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<a href="a00941.html">Go to the documentation of this file.</a><div class="fragment"><div class="line"><a name="l00001"></a><span class="lineno"> 1</span> <span class="comment">// -*- C++ -*-</span></div><div class="line"><a name="l00002"></a><span class="lineno"> 2</span> </div><div class="line"><a name="l00003"></a><span class="lineno"> 3</span> <span class="comment">// Copyright (C) 2007-2018 Free Software Foundation, Inc.</span></div><div class="line"><a name="l00004"></a><span class="lineno"> 4</span> <span class="comment">//</span></div><div class="line"><a name="l00005"></a><span class="lineno"> 5</span> <span class="comment">// This file is part of the GNU ISO C++ Library. This library is free</span></div><div class="line"><a name="l00006"></a><span class="lineno"> 6</span> <span class="comment">// software; you can redistribute it and/or modify it under the terms</span></div><div class="line"><a name="l00007"></a><span class="lineno"> 7</span> <span class="comment">// of the GNU General Public License as published by the Free Software</span></div><div class="line"><a name="l00008"></a><span class="lineno"> 8</span> <span class="comment">// Foundation; either version 3, or (at your option) any later</span></div><div class="line"><a name="l00009"></a><span class="lineno"> 9</span> <span class="comment">// version.</span></div><div class="line"><a name="l00010"></a><span class="lineno"> 10</span> </div><div class="line"><a name="l00011"></a><span class="lineno"> 11</span> <span class="comment">// This library is distributed in the hope that it will be useful, but</span></div><div class="line"><a name="l00012"></a><span class="lineno"> 12</span> <span class="comment">// WITHOUT ANY WARRANTY; without even the implied warranty of</span></div><div class="line"><a name="l00013"></a><span class="lineno"> 13</span> <span class="comment">// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU</span></div><div class="line"><a name="l00014"></a><span class="lineno"> 14</span> <span class="comment">// General Public License for more details.</span></div><div class="line"><a name="l00015"></a><span class="lineno"> 15</span> </div><div class="line"><a name="l00016"></a><span class="lineno"> 16</span> <span class="comment">// Under Section 7 of GPL version 3, you are granted additional</span></div><div class="line"><a name="l00017"></a><span class="lineno"> 17</span> <span class="comment">// permissions described in the GCC Runtime Library Exception, version</span></div><div class="line"><a name="l00018"></a><span class="lineno"> 18</span> <span class="comment">// 3.1, as published by the Free Software Foundation.</span></div><div class="line"><a name="l00019"></a><span class="lineno"> 19</span> </div><div class="line"><a name="l00020"></a><span class="lineno"> 20</span> <span class="comment">// You should have received a copy of the GNU General Public License and</span></div><div class="line"><a name="l00021"></a><span class="lineno"> 21</span> <span class="comment">// a copy of the GCC Runtime Library Exception along with this program;</span></div><div class="line"><a name="l00022"></a><span class="lineno"> 22</span> <span class="comment">// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see</span></div><div class="line"><a name="l00023"></a><span class="lineno"> 23</span> <span class="comment">// <http://www.gnu.org/licenses/>.</span></div><div class="line"><a name="l00024"></a><span class="lineno"> 24</span> <span class="comment"></span></div><div class="line"><a name="l00025"></a><span class="lineno"> 25</span> <span class="comment">/** @file parallel/partition.h</span></div><div class="line"><a name="l00026"></a><span class="lineno"> 26</span> <span class="comment"> * @brief Parallel implementation of std::partition(),</span></div><div class="line"><a name="l00027"></a><span class="lineno"> 27</span> <span class="comment"> * std::nth_element(), and std::partial_sort().</span></div><div class="line"><a name="l00028"></a><span class="lineno"> 28</span> <span class="comment"> * This file is a GNU parallel extension to the Standard C++ Library.</span></div><div class="line"><a name="l00029"></a><span class="lineno"> 29</span> <span class="comment"> */</span></div><div class="line"><a name="l00030"></a><span class="lineno"> 30</span> </div><div class="line"><a name="l00031"></a><span class="lineno"> 31</span> <span class="comment">// Written by Johannes Singler and Felix Putze.</span></div><div class="line"><a name="l00032"></a><span class="lineno"> 32</span> </div><div class="line"><a name="l00033"></a><span class="lineno"> 33</span> <span class="preprocessor">#ifndef _GLIBCXX_PARALLEL_PARTITION_H</span></div><div class="line"><a name="l00034"></a><span class="lineno"> 34</span> <span class="preprocessor">#define _GLIBCXX_PARALLEL_PARTITION_H 1</span></div><div class="line"><a name="l00035"></a><span class="lineno"> 35</span> </div><div class="line"><a name="l00036"></a><span class="lineno"> 36</span> <span class="preprocessor">#include <<a class="code" href="a00875.html">parallel/basic_iterator.h</a>></span></div><div class="line"><a name="l00037"></a><span class="lineno"> 37</span> <span class="preprocessor">#include <<a class="code" href="a00965.html">parallel/sort.h</a>></span></div><div class="line"><a name="l00038"></a><span class="lineno"> 38</span> <span class="preprocessor">#include <<a class="code" href="a00950.html">parallel/random_number.h</a>></span></div><div class="line"><a name="l00039"></a><span class="lineno"> 39</span> <span class="preprocessor">#include <<a class="code" href="a00527.html">bits/stl_algo.h</a>></span></div><div class="line"><a name="l00040"></a><span class="lineno"> 40</span> <span class="preprocessor">#include <<a class="code" href="a00935.html">parallel/parallel.h</a>></span></div><div class="line"><a name="l00041"></a><span class="lineno"> 41</span> <span class="comment"></span></div><div class="line"><a name="l00042"></a><span class="lineno"> 42</span> <span class="comment">/** @brief Decide whether to declare certain variables volatile. */</span></div><div class="line"><a name="l00043"></a><span class="lineno"><a class="line" href="a00941.html#a1c61e6ca8bdd220c11ec4b64f7539712"> 43</a></span> <span class="preprocessor">#define _GLIBCXX_VOLATILE volatile</span></div><div class="line"><a name="l00044"></a><span class="lineno"> 44</span> </div><div class="line"><a name="l00045"></a><span class="lineno"> 45</span> <span class="keyword">namespace </span><a class="code" href="a01575.html">__gnu_parallel</a></div><div class="line"><a name="l00046"></a><span class="lineno"> 46</span> {<span class="comment"></span></div><div class="line"><a name="l00047"></a><span class="lineno"> 47</span> <span class="comment"> /** @brief Parallel implementation of std::partition.</span></div><div class="line"><a name="l00048"></a><span class="lineno"> 48</span> <span class="comment"> * @param __begin Begin iterator of input sequence to split.</span></div><div class="line"><a name="l00049"></a><span class="lineno"> 49</span> <span class="comment"> * @param __end End iterator of input sequence to split.</span></div><div class="line"><a name="l00050"></a><span class="lineno"> 50</span> <span class="comment"> * @param __pred Partition predicate, possibly including some kind</span></div><div class="line"><a name="l00051"></a><span class="lineno"> 51</span> <span class="comment"> * of pivot.</span></div><div class="line"><a name="l00052"></a><span class="lineno"> 52</span> <span class="comment"> * @param __num_threads Maximum number of threads to use for this task.