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1 // tc-givens.cc -*- C++ -*- |
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2 /* |
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3 |
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4 Copyright (C) 1993 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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24 // Written by A. S. Hodel <scotte@eng.auburn.edu> |
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25 |
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26 #ifdef __GNUG__ |
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27 #pragma implementation |
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28 #endif |
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29 |
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30 #include "Matrix.h" |
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31 |
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32 #include "tree-const.h" |
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33 #include "user-prefs.h" |
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34 #include "error.h" |
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35 #include "gripes.h" |
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36 |
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47
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37 extern "C" |
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38 { |
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39 int F77_FCN (dlartg) (const double*, const double*, double*, double*, |
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40 double*); |
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33
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41 |
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47
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42 int F77_FCN (zlartg) (const Complex*, const Complex*, double*, |
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43 Complex*, Complex*); |
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44 } |
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33
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45 |
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46 // These aren't used? |
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47 #if 0 |
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48 int F77_FCN (dorgqr) (const int*, const int*, const int*, double*, |
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49 const int*, double*, double*, const int*, int*); |
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50 |
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51 int F77_FCN (zunghr) (const int*, const int*, const int*, Complex*, |
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52 const int*, Complex*, Complex*, const int*, |
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53 int*, long, long); |
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54 #endif |
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55 |
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56 #ifdef WITH_DLD |
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57 tree_constant * |
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58 builtin_givens_2 (tree_constant *args, int nargin, int nargout) |
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59 { |
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60 return givens (args, nargin, nargout); |
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61 } |
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62 #endif |
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63 |
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64 tree_constant * |
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65 givens (tree_constant *args, int nargin, int nargout) |
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66 { |
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67 |
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68 tree_constant *retval = NULL_TREE_CONST; |
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69 |
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70 tree_constant arga = args[1].make_numeric (); |
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71 tree_constant argb = args[2].make_numeric (); |
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72 |
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73 if (! arga.is_scalar_type () && argb.is_scalar_type ()) |
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74 { |
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75 error("givens: requires two scalar arguments"); |
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76 } |
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77 else |
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78 { |
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79 |
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80 retval = new tree_constant [nargout+1]; |
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81 |
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82 Complex cx, cy; |
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83 double x, y; |
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84 |
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85 if (arga.is_complex_type ()) |
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86 cx = arga.complex_value (); |
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87 else |
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88 { |
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89 x = arga.double_value (); |
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90 cx = x; // copy to complex just in case |
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91 } |
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92 |
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93 if (argb.is_complex_type ()) |
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94 cy = argb.complex_value (); |
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95 else |
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96 { |
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97 y = argb.double_value (); |
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98 cy = y; // copy to complex just in case |
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99 } |
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100 |
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101 // Now compute the rotation. |
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102 |
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103 double cc; |
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104 if (arga.is_complex_type () || argb.is_complex_type ()) |
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105 { |
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106 Complex cs, temp_r; |
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107 |
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108 F77_FCN (zlartg) (&cx, &cy, &cc, &cs, &temp_r); |
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109 |
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110 switch (nargout) |
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111 { |
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112 case 1: // output a matrix |
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113 { |
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114 ComplexMatrix g (2, 2); |
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115 g.elem (0, 0) = cc; |
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116 g.elem (1, 1) = cc; |
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117 g.elem (0, 1) = cs; |
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118 g.elem (1, 0) = -conj (cs); |
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119 |
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120 retval[0] = tree_constant (g); |
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121 } |
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122 break; |
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123 |
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124 case 2: // output scalar values |
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125 retval[0] = tree_constant(cc); |
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126 retval[1] = tree_constant(cs); |
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127 break; |
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128 |
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129 default: |
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130 error ("givens: illegal number of output arguments"); |
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131 break; |
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132 } |
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133 } |
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134 else |
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135 { |
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136 double s, temp_r; |
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137 |
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138 F77_FCN (dlartg) (&x, &y, &cc, &s, &temp_r); |
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139 |
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140 switch (nargout) |
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141 { |
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142 case 1: // output a matrix |
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143 { |
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144 Matrix g (2, 2); |
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145 g.elem (0, 0) = cc; |
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146 g.elem (1, 1) = cc; |
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147 g.elem (0, 1) = s; |
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148 g.elem (1, 0) = -s; |
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149 |
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150 retval[0] = tree_constant (g); |
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151 } |
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152 break; |
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153 |
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154 case 2: // output scalar values |
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155 retval[0] = tree_constant (cc); |
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156 retval[1] = tree_constant (s); |
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157 break; |
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158 |
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159 default: |
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160 error ("givens: illegal number of output arguments"); |
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161 break; |
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162 } |
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163 } |
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164 } |
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165 |
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166 return retval; |
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167 } |
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168 |
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169 /* |
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170 ;;; Local Variables: *** |
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171 ;;; mode: C++ *** |
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172 ;;; page-delimiter: "^/\\*" *** |
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173 ;;; End: *** |
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174 */ |
