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1 // -*- C++ -*- |
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2 /* |
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3 |
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4 Copyright (C) 1996 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, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
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21 |
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22 */ |
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23 |
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24 #if defined (__GNUG__) |
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25 #pragma implementation |
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26 #endif |
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27 |
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28 #ifdef HAVE_CONFIG_H |
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29 #include <config.h> |
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30 #endif |
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31 |
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32 #include "dbleLU.h" |
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33 #include "f77-fcn.h" |
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34 #include "lo-error.h" |
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35 #include "mx-inlines.cc" |
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36 |
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37 extern "C" |
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38 { |
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39 int F77_FCN (dgesv, DGESV) (const int&, const int&, double*, |
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40 const int&, int*, double&, const int&, |
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41 int&); |
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42 } |
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43 |
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44 LU::LU (const Matrix& a) |
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45 { |
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46 int a_nr = a.rows (); |
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47 int a_nc = a.cols (); |
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48 |
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49 if (a_nr == 0 || a_nc == 0 || a_nr != a_nc) |
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50 { |
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51 (*current_liboctave_error_handler) ("LU requires square matrix"); |
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52 return; |
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53 } |
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54 |
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55 int n = a_nr; |
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56 |
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57 Array<int> ipvt (n); |
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58 int *pipvt = ipvt.fortran_vec (); |
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59 |
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60 Matrix A_fact = a; |
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61 double *tmp_data = A_fact.fortran_vec (); |
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62 |
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63 int info = 0; |
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64 double dummy = 0; |
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65 |
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66 F77_XFCN (dgesv, DGESV, (n, 0, tmp_data, n, pipvt, dummy, n, info)); |
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67 |
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68 if (f77_exception_encountered) |
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69 (*current_liboctave_error_handler) ("unrecoverable error in dgesv"); |
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70 else |
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71 { |
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72 Array<int> pvt (n); |
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73 |
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74 for (int i = 0; i < n; i++) |
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75 { |
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76 ipvt.elem (i) -= 1; |
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77 pvt.elem (i) = i; |
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78 } |
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79 |
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80 for (int i = 0; i < n - 1; i++) |
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81 { |
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82 int k = ipvt.elem (i); |
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83 if (k != i) |
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84 { |
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85 int tmp = pvt.elem (k); |
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86 pvt.elem (k) = pvt.elem (i); |
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87 pvt.elem (i) = tmp; |
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88 } |
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89 } |
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90 |
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91 l.resize (n, n, 0.0); |
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92 u.resize (n, n, 0.0); |
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93 p.resize (n, n, 0.0); |
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94 |
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95 for (int i = 0; i < n; i++) |
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96 { |
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97 p.elem (i, pvt.elem (i)) = 1.0; |
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98 |
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99 l.elem (i, i) = 1.0; |
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100 for (int j = 0; j < i; j++) |
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101 l.elem (i, j) = A_fact.elem (i, j); |
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102 |
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103 for (int j = i; j < n; j++) |
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104 u.elem (i, j) = A_fact.elem (i, j); |
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105 } |
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106 } |
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107 } |
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108 |
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109 /* |
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110 ;;; Local Variables: *** |
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111 ;;; mode: C++ *** |
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112 ;;; page-delimiter: "^/\\*" *** |
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113 ;;; End: *** |
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114 */ |