</span></div><div class="line"><a name="l00053"></a><span class="lineno"> 53</span> <span class="comment"> * @return Number of elements not fulfilling the predicate. */</span></div><div class="line"><a name="l00054"></a><span class="lineno"> 54</span>  <span class="keyword">template</span><<span class="keyword">typename</span> _RAIter, <span class="keyword">typename</span> _Predicate></div><div class="line"><a name="l00055"></a><span class="lineno"> 55</span>  <span class="keyword">typename</span> std::iterator_traits<_RAIter>::difference_type</div><div class="line"><a name="l00056"></a><span class="lineno"><a class="line" href="a01575.html#aa56788b479955dd136d6af173d2cae0b"> 56</a></span>  <a class="code" href="a01575.html#aa56788b479955dd136d6af173d2cae0b">__parallel_partition</a>(_RAIter __begin, _RAIter __end,</div><div class="line"><a name="l00057"></a><span class="lineno"> 57</span>  _Predicate __pred, <a class="code" href="a01575.html#a05e502e51bfc3233671730f74a44dc6a">_ThreadIndex</a> __num_threads)</div><div class="line"><a name="l00058"></a><span class="lineno"> 58</span>  {</div><div class="line"><a name="l00059"></a><span class="lineno"> 59</span>  <span class="keyword">typedef</span> std::iterator_traits<_RAIter> _TraitsType;</div><div class="line"><a name="l00060"></a><span class="lineno"> 60</span>  <span class="keyword">typedef</span> <span class="keyword">typename</span> _TraitsType::value_type _ValueType;</div><div class="line"><a name="l00061"></a><span class="lineno"> 61</span>  <span class="keyword">typedef</span> <span class="keyword">typename</span> _TraitsType::difference_type _DifferenceType;</div><div class="line"><a name="l00062"></a><span class="lineno"> 62</span> </div><div class="line"><a name="l00063"></a><span class="lineno"> 63</span>  _DifferenceType __n = __end - __begin;</div><div class="line"><a name="l00064"></a><span class="lineno"> 64</span> </div><div class="line"><a name="l00065"></a><span class="lineno"> 65</span>  <a class="code" href="a00881.html#a77fb93c9cecec331ccee755972695128">_GLIBCXX_CALL</a>(__n)</div><div class="line"><a name="l00066"></a><span class="lineno"> 66</span> </div><div class="line"><a name="l00067"></a><span class="lineno"> 67</span>  <span class="keyword">const</span> <a class="code" href="a09635.html">_Settings</a>& __s = <a class="code" href="a09635.html#abc4965eacae0b49945ebc887cb11adc1">_Settings::get</a>();</div><div class="line"><a name="l00068"></a><span class="lineno"> 68</span> </div><div class="line"><a name="l00069"></a><span class="lineno"> 69</span>  <span class="comment">// shared</span></div><div class="line"><a name="l00070"></a><span class="lineno"> 70</span>  <a class="code" href="a00941.html#a1c61e6ca8bdd220c11ec4b64f7539712">_GLIBCXX_VOLATILE</a> _DifferenceType __left = 0, __right = __n - 1,</div><div class="line"><a name="l00071"></a><span class="lineno"> 71</span>  __dist = __n,</div><div class="line"><a name="l00072"></a><span class="lineno"> 72</span>  __leftover_left, __leftover_right,</div><div class="line"><a name="l00073"></a><span class="lineno"> 73</span>  __leftnew, __rightnew;</div><div class="line"><a name="l00074"></a><span class="lineno"> 74</span> </div><div class="line"><a name="l00075"></a><span class="lineno"> 75</span>  <span class="comment">// just 0 or 1, but int to allow atomic operations</span></div><div class="line"><a name="l00076"></a><span class="lineno"> 76</span>  <span class="keywordtype">int</span>* __reserved_left = 0, * __reserved_right = 0;</div><div class="line"><a name="l00077"></a><span class="lineno"> 77</span> </div><div class="line"><a name="l00078"></a><span class="lineno"> 78</span>  _DifferenceType __chunk_size = __s.<a class="code" href="a09635.html#ad796aab8446ea9eaadfbc0b7b0787c71">partition_chunk_size</a>;</div><div class="line"><a name="l00079"></a><span class="lineno"> 79</span> </div><div class="line"><a name="l00080"></a><span class="lineno"> 80</span>  <span class="comment">//at least two chunks per thread</span></div><div class="line"><a name="l00081"></a><span class="lineno"> 81</span>  <span class="keywordflow">if</span> (__dist >= 2 * __num_threads * __chunk_size)</div><div class="line"><a name="l00082"></a><span class="lineno"> 82</span> <span class="preprocessor"># pragma omp parallel num_threads(__num_threads)</span></div><div class="line"><a name="l00083"></a><span class="lineno"> 83</span>  {</div><div class="line"><a name="l00084"></a><span class="lineno"> 84</span> <span class="preprocessor"># pragma omp single</span></div><div class="line"><a name="l00085"></a><span class="lineno"> 85</span>  {</div><div class="line"><a name="l00086"></a><span class="lineno"> 86</span>  __num_threads = omp_get_num_threads();</div><div class="line"><a name="l00087"></a><span class="lineno"> 87</span>  __reserved_left = <span class="keyword">new</span> <span class="keywordtype">int</span>[__num_threads];</div><div class="line"><a name="l00088"></a><span class="lineno"> 88</span>  __reserved_right = <span class="keyword">new</span> <span class="keywordtype">int</span>[__num_threads];</div><div class="line"><a name="l00089"></a><span class="lineno"> 89</span> </div><div class="line"><a name="l00090"></a><span class="lineno"> 90</span>  <span class="keywordflow">if</span> (__s.<a class="code" href="a09635.html#aaac9b17f2715c8b9101a2905562a43d1">partition_chunk_share</a> > 0.0)</div><div class="line"><a name="l00091"></a><span class="lineno"> 91</span>  __chunk_size = std::max<_DifferenceType></div><div class="line"><a name="l00092"></a><span class="lineno"> 92</span>  (__s.<a class="code" href="a09635.html#ad796aab8446ea9eaadfbc0b7b0787c71">partition_chunk_size</a>, (<span class="keywordtype">double</span>)__n </div><div class="line"><a name="l00093"></a><span class="lineno"> 93</span>  * __s.<a class="code" href="a09635.html#aaac9b17f2715c8b9101a2905562a43d1">partition_chunk_share</a> / (<span class="keywordtype">double</span>)__num_threads);</div><div class="line"><a name="l00094"></a><span class="lineno"> 94</span>  <span class="keywordflow">else</span></div><div class="line"><a name="l00095"></a><span class="lineno"> 95</span>  __chunk_size = __s.<a class="code" href="a09635.html#ad796aab8446ea9eaadfbc0b7b0787c71">partition_chunk_size</a>;</div><div class="line"><a name="l00096"></a><span class="lineno"> 96</span>  }</div><div class="line"><a name="l00097"></a><span class="lineno"> 97</span> </div><div class="line"><a name="l00098"></a><span class="lineno"> 98</span>  <span class="keywordflow">while</span> (__dist >= 2 * __num_threads * __chunk_size)</div><div class="line"><a name="l00099"></a><span class="lineno"> 99</span>  {</div><div class="line"><a name="l00100"></a><span class="lineno"> 100</span> <span class="preprocessor"># pragma omp single</span></div><div class="line"><a name="l00101"></a><span class="lineno"> 101</span>  {</div><div class="line"><a name="l00102"></a><span class="lineno"> 102</span>  _DifferenceType __num_chunks = __dist / __chunk_size;</div><div class="line"><a name="l00103"></a><span class="lineno"> 103</span> </div><div class="line"><a name="l00104"></a><span class="lineno"> 104</span>  <span class="keywordflow">for</span> (<a class="code" href="a01575.html#a05e502e51bfc3233671730f74a44dc6a">_ThreadIndex</a> __r = 0; __r < __num_threads; ++__r)</div><div class="line"><a name="l00105"></a><span class="lineno"> 105</span>  {</div><div class="line"><a name="l00106"></a><span class="lineno"> 106</span>  __reserved_left [__r] = 0; <span class="comment">// false</span></div><div class="line"><a name="l00107"></a><span class="lineno"> 107</span>  __reserved_right[__r] = 0; <span class="comment">// false</span></div><div class="line"><a name="l00108"></a><span class="lineno"> 108</span>  }</div><div class="line"><a name="l00109"></a><span class="lineno"> 109</span>  __leftover_left = 0;</div><div class="line"><a name="l00110"></a><span class="lineno"> 110</span>  __leftover_right = 0;</div><div class="line"><a name="l00111"></a><span class="lineno"> 111</span>  } <span class="comment">//implicit barrier</span></div><div class="line"><a name="l00112"></a><span class="lineno"> 112</span> </div><div class="line"><a name="l00113"></a><span class="lineno"> 113</span>  <span class="comment">// Private.