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1 // f-balance.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 "dbleAEPBAL.h" |
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33 #include "CmplxAEPBAL.h" |
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34 #include "dbleAEPBAL.h" |
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35 #include "CmplxAEPBAL.h" |
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36 #include "dbleGEPBAL.h" |
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37 |
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38 #include "tree-const.h" |
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39 #include "user-prefs.h" |
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40 #include "gripes.h" |
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41 #include "error.h" |
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42 #include "utils.h" |
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43 #include "help.h" |
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44 #include "defun-dld.h" |
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45 |
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46 DEFUN_DLD_BUILTIN ("balance", Fbalance, Sbalance, 4, 4, |
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47 "AA = balance (A [, OPT]) or [[DD,] AA] = balance (A [, OPT])\n\ |
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48 \n\ |
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49 generalized eigenvalue problem:\n\ |
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50 \n\ |
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51 [cc, dd, aa, bb] = balance (a, b [, opt])\n\ |
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52 \n\ |
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53 where OPT is an optional single character argument as follows: \n\ |
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54 \n\ |
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55 N: no balancing; arguments copied, transformation(s) set to identity\n\ |
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56 P: permute argument(s) to isolate eigenvalues where possible\n\ |
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57 S: scale to improve accuracy of computed eigenvalues\n\ |
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58 B: (default) permute and scale, in that order. Rows/columns\n\ |
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59 of a (and b) that are isolated by permutation are not scaled\n\ |
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60 \n\ |
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61 [DD, AA] = balance (A, OPT) returns aa = dd\a*dd,\n\ |
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62 \n\ |
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63 [CC, DD, AA, BB] = balance (A, B, OPT) returns AA (BB) = CC*A*DD (CC*B*DD)") |
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64 { |
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65 Octave_object retval; |
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66 |
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67 int nargin = args.length (); |
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68 |
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69 if (nargin < 1 || nargin > 3 || nargout < 0 || nargout > 4) |
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70 { |
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71 print_usage ("balance"); |
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72 return retval; |
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73 } |
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74 |
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75 char *bal_job; |
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76 int my_nargin; // # args w/o optional string arg |
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77 |
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78 // Determine if balancing option is listed. Set my_nargin to the |
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79 // number of matrix inputs. |
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80 |
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81 if (args(nargin-1).is_string ()) |
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82 { |
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83 bal_job = args(nargin-1).string_value (); |
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84 my_nargin = nargin-1; |
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85 } |
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86 else |
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87 { |
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88 bal_job = "B"; |
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89 my_nargin = nargin; |
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90 } |
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91 |
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92 tree_constant arg_a = args(0); |
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93 |
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94 int a_nr = arg_a.rows (); |
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95 int a_nc = arg_a.columns (); |
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96 |
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97 // Check argument 1 dimensions. |
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98 |
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99 if (empty_arg ("balance", a_nr, a_nc) < 0) |
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100 return retval; |
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101 |
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102 if (a_nr != a_nc) |
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103 { |
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104 gripe_square_matrix_required ("balance"); |
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105 return retval; |
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106 } |
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107 |
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108 // Extract argument 1 parameter for both AEP and GEP. |
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109 |
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110 Matrix aa; |
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111 ComplexMatrix caa; |
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112 if (arg_a.is_complex_type ()) |
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113 caa = arg_a.complex_matrix_value (); |
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114 else |
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115 aa = arg_a.matrix_value (); |
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116 |
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117 if (error_state) |
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118 return retval; |
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119 |
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120 // Treat AEP/ GEP cases. |
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121 |
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122 switch (my_nargin) |
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123 { |
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124 case 1: |
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125 |
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126 // Algebraic eigenvalue problem. |
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127 |
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128 if (arg_a.is_complex_type ()) |
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129 { |
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130 ComplexAEPBALANCE result (caa, bal_job); |
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131 |
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132 if (nargout == 0 || nargout == 1) |
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133 retval(0) = result.balanced_matrix (); |
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134 else |
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135 { |
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136 retval(1) = result.balanced_matrix (); |
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137 retval(0) = result.balancing_matrix (); |
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138 } |
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139 } |
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140 else |
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141 { |
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142 AEPBALANCE result (aa, bal_job); |
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143 |
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144 if (nargout == 0 || nargout == 1) |
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145 retval(0) = result.balanced_matrix (); |
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146 else |
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147 { |
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148 retval(1) = result.balanced_matrix (); |
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149 retval(0) = result.balancing_matrix (); |
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150 } |
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151 } |
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152 break; |
