1 | // Copyright (C) 2012 Ryan Curtin |
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2 | // Copyright (C) 2012 Conrad Sanderson |
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3 | // |
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4 | // This Source Code Form is subject to the terms of the Mozilla Public |
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5 | // License, v. 2.0. If a copy of the MPL was not distributed with this |
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6 | // file, You can obtain one at http://mozilla.org/MPL/2.0/. |
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7 | |
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8 | |
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9 | //! \addtogroup spop_mean |
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10 | //! @{ |
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11 | |
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12 | |
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13 | |
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14 | template<typename T1> |
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15 | inline |
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16 | void |
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17 | spop_mean::apply(SpMat<typename T1::elem_type>& out, const SpOp<T1, spop_mean>& in) |
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18 | { |
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19 | arma_extra_debug_sigprint(); |
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20 | |
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21 | typedef typename T1::elem_type eT; |
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22 | |
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23 | const uword dim = in.aux_uword_a; |
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24 | arma_debug_check((dim > 1), "mean(): incorrect usage. dim must be 0 or 1"); |
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25 | |
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26 | SpProxy<T1> p(in.m); |
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27 | |
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28 | if(p.is_alias(out) == false) |
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29 | { |
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30 | spop_mean::apply_noalias(out, p, dim); |
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31 | } |
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32 | else |
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33 | { |
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34 | SpMat<eT> tmp; |
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35 | |
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36 | spop_mean::apply_noalias(tmp, p, dim); |
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37 | |
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38 | out.steal_mem(tmp); |
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39 | } |
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40 | } |
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41 | |
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42 | |
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43 | |
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44 | template<typename T1> |
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45 | inline |
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46 | void |
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47 | spop_mean::apply_noalias |
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48 | ( |
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49 | SpMat<typename T1::elem_type>& out_ref, |
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50 | const SpProxy<T1>& p, |
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51 | const uword dim |
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52 | ) |
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53 | { |
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54 | arma_extra_debug_sigprint(); |
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55 | |
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56 | typedef typename T1::elem_type eT; |
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57 | |
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58 | const uword p_n_rows = p.get_n_rows(); |
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59 | const uword p_n_cols = p.get_n_cols(); |
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60 | |
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61 | if (dim == 0) |
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62 | { |
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63 | arma_extra_debug_print("spop_mean::apply_noalias(), dim = 0"); |
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64 | |
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65 | out_ref.set_size((p_n_rows > 0) ? 1 : 0, p_n_cols); |
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66 | |
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67 | if(p_n_rows > 0) |
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68 | { |
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69 | for(uword col = 0; col < p_n_cols; ++col) |
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70 | { |
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71 | // Do we have to use an iterator or can we use memory directly? |
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72 | if(SpProxy<T1>::must_use_iterator == true) |
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73 | { |
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74 | typename SpProxy<T1>::const_iterator_type it = p.begin_col(col); |
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75 | typename SpProxy<T1>::const_iterator_type end = p.begin_col(col + 1); |
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76 | |
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77 | const uword n_zero = p.get_n_rows() - (end.pos() - it.pos()); |
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78 | |
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79 | out_ref.at(col) = spop_mean::iterator_mean(it, end, n_zero, eT(0)); |
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80 | } |
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81 | else |
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82 | { |
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83 | out_ref.at(col) = spop_mean::direct_mean |
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84 | ( |
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85 | &p.get_values()[p.get_col_ptrs()[col]], |
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86 | p.get_col_ptrs()[col + 1] - p.get_col_ptrs()[col], |
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87 | p.get_n_rows() |
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88 | ); |
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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 | else if (dim == 1) |
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94 | { |
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95 | arma_extra_debug_print("spop_mean::apply_noalias(), dim = 1"); |
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96 | |
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97 | out_ref.set_size(p_n_rows, (p_n_cols > 0) ? 1 : 0); |
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98 | |
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99 | if(p_n_cols > 0) |
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100 | { |
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101 | for(uword row = 0; row < p_n_rows; ++row) |
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102 | { |
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103 | // We must use an iterator regardless of how it is stored. |
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104 | typename SpProxy<T1>::const_row_iterator_type it = p.begin_row(row); |
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105 | typename SpProxy<T1>::const_row_iterator_type end = p.end_row(row); |
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106 | |
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107 | const uword n_zero = p.get_n_cols() - (end.pos() - it.pos()); |
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108 | |
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109 | out_ref.at(row) = spop_mean::iterator_mean(it, end, n_zero, eT(0)); |
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110 | } |
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111 | } |
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112 | } |
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113 | } |
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114 | |
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115 | |
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116 | |
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117 | template<typename eT> |
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118 | inline |
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119 | eT |
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120 | spop_mean::direct_mean |
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121 | ( |
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122 | const eT* const X, |
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123 | const uword length, |
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124 | const uword N |
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125 | ) |
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126 | { |
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127 | arma_extra_debug_sigprint(); |
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128 | |
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129 | typedef typename get_pod_type<eT>::result T; |
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130 | |