</span></div><div class="line"><a name="l00114"></a><span class="lineno"> 114</span>  _DifferenceType __thread_left, __thread_left_border,</div><div class="line"><a name="l00115"></a><span class="lineno"> 115</span>  __thread_right, __thread_right_border;</div><div class="line"><a name="l00116"></a><span class="lineno"> 116</span> </div><div class="line"><a name="l00117"></a><span class="lineno"> 117</span>  __thread_left = __left + 1;</div><div class="line"><a name="l00118"></a><span class="lineno"> 118</span>  <span class="comment">// Just to satisfy the condition below.</span></div><div class="line"><a name="l00119"></a><span class="lineno"> 119</span>  __thread_left_border = __thread_left - 1;</div><div class="line"><a name="l00120"></a><span class="lineno"> 120</span> </div><div class="line"><a name="l00121"></a><span class="lineno"> 121</span>  __thread_right = __n - 1;</div><div class="line"><a name="l00122"></a><span class="lineno"> 122</span>  <span class="comment">// Just to satisfy the condition below.</span></div><div class="line"><a name="l00123"></a><span class="lineno"> 123</span>  __thread_right_border = __thread_right + 1;</div><div class="line"><a name="l00124"></a><span class="lineno"> 124</span> </div><div class="line"><a name="l00125"></a><span class="lineno"> 125</span>  <span class="keywordtype">bool</span> __iam_finished = <span class="keyword">false</span>;</div><div class="line"><a name="l00126"></a><span class="lineno"> 126</span>  <span class="keywordflow">while</span> (!__iam_finished)</div><div class="line"><a name="l00127"></a><span class="lineno"> 127</span>  {</div><div class="line"><a name="l00128"></a><span class="lineno"> 128</span>  <span class="keywordflow">if</span> (__thread_left > __thread_left_border)</div><div class="line"><a name="l00129"></a><span class="lineno"> 129</span>  {</div><div class="line"><a name="l00130"></a><span class="lineno"> 130</span>  _DifferenceType __former_dist =</div><div class="line"><a name="l00131"></a><span class="lineno"> 131</span>  <a class="code" href="a01575.html#a56a5a84c8a6049cd3cc83968c6eae088">__fetch_and_add</a>(&__dist, -__chunk_size);</div><div class="line"><a name="l00132"></a><span class="lineno"> 132</span>  <span class="keywordflow">if</span> (__former_dist < __chunk_size)</div><div class="line"><a name="l00133"></a><span class="lineno"> 133</span>  {</div><div class="line"><a name="l00134"></a><span class="lineno"> 134</span>  <a class="code" href="a01575.html#a56a5a84c8a6049cd3cc83968c6eae088">__fetch_and_add</a>(&__dist, __chunk_size);</div><div class="line"><a name="l00135"></a><span class="lineno"> 135</span>  __iam_finished = <span class="keyword">true</span>;</div><div class="line"><a name="l00136"></a><span class="lineno"> 136</span>  <span class="keywordflow">break</span>;</div><div class="line"><a name="l00137"></a><span class="lineno"> 137</span>  }</div><div class="line"><a name="l00138"></a><span class="lineno"> 138</span>  <span class="keywordflow">else</span></div><div class="line"><a name="l00139"></a><span class="lineno"> 139</span>  {</div><div class="line"><a name="l00140"></a><span class="lineno"> 140</span>  __thread_left =</div><div class="line"><a name="l00141"></a><span class="lineno"> 141</span>  <a class="code" href="a01575.html#a56a5a84c8a6049cd3cc83968c6eae088">__fetch_and_add</a>(&__left, __chunk_size);</div><div class="line"><a name="l00142"></a><span class="lineno"> 142</span>  __thread_left_border =</div><div class="line"><a name="l00143"></a><span class="lineno"> 143</span>  __thread_left + (__chunk_size - 1);</div><div class="line"><a name="l00144"></a><span class="lineno"> 144</span>  }</div><div class="line"><a name="l00145"></a><span class="lineno"> 145</span>  }</div><div class="line"><a name="l00146"></a><span class="lineno"> 146</span> </div><div class="line"><a name="l00147"></a><span class="lineno"> 147</span>  <span class="keywordflow">if</span> (__thread_right < __thread_right_border)</div><div class="line"><a name="l00148"></a><span class="lineno"> 148</span>  {</div><div class="line"><a name="l00149"></a><span class="lineno"> 149</span>  _DifferenceType __former_dist =</div><div class="line"><a name="l00150"></a><span class="lineno"> 150</span>  <a class="code" href="a01575.html#a56a5a84c8a6049cd3cc83968c6eae088">__fetch_and_add</a>(&__dist, -__chunk_size);</div><div class="line"><a name="l00151"></a><span class="lineno"> 151</span>  <span class="keywordflow">if</span> (__former_dist < __chunk_size)</div><div class="line"><a name="l00152"></a><span class="lineno"> 152</span>  {</div><div class="line"><a name="l00153"></a><span class="lineno"> 153</span>  <a class="code" href="a01575.html#a56a5a84c8a6049cd3cc83968c6eae088">__fetch_and_add</a>(&__dist, __chunk_size);</div><div class="line"><a name="l00154"></a><span class="lineno"> 154</span>  __iam_finished = <span class="keyword">true</span>;</div><div class="line"><a name="l00155"></a><span class="lineno"> 155</span>  <span class="keywordflow">break</span>;</div><div class="line"><a name="l00156"></a><span class="lineno"> 156</span>  }</div><div class="line"><a name="l00157"></a><span class="lineno"> 157</span>  <span class="keywordflow">else</span></div><div class="line"><a name="l00158"></a><span class="lineno"> 158</span>  {</div><div class="line"><a name="l00159"></a><span class="lineno"> 159</span>  __thread_right =</div><div class="line"><a name="l00160"></a><span class="lineno"> 160</span>  <a class="code" href="a01575.html#a56a5a84c8a6049cd3cc83968c6eae088">__fetch_and_add</a>(&__right, -__chunk_size);</div><div class="line"><a name="l00161"></a><span class="lineno"> 161</span>  __thread_right_border =</div><div class="line"><a name="l00162"></a><span class="lineno"> 162</span>  __thread_right - (__chunk_size - 1);</div><div class="line"><a name="l00163"></a><span class="lineno"> 163</span>  }</div><div class="line"><a name="l00164"></a><span class="lineno"> 164</span>  }</div><div class="line"><a name="l00165"></a><span class="lineno"> 165</span> </div><div class="line"><a name="l00166"></a><span class="lineno"> 166</span>  <span class="comment">// Swap as usual.</span></div><div class="line"><a name="l00167"></a><span class="lineno"> 167</span>  <span class="keywordflow">while</span> (__thread_left < __thread_right)</div><div class="line"><a name="l00168"></a><span class="lineno"> 168</span>  {</div><div class="line"><a name="l00169"></a><span class="lineno"> 169</span>  <span class="keywordflow">while</span> (__pred(__begin[__thread_left])</div><div class="line"><a name="l00170"></a><span class="lineno"> 170</span>  && __thread_left <= __thread_left_border)</div><div class="line"><a name="l00171"></a><span class="lineno"> 171</span>  ++__thread_left;</div><div class="line"><a name="l00172"></a><span class="lineno"> 172</span>  <span class="keywordflow">while</span> (!__pred(__begin[__thread_right])</div><div class="line"><a name="l00173"></a><span class="lineno"> 173</span>  && __thread_right >= __thread_right_border)</div><div class="line"><a name="l00174"></a><span class="lineno"> 174</span>  --__thread_right;</div><div class="line"><a name="l00175"></a><span class="lineno"> 175</span> </div><div class="line"><a name="l00176"></a><span class="lineno"> 176</span>  <span class="keywordflow">if</span> (__thread_left > __thread_left_border</div><div class="line"><a name="l00177"></a><span class="lineno"> 177</span>  || __thread_right < __thread_right_border)</div><div class="line"><a name="l00178"></a><span class="lineno"> 178</span>  <span class="comment">// Fetch new chunk(__s).