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<div class="title">/data/users/matthijs/github_faiss/faiss/hamming.h</div> </div>
</div><!--header-->
<div class="contents">
<div class="fragment"><div class="line"><a name="l00001"></a><span class="lineno"> 1</span> <span class="comment">/**</span></div>
<div class="line"><a name="l00002"></a><span class="lineno"> 2</span> <span class="comment"> * Copyright (c) 2015-present, Facebook, Inc.</span></div>
<div class="line"><a name="l00003"></a><span class="lineno"> 3</span> <span class="comment"> * All rights reserved.</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 source code is licensed under the BSD+Patents license found in the</span></div>
<div class="line"><a name="l00006"></a><span class="lineno"> 6</span> <span class="comment"> * LICENSE file in the root directory of this source tree.</span></div>
<div class="line"><a name="l00007"></a><span class="lineno"> 7</span> <span class="comment"> */</span></div>
<div class="line"><a name="l00008"></a><span class="lineno"> 8</span> </div>
<div class="line"><a name="l00009"></a><span class="lineno"> 9</span> </div>
<div class="line"><a name="l00010"></a><span class="lineno"> 10</span> <span class="comment">/* Copyright 2004-present Facebook. All Rights Reserved.</span></div>
<div class="line"><a name="l00011"></a><span class="lineno"> 11</span> <span class="comment"> *</span></div>
<div class="line"><a name="l00012"></a><span class="lineno"> 12</span> <span class="comment"> * Hamming distances. The binary vector dimensionality should be a multiple</span></div>
<div class="line"><a name="l00013"></a><span class="lineno"> 13</span> <span class="comment"> * of 64, as the elementary operations operate on words. If you really need</span></div>
<div class="line"><a name="l00014"></a><span class="lineno"> 14</span> <span class="comment"> * other sizes, just pad with 0s (this is done by function fvecs2bitvecs).</span></div>
<div class="line"><a name="l00015"></a><span class="lineno"> 15</span> <span class="comment"> *</span></div>
<div class="line"><a name="l00016"></a><span class="lineno"> 16</span> <span class="comment"> * User-defined type hamdis_t is used for distances because at this time</span></div>
<div class="line"><a name="l00017"></a><span class="lineno"> 17</span> <span class="comment"> * it is still uncler clear how we will need to balance</span></div>
<div class="line"><a name="l00018"></a><span class="lineno"> 18</span> <span class="comment"> * - flexibility in vector size (may need 16- or even 8-bit vectors)</span></div>
<div class="line"><a name="l00019"></a><span class="lineno"> 19</span> <span class="comment"> * - memory usage</span></div>
<div class="line"><a name="l00020"></a><span class="lineno"> 20</span> <span class="comment"> * - cache-misses when dealing with large volumes of data (fewer bits is better)</span></div>
<div class="line"><a name="l00021"></a><span class="lineno"> 21</span> <span class="comment"> *</span></div>
<div class="line"><a name="l00022"></a><span class="lineno"> 22</span> <span class="comment"> * hamdis_t should optimally be compatibe with one of the Torch Storage</span></div>
<div class="line"><a name="l00023"></a><span class="lineno"> 23</span> <span class="comment"> * (Byte,Short,Long) and therefore should be signed for 2-bytes and 4-bytes.</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> </div>
<div class="line"><a name="l00026"></a><span class="lineno"> 26</span> <span class="preprocessor">#ifndef FAISS_hamming_h</span></div>
<div class="line"><a name="l00027"></a><span class="lineno"> 27</span> <span class="preprocessor"></span><span class="preprocessor">#define FAISS_hamming_h</span></div>
<div class="line"><a name="l00028"></a><span class="lineno"> 28</span> <span class="preprocessor"></span></div>
<div class="line"><a name="l00029"></a><span class="lineno"> 29</span> </div>
<div class="line"><a name="l00030"></a><span class="lineno"> 30</span> <span class="preprocessor">#include <stdint.h></span></div>
