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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 // 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 <string> |
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30 |
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31 #include "CmplxAEPBAL.h" |
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32 #include "CmplxAEPBAL.h" |
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33 #include "dbleAEPBAL.h" |
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34 #include "dbleAEPBAL.h" |
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35 |
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36 #include "defun-dld.h" |
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37 #include "error.h" |
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38 #include "f77-fcn.h" |
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39 #include "gripes.h" |
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40 #include "oct-obj.h" |
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41 #include "utils.h" |
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42 |
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43 extern "C" |
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44 { |
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45 int F77_FCN( dggbal, DGGBAL) (const char* JOB, const int& N, |
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46 double* A, const int& LDA, double* B, const int& LDB, |
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47 int& ILO, int & IHI, double* LSCALE, |
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48 double* RSCALE, double* WORK, int& INFO, long ); |
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49 |
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50 int F77_FCN( dggbak, DGGBAK) (const char* JOB, const char* SIDE, |
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51 const int& N, const int& ILO, const int& IHI, |
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52 double* LSCALE, double* RSCALE, int& M, |
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53 double* V, const int& LDV, int& INFO, long, long); |
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54 |
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55 int F77_FCN( zggbal, ZGGBAL) ( const char* JOB, const int& N, |
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56 Complex* A, const int& LDA, Complex* B, const int& LDB, |
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57 int& ILO, int & IHI, double* LSCALE, |
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58 double* RSCALE, double* WORK, int& INFO, long ); |
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59 } |
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60 |
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61 DEFUN_DLD (balance, args, nargout, |
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62 "AA = balance (A [, OPT]) or [[DD,] AA] = balance (A [, OPT])\n\ |
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63 \n\ |
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64 generalized eigenvalue problem:\n\ |
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65 \n\ |
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66 [cc, dd, aa, bb] = balance (a, b [, opt])\n\ |
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67 \n\ |
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68 where OPT is an optional single character argument as follows: \n\ |
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69 \n\ |
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70 N: no balancing; arguments copied, transformation(s) set to identity\n\ |
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71 P: permute argument(s) to isolate eigenvalues where possible\n\ |
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72 S: scale to improve accuracy of computed eigenvalues\n\ |
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73 B: (default) permute and scale, in that order. Rows/columns\n\ |
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74 of a (and b) that are isolated by permutation are not scaled\n\ |
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75 \n\ |
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76 [DD, AA] = balance (A, OPT) returns aa = dd*a*dd,\n\ |
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77 \n\ |
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78 [CC, DD, AA, BB] = balance (A, B, OPT) returns AA (BB) = CC*A*DD (CC*B*DD)") |
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79 { |
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80 |
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81 octave_value_list retval; |
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82 |
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83 int nargin = args.length (); |
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84 |
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85 if (nargin < 1 || nargin > 3 || nargout < 0 || nargout > 4) |
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86 { |
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87 print_usage ("balance"); |
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88 return retval; |
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89 } |
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90 |
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91 // determine if it's AEP or GEP |
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92 int AEPcase = (nargin == 1 ? 1 : args(1).is_string() ); |
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93 string bal_job; |
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94 |
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95 // problem dimension |
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96 int nn = args(0).rows (); |
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97 |
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98 int arg_is_empty = empty_arg ("balance", nn, args(0).columns()); |
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99 |
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100 if (arg_is_empty < 0) |
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101 return retval; |
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102 if (arg_is_empty > 0) |
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103 return octave_value_list (2, Matrix ()); |
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104 |
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105 if (nn != args(0).columns()) |
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106 { |
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107 gripe_square_matrix_required ("balance"); |
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108 return retval; |
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109 } |
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110 |
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111 // Extract argument 1 parameter for both AEP and GEP. |
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112 Matrix aa; |
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113 ComplexMatrix caa; |
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114 if (args(0).is_complex_type ()) caa = args(0).complex_matrix_value (); |
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115 else aa = args(0).matrix_value (); |
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116 if (error_state) return retval; |
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117 |
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118 // Treat AEP/GEP cases. |
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119 if(AEPcase) |
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120 { |
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121 // Algebraic eigenvalue problem. |
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122 if(nargin == 1) |
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123 bal_job = "B"; |
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124 else if(args(1).is_string()) |
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125 bal_job = args(1).string_value(); |
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126 // the next line should never execute, but better safe than sorry. |
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127 else error("balance: AEP argument 2 must be a string"); |
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128 |
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129 // balance the AEP |
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130 if (args(0).is_complex_type ()) |
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131 { |
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132 ComplexAEPBALANCE result (caa, bal_job); |
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133 |
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134 if (nargout == 0 || nargout == 1) |
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135 retval(0) = result.balanced_matrix (); |
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136 else |
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137 { |
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138 retval(1) = result.balanced_matrix (); |
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139 retval(0) = result.balancing_matrix (); |
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140 } |
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141 } |
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142 else |
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143 { |
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144 AEPBALANCE result (aa, bal_job); |
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145 |
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146 if (nargout == 0 || nargout == 1) |
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147 retval(0) = result.balanced_matrix (); |
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148 else |
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149 { |
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150 retval(1) = result.balanced_matrix (); |
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151 retval(0) = result.balancing_matrix (); |
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152 } |
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153 } |