</span></div><div class="line"><a name="l00179"></a><span class="lineno"> 179</span>  <span class="keywordflow">break</span>;</div><div class="line"><a name="l00180"></a><span class="lineno"> 180</span> </div><div class="line"><a name="l00181"></a><span class="lineno"> 181</span>  std::iter_swap(__begin + __thread_left,</div><div class="line"><a name="l00182"></a><span class="lineno"> 182</span>  __begin + __thread_right);</div><div class="line"><a name="l00183"></a><span class="lineno"> 183</span>  ++__thread_left;</div><div class="line"><a name="l00184"></a><span class="lineno"> 184</span>  --__thread_right;</div><div class="line"><a name="l00185"></a><span class="lineno"> 185</span>  }</div><div class="line"><a name="l00186"></a><span class="lineno"> 186</span>  }</div><div class="line"><a name="l00187"></a><span class="lineno"> 187</span> </div><div class="line"><a name="l00188"></a><span class="lineno"> 188</span>  <span class="comment">// Now swap the leftover chunks to the right places.</span></div><div class="line"><a name="l00189"></a><span class="lineno"> 189</span>  <span class="keywordflow">if</span> (__thread_left <= __thread_left_border)</div><div class="line"><a name="l00190"></a><span class="lineno"> 190</span> <span class="preprocessor"># pragma omp atomic</span></div><div class="line"><a name="l00191"></a><span class="lineno"> 191</span>  ++__leftover_left;</div><div class="line"><a name="l00192"></a><span class="lineno"> 192</span>  <span class="keywordflow">if</span> (__thread_right >= __thread_right_border)</div><div class="line"><a name="l00193"></a><span class="lineno"> 193</span> <span class="preprocessor"># pragma omp atomic</span></div><div class="line"><a name="l00194"></a><span class="lineno"> 194</span>  ++__leftover_right;</div><div class="line"><a name="l00195"></a><span class="lineno"> 195</span> </div><div class="line"><a name="l00196"></a><span class="lineno"> 196</span> <span class="preprocessor"># pragma omp barrier</span></div><div class="line"><a name="l00197"></a><span class="lineno"> 197</span> </div><div class="line"><a name="l00198"></a><span class="lineno"> 198</span>  _DifferenceType</div><div class="line"><a name="l00199"></a><span class="lineno"> 199</span>  __leftold = __left,</div><div class="line"><a name="l00200"></a><span class="lineno"> 200</span>  __leftnew = __left - __leftover_left * __chunk_size,</div><div class="line"><a name="l00201"></a><span class="lineno"> 201</span>  __rightold = __right,</div><div class="line"><a name="l00202"></a><span class="lineno"> 202</span>  __rightnew = __right + __leftover_right * __chunk_size;</div><div class="line"><a name="l00203"></a><span class="lineno"> 203</span> </div><div class="line"><a name="l00204"></a><span class="lineno"> 204</span>  <span class="comment">// <=> __thread_left_border + (__chunk_size - 1) >= __leftnew</span></div><div class="line"><a name="l00205"></a><span class="lineno"> 205</span>  <span class="keywordflow">if</span> (__thread_left <= __thread_left_border</div><div class="line"><a name="l00206"></a><span class="lineno"> 206</span>  && __thread_left_border >= __leftnew)</div><div class="line"><a name="l00207"></a><span class="lineno"> 207</span>  {</div><div class="line"><a name="l00208"></a><span class="lineno"> 208</span>  <span class="comment">// Chunk already in place, reserve spot.</span></div><div class="line"><a name="l00209"></a><span class="lineno"> 209</span>  __reserved_left[(__left - (__thread_left_border + 1))</div><div class="line"><a name="l00210"></a><span class="lineno"> 210</span>  / __chunk_size] = 1;</div><div class="line"><a name="l00211"></a><span class="lineno"> 211</span>  }</div><div class="line"><a name="l00212"></a><span class="lineno"> 212</span> </div><div class="line"><a name="l00213"></a><span class="lineno"> 213</span>  <span class="comment">// <=> __thread_right_border - (__chunk_size - 1) <= __rightnew</span></div><div class="line"><a name="l00214"></a><span class="lineno"> 214</span>  <span class="keywordflow">if</span> (__thread_right >= __thread_right_border</div><div class="line"><a name="l00215"></a><span class="lineno"> 215</span>  && __thread_right_border <= __rightnew)</div><div class="line"><a name="l00216"></a><span class="lineno"> 216</span>  {</div><div class="line"><a name="l00217"></a><span class="lineno"> 217</span>  <span class="comment">// Chunk already in place, reserve spot.</span></div><div class="line"><a name="l00218"></a><span class="lineno"> 218</span>  __reserved_right[((__thread_right_border - 1) - __right)</div><div class="line"><a name="l00219"></a><span class="lineno"> 219</span>  / __chunk_size] = 1;</div><div class="line"><a name="l00220"></a><span class="lineno"> 220</span>  }</div><div class="line"><a name="l00221"></a><span class="lineno"> 221</span> </div><div class="line"><a name="l00222"></a><span class="lineno"> 222</span> <span class="preprocessor"># pragma omp barrier</span></div><div class="line"><a name="l00223"></a><span class="lineno"> 223</span> </div><div class="line"><a name="l00224"></a><span class="lineno"> 224</span>  <span class="keywordflow">if</span> (__thread_left <= __thread_left_border</div><div class="line"><a name="l00225"></a><span class="lineno"> 225</span>  && __thread_left_border < __leftnew)</div><div class="line"><a name="l00226"></a><span class="lineno"> 226</span>  {</div><div class="line"><a name="l00227"></a><span class="lineno"> 227</span>  <span class="comment">// Find spot and swap.</span></div><div class="line"><a name="l00228"></a><span class="lineno"> 228</span>  _DifferenceType __swapstart = -1;</div><div class="line"><a name="l00229"></a><span class="lineno"> 229</span>  <span class="keywordflow">for</span> (<span class="keywordtype">int</span> __r = 0; __r < __leftover_left; ++__r)</div><div class="line"><a name="l00230"></a><span class="lineno"> 230</span>  <span class="keywordflow">if</span> (__reserved_left[__r] == 0</div><div class="line"><a name="l00231"></a><span class="lineno"> 231</span>  && <a class="code" href="a01575.html#accd4441e0f846fee44966195a91e9e68">__compare_and_swap</a>(&(__reserved_left[__r]), 0, 1))</div><div class="line"><a name="l00232"></a><span class="lineno"> 232</span>  {</div><div class="line"><a name="l00233"></a><span class="lineno"> 233</span>  __swapstart = __leftold - (__r + 1) * __chunk_size;</div><div class="line"><a name="l00234"></a><span class="lineno"> 234</span>  <span class="keywordflow">break</span>;</div><div class="line"><a name="l00235"></a><span class="lineno"> 235</span>  }</div><div class="line"><a name="l00236"></a><span class="lineno"> 236</span> </div><div class="line"><a name="l00237"></a><span class="lineno"> 237</span> <span class="preprocessor">#if _GLIBCXX_PARALLEL_ASSERTIONS</span></div><div class="line"><a name="l00238"></a><span class="lineno"> 238</span>  _GLIBCXX_PARALLEL_ASSERT(__swapstart != -1);</div><div class="line"><a name="l00239"></a><span class="lineno"> 239</span> <span class="preprocessor">#endif</span></div><div class="line"><a name="l00240"></a><span class="lineno"> 240</span> </div><div class="line"><a name="l00241"></a><span class="lineno"> 241</span>  std::swap_ranges(__begin + __thread_left_border</div><div class="line"><a name="l00242"></a><span class="lineno"> 242</span>  - (__chunk_size - 1),</div><div class="line"><a name="l00243"></a><span class="lineno"> 243</span>  __begin + __thread_left_border + 1,</div><div class="line"><a name="l00244"></a><span class="lineno"> 244</span>  __begin + __swapstart);</div><div class="line"><a name="l00245"></a><span class="lineno"> 245</span>  }</div><div class="line"><a name="l00246"></a><span class="lineno"> 246</span> </div><div class="line"><a name="l00247"></a><span class="lineno"> 247</span>  <span class="keywordflow">if</span> (__thread_right >= __thread_right_border</div><div class="line"><a name="l00248"></a><span class="lineno"> 248</span>  && __thread_right_border > __rightnew)</div><div class="line"><a name="l00249"></a><span class="lineno"> 249</span>  {</div><div class="line"><a name="l00250"></a><span class="lineno"> 250</span>  <span class="comment">// Find spot and swap</span></div><div class="line"><a name="l00251"></a><span class="lineno"> 251</span>  _DifferenceType __swapstart = -1;</div><div class="line"><a name="l00252"></a><span class="lineno"> 252</span>  <span class="keywordflow">for</span> (<span class="keywordtype">int</span> __r = 0; __r < __leftover_right; ++__r)</div><div class="line"><a name="l00253"></a><span