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1 /* |
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2 |
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3 Copyright (C) 2006 David Bateman |
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4 |
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5 Octave is free software; you can redistribute it and/or modify it |
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6 under the terms of the GNU General Public License as published by the |
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7 Free Software Foundation; either version 2, or (at your option) any |
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8 later version. |
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9 |
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10 Octave is distributed in the hope that it will be useful, but WITHOUT |
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11 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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12 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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13 for more details. |
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14 |
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15 You should have received a copy of the GNU General Public License |
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16 along with this program; see the file COPYING. If not, write to the |
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17 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, |
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18 Boston, MA 02110-1301, USA. |
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19 |
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20 */ |
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21 |
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22 #ifdef HAVE_CONFIG_H |
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23 #include <config.h> |
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24 #endif |
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25 |
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26 #include <cstdlib> |
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27 #include <string> |
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28 |
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29 #include "variables.h" |
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30 #include "utils.h" |
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31 #include "pager.h" |
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32 #include "defun-dld.h" |
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33 #include "gripes.h" |
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34 #include "quit.h" |
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35 |
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36 #include "ov-re-sparse.h" |
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37 #include "ov-cx-sparse.h" |
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38 |
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39 template <typename T, typename M> |
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40 octave_value_list |
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41 sparse_find_non_zero_elem_idx (const T& v, M& val, int nargout, |
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42 octave_idx_type n_to_find, int direction) |
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43 { |
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44 octave_value_list retval ((nargout == 0 ? 1 : nargout), Matrix ()); |
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45 |
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46 |
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47 octave_idx_type nc = v.cols(); |
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48 octave_idx_type nr = v.rows(); |
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49 octave_idx_type nz = v.nnz(); |
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50 |
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51 // Search in the default range. |
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52 octave_idx_type start_nc = -1; |
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53 octave_idx_type end_nc = -1; |
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54 octave_idx_type count; |
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55 |
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56 // Search for the range to search |
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57 if (n_to_find < 0) |
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58 { |
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59 start_nc = 0; |
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60 end_nc = nc; |
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61 n_to_find = nz; |
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62 count = nz; |
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63 } |
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64 else if (direction > 0) |
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65 { |
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66 for (octave_idx_type j = 0; j < nc; j++) |
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67 { |
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68 OCTAVE_QUIT; |
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69 if (v.cidx(j) == 0 && v.cidx(j+1) != 0) |
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70 start_nc = j; |
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71 if (v.cidx(j+1) >= n_to_find) |
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72 { |
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73 end_nc = j + 1; |
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74 break; |
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75 } |
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76 } |
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77 } |
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78 else |
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79 { |
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80 for (octave_idx_type j = nc; j > 0; j--) |
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81 { |
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82 OCTAVE_QUIT; |
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83 if (v.cidx(j) == nz && v.cidx(j-1) != nz) |
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84 end_nc = j; |
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85 if (nz - v.cidx(j-1) >= n_to_find) |
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86 { |
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87 start_nc = j - 1; |
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88 break; |
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89 } |
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90 } |
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91 } |
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92 |
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93 count = (n_to_find > v.cidx(end_nc) - v.cidx(start_nc) ? |
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94 v.cidx(end_nc) - v.cidx(start_nc) : n_to_find); |
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95 |
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96 // If the original argument was a row vector, force a row vector of |
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97 // the overall indices to be returned. But see below for scalar |
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98 // case... |
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99 |
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100 octave_idx_type result_nr = count; |
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101 octave_idx_type result_nc = 1; |
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102 |
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103 bool scalar_arg = false; |
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104 |
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105 if (v.rows () == 1) |
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106 { |
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107 result_nr = 1; |
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108 result_nc = count; |
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109 |
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110 scalar_arg = (v.columns () == 1); |
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111 } |
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112 |
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113 Matrix idx (result_nr, result_nc); |
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114 |
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115 Matrix i_idx (result_nr, result_nc); |
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116 Matrix j_idx (result_nr, result_nc); |
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117 |
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118 val = M(result_nr, result_nc); |
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119 |
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120 if (count > 0) |
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121 { |
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122 // Search for elements to return. Only search the region where |
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123 // there are elements to be found using the count that we want |
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124 // to find. |
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125 for (octave_idx_type j = start_nc, cx = 0; j < end_nc; j++) |
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126 for (octave_idx_type i = v.cidx(j); i < v.cidx(j+1); i++ ) |
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127 { |
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128 OCTAVE_QUIT; |
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129 if (direction < 0 && i < nz - count) |
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130 continue; |
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131 i_idx (cx) = static_cast<double> (v.ridx(i) + 1); |
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132 j_idx (cx) = static_cast<double> (j + 1); |
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133 idx (cx) = j * nr + v.ridx(i) + 1; |
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134 val (cx) = v.data(i); |
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135 cx++; |
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136 if (cx == count) |
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137 break; |
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138 } |
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139 } |
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140 else if (scalar_arg) |
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141 { |
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142 idx.resize (0, 0); |
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143 |
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144 i_idx.resize (0, 0); |