<div class="line"><a name="l00031"></a><span class="lineno"> 31</span> </div>
<div class="line"><a name="l00032"></a><span class="lineno"> 32</span> <span class="preprocessor">#include "Heap.h"</span></div>
<div class="line"><a name="l00033"></a><span class="lineno"> 33</span> </div>
<div class="line"><a name="l00034"></a><span class="lineno"> 34</span> </div>
<div class="line"><a name="l00035"></a><span class="lineno"> 35</span> <span class="comment">/* The Hamming distance type should be exportable to Lua Tensor, which</span></div>
<div class="line"><a name="l00036"></a><span class="lineno"> 36</span> <span class="comment"> excludes most unsigned type */</span></div>
<div class="line"><a name="l00037"></a><span class="lineno"> 37</span> <span class="keyword">typedef</span> int32_t hamdis_t;</div>
<div class="line"><a name="l00038"></a><span class="lineno"> 38</span> </div>
<div class="line"><a name="l00039"></a><span class="lineno"> 39</span> <span class="keyword">namespace </span>faiss {</div>
<div class="line"><a name="l00040"></a><span class="lineno"> 40</span> </div>
<div class="line"><a name="l00041"></a><span class="lineno"> 41</span> <span class="keyword">inline</span> <span class="keywordtype">int</span> popcount64(uint64_t x) {</div>
<div class="line"><a name="l00042"></a><span class="lineno"> 42</span>  <span class="keywordflow">return</span> __builtin_popcountl(x);</div>
<div class="line"><a name="l00043"></a><span class="lineno"> 43</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="comment"></span></div>
<div class="line"><a name="l00046"></a><span class="lineno"> 46</span> <span class="comment">/** Compute a set of Hamming distances between na and nb binary vectors</span></div>
<div class="line"><a name="l00047"></a><span class="lineno"> 47</span> <span class="comment"> *</span></div>
<div class="line"><a name="l00048"></a><span class="lineno"> 48</span> <span class="comment"> * @param a size na * nbytespercode</span></div>
<div class="line"><a name="l00049"></a><span class="lineno"> 49</span> <span class="comment"> * @param b size nb * nbytespercode</span></div>
<div class="line"><a name="l00050"></a><span class="lineno"> 50</span> <span class="comment"> * @param nbytespercode should be multiple of 8</span></div>
<div class="line"><a name="l00051"></a><span class="lineno"> 51</span> <span class="comment"> * @param dis output distances, size na * nb</span></div>
<div class="line"><a name="l00052"></a><span class="lineno"> 52</span> <span class="comment"> */</span></div>
<div class="line"><a name="l00053"></a><span class="lineno"> 53</span> <span class="keywordtype">void</span> hammings (</div>
<div class="line"><a name="l00054"></a><span class="lineno"> 54</span>  <span class="keyword">const</span> uint8_t * a,</div>
<div class="line"><a name="l00055"></a><span class="lineno"> 55</span>  <span class="keyword">const</span> uint8_t * b,</div>
<div class="line"><a name="l00056"></a><span class="lineno"> 56</span>  <span class="keywordtype">size_t</span> na, <span class="keywordtype">size_t</span> nb,</div>
<div class="line"><a name="l00057"></a><span class="lineno"> 57</span>  <span class="keywordtype">size_t</span> nbytespercode,</div>
<div class="line"><a name="l00058"></a><span class="lineno"> 58</span>  hamdis_t * dis);</div>
<div class="line"><a name="l00059"></a><span class="lineno"> 59</span> </div>
<div class="line"><a name="l00060"></a><span class="lineno"> 60</span> <span class="keywordtype">void</span> bitvec_print (<span class="keyword">const</span> uint8_t * b, <span class="keywordtype">size_t</span> d);</div>
<div class="line"><a name="l00061"></a><span class="lineno"> 61</span> </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> <span class="comment">/* Functions for casting vectors of regular types to compact bits.</span></div>
<div class="line"><a name="l00064"></a><span class="lineno"> 64</span> <span class="comment"> They assume proper allocation done beforehand, meaning that b</span></div>