class="lineno"> 253</span>  <span class="keywordflow">if</span> (__reserved_right[__r] == 0</div><div class="line"><a name="l00254"></a><span class="lineno"> 254</span>  && <a class="code" href="a01575.html#accd4441e0f846fee44966195a91e9e68">__compare_and_swap</a>(&(__reserved_right[__r]), 0, 1))</div><div class="line"><a name="l00255"></a><span class="lineno"> 255</span>  {</div><div class="line"><a name="l00256"></a><span class="lineno"> 256</span>  __swapstart = __rightold + __r * __chunk_size + 1;</div><div class="line"><a name="l00257"></a><span class="lineno"> 257</span>  <span class="keywordflow">break</span>;</div><div class="line"><a name="l00258"></a><span class="lineno"> 258</span>  }</div><div class="line"><a name="l00259"></a><span class="lineno"> 259</span> </div><div class="line"><a name="l00260"></a><span class="lineno"> 260</span> <span class="preprocessor">#if _GLIBCXX_PARALLEL_ASSERTIONS</span></div><div class="line"><a name="l00261"></a><span class="lineno"> 261</span>  _GLIBCXX_PARALLEL_ASSERT(__swapstart != -1);</div><div class="line"><a name="l00262"></a><span class="lineno"> 262</span> <span class="preprocessor">#endif</span></div><div class="line"><a name="l00263"></a><span class="lineno"> 263</span> </div><div class="line"><a name="l00264"></a><span class="lineno"> 264</span>  std::swap_ranges(__begin + __thread_right_border,</div><div class="line"><a name="l00265"></a><span class="lineno"> 265</span>  __begin + __thread_right_border</div><div class="line"><a name="l00266"></a><span class="lineno"> 266</span>  + __chunk_size, __begin + __swapstart);</div><div class="line"><a name="l00267"></a><span class="lineno"> 267</span>  }</div><div class="line"><a name="l00268"></a><span class="lineno"> 268</span> <span class="preprocessor">#if _GLIBCXX_PARALLEL_ASSERTIONS</span></div><div class="line"><a name="l00269"></a><span class="lineno"> 269</span> <span class="preprocessor"># pragma omp barrier</span></div><div class="line"><a name="l00270"></a><span class="lineno"> 270</span> </div><div class="line"><a name="l00271"></a><span class="lineno"> 271</span> <span class="preprocessor"># pragma omp single</span></div><div class="line"><a name="l00272"></a><span class="lineno"> 272</span>  {</div><div class="line"><a name="l00273"></a><span class="lineno"> 273</span>  <span class="keywordflow">for</span> (_DifferenceType __r = 0; __r < __leftover_left; ++__r)</div><div class="line"><a name="l00274"></a><span class="lineno"> 274</span>  _GLIBCXX_PARALLEL_ASSERT(__reserved_left[__r] == 1);</div><div class="line"><a name="l00275"></a><span class="lineno"> 275</span>  <span class="keywordflow">for</span> (_DifferenceType __r = 0; __r < __leftover_right; ++__r)</div><div class="line"><a name="l00276"></a><span class="lineno"> 276</span>  _GLIBCXX_PARALLEL_ASSERT(__reserved_right[__r] == 1);</div><div class="line"><a name="l00277"></a><span class="lineno"> 277</span>  }</div><div class="line"><a name="l00278"></a><span class="lineno"> 278</span> <span class="preprocessor">#endif</span></div><div class="line"><a name="l00279"></a><span class="lineno"> 279</span> </div><div class="line"><a name="l00280"></a><span class="lineno"> 280</span>  __left = __leftnew;</div><div class="line"><a name="l00281"></a><span class="lineno"> 281</span>  __right = __rightnew;</div><div class="line"><a name="l00282"></a><span class="lineno"> 282</span>  __dist = __right - __left + 1;</div><div class="line"><a name="l00283"></a><span class="lineno"> 283</span>  }</div><div class="line"><a name="l00284"></a><span class="lineno"> 284</span> </div><div class="line"><a name="l00285"></a><span class="lineno"> 285</span> <span class="preprocessor"># pragma omp flush(__left, __right)</span></div><div class="line"><a name="l00286"></a><span class="lineno"> 286</span>  } <span class="comment">// end "recursion" //parallel</span></div><div class="line"><a name="l00287"></a><span class="lineno"> 287</span> </div><div class="line"><a name="l00288"></a><span class="lineno"> 288</span>  _DifferenceType __final_left = __left, __final_right = __right;</div><div class="line"><a name="l00289"></a><span class="lineno"> 289</span> </div><div class="line"><a name="l00290"></a><span class="lineno"> 290</span>  <span class="keywordflow">while</span> (__final_left < __final_right)</div><div class="line"><a name="l00291"></a><span class="lineno"> 291</span>  {</div><div class="line"><a name="l00292"></a><span class="lineno"> 292</span>  <span class="comment">// Go right until key is geq than pivot.</span></div><div class="line"><a name="l00293"></a><span class="lineno"> 293</span>  <span class="keywordflow">while</span> (__pred(__begin[__final_left])</div><div class="line"><a name="l00294"></a><span class="lineno"> 294</span>  && __final_left < __final_right)</div><div class="line"><a name="l00295"></a><span class="lineno"> 295</span>  ++__final_left;</div><div class="line"><a name="l00296"></a><span class="lineno"> 296</span> </div><div class="line"><a name="l00297"></a><span class="lineno"> 297</span>  <span class="comment">// Go left until key is less than pivot.</span></div><div class="line"><a name="l00298"></a><span class="lineno"> 298</span>  <span class="keywordflow">while</span> (!__pred(__begin[__final_right])</div><div class="line"><a name="l00299"></a><span class="lineno"> 299</span>  && __final_left < __final_right)</div><div class="line"><a name="l00300"></a><span class="lineno"> 300</span>  --__final_right;</div><div class="line"><a name="l00301"></a><span class="lineno"> 301</span> </div><div class="line"><a name="l00302"></a><span class="lineno"> 302</span>  <span class="keywordflow">if</span> (__final_left == __final_right)</div><div class="line"><a name="l00303"></a><span class="lineno"> 303</span>  <span class="keywordflow">break</span>;</div><div class="line"><a name="l00304"></a><span class="lineno"> 304</span>  std::iter_swap(__begin + __final_left, __begin + __final_right);</div><div class="line"><a name="l00305"></a><span class="lineno"> 305</span>  ++__final_left;</div><div class="line"><a name="l00306"></a><span class="lineno"> 306</span>  --__final_right;</div><div class="line"><a name="l00307"></a><span class="lineno"> 307</span>  }</div><div class="line"><a name="l00308"></a><span class="lineno"> 308</span> </div><div class="line"><a name="l00309"></a><span class="lineno"> 309</span>  <span class="comment">// All elements on the left side are < piv, all elements on the</span></div><div class="line"><a name="l00310"></a><span class="lineno"> 310</span>  <span class="comment">// right are >= piv</span></div><div class="line"><a name="l00311"></a><span class="lineno"> 311</span>  <span class="keyword">delete</span>[] __reserved_left;</div><div class="line"><a name="l00312"></a><span class="lineno"> 312</span>  <span class="keyword">delete</span>[] __reserved_right;</div><div class="line"><a name="l00313"></a><span class="lineno"> 313</span> </div><div class="line"><a name="l00314"></a><span class="lineno"> 314</span>  <span class="comment">// Element "between" __final_left and __final_right might not have</span></div><div class="line"><a name="l00315"></a><span class="lineno"> 315</span>  <span class="comment">// been regarded yet</span></div><div class="line"><a name="l00316"></a><span class="lineno"> 316</span>  <span class="keywordflow">if</span> (__final_left < __n && !__pred(__begin[__final_left]))</div><div class="line"><a name="l00317"></a><span class="lineno"> 317</span>  <span class="comment">// Really swapped.</span></div><div class="line"><a name="l00318"></a><span class="lineno"> 318</span>  <span class="keywordflow">return</span> __final_left;</div><div class="line"><a name="l00319"></a><span class="lineno"> 319</span>  <span class="keywordflow">else</span></div><div class="line"><a name="l00320"></a><span class="lineno"> 320</span>  <span class="keywordflow">return</span> __final_left + 1;</div><div class="line"><a name="l00321"></a><span class="lineno"> 321</span>  }</div><div class="line"><a name="l00322"></a><span class="lineno"> 322</span> <span class="comment"></span></div><div class="line"><a name="l00323"></a><span class="lineno"> 323</span> <span class="comment"> /**</span></div><div class="line"><a name="l00324"></a><span class="lineno"> 324</span> <span class="comment"> * @brief Parallel implementation of std::nth_element().