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1 // tc-syl.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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234
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31 #include "f77-uscore.h" |
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32 |
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33 #include "tree-const.h" |
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34 #include "user-prefs.h" |
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35 #include "gripes.h" |
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36 #include "error.h" |
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49
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37 #include "f-syl.h" |
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37
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38 |
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47
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39 extern "C" |
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40 { |
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41 int F77_FCN (dtrsyl) (const char*, const char*, const int*, |
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42 const int*, const int*, const double*, |
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43 const int*, const double*, const int*, |
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44 const double*, const int*, double*, int*, |
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45 long, long); |
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46 |
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47
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47 int F77_FCN (ztrsyl) (const char*, const char*, const int*, |
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48 const int*, const int*, const Complex*, |
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49 const int*, const Complex*, const int*, |
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50 const Complex*, const int*, double*, int*, |
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51 long, long); |
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52 } |
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53 |
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54 #ifdef WITH_DLD |
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55 tree_constant * |
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162
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56 builtin_syl_2 (const tree_constant *args, int nargin, int nargout) |
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57 { |
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58 return syl (args, nargin, nargout); |
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59 } |
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60 #endif |
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61 |
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62 tree_constant * |
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63 syl (const tree_constant *args, int nargin, int nargout) |
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64 { |
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65 tree_constant *retval = NULL_TREE_CONST; |
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66 |
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67 tree_constant arga = args[1].make_numeric (); |
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68 tree_constant argb = args[2].make_numeric (); |
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69 tree_constant argc = args[3].make_numeric (); |
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70 |
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92
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71 if (arga.is_empty () || argb.is_empty () || argc.is_empty ()) |
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72 retval = vector_of_empties (nargout, "syl"); |
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73 else |
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74 { |
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75 |
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76 // Arguments are not empty, so check for correct dimensions. |
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77 |
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78 int a_rows = arga.rows (); |
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79 int a_cols = arga.columns (); |
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80 int b_rows = argb.rows (); |
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81 int b_cols = argb.columns (); |
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82 int c_rows = argc.rows (); |
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83 int c_cols = argc.columns (); |
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84 |
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85 if ((a_rows != a_cols) || (b_rows != b_cols)) |
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86 { |
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87 gripe_square_matrix_required ("syl: first two parameters:"); |
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88 return retval; |
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89 } |
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90 else if ((a_rows != c_rows) || (b_rows != c_cols)) |
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91 { |
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92 gripe_nonconformant (); |
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93 return retval; |
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94 } |
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95 |
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96 // Dimensions look o.k., let's solve the problem. |
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97 |
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98 retval = new tree_constant[nargout+1]; |
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99 |
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100 if (arga.is_complex_type () || argb.is_complex_type () |
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101 || argc.is_complex_type ()) |
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102 { |
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103 |
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104 // Do everything in complex arithmetic; |
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105 |
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100
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106 ComplexMatrix ca = arga.complex_matrix_value (); |
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107 ComplexMatrix cb = argb.complex_matrix_value (); |
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108 ComplexMatrix cc = argc.complex_matrix_value (); |
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109 |
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110 // Compute Schur decompositions |
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111 |
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112 ComplexSCHUR as (ca, "U"); |
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113 ComplexSCHUR bs (cb, "U"); |
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114 |
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115 // Transform cc to new coordinates. |
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116 |
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117 ComplexMatrix ua = as.unitary_matrix (); |
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118 ComplexMatrix sch_a = as.schur_matrix (); |
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119 ComplexMatrix ub = bs.unitary_matrix (); |
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120 ComplexMatrix sch_b = bs.schur_matrix (); |
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121 |
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122 ComplexMatrix cx = ua.hermitian () * cc * ub; |
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123 |
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124 // Solve the sylvester equation, back-transform, and return the solution. |
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125 |
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126 double scale; |
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127 int info; |
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128 int one = 1; |
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129 |
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130 F77_FCN (ztrsyl) ("N", "N", &one, &a_rows, &b_rows, |
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131 sch_a.fortran_vec (), &a_rows, |
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132 sch_b.fortran_vec (), &b_rows, |
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133 cx.fortran_vec (), &a_rows, &scale, &info, |
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134 1L, 1L); |
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135 |
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136 cx = -ua * cx * ub.hermitian (); |
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137 |
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138 retval[0] = tree_constant (cx); |
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139 } |
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140 else |
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141 { |
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142 |
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143 // Do everything in real arithmetic; |
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144 |
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145 Matrix ca = arga.to_matrix (); |
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146 Matrix cb = argb.to_matrix (); |
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147 Matrix cc = argc.to_matrix (); |
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148 |
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149 // Compute Schur decompositions. |
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150 |
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151 SCHUR as (ca, "U"); |
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152 SCHUR bs (cb, "U"); |
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153 |
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154 // Transform cc to new coordinates. |
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155 |
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156 Matrix ua = as.unitary_matrix (); |
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157 Matrix sch_a = as.schur_matrix (); |
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158 Matrix ub = bs.unitary_matrix (); |
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159 Matrix sch_b = bs.schur_matrix (); |
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160 |
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161 Matrix cx = ua.transpose () * cc * ub; |
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162 |
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163 // Solve the sylvester equation, back-transform, and return the solution. |
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164 |
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165 double scale; |
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166 int info; |
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167 int one = 1; |
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168 |
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169 F77_FCN (dtrsyl) ("N", "N", &one, &a_rows, &b_rows, |
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170 sch_a.fortran_vec (), &a_rows, |
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171 sch_b.fortran_vec (), &b_rows, |
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172 cx.fortran_vec (), &a_rows, &scale, &info, |
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173 1L, 1L); |
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174 |
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175 if (info) |
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176 error ("syl: trouble in dtrsyl info = %d", info); |
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177 |
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178 cx = -ua*cx*ub.transpose (); |
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179 |
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180 retval[0] = tree_constant (cx); |
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181 } |
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182 } |
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183 return retval; |
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184 } |
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185 |
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186 /* |
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187 ;;; Local Variables: *** |
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188 ;;; mode: C++ *** |
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189 ;;; page-delimiter: "^/\\*" *** |
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190 ;;; End: *** |
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191 */ |