<div class="line"><a name="l00065"></a><span class="lineno"> 65</span> <span class="comment"> should be be able to receive as many bits as x may produce. */</span></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="comment">/* Makes an array of bits from the signs of a float array. The length</span></div>
<div class="line"><a name="l00068"></a><span class="lineno"> 68</span> <span class="comment"> of the output array b is rounded up to byte size (allocate</span></div>
<div class="line"><a name="l00069"></a><span class="lineno"> 69</span> <span class="comment"> accordingly) */</span></div>
<div class="line"><a name="l00070"></a><span class="lineno"> 70</span> <span class="keywordtype">void</span> fvecs2bitvecs (</div>
<div class="line"><a name="l00071"></a><span class="lineno"> 71</span>  <span class="keyword">const</span> <span class="keywordtype">float</span> * x,</div>
<div class="line"><a name="l00072"></a><span class="lineno"> 72</span>  uint8_t * b,</div>
<div class="line"><a name="l00073"></a><span class="lineno"> 73</span>  <span class="keywordtype">size_t</span> d,</div>
<div class="line"><a name="l00074"></a><span class="lineno"> 74</span>  <span class="keywordtype">size_t</span> n);</div>
<div class="line"><a name="l00075"></a><span class="lineno"> 75</span> </div>
<div class="line"><a name="l00076"></a><span class="lineno"> 76</span> </div>
<div class="line"><a name="l00077"></a><span class="lineno"> 77</span> <span class="keywordtype">void</span> fvec2bitvec (<span class="keyword">const</span> <span class="keywordtype">float</span> * x, uint8_t * b, <span class="keywordtype">size_t</span> d);</div>
<div class="line"><a name="l00078"></a><span class="lineno"> 78</span> </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"></span></div>
<div class="line"><a name="l00081"></a><span class="lineno"> 81</span> <span class="comment">/** Return the k smallest Hamming distances for a set of binary query vectors</span></div>
<div class="line"><a name="l00082"></a><span class="lineno"> 82</span> <span class="comment"> * @param a queries, size ha->nh * ncodes</span></div>
<div class="line"><a name="l00083"></a><span class="lineno"> 83</span> <span class="comment"> * @param b database, size nb * ncodes</span></div>
<div class="line"><a name="l00084"></a><span class="lineno"> 84</span> <span class="comment"> * @param nb number of database vectors</span></div>
<div class="line"><a name="l00085"></a><span class="lineno"> 85</span> <span class="comment"> * @param ncodes size of the binary codes (bytes)</span></div>
<div class="line"><a name="l00086"></a><span class="lineno"> 86</span> <span class="comment"> * @param ordered if != 0: order the results by decreasing distance</span></div>
<div class="line"><a name="l00087"></a><span class="lineno"> 87</span> <span class="comment"> * (may be bottleneck for k/n > 0.01) */</span></div>
<div class="line"><a name="l00088"></a><span class="lineno"> 88</span> <span class="keywordtype">void</span> <a class="code" href="namespacefaiss.html#ac0b4dc73a8470d61f510396dc460ca18">hammings_knn</a> (</div>
<div class="line"><a name="l00089"></a><span class="lineno"> 89</span>  int_maxheap_array_t * ha,</div>
<div class="line"><a name="l00090"></a><span class="lineno"> 90</span>  <span class="keyword">const</span> uint8_t * a,</div>
<div class="line"><a name="l00091"></a><span class="lineno"> 91</span>  <span class="keyword">const</span> uint8_t * b,</div>
<div class="line"><a name="l00092"></a><span class="lineno"> 92</span>  <span class="keywordtype">size_t</span> nb,</div>
<div class="line"><a name="l00093"></a><span class="lineno"> 93</span>  <span class="keywordtype">size_t</span> ncodes,</div>
<div class="line"><a name="l00094"></a><span class="lineno"> 94</span>  <span class="keywordtype">int</span> ordered);</div>
<div class="line"><a name="l00095"></a><span class="lineno"> 95</span> </div>
<div class="line"><a name="l00096"></a><span class="lineno"> 96</span> <span class="comment">/* The core function, without initialization and no re-ordering */</span></div>
