 print_usage ("givens"); |
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49 return retval; |
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50 } |
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51 else |
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52 { |
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53 if (args(0).is_complex_type () || args(1).is_complex_type ()) |
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54 { |
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55 Complex cx = args(0).complex_value (); |
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56 Complex cy = args(1).complex_value (); |
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57 |
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58 if (! error_state) |
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59 { |
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60 ComplexMatrix result = Givens (cx, cy); |
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61 |
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62 if (! error_state) |
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63 { |
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64 switch (nargout) |
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65 { |
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66 case 0: |
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67 case 1: |
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68 retval(0) = result; |
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69 break; |
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70 |
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71 case 2: |
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72 retval(1) = result (0, 1); |
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73 retval(0) = result (0, 0); |
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74 break; |
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75 |
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76 default: |
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77 error ("givens: invalid number of output arguments"); |
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78 break; |
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79 } |
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80 } |
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81 } |
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82 } |
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83 else |
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84 { |
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85 double x = args(0).double_value (); |
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86 double y = args(1).double_value (); |
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87 |
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88 if (! error_state) |
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89 { |
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90 Matrix result = Givens (x, y); |
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91 |
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92 if (! error_state) |
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93 { |
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94 switch (nargout) |
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95 { |
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96 case 0: |
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97 case 1: |
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98 retval(0) = result; |
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99 break; |
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100 |
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101 case 2: |
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102 retval(1) = result (0, 1); |
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103 retval(0) = result (0, 0); |
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104 break; |
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105 |
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106 default: |
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107 error ("givens: invalid number of output arguments"); |
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108 break; |
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109 } |
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110 } |
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111 } |
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112 } |
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113 } |
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114 |
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115 return retval; |
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116 } |
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117 |
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118 /* |
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119 ;;; Local Variables: *** |
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120 ;;; mode: C++ *** |
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121 ;;; End: *** |
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122 */ |