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153 |
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154 case 2: |
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155 { |
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156 // Generalized eigenvalue problem. |
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157 |
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158 // 1st we have to check argument 2 dimensions and type... |
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159 |
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160 tree_constant arg_b = args(1); |
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161 |
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162 int b_nr = arg_b.rows (); |
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163 int b_nc = arg_b.columns (); |
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164 |
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165 // Check argument 2 dimensions -- must match arg 1. |
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166 |
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167 if (b_nr != b_nc || b_nr != a_nr) |
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168 { |
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169 gripe_nonconformant (); |
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170 return retval; |
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171 } |
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172 |
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173 // Now, extract the second matrix... |
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174 // Extract argument 1 parameter for both AEP and GEP. |
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175 |
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176 Matrix bb; |
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177 ComplexMatrix cbb; |
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178 if (arg_b.is_complex_type ()) |
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179 cbb = arg_b.complex_matrix_value (); |
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180 else |
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181 bb = arg_b.matrix_value (); |
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182 |
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183 if (error_state) |
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184 return retval; |
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185 |
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186 // Both matrices loaded, now let's check what kind of arithmetic: |
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187 |
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188 if (arg_a.is_complex_type () || arg_b.is_complex_type ()) |
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189 { |
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190 if (arg_a.is_real_type ()) |
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191 caa = aa; |
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192 |
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193 if (arg_b.is_real_type ()) |
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194 cbb = bb; |
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195 |
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196 // Compute magnitudes of elements for balancing purposes. |
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197 // Surely there's a function I can call someplace! |
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198 |
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199 for (int i = 0; i < a_nr; i++) |
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200 for (int j = 0; j < a_nc; j++) |
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201 { |
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202 aa.elem (i, j) = abs (caa.elem (i, j)); |
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203 bb.elem (i, j) = abs (cbb.elem (i, j)); |
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204 } |
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205 } |
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206 |
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207 GEPBALANCE result (aa, bb, bal_job); |
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208 |
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209 if (arg_a.is_complex_type () || arg_b.is_complex_type ()) |
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210 { |
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211 caa = result.left_balancing_matrix () * caa |
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212 * result.right_balancing_matrix (); |
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213 |
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214 cbb = result.left_balancing_matrix () * cbb |
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215 * result.right_balancing_matrix (); |
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216 |
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217 switch (nargout) |
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218 { |
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219 case 0: |
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220 case 1: |
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221 warning ("balance: should use two output arguments"); |
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222 retval(0) = caa; |
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223 break; |
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224 |
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225 case 2: |
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226 retval(1) = cbb; |
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227 retval(0) = caa; |
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228 break; |
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229 |
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230 case 4: |
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231 retval(3) = cbb; |
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232 retval(2) = caa; |
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233 retval(1) = result.right_balancing_matrix (); |
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234 retval(0) = result.left_balancing_matrix (); |
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235 break; |
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236 |
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237 default: |
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238 error ("balance: invalid number of output arguments"); |
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239 break; |
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240 } |
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241 } |
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242 else |
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243 { |
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244 switch (nargout) |
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245 { |
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246 case 0: |
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247 case 1: |
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248 warning ("balance: should use two output arguments"); |
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249 retval(0) = result.balanced_a_matrix (); |
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250 break; |
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251 |
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252 case 2: |
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253 retval(1) = result.balanced_b_matrix (); |
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254 retval(0) = result.balanced_a_matrix (); |
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255 break; |
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256 |
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257 case 4: |
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258 retval(3) = result.balanced_b_matrix (); |
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259 retval(2) = result.balanced_a_matrix (); |
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260 retval(1) = result.right_balancing_matrix (); |
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261 retval(0) = result.left_balancing_matrix (); |
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262 break; |
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263 |
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264 default: |
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265 error ("balance: invalid number of output arguments"); |
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266 break; |
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267 } |
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268 } |
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269 } |
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270 break; |
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271 |
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272 default: |
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273 error ("balance requires one (AEP) or two (GEP) numeric 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 ;;; page-delimiter: "^/\\*" *** |
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284 ;;; End: *** |
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285 */ |
