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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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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 "gripes.h" |
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35 #include "error.h" |
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36 |
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37 int F77_FCN (dtrsyl) (const char*, const char*, const int*, const |
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38 int*, const int*, const double*, const int*, |
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39 const double*, const int*, const double*, const |
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40 int*, double*, int*, long, long); |
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41 |
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42 int F77_FCN (ztrsyl) (const char*, const char*, const int*, const |
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43 int*, const int*, const Complex*, const int*, |
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44 const Complex*, const int*, const Complex*, |
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45 const int*, double*, int*, long, long); |
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46 |
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47 // Local function: check for empty matrix arguments. Probably should make |
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48 // this available elsewhere, since tc-xxx functions do this a lot. |
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49 |
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50 static inline int |
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51 empty_arg (tree_constant& arg) |
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52 { |
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53 return (arg.rows () == 0 || arg.columns () == 0); |
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54 } |
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55 |
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56 |
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57 // Local function: construct return vector of empty matrices. Return |
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58 // empty matrices and/or gripe when appropriate. Probably should make |
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59 // this available elsewhere, since tc-xxx functions do this a lot. |
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60 |
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61 tree_constant * |
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62 empty_tree (int nargout, char* fcn_name) |
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63 { |
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64 tree_constant *retval = NULL_TREE_CONST; |
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65 |
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66 // Got an empty argument, check if should gripe/return empty values. |
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67 |
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68 int flag = user_pref.propagate_empty_matrices; |
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69 if (flag != 0) |
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70 { |
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71 if (flag < 0) |
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72 gripe_empty_arg (fcn_name, 0); |
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73 |
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74 Matrix m; |
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75 retval = new tree_constant [nargout+1]; |
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76 for (int i = 0; i < nargout; i++) |
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77 retval[i] = tree_constant (m); |
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78 } |
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79 else |
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80 gripe_empty_arg (fcn_name, 1); |
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81 |
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82 return retval; |
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83 } |
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84 |
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85 // Return value of tree_constant argument as ComplexMatrix. |
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86 |
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87 ComplexMatrix |
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88 ComplexMatrixLoad (tree_constant& arg) |
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89 { |
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90 ComplexMatrix retval; |
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91 |
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92 // Set argument size for scalar (for later). |
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93 |
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94 switch (arg.const_type ()) |
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95 { |
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96 case tree_constant_rep::scalar_constant: |
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97 retval.resize (1, 1); |
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98 { |
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99 double real_val = arg.double_value (); |
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100 retval.elem (0, 0) = real_val; |
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101 } |
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102 break; |
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103 case tree_constant_rep::complex_scalar_constant: |
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104 retval.resize (1, 1); |
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105 retval.elem (0, 0) = arg.complex_value (); |
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106 break; |
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107 case tree_constant_rep::matrix_constant: |
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108 { |
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109 Matrix tmp = arg.matrix_value (); |
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110 retval = tmp; |
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111 } |
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112 break; |
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113 case tree_constant_rep::complex_matrix_constant: |
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114 retval = arg.complex_matrix_value (); |
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115 break; |
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116 default: |
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117 panic_impossible (); |
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118 break; |
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119 } |
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120 return retval; |
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121 } |
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122 |
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123 #ifdef WITH_DLD |
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124 tree_constant * |
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125 builtin_syl_2 (tree_constant *args, int nargin, int nargout) |
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126 { |
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127 return syl (args, nargin, nargout); |
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128 } |
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129 #endif |
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130 |
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131 tree_constant * |
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132 syl (tree_constant *args, int nargin, int nargout) |
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133 { |
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134 tree_constant *retval = NULL_TREE_CONST; |
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135 |
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136 tree_constant arga = args[1].make_numeric (); |
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137 tree_constant argb = args[2].make_numeric (); |
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138 tree_constant argc = args[3].make_numeric (); |
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139 |
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140 if (empty_arg (arga) || empty_arg (argb) || empty_arg (argc)) |
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141 retval = empty_tree (nargout, "syl"); |
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142 else |
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143 { |
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144 |