</span></div><div class="line"><a name="l00325"></a><span class="lineno"> 325</span> <span class="comment"> * @param __begin Begin iterator of input sequence.</span></div><div class="line"><a name="l00326"></a><span class="lineno"> 326</span> <span class="comment"> * @param __nth _Iterator of element that must be in position afterwards.</span></div><div class="line"><a name="l00327"></a><span class="lineno"> 327</span> <span class="comment"> * @param __end End iterator of input sequence.</span></div><div class="line"><a name="l00328"></a><span class="lineno"> 328</span> <span class="comment"> * @param __comp Comparator.</span></div><div class="line"><a name="l00329"></a><span class="lineno"> 329</span> <span class="comment"> */</span></div><div class="line"><a name="l00330"></a><span class="lineno"> 330</span>  <span class="keyword">template</span><<span class="keyword">typename</span> _RAIter, <span class="keyword">typename</span> _Compare></div><div class="line"><a name="l00331"></a><span class="lineno"> 331</span>  <span class="keywordtype">void</span> </div><div class="line"><a name="l00332"></a><span class="lineno"><a class="line" href="a01575.html#a1567c37a7562eaee17d13ebda1172586"> 332</a></span>  <a class="code" href="a01575.html#a1567c37a7562eaee17d13ebda1172586">__parallel_nth_element</a>(_RAIter __begin, _RAIter __nth, </div><div class="line"><a name="l00333"></a><span class="lineno"> 333</span>  _RAIter __end, _Compare __comp)</div><div class="line"><a name="l00334"></a><span class="lineno"> 334</span>  {</div><div class="line"><a name="l00335"></a><span class="lineno"> 335</span>  <span class="keyword">typedef</span> std::iterator_traits<_RAIter> _TraitsType;</div><div class="line"><a name="l00336"></a><span class="lineno"> 336</span>  <span class="keyword">typedef</span> <span class="keyword">typename</span> _TraitsType::value_type _ValueType;</div><div class="line"><a name="l00337"></a><span class="lineno"> 337</span>  <span class="keyword">typedef</span> <span class="keyword">typename</span> _TraitsType::difference_type _DifferenceType;</div><div class="line"><a name="l00338"></a><span class="lineno"> 338</span> </div><div class="line"><a name="l00339"></a><span class="lineno"> 339</span>  <a class="code" href="a00881.html#a77fb93c9cecec331ccee755972695128">_GLIBCXX_CALL</a>(__end - __begin)</div><div class="line"><a name="l00340"></a><span class="lineno"> 340</span> </div><div class="line"><a name="l00341"></a><span class="lineno"> 341</span>  _RAIter __split;</div><div class="line"><a name="l00342"></a><span class="lineno"> 342</span>  <a class="code" href="a09607.html">_RandomNumber</a> __rng;</div><div class="line"><a name="l00343"></a><span class="lineno"> 343</span> </div><div class="line"><a name="l00344"></a><span class="lineno"> 344</span>  <span class="keyword">const</span> <a class="code" href="a09635.html">_Settings</a>& __s = <a class="code" href="a09635.html#abc4965eacae0b49945ebc887cb11adc1">_Settings::get</a>();</div><div class="line"><a name="l00345"></a><span class="lineno"> 345</span>  _DifferenceType __minimum_length = std::max<_DifferenceType>(2,</div><div class="line"><a name="l00346"></a><span class="lineno"> 346</span>  <a class="code" href="a01485.html#ga84d30d8c4b3f2cbe8ec2055c34a578da">std::max</a>(__s.<a class="code" href="a09635.html#a34bef940cd171e22210e1c349152aab9">nth_element_minimal_n</a>, __s.<a class="code" href="a09635.html#ae56b6a01dc27becaa478828011527b4b">partition_minimal_n</a>));</div><div class="line"><a name="l00347"></a><span class="lineno"> 347</span> </div><div class="line"><a name="l00348"></a><span class="lineno"> 348</span>  <span class="comment">// Break if input range to small.</span></div><div class="line"><a name="l00349"></a><span class="lineno"> 349</span>  <span class="keywordflow">while</span> (static_cast<_SequenceIndex>(__end - __begin) >= __minimum_length)</div><div class="line"><a name="l00350"></a><span class="lineno"> 350</span>  {</div><div class="line"><a name="l00351"></a><span class="lineno"> 351</span>  _DifferenceType __n = __end - __begin;</div><div class="line"><a name="l00352"></a><span class="lineno"> 352</span> </div><div class="line"><a name="l00353"></a><span class="lineno"> 353</span>  _RAIter __pivot_pos = __begin + __rng(__n);</div><div class="line"><a name="l00354"></a><span class="lineno"> 354</span> </div><div class="line"><a name="l00355"></a><span class="lineno"> 355</span>  <span class="comment">// Swap __pivot_pos value to end.</span></div><div class="line"><a name="l00356"></a><span class="lineno"> 356</span>  <span class="keywordflow">if</span> (__pivot_pos != (__end - 1))</div><div class="line"><a name="l00357"></a><span class="lineno"> 357</span>  std::iter_swap(__pivot_pos, __end - 1);</div><div class="line"><a name="l00358"></a><span class="lineno"> 358</span>  __pivot_pos = __end - 1;</div><div class="line"><a name="l00359"></a><span class="lineno"> 359</span> </div><div class="line"><a name="l00360"></a><span class="lineno"> 360</span>  <span class="comment">// _Compare must have first_value_type, second_value_type,</span></div><div class="line"><a name="l00361"></a><span class="lineno"> 361</span>  <span class="comment">// result_type</span></div><div class="line"><a name="l00362"></a><span class="lineno"> 362</span>  <span class="comment">// _Compare ==</span></div><div class="line"><a name="l00363"></a><span class="lineno"> 363</span>  <span class="comment">// __gnu_parallel::_Lexicographic<S, int,</span></div><div class="line"><a name="l00364"></a><span class="lineno"> 364</span>  <span class="comment">// __gnu_parallel::_Less<S, S> ></span></div><div class="line"><a name="l00365"></a><span class="lineno"> 365</span>  <span class="comment">// __pivot_pos == std::pair<S, int>*</span></div><div class="line"><a name="l00366"></a><span class="lineno"> 366</span>  <a class="code" href="a09299.html">__gnu_parallel::__binder2nd<_Compare, _ValueType, _ValueType, bool></a></div><div class="line"><a name="l00367"></a><span class="lineno"> 367</span>  __pred(__comp, *__pivot_pos);</div><div class="line"><a name="l00368"></a><span class="lineno"> 368</span> </div><div class="line"><a name="l00369"></a><span class="lineno"> 369</span>  <span class="comment">// Divide, leave pivot unchanged in last place.</span></div><div class="line"><a name="l00370"></a><span class="lineno"> 370</span>  _RAIter __split_pos1, __split_pos2;</div><div class="line"><a name="l00371"></a><span class="lineno"> 371</span>  __split_pos1 = __begin + <a class="code" href="a01575.html#aa56788b479955dd136d6af173d2cae0b">__parallel_partition</a>(__begin, __end - 1,</div><div class="line"><a name="l00372"></a><span class="lineno"> 372</span>  __pred,</div><div class="line"><a name="l00373"></a><span class="lineno"> 373</span>  __get_max_threads());</div><div class="line"><a name="l00374"></a><span class="lineno"> 374</span> </div><div class="line"><a name="l00375"></a><span class="lineno"> 375</span>  <span class="comment">// Left side: < __pivot_pos; __right side: >= __pivot_pos</span></div><div class="line"><a name="l00376"></a><span class="lineno"> 376</span> </div><div class="line"><a name="l00377"></a><span class="lineno"> 377</span>  <span class="comment">// Swap pivot back to middle.