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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, 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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24 // Written by A. S. Hodel <scotte@eng.auburn.edu> |
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25 |
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240
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26 #ifdef HAVE_CONFIG_H |
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27 #include "config.h" |
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28 #endif |
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29 |
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30 #include "dMatrix.h" |
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31 #include "CMatrix.h" |
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32 #include "dbleSCHUR.h" |
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33 #include "CmplxSCHUR.h" |
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234
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34 #include "f77-uscore.h" |
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35 |
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36 #include "tree-const.h" |
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37 #include "user-prefs.h" |
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38 #include "gripes.h" |
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39 #include "error.h" |
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40 #include "f-syl.h" |
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41 |
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42 extern "C" |
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43 { |
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44 int F77_FCN (dtrsyl) (const char*, const char*, const int*, |
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45 const int*, const int*, const double*, |
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46 const int*, const double*, const int*, |
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47 const double*, const int*, double*, int*, |
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48 long, long); |
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49 |
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47
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50 int F77_FCN (ztrsyl) (const char*, const char*, const int*, |
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51 const int*, const int*, const Complex*, |
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52 const int*, const Complex*, const int*, |
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53 const Complex*, const int*, double*, int*, |
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54 long, long); |
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55 } |
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56 |
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57 #ifdef WITH_DLD |
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58 tree_constant * |
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59 builtin_syl_2 (const tree_constant *args, int nargin, int nargout) |
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60 { |
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61 return syl (args, nargin, nargout); |
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62 } |
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63 #endif |
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64 |
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65 tree_constant * |
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66 syl (const tree_constant *args, int nargin, int nargout) |
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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 tree_constant argc = args[3].make_numeric (); |
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73 |
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74 if (arga.is_empty () || argb.is_empty () || argc.is_empty ()) |
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75 retval = vector_of_empties (nargout, "syl"); |
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76 else |
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77 { |
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78 |
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79 // Arguments are not empty, so check for correct dimensions. |
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80 |
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81 int a_rows = arga.rows (); |
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82 int a_cols = arga.columns (); |
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83 int b_rows = argb.rows (); |
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84 int b_cols = argb.columns (); |
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85 int c_rows = argc.rows (); |
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86 int c_cols = argc.columns (); |
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87 |
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88 if ((a_rows != a_cols) || (b_rows != b_cols)) |
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89 { |
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90 gripe_square_matrix_required ("syl: first two parameters:"); |
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91 return retval; |
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92 } |
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93 else if ((a_rows != c_rows) || (b_rows != c_cols)) |
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94 { |
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95 gripe_nonconformant (); |
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96 return retval; |
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97 } |
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98 |
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99 // Dimensions look o.k., let's solve the problem. |
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100 |
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101 retval = new tree_constant[nargout+1]; |
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102 |
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103 if (arga.is_complex_type () || argb.is_complex_type () |
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104 || argc.is_complex_type ()) |
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105 { |
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106 |
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107 // Do everything in complex arithmetic; |
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108 |
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109 ComplexMatrix ca = arga.complex_matrix_value (); |
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110 ComplexMatrix cb = argb.complex_matrix_value (); |
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111 ComplexMatrix cc = argc.complex_matrix_value (); |
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112 |
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113 // Compute Schur decompositions |
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114 |
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115 ComplexSCHUR as (ca, "U"); |
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116 ComplexSCHUR bs (cb, "U"); |
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117 |
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118 // Transform cc to new coordinates. |
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119 |
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120 ComplexMatrix ua = as.unitary_matrix (); |
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121 ComplexMatrix sch_a = as.schur_matrix (); |
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122 ComplexMatrix ub = bs.unitary_matrix (); |
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123 ComplexMatrix sch_b = bs.schur_matrix (); |
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124 |
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125 ComplexMatrix cx = ua.hermitian () * cc * ub; |
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126 |
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127 // Solve the sylvester equation, back-transform, and return the solution. |
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128 |
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129 double scale; |
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130 int info; |
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131 int one = 1; |
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132 |
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133 F77_FCN (ztrsyl) ("N", "N", &one, &a_rows, &b_rows, |
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134 sch_a.fortran_vec (), &a_rows, |
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135 sch_b.fortran_vec (), &b_rows, |
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136 cx.fortran_vec (), &a_rows, &scale, &info, |
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137 1L, 1L); |
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138 |
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139 cx = -ua * cx * ub.hermitian (); |
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140 |
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141 retval[0] = tree_constant (cx); |
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142 } |
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143 else |
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144 { |
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145 |
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146 // Do everything in real arithmetic; |
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147 |
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148 Matrix ca = arga.to_matrix (); |
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149 Matrix cb = argb.to_matrix (); |
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150 Matrix cc = argc.to_matrix (); |
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151 |
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152 // Compute Schur decompositions. |
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153 |
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154 SCHUR as (ca, "U"); |
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155 SCHUR bs (cb, "U"); |
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156 |
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157 // Transform cc to new coordinates. |
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158 |
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159 Matrix ua = as.unitary_matrix (); |
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160 Matrix sch_a = as.schur_matrix (); |
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161 Matrix ub = bs.unitary_matrix (); |
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162 Matrix sch_b = bs.schur_matrix (); |
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163 |
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164 Matrix cx = ua.transpose () * cc * ub; |
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165 |
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166 // Solve the sylvester equation, back-transform, and return the solution. |
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167 |
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168 double scale; |
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169 int info; |
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170 int one = 1; |
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171 |
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172 F77_FCN (dtrsyl) ("N", "N", &one, &a_rows, &b_rows, |
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173 sch_a.fortran_vec (), &a_rows, |
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174 sch_b.fortran_vec (), &b_rows, |
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175 cx.fortran_vec (), &a_rows, &scale, &info, |
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176 1L, 1L); |
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177 |
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178 if (info) |
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179 error ("syl: trouble in dtrsyl info = %d", info); |
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180 |
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181 cx = -ua*cx*ub.transpose (); |
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182 |
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183 retval[0] = tree_constant (cx); |
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184 } |
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185 } |
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186 return retval; |
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187 } |
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188 |
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189 /* |
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190 ;;; Local Variables: *** |
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191 ;;; mode: C++ *** |
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192 ;;; page-delimiter: "^/\\*" *** |
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193 ;;; End: *** |
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194 */ |