<div class="line"><a name="l00097"></a><span class="lineno"> 97</span> <span class="keywordtype">void</span> hammings_knn_core (</div>
<div class="line"><a name="l00098"></a><span class="lineno"> 98</span>  int_maxheap_array_t * ha,</div>
<div class="line"><a name="l00099"></a><span class="lineno"> 99</span>  <span class="keyword">const</span> uint8_t * a,</div>
<div class="line"><a name="l00100"></a><span class="lineno"> 100</span>  <span class="keyword">const</span> uint8_t * b,</div>
<div class="line"><a name="l00101"></a><span class="lineno"> 101</span>  <span class="keywordtype">size_t</span> nb,</div>
<div class="line"><a name="l00102"></a><span class="lineno"> 102</span>  <span class="keywordtype">size_t</span> ncodes);</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> </div>
<div class="line"><a name="l00105"></a><span class="lineno"> 105</span> <span class="comment">/* Counting the number of matches or of cross-matches (without returning them)</span></div>
<div class="line"><a name="l00106"></a><span class="lineno"> 106</span> <span class="comment"> For use with function that assume pre-allocated memory */</span></div>
<div class="line"><a name="l00107"></a><span class="lineno"> 107</span> <span class="keywordtype">void</span> hamming_count_thres (</div>
<div class="line"><a name="l00108"></a><span class="lineno"> 108</span>  <span class="keyword">const</span> uint8_t * bs1,</div>
<div class="line"><a name="l00109"></a><span class="lineno"> 109</span>  <span class="keyword">const</span> uint8_t * bs2,</div>
<div class="line"><a name="l00110"></a><span class="lineno"> 110</span>  <span class="keywordtype">size_t</span> n1,</div>
<div class="line"><a name="l00111"></a><span class="lineno"> 111</span>  <span class="keywordtype">size_t</span> n2,</div>
<div class="line"><a name="l00112"></a><span class="lineno"> 112</span>  hamdis_t ht,</div>
<div class="line"><a name="l00113"></a><span class="lineno"> 113</span>  <span class="keywordtype">size_t</span> ncodes,</div>
<div class="line"><a name="l00114"></a><span class="lineno"> 114</span>  <span class="keywordtype">size_t</span> * nptr);</div>
<div class="line"><a name="l00115"></a><span class="lineno"> 115</span> </div>
<div class="line"><a name="l00116"></a><span class="lineno"> 116</span> <span class="comment">/* Return all Hamming distances/index passing a thres. Pre-allocation of output</span></div>
<div class="line"><a name="l00117"></a><span class="lineno"> 117</span> <span class="comment"> is required. Use hamming_count_thres to determine the proper size. */</span></div>
<div class="line"><a name="l00118"></a><span class="lineno"> 118</span> <span class="keywordtype">size_t</span> match_hamming_thres (</div>
<div class="line"><a name="l00119"></a><span class="lineno"> 119</span>  <span class="keyword">const</span> uint8_t * bs1,</div>
<div class="line"><a name="l00120"></a><span class="lineno"> 120</span>  <span class="keyword">const</span> uint8_t * bs2,</div>
<div class="line"><a name="l00121"></a><span class="lineno"> 121</span>  <span class="keywordtype">size_t</span> n1,</div>
<div class="line"><a name="l00122"></a><span class="lineno"> 122</span>  <span class="keywordtype">size_t</span> n2,</div>
<div class="line"><a name="l00123"></a><span class="lineno"> 123</span>  hamdis_t ht,</div>
<div class="line"><a name="l00124"></a><span class="lineno"> 124</span>  <span class="keywordtype">size_t</span> ncodes,</div>
<div class="line"><a name="l00125"></a><span class="lineno"> 125</span>  <span class="keywordtype">long</span> * idx,</div>
<div class="line"><a name="l00126"></a><span class="lineno"> 126</span>  hamdis_t * dis);</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="comment">/* Cross-matching in a set of vectors */</span></div>
<div class="line"><a name="l00129"></a><span class="lineno"> 129</span> <span class="keywordtype">void</span> crosshamming_count_thres (</div>