</span></div><div class="line"><a name="l00378"></a><span class="lineno"> 378</span>  <span class="keywordflow">if</span> (__split_pos1 != __pivot_pos)</div><div class="line"><a name="l00379"></a><span class="lineno"> 379</span>  std::iter_swap(__split_pos1, __pivot_pos);</div><div class="line"><a name="l00380"></a><span class="lineno"> 380</span>  __pivot_pos = __split_pos1;</div><div class="line"><a name="l00381"></a><span class="lineno"> 381</span> </div><div class="line"><a name="l00382"></a><span class="lineno"> 382</span>  <span class="comment">// In case all elements are equal, __split_pos1 == 0</span></div><div class="line"><a name="l00383"></a><span class="lineno"> 383</span>  <span class="keywordflow">if</span> ((__split_pos1 + 1 - __begin) < (__n >> 7)</div><div class="line"><a name="l00384"></a><span class="lineno"> 384</span>  || (__end - __split_pos1) < (__n >> 7))</div><div class="line"><a name="l00385"></a><span class="lineno"> 385</span>  {</div><div class="line"><a name="l00386"></a><span class="lineno"> 386</span>  <span class="comment">// Very unequal split, one part smaller than one 128th</span></div><div class="line"><a name="l00387"></a><span class="lineno"> 387</span>  <span class="comment">// elements not strictly larger than the pivot.</span></div><div class="line"><a name="l00388"></a><span class="lineno"> 388</span>  <a class="code" href="a09291.html">__gnu_parallel::__unary_negate</a><__gnu_parallel::</div><div class="line"><a name="l00389"></a><span class="lineno"> 389</span>  __binder1st<_Compare, _ValueType,</div><div class="line"><a name="l00390"></a><span class="lineno"> 390</span>  _ValueType, <span class="keywordtype">bool</span>>, _ValueType></div><div class="line"><a name="l00391"></a><span class="lineno"> 391</span>  __pred(<a class="code" href="a09295.html">__gnu_parallel::__binder1st</a><_Compare, _ValueType,</div><div class="line"><a name="l00392"></a><span class="lineno"> 392</span>  _ValueType, <span class="keywordtype">bool</span>>(__comp, *__pivot_pos));</div><div class="line"><a name="l00393"></a><span class="lineno"> 393</span> </div><div class="line"><a name="l00394"></a><span class="lineno"> 394</span>  <span class="comment">// Find other end of pivot-equal range.</span></div><div class="line"><a name="l00395"></a><span class="lineno"> 395</span>  __split_pos2 = __gnu_sequential::partition(__split_pos1 + 1,</div><div class="line"><a name="l00396"></a><span class="lineno"> 396</span>  __end, __pred);</div><div class="line"><a name="l00397"></a><span class="lineno"> 397</span>  }</div><div class="line"><a name="l00398"></a><span class="lineno"> 398</span>  <span class="keywordflow">else</span></div><div class="line"><a name="l00399"></a><span class="lineno"> 399</span>  <span class="comment">// Only skip the pivot.</span></div><div class="line"><a name="l00400"></a><span class="lineno"> 400</span>  __split_pos2 = __split_pos1 + 1;</div><div class="line"><a name="l00401"></a><span class="lineno"> 401</span> </div><div class="line"><a name="l00402"></a><span class="lineno"> 402</span>  <span class="comment">// Compare iterators.</span></div><div class="line"><a name="l00403"></a><span class="lineno"> 403</span>  <span class="keywordflow">if</span> (__split_pos2 <= __nth)</div><div class="line"><a name="l00404"></a><span class="lineno"> 404</span>  __begin = __split_pos2;</div><div class="line"><a name="l00405"></a><span class="lineno"> 405</span>  <span class="keywordflow">else</span> <span class="keywordflow">if</span> (__nth < __split_pos1)</div><div class="line"><a name="l00406"></a><span class="lineno"> 406</span>  __end = __split_pos1;</div><div class="line"><a name="l00407"></a><span class="lineno"> 407</span>  <span class="keywordflow">else</span></div><div class="line"><a name="l00408"></a><span class="lineno"> 408</span>  <span class="keywordflow">break</span>;</div><div class="line"><a name="l00409"></a><span class="lineno"> 409</span>  }</div><div class="line"><a name="l00410"></a><span class="lineno"> 410</span> </div><div class="line"><a name="l00411"></a><span class="lineno"> 411</span>  <span class="comment">// Only at most _Settings::partition_minimal_n __elements __left.</span></div><div class="line"><a name="l00412"></a><span class="lineno"> 412</span>  __gnu_sequential::nth_element(__begin, __nth, __end, __comp);</div><div class="line"><a name="l00413"></a><span class="lineno"> 413</span>  }</div><div class="line"><a name="l00414"></a><span class="lineno"> 414</span> <span class="comment"></span></div><div class="line"><a name="l00415"></a><span class="lineno"> 415</span> <span class="comment"> /** @brief Parallel implementation of std::partial_sort().</span></div><div class="line"><a name="l00416"></a><span class="lineno"> 416</span> <span class="comment"> * @param __begin Begin iterator of input sequence.</span></div><div class="line"><a name="l00417"></a><span class="lineno"> 417</span> <span class="comment"> * @param __middle Sort until this position.</span></div><div class="line"><a name="l00418"></a><span class="lineno"> 418</span> <span class="comment"> * @param __end End iterator of input sequence.</span></div><div class="line"><a name="l00419"></a><span class="lineno"> 419</span> <span class="comment"> * @param __comp Comparator. */</span></div><div class="line"><a name="l00420"></a><span class="lineno"> 420</span>  <span class="keyword">template</span><<span class="keyword">typename</span> _RAIter, <span class="keyword">typename</span> _Compare></div><div class="line"><a name="l00421"></a><span class="lineno"> 421</span>  <span class="keywordtype">void</span></div><div class="line"><a name="l00422"></a><span class="lineno"><a class="line" href="a01575.html#abe60c5cc3788e1b1602175af0057d3f8"> 422</a></span>  <a class="code" href="a01575.html#abe60c5cc3788e1b1602175af0057d3f8">__parallel_partial_sort</a>(_RAIter __begin,</div><div class="line"><a name="l00423"></a><span class="lineno"> 423</span>  _RAIter __middle,</div><div class="line"><a name="l00424"></a><span class="lineno"> 424</span>  _RAIter __end, _Compare __comp)</div><div class="line"><a name="l00425"></a><span class="lineno"> 425</span>  {</div><div class="line"><a name="l00426"></a><span class="lineno"> 426</span>  <a class="code" href="a01575.html#a1567c37a7562eaee17d13ebda1172586">__parallel_nth_element</a>(__begin, __middle, __end, __comp);</div><div class="line"><a name="l00427"></a><span class="lineno"> 427</span>  std::sort(__begin, __middle, __comp);</div><div class="line"><a name="l00428"></a><span class="lineno"> 428</span>  }</div><div class="line"><a name="l00429"></a><span class="lineno"> 429</span> </div><div class="line"><a name="l00430"></a><span class="lineno"> 430</span> } <span class="comment">//namespace __gnu_parallel</span></div><div class="line"><a name="l00431"></a><span class="lineno"> 431</span> </div><div class="line"><a name="l00432"></a><span class="lineno"> 432</span> <span class="preprocessor">#undef _GLIBCXX_VOLATILE</span></div><div class="line"><a name="l00433"></a><span class="lineno"> 433</span> </div><div class="line"><a name="l00434"></a><span class="lineno"> 434</span> <span class="preprocessor">#endif </span><span class="comment">/* _GLIBCXX_PARALLEL_PARTITION_H */</span><span class="preprocessor"></span></div><div class="ttc" id="a09291_html"><div class="ttname"><a href="a09291.html">__gnu_parallel::__unary_negate</a></div><div class="ttdoc">Similar to std::unary_negate, but giving the argument types explicitly.</div><div class="ttdef"><b>Definition:</b> <a href="a16491_source.html#l00173">parallel/base.h:173</a></div></div>
<div class="ttc" id="a09635_html_a34bef940cd171e22210e1c349152aab9"><div class="ttname"><a href="a09635.html#a34bef940cd171e22210e1c349152aab9">__gnu_parallel::_Settings::nth_element_minimal_n</a></div><div class="ttdeci">_SequenceIndex nth_element_minimal_n</div><div class="ttdoc">Minimal input size for nth_element.</div><div class="ttdef"><b>Definition:</b> <a href="a00962_source.html#l00190">settings.h:190</a></div></div>
<div class="ttc" id="a01575_html_a1567c37a7562eaee17d13ebda1172586"><div class="ttname"><a href="a01575.html#a1567c37a7562eaee17d13ebda1172586">__gnu_parallel::__parallel_nth_element</a></div><div class="ttdeci">void __parallel_nth_element(_RAIter __begin, _RAIter __nth, _RAIter __end, _Compare __comp)</div><div class="ttdoc">Parallel implementation of std::nth_element().</div><div class="ttdef"><b>Definition:</b> <a href="a00941_source.html#l00332">partition.h:332</a></div></div>