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145 // Arguments are not empty, so check for correct dimensions. |
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146 |
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147 int a_rows = arga.rows (); |
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148 int a_cols = arga.columns (); |
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149 int b_rows = argb.rows (); |
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150 int b_cols = argb.columns (); |
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151 int c_rows = argc.rows (); |
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152 int c_cols = argc.columns (); |
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153 |
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154 if ((a_rows != a_cols) || (b_rows != b_cols)) |
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155 { |
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156 gripe_square_matrix_required ("syl: first two parameters:"); |
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157 return retval; |
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158 } |
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159 else if ((a_rows != c_rows) || (b_rows != c_cols)) |
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160 { |
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161 gripe_nonconformant (); |
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162 return retval; |
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163 } |
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164 |
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165 // Dimensions look o.k., let's solve the problem. |
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166 |
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167 retval = new tree_constant[nargout+1]; |
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168 |
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169 if (arga.is_complex_type () || argb.is_complex_type () |
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170 || argc.is_complex_type ()) |
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171 { |
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172 |
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173 // Do everything in complex arithmetic; |
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174 |
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175 ComplexMatrix ca = ComplexMatrixLoad (arga); |
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176 ComplexMatrix cb = ComplexMatrixLoad (argb); |
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177 ComplexMatrix cc = ComplexMatrixLoad (argc); |
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178 |
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179 // Compute Schur decompositions |
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180 |
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181 ComplexSCHUR as (ca, "U"); |
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182 ComplexSCHUR bs (cb, "U"); |
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183 |
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184 // Transform cc to new coordinates. |
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185 |
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186 ComplexMatrix ua = as.unitary_matrix (); |
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187 ComplexMatrix sch_a = as.schur_matrix (); |
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188 ComplexMatrix ub = bs.unitary_matrix (); |
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189 ComplexMatrix sch_b = bs.schur_matrix (); |
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190 |
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191 cx = ua.hermitian () * cc * ub; |
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192 |
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193 // Solve the sylvester equation, back-transform, and return the solution. |
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194 |
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195 double scale; |
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196 int info; |
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197 int one = 1; |
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198 |
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199 F77_FCN (ztrsyl) ("N", "N", &one, &a_rows, &b_rows, |
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200 sch_a.fortran_vec (), &a_rows, |
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201 sch_b.fortran_vec (), &b_rows, |
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202 cx.fortran_vec (), &a_rows, &scale, &info, |
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203 1L, 1L); |
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204 |
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205 cx = -ua * cx * ub.hermitian (); |
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206 |
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207 retval[0] = tree_constant (cx); |
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208 } |
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209 else |
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210 { |
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211 |
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212 // Do everything in real arithmetic; |
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213 |
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214 Matrix ca = arga.to_matrix (); |
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215 Matrix cb = argb.to_matrix (); |
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216 Matrix cc = argc.to_matrix (); |
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217 |
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218 // Compute Schur decompositions. |
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219 |
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220 SCHUR as (ca, "U"); |
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221 SCHUR bs (cb, "U"); |
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222 |
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223 // Transform cc to new coordinates. |
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224 |
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225 Matrix ua = as.unitary_matrix (); |
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226 Matrix sch_a = as.schur_matrix (); |
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227 Matrix ub = bs.unitary_matrix (); |
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228 Matrix sch_b = bs.schur_matrix (); |
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229 |
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230 cx = ua.transpose () * cc * ub; |
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231 |
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232 // Solve the sylvester equation, back-transform, and return the solution. |
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233 |
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234 double scale; |
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235 int info; |
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236 int one = 1; |
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237 |
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238 F77_FCN (dtrsyl) ("N", "N", &one, &a_rows, &b_rows, |
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239 sch_a.fortran_vec (), &a_rows, |
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240 sch_b.fortran_vec (), &b_rows, |
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241 cx.fortran_vec (), &a_rows, &scale, &info, |
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242 1L, 1L); |
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243 |
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244 if (info) |
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245 error ("syl: trouble in dtrsyl info = %d", info); |
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246 |
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247 cx = -ua*cx*ub.transpose (); |
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248 |
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249 retval[0] = tree_constant (cx); |
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250 } |
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251 } |
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252 return retval; |
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253 } |
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254 |
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255 /* |
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256 ;;; Local Variables: *** |
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257 ;;; mode: C++ *** |
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258 ;;; page-delimiter: "^/\\*" *** |
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259 ;;; End: *** |
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260 */ |