<div class="line"><a name="l00130"></a><span class="lineno"> 130</span>  <span class="keyword">const</span> uint8_t * dbs,</div>
<div class="line"><a name="l00131"></a><span class="lineno"> 131</span>  <span class="keywordtype">size_t</span> n,</div>
<div class="line"><a name="l00132"></a><span class="lineno"> 132</span>  hamdis_t ht,</div>
<div class="line"><a name="l00133"></a><span class="lineno"> 133</span>  <span class="keywordtype">size_t</span> ncodes,</div>
<div class="line"><a name="l00134"></a><span class="lineno"> 134</span>  <span class="keywordtype">size_t</span> * nptr);</div>
<div class="line"><a name="l00135"></a><span class="lineno"> 135</span> </div>
<div class="line"><a name="l00136"></a><span class="lineno"> 136</span> </div>
<div class="line"><a name="l00137"></a><span class="lineno"> 137</span> <span class="comment">/* compute the Hamming distances between two codewords of nwords*64 bits */</span></div>
<div class="line"><a name="l00138"></a><span class="lineno"> 138</span> hamdis_t hamming (</div>
<div class="line"><a name="l00139"></a><span class="lineno"> 139</span>  <span class="keyword">const</span> uint64_t * bs1,</div>
<div class="line"><a name="l00140"></a><span class="lineno"> 140</span>  <span class="keyword">const</span> uint64_t * bs2,</div>
<div class="line"><a name="l00141"></a><span class="lineno"> 141</span>  <span class="keywordtype">size_t</span> nwords);</div>
<div class="line"><a name="l00142"></a><span class="lineno"> 142</span> </div>
<div class="line"><a name="l00143"></a><span class="lineno"> 143</span> </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> <span class="comment">/******************************************************************</span></div>
<div class="line"><a name="l00147"></a><span class="lineno"> 147</span> <span class="comment"> * The HammingComputer series of classes compares a single code of</span></div>
<div class="line"><a name="l00148"></a><span class="lineno"> 148</span> <span class="comment"> * size 4 to 32 to incoming codes. They are intended for use as a</span></div>
<div class="line"><a name="l00149"></a><span class="lineno"> 149</span> <span class="comment"> * template class where it would be inefficient to switch on the code</span></div>
<div class="line"><a name="l00150"></a><span class="lineno"> 150</span> <span class="comment"> * size in the inner loop. Hopefully the compiler will inline the</span></div>
<div class="line"><a name="l00151"></a><span class="lineno"> 151</span> <span class="comment"> * hamming() functions and put the a0, a1, ... in registers.</span></div>
<div class="line"><a name="l00152"></a><span class="lineno"> 152</span> <span class="comment"> ******************************************************************/</span></div>
<div class="line"><a name="l00153"></a><span class="lineno"> 153</span> </div>
<div class="line"><a name="l00154"></a><span class="lineno"> 154</span> </div>
<div class="line"><a name="l00155"></a><span class="lineno"><a class="line" href="structfaiss_1_1HammingComputer4.html"> 155</a></span> <span class="keyword">struct </span><a class="code" href="structfaiss_1_1HammingComputer4.html">HammingComputer4</a> {</div>
<div class="line"><a name="l00156"></a><span class="lineno"> 156</span>  uint32_t a0;</div>
<div class="line"><a name="l00157"></a><span class="lineno"> 157</span> </div>
<div class="line"><a name="l00158"></a><span class="lineno"> 158</span>  <a class="code" href="structfaiss_1_1HammingComputer4.html">HammingComputer4</a> (<span class="keyword">const</span> uint8_t *a, <span class="keywordtype">int</span> code_size) {</div>
<div class="line"><a name="l00159"></a><span class="lineno"> 159</span>  assert (code_size == 4);</div>
<div class="line"><a name="l00160"></a><span class="lineno"> 160</span>  a0 = *(uint32_t *)a;</div>
<div class="line"><a name="l00161"></a><span class="lineno"> 161</span>  }</div>
<div class="line"><a name="l00162"></a><span class="lineno"> 162</span> </div>