<div class="ttc" id="a00527_html"><div class="ttname"><a href="a00527.html">stl_algo.h</a></div></div>
<div class="ttc" id="a09635_html"><div class="ttname"><a href="a09635.html">__gnu_parallel::_Settings</a></div><div class="ttdoc">class _Settings Run-time settings for the parallel mode including all tunable parameters.</div><div class="ttdef"><b>Definition:</b> <a href="a00962_source.html#l00123">settings.h:123</a></div></div>
<div class="ttc" id="a01575_html_aa56788b479955dd136d6af173d2cae0b"><div class="ttname"><a href="a01575.html#aa56788b479955dd136d6af173d2cae0b">__gnu_parallel::__parallel_partition</a></div><div class="ttdeci">std::iterator_traits< _RAIter >::difference_type __parallel_partition(_RAIter __begin, _RAIter __end, _Predicate __pred, _ThreadIndex __num_threads)</div><div class="ttdoc">Parallel implementation of std::partition.</div><div class="ttdef"><b>Definition:</b> <a href="a00941_source.html#l00056">partition.h:56</a></div></div>
<div class="ttc" id="a00935_html"><div class="ttname"><a href="a00935.html">parallel.h</a></div><div class="ttdoc">End-user include file. Provides advanced settings and tuning options. This file is a GNU parallel ext...</div></div>
<div class="ttc" id="a09635_html_ae56b6a01dc27becaa478828011527b4b"><div class="ttname"><a href="a09635.html#ae56b6a01dc27becaa478828011527b4b">__gnu_parallel::_Settings::partition_minimal_n</a></div><div class="ttdeci">_SequenceIndex partition_minimal_n</div><div class="ttdoc">Minimal input size for partition.</div><div class="ttdef"><b>Definition:</b> <a href="a00962_source.html#l00200">settings.h:200</a></div></div>
<div class="ttc" id="a00950_html"><div class="ttname"><a href="a00950.html">random_number.h</a></div><div class="ttdoc">Random number generator based on the Mersenne twister. This file is a GNU parallel extension to the S...</div></div>
<div class="ttc" id="a09299_html"><div class="ttname"><a href="a09299.html">__gnu_parallel::__binder2nd</a></div><div class="ttdoc">Similar to std::binder2nd, but giving the argument types explicitly.</div><div class="ttdef"><b>Definition:</b> <a href="a16491_source.html#l00220">parallel/base.h:220</a></div></div>
<div class="ttc" id="a09635_html_aaac9b17f2715c8b9101a2905562a43d1"><div class="ttname"><a href="a09635.html#aaac9b17f2715c8b9101a2905562a43d1">__gnu_parallel::_Settings::partition_chunk_share</a></div><div class="ttdeci">double partition_chunk_share</div><div class="ttdoc">Chunk size for partition, relative to input size. If > 0.0, this value overrides partition_chunk_size...</div><div class="ttdef"><b>Definition:</b> <a href="a00962_source.html#l00197">settings.h:197</a></div></div>
<div class="ttc" id="a00875_html"><div class="ttname"><a href="a00875.html">basic_iterator.h</a></div><div class="ttdoc">Includes the original header files concerned with iterators except for stream iterators....</div></div>
<div class="ttc" id="a09295_html"><div class="ttname"><a href="a09295.html">__gnu_parallel::__binder1st</a></div><div class="ttdoc">Similar to std::binder1st, but giving the argument types explicitly.</div><div class="ttdef"><b>Definition:</b> <a href="a16491_source.html#l00192">parallel/base.h:192</a></div></div>
<div class="ttc" id="a00881_html_a77fb93c9cecec331ccee755972695128"><div class="ttname"><a href="a00881.html#a77fb93c9cecec331ccee755972695128">_GLIBCXX_CALL</a></div><div class="ttdeci">#define _GLIBCXX_CALL(__n)</div><div class="ttdoc">Macro to produce log message when entering a function.</div><div class="ttdef"><b>Definition:</b> <a href="a00881_source.html#l00044">compiletime_settings.h:44</a></div></div>
<div class="ttc" id="a01575_html_accd4441e0f846fee44966195a91e9e68"><div class="ttname"><a href="a01575.html#accd4441e0f846fee44966195a91e9e68">__gnu_parallel::__compare_and_swap</a></div><div class="ttdeci">bool __compare_and_swap(volatile _Tp *__ptr, _Tp __comparand, _Tp __replacement)</div><div class="ttdoc">Compare-and-swap.</div><div class="ttdef"><b>Definition:</b> <a href="a16530_source.html#l00108">parallel/compatibility.h:108</a></div></div>
<div class="ttc" id="a01575_html_a56a5a84c8a6049cd3cc83968c6eae088"><div class="ttname"><a href="a01575.html#a56a5a84c8a6049cd3cc83968c6eae088">__gnu_parallel::__fetch_and_add</a></div><div class="ttdeci">_Tp __fetch_and_add(volatile _Tp *__ptr, _Tp __addend)</div><div class="ttdoc">Add a value to a variable, atomically.</div><div class="ttdef"><b>Definition:</b> <a href="a16530_source.html#l00074">parallel/compatibility.h:74</a></div></div>
<div class="ttc" id="a01575_html"><div class="ttname"><a href="a01575.html">__gnu_parallel</a></div><div class="ttdoc">GNU parallel code for public use.</div><div class="ttdef"><b>Definition:</b> <a href="a00872_source.html#l00061">balanced_quicksort.h:61</a></div></div>
<div class="ttc" id="a00941_html_a1c61e6ca8bdd220c11ec4b64f7539712"><div class="ttname"><a href="a00941.html#a1c61e6ca8bdd220c11ec4b64f7539712">_GLIBCXX_VOLATILE</a></div><div class="ttdeci">#define _GLIBCXX_VOLATILE</div><div class="ttdoc">Decide whether to declare certain variables volatile.</div><div class="ttdef"><b>Definition:</b> <a href="a00941_source.html#l00043">partition.h:43</a></div></div>
<div class="ttc" id="a01575_html_abe60c5cc3788e1b1602175af0057d3f8"><div class="ttname"><a href="a01575.html#abe60c5cc3788e1b1602175af0057d3f8">__gnu_parallel::__parallel_partial_sort</a></div><div class="ttdeci">void __parallel_partial_sort(_RAIter __begin, _RAIter __middle, _RAIter __end, _Compare __comp)</div><div class="ttdoc">Parallel implementation of std::partial_sort().</div><div class="ttdef"><b>Definition:</b> <a href="a00941_source.html#l00422">partition.h:422</a></div></div>
<div class="ttc" id="a09635_html_ad796aab8446ea9eaadfbc0b7b0787c71"><div class="ttname"><a href="a09635.html#ad796aab8446ea9eaadfbc0b7b0787c71">__gnu_parallel::_Settings::partition_chunk_size</a></div><div class="ttdeci">_SequenceIndex partition_chunk_size</div><div class="ttdoc">Chunk size for partition.</div><div class="ttdef"><b>Definition:</b> <a href="a00962_source.html#l00193">settings.h:193</a></div></div>
<div class="ttc" id="a00965_html"><div class="ttname"><a href="a00965.html">sort.h</a></div><div class="ttdoc">Parallel sorting algorithm switch. This file is a GNU parallel extension to the Standard C++ Library.</div></div>
<div class="ttc" id="a09635_html_abc4965eacae0b49945ebc887cb11adc1"><div class="ttname"><a href="a09635.html#abc4965eacae0b49945ebc887cb11adc1">__gnu_parallel::_Settings::get</a></div><div class="ttdeci">static const _Settings & get()</div><div class="ttdoc">Get the global settings.</div></div>
<div class="ttc" id="a01575_html_a05e502e51bfc3233671730f74a44dc6a"><div class="ttname"><a href="a01575.html#a05e502e51bfc3233671730f74a44dc6a">__gnu_parallel::_ThreadIndex</a></div><div class="ttdeci">uint16_t _ThreadIndex</div><div class="ttdoc">Unsigned integer to index a thread number. The maximum thread number (for each processor) must fit in...</div><div class="ttdef"><b>Definition:</b> <a href="a00971_source.html#l00123">types.h:123</a></div></div>
<div class="ttc" id="a09607_html"><div class="ttname"><a href="a09607.html">__gnu_parallel::_RandomNumber</a></div><div class="ttdoc">Random number generator, based on the Mersenne twister.</div><div class="ttdef"><b>Definition:</b> <a href="a00950_source.html#l00042">random_number.h:42</a></div></div>
<div class="ttc" id="a01485_html_ga84d30d8c4b3f2cbe8ec2055c34a578da"><div class="ttname"><a href="a01485.html#ga84d30d8c4b3f2cbe8ec2055c34a578da">std::max</a></div><div class="ttdeci">_GLIBCXX14_CONSTEXPR const _Tp & max(const _Tp &, const _Tp &)</div><div class="ttdoc">This does what you think it does.</div><div class="ttdef"><b>Definition:</b> <a href="a00530_source.html#l00219">stl_algobase.h:219</a></div></div>
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