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154 } |
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155 // |
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156 // end of AEP case, now do GEP case |
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157 else |
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158 { |
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159 // Generalized eigenvalue problem. |
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160 if(nargin == 2) |
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161 bal_job = "B"; |
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162 else if(args(2).is_string()) |
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163 bal_job = args(2).string_value(); |
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164 else error("balance: GEP argument 3 must be a string"); |
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165 |
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166 if( (nn != args(1).columns()) || (nn != args(1).rows() ) ) |
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167 { |
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168 gripe_nonconformant (); |
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169 return retval; |
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170 } |
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171 Matrix bb; |
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172 ComplexMatrix cbb; |
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173 if (args(1).is_complex_type ()) cbb = args(1).complex_matrix_value (); |
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174 else bb = args(1).matrix_value (); |
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175 if (error_state) return retval; |
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176 |
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177 // |
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178 // Both matrices loaded, now let's check what kind of arithmetic: |
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179 // first, declare variables used in both the real and complex case |
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180 int ilo, ihi, info; |
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181 RowVector lscale(nn), rscale(nn), work(6*nn); |
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182 char job = bal_job[0]; |
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183 static int complex_case = (args(0).is_complex_type() |
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184 || args(1).is_complex_type()); |
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185 |
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186 // now balance |
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187 if (complex_case) |
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188 { |
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189 if (args(0).is_real_type ()) caa = aa; |
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190 if (args(1).is_real_type ()) cbb = bb; |
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191 |
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192 F77_XFCN( zggbal, ZGGBAL, ( &job, nn, caa.fortran_vec(), nn, |
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193 cbb.fortran_vec(), nn, ilo, ihi, lscale.fortran_vec(), |
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194 rscale.fortran_vec(), work.fortran_vec(), info, 1L)); |
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195 } |
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196 else // real matrices case |
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197 { |
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198 F77_XFCN( dggbal, DGGBAL, (&job, nn, aa.fortran_vec(), |
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199 nn, bb.fortran_vec() , nn, ilo, ihi, lscale.fortran_vec(), |
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200 rscale.fortran_vec(), work.fortran_vec(), info , 1L)); |
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201 |
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202 if(f77_exception_encountered) |
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203 (*current_liboctave_error_handler) |
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204 ("unrecoverable error in balance GEP"); |
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205 } |
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206 |
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207 // Since we just want the balancing matrices, we can use dggbal |
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208 // for both the real and complex cases; |
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209 Matrix Pl(nn,nn), Pr(nn,nn); |
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210 for(int ii=0; ii < nn ; ii++) |
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211 for( int jj=0; jj < nn ; jj++) |
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212 Pl(ii,jj) = Pr(ii,jj) = (ii == jj ? 1.0 : 0.0); |
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213 |
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214 // left first |
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215 F77_XFCN( dggbak, DGGBAK, (&job, "L", |
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216 nn, ilo, ihi, lscale.fortran_vec(), |
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217 rscale.fortran_vec(), nn, Pl.fortran_vec(), |
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218 nn, info, 1L, 1L)); |
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219 |
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220 if(f77_exception_encountered) |
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221 (*current_liboctave_error_handler) |
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222 ("unrecoverable error in balance GEP(L)"); |
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223 |
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224 // then right |
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225 F77_XFCN(dggbak, DGGBAK, (&job, "R", |
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226 nn, ilo, ihi, lscale.fortran_vec(), |
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227 rscale.fortran_vec(), nn, Pr.fortran_vec(), |
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228 nn, info, 1L, 1L)); |
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229 if(f77_exception_encountered) |
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230 (*current_liboctave_error_handler) |
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231 ("unrecoverable error in balance GEP(R)"); |
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232 |
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233 switch (nargout) |
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234 { |
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235 case 0: |
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236 case 1: |
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237 warning ("balance: used GEP, should have two output arguments"); |
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238 if(complex_case) |
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239 retval(0) = caa; |
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240 else |
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241 retval(0) = aa; |
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242 break; |
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243 |
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244 case 2: |
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245 if(complex_case) |
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246 { |
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247 retval(1) = cbb; |
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248 retval(0) = caa; |
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249 } |
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250 else |
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251 { |
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252 retval(1) = bb; |
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253 retval(0) = aa; |
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254 } |
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255 break; |
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256 |
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257 case 4: |
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258 if(complex_case) |
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259 { |
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260 retval(3) = cbb; |
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261 retval(2) = caa; |
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262 } |
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263 else |
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264 { |
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265 retval(3) = bb; |
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266 retval(2) = aa; |
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267 } |
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268 retval(1) = Pr; |
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269 retval(0) = Pl.transpose(); // so that aa_bal = cc*aa*dd, etc. |
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270 break; |
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271 |
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272 default: |
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273 error ("balance: invalid number of output arguments"); |
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274 break; |
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275 } |
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276 } |
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277 return retval; |
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278 } |
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279 |
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280 /* |
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281 ;;; Local Variables: *** |
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282 ;;; mode: C++ *** |
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283 ;;; End: *** |
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284 */ |