<div class="line"><a name="l00163"></a><span class="lineno"> 163</span>  <span class="keyword">inline</span> <span class="keywordtype">int</span> hamming (<span class="keyword">const</span> uint8_t *b)<span class="keyword"> const </span>{</div>
<div class="line"><a name="l00164"></a><span class="lineno"> 164</span>  <span class="keywordflow">return</span> popcount64 (*(uint32_t *)b ^ a0);</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> </div>
<div class="line"><a name="l00167"></a><span class="lineno"> 167</span> };</div>
<div class="line"><a name="l00168"></a><span class="lineno"> 168</span> </div>
<div class="line"><a name="l00169"></a><span class="lineno"><a class="line" href="structfaiss_1_1HammingComputer8.html"> 169</a></span> <span class="keyword">struct </span><a class="code" href="structfaiss_1_1HammingComputer8.html">HammingComputer8</a> {</div>
<div class="line"><a name="l00170"></a><span class="lineno"> 170</span>  uint64_t a0;</div>
<div class="line"><a name="l00171"></a><span class="lineno"> 171</span> </div>
<div class="line"><a name="l00172"></a><span class="lineno"> 172</span>  <a class="code" href="structfaiss_1_1HammingComputer8.html">HammingComputer8</a> (<span class="keyword">const</span> uint8_t *a, <span class="keywordtype">int</span> code_size) {</div>
<div class="line"><a name="l00173"></a><span class="lineno"> 173</span>  assert (code_size == 8);</div>
<div class="line"><a name="l00174"></a><span class="lineno"> 174</span>  a0 = *(uint64_t *)a;</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> </div>
<div class="line"><a name="l00177"></a><span class="lineno"> 177</span>  <span class="keyword">inline</span> <span class="keywordtype">int</span> hamming (<span class="keyword">const</span> uint8_t *b)<span class="keyword"> const </span>{</div>
<div class="line"><a name="l00178"></a><span class="lineno"> 178</span>  <span class="keywordflow">return</span> popcount64 (*(uint64_t *)b ^ a0);</div>
<div class="line"><a name="l00179"></a><span class="lineno"> 179</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> };</div>
<div class="line"><a name="l00182"></a><span class="lineno"> 182</span> </div>
<div class="line"><a name="l00183"></a><span class="lineno"> 183</span> </div>
<div class="line"><a name="l00184"></a><span class="lineno"><a class="line" href="structfaiss_1_1HammingComputer16.html"> 184</a></span> <span class="keyword">struct </span><a class="code" href="structfaiss_1_1HammingComputer16.html">HammingComputer16</a> {</div>
<div class="line"><a name="l00185"></a><span class="lineno"> 185</span>  uint64_t a0, a1;</div>
<div class="line"><a name="l00186"></a><span class="lineno"> 186</span>  <a class="code" href="structfaiss_1_1HammingComputer16.html">HammingComputer16</a> (<span class="keyword">const</span> uint8_t *a8, <span class="keywordtype">int</span> code_size) {</div>
<div class="line"><a name="l00187"></a><span class="lineno"> 187</span>  assert (code_size == 16);</div>
<div class="line"><a name="l00188"></a><span class="lineno"> 188</span>  <span class="keyword">const</span> uint64_t *a = (uint64_t *)a8;</div>
<div class="line"><a name="l00189"></a><span class="lineno"> 189</span>  a0 = a[0]; a1 = a[1];</div>
<div class="line"><a name="l00190"></a><span class="lineno"> 190</span>  }</div>
<div class="line"><a name="l00191"></a><span class="lineno"> 191</span> </div>
<div class="line"><a name="l00192"></a><span class="lineno"> 192</span>  <span class="keyword">inline</span> <span class="keywordtype">int</span> hamming (<span class="keyword">const</span> uint8_t *b8)<span class="keyword"> const </span>{</div>
<div class="line"><a name="l00193"></a><span class="lineno"> 193</span>  <span class="keyword">const</span> uint64_t *b = (uint64_t *)b8;</div>
<div class="line"><a name="l00194"></a><span class="lineno"> 194</span>  <span class="keywordflow">return</span> popcount64 (b[0] ^ a0) + popcount64 (b[1] ^ a1);</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> </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> </div>