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145 j_idx.resize (0, 0); |
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146 |
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147 val.resize (0, 0); |
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148 } |
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149 |
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150 switch (nargout) |
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151 { |
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152 case 0: |
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153 case 1: |
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154 retval(0) = idx; |
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155 break; |
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156 |
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157 case 5: |
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158 retval(4) = nc; |
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159 // Fall through |
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160 |
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161 case 4: |
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162 retval(3) = nr; |
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163 // Fall through |
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164 |
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165 case 3: |
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166 retval(2) = val; |
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167 // Fall through! |
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168 |
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169 case 2: |
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170 retval(1) = j_idx; |
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171 retval(0) = i_idx; |
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172 break; |
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173 |
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174 default: |
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175 panic_impossible (); |
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176 break; |
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177 } |
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178 |
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179 return retval; |
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180 } |
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181 |
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182 template octave_value_list sparse_find_non_zero_elem_idx |
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183 (const SparseMatrix&, Matrix&, int, octave_idx_type, int); |
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184 |
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185 template octave_value_list sparse_find_non_zero_elem_idx |
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186 (const SparseComplexMatrix&, ComplexMatrix&, int, octave_idx_type, int); |
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187 |
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188 |
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189 // PKG_ADD: dispatch ("find", "spfind", "sparse matrix"); |
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190 // PKG_ADD: dispatch ("find", "spfind", "sparse complex matrix"); |
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191 // PKG_ADD: dispatch ("find", "spfind", "sparse bool matrix"); |
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192 DEFUN_DLD (spfind, args, nargout, |
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193 "-*- texinfo -*-\n\ |
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194 @deftypefn {Loadable Function} {} spfind (@var{x})\n\ |
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195 @deftypefnx {Loadable Function} {} spfind (@var{x}, @var{n})\n\ |
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196 @deftypefnx {Loadable Function} {} spfind (@var{x}, @var{n}, @var{direction})\n\ |
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197 @deftypefnx {Loadable Function} {[@var{i}, @var{j}, @var{v}} spfind (@dots{})\n\ |
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198 \n\ |
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199 A sparse version of the @code{find} function. Please see the @code{find}\n\ |
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200 for details of its use.\n\ |
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201 \n\ |
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202 Note that this function is particularly useful for sparse matrices, as\n\ |
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203 it extracts the non-zero elements as vectors, which can then be used to\n\ |
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204 create the original matrix. For example,\n\ |
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205 \n\ |
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206 @example\n\ |
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207 @group\n\ |
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208 sz = size(a);\n\ |
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209 [i, j, v] = spfind (a);\n\ |
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210 b = sparse(i, j, v, sz(1), sz(2));\n\ |
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211 @end group\n\ |
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212 @end example\n\ |
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213 @seealso{sparse}\n\ |
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214 @end deftypefn") |
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215 { |
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216 octave_value_list retval; |
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217 int nargin = args.length (); |
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218 |
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219 if (nargin > 3 || nargin < 1) |
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220 { |
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221 print_usage (); |
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222 return retval; |
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223 } |
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224 |
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225 // Setup the default options. |
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226 octave_idx_type n_to_find = -1; |
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227 if (nargin > 1) |
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228 { |
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229 n_to_find = args(1).int_value (); |
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230 if (error_state) |
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231 { |
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232 error ("find: expecting second argument to be an integer"); |
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233 return retval; |
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234 } |
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235 } |
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236 |
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237 // Direction to do the searching (1 == forward, -1 == reverse). |
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238 int direction = 1; |
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239 if (nargin > 2) |
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240 { |
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241 direction = 0; |
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242 |
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243 std::string s_arg = args(2).string_value (); |
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244 |
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245 if (! error_state) |
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246 { |
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247 if (s_arg == "first") |
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248 direction = 1; |
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249 else if (s_arg == "last") |
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250 direction = -1; |
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251 } |
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252 |
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253 if (direction == 0) |
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254 { |
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255 error ("find: expecting third argument to be \"first\" or \"last\""); |
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256 return retval; |
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257 } |
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258 } |
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259 |
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260 octave_value arg = args(0); |
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261 |
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262 if (arg.is_real_type ()) |
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263 { |
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264 SparseMatrix v = arg.sparse_matrix_value (); |
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265 Matrix val; |
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266 |
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267 if (! error_state) |
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268 retval = sparse_find_non_zero_elem_idx (v, val, nargout, n_to_find, direction); |
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269 } |
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270 else if (arg.is_complex_type ()) |
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271 { |
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272 SparseComplexMatrix v = arg.sparse_complex_matrix_value (); |
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273 ComplexMatrix val; |
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274 |
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275 if (! error_state) |
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276 retval = sparse_find_non_zero_elem_idx (v, val, nargout, n_to_find, direction); |
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277 } |
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278 else |
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279 gripe_wrong_type_arg ("spfind", arg); |
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280 |
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281 return retval; |
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282 } |
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283 |
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284 /* |
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285 ;;; Local Variables: *** |
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286 ;;; mode: C++ *** |
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287 ;;; End: *** |
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288 */ |