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131 | const eT result = arrayops::accumulate(X, length) / T(N); |
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132 | |
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133 | return arma_isfinite(result) ? result : spop_mean::direct_mean_robust(X, length, N); |
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134 | } |
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135 | |
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136 | |
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137 | |
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138 | template<typename eT> |
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139 | inline |
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140 | eT |
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141 | spop_mean::direct_mean_robust |
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142 | ( |
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143 | const eT* const X, |
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144 | const uword length, |
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145 | const uword N |
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146 | ) |
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147 | { |
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148 | arma_extra_debug_sigprint(); |
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149 | |
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150 | typedef typename get_pod_type<eT>::result T; |
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151 | |
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152 | uword i, j; |
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153 | |
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154 | eT r_mean = eT(0); |
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155 | |
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156 | const uword diff = (N - length); // number of zeros |
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157 | |
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158 | for(i = 0, j = 1; j < length; i += 2, j += 2) |
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159 | { |
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160 | const eT Xi = X[i]; |
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161 | const eT Xj = X[j]; |
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162 | |
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163 | r_mean += (Xi - r_mean) / T(diff + j); |
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164 | r_mean += (Xj - r_mean) / T(diff + j + 1); |
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165 | } |
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166 | |
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167 | if(i < length) |
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168 | { |
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169 | const eT Xi = X[i]; |
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170 | |
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171 | r_mean += (Xi - r_mean) / T(diff + i + 1); |
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172 | } |
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173 | |
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174 | return r_mean; |
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175 | } |
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176 | |
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177 | |
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178 | |
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179 | template<typename T1> |
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180 | inline |
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181 | typename T1::elem_type |
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182 | spop_mean::mean_all(const SpBase<typename T1::elem_type, T1>& X) |
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183 | { |
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184 | arma_extra_debug_sigprint(); |
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185 | |
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186 | SpProxy<T1> p(X.get_ref()); |
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187 | |
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188 | if (SpProxy<T1>::must_use_iterator == true) |
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189 | { |
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190 | typename SpProxy<T1>::const_iterator_type it = p.begin(); |
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191 | typename SpProxy<T1>::const_iterator_type end = p.end(); |
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192 | |
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193 | return spop_mean::iterator_mean(it, end, p.get_n_elem() - p.get_n_nonzero(), typename T1::elem_type(0)); |
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194 | } |
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195 | else // must_use_iterator == false; that is, we can directly access the values array |
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196 | { |
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197 | return spop_mean::direct_mean(p.get_values(), p.get_n_nonzero(), p.get_n_elem()); |
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198 | } |
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199 | } |
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200 | |
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201 | |
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202 | |
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203 | template<typename T1, typename eT> |
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204 | inline |
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205 | eT |
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206 | spop_mean::iterator_mean(T1& it, const T1& end, const uword n_zero, const eT junk) |
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207 | { |
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208 | arma_extra_debug_sigprint(); |
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209 | arma_ignore(junk); |
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210 | |
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211 | typedef typename get_pod_type<eT>::result T; |
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212 | |
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213 | eT sum = eT(0); |
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214 | |
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215 | T1 backup_it(it); // in case we have to use robust iterator_mean |
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216 | |
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217 | const uword it_begin_pos = it.pos(); |
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218 | |
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219 | while (it != end) |
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220 | { |
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221 | sum += (*it); |
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222 | ++it; |
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223 | } |
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224 | |
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225 | const eT result = sum / T(n_zero + (it.pos() - it_begin_pos)); |
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226 | |
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227 | return arma_isfinite(result) ? result : spop_mean::iterator_mean_robust(backup_it, end, n_zero, eT(0)); |
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228 | } |
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229 | |
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230 | |
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231 | |
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232 | template<typename T1, typename eT> |
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233 | inline |
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234 | eT |
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235 | spop_mean::iterator_mean_robust(T1& it, const T1& end, const uword n_zero, const eT junk) |
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236 | { |
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237 | arma_extra_debug_sigprint(); |
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238 | arma_ignore(junk); |
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239 | |
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240 | typedef typename get_pod_type<eT>::result T; |
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241 | |
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242 | eT r_mean = eT(0); |
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243 | |
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244 | const uword it_begin_pos = it.pos(); |
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245 | |
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246 | while (it != end) |
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247 | { |
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248 | r_mean += ((*it - r_mean) / T(n_zero + (it.pos() - it_begin_pos) + 1)); |
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249 | ++it; |
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250 | } |
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251 | |
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252 | return r_mean; |
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253 | } |
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254 | |
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255 | |
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256 | |
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257 | //! @} |
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