<div class="line"><a name="l00199"></a><span class="lineno"> 199</span> <span class="comment">// when applied to an array, 1/2 of the 64-bit accesses are unaligned.</span></div>
<div class="line"><a name="l00200"></a><span class="lineno"> 200</span> <span class="comment">// This incurs a penalty of ~10% wrt. fully aligned accesses.</span></div>
<div class="line"><a name="l00201"></a><span class="lineno"><a class="line" href="structfaiss_1_1HammingComputer20.html"> 201</a></span> <span class="keyword">struct </span><a class="code" href="structfaiss_1_1HammingComputer20.html">HammingComputer20</a> {</div>
<div class="line"><a name="l00202"></a><span class="lineno"> 202</span>  uint64_t a0, a1;</div>
<div class="line"><a name="l00203"></a><span class="lineno"> 203</span>  uint32_t a2;</div>
<div class="line"><a name="l00204"></a><span class="lineno"> 204</span> </div>
<div class="line"><a name="l00205"></a><span class="lineno"> 205</span>  <a class="code" href="structfaiss_1_1HammingComputer20.html">HammingComputer20</a> (<span class="keyword">const</span> uint8_t *a8, <span class="keywordtype">int</span> code_size) {</div>
<div class="line"><a name="l00206"></a><span class="lineno"> 206</span>  assert (code_size == 20);</div>
<div class="line"><a name="l00207"></a><span class="lineno"> 207</span>  <span class="keyword">const</span> uint64_t *a = (uint64_t *)a8;</div>
<div class="line"><a name="l00208"></a><span class="lineno"> 208</span>  a0 = a[0]; a1 = a[1]; a2 = a[2];</div>
<div class="line"><a name="l00209"></a><span class="lineno"> 209</span>  }</div>
<div class="line"><a name="l00210"></a><span class="lineno"> 210</span> </div>
<div class="line"><a name="l00211"></a><span class="lineno"> 211</span>  <span class="keyword">inline</span> <span class="keywordtype">int</span> hamming (<span class="keyword">const</span> uint8_t *b8)<span class="keyword"> const </span>{</div>
<div class="line"><a name="l00212"></a><span class="lineno"> 212</span>  <span class="keyword">const</span> uint64_t *b = (uint64_t *)b8;</div>
<div class="line"><a name="l00213"></a><span class="lineno"> 213</span>  <span class="keywordflow">return</span> popcount64 (b[0] ^ a0) + popcount64 (b[1] ^ a1) +</div>
<div class="line"><a name="l00214"></a><span class="lineno"> 214</span>  popcount64 (*(uint32_t*)(b + 2) ^ a2);</div>
<div class="line"><a name="l00215"></a><span class="lineno"> 215</span>  }</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> </div>
<div class="line"><a name="l00218"></a><span class="lineno"><a class="line" href="structfaiss_1_1HammingComputer32.html"> 218</a></span> <span class="keyword">struct </span><a class="code" href="structfaiss_1_1HammingComputer32.html">HammingComputer32</a> {</div>
<div class="line"><a name="l00219"></a><span class="lineno"> 219</span>  uint64_t a0, a1, a2, a3;</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>  <a class="code" href="structfaiss_1_1HammingComputer32.html">HammingComputer32</a> (<span class="keyword">const</span> uint8_t *a8, <span class="keywordtype">int</span> code_size) {</div>
<div class="line"><a name="l00222"></a><span class="lineno"> 222</span>  assert (code_size == 32);</div>
<div class="line"><a name="l00223"></a><span class="lineno"> 223</span>  <span class="keyword">const</span> uint64_t *a = (uint64_t *)a8;</div>
<div class="line"><a name="l00224"></a><span class="lineno"> 224</span>  a0 = a[0]; a1 = a[1]; a2 = a[2]; a3 = a[3];</div>
<div class="line"><a name="l00225"></a><span class="lineno"> 225</span>  }</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="keyword">inline</span> <span class="keywordtype">int</span> hamming (<span class="keyword">const</span> uint8_t *b8)<span class="keyword"> const </span>{</div>
<div class="line"><a name="l00228"></a><span class="lineno"> 228</span>  <span class="keyword">const</span> uint64_t *b = (uint64_t *)b8;</div>
<div class="line"><a name="l00229"></a><span class="lineno"> 229</span>  <span class="keywordflow">return</span> popcount64 (b[0] ^ a0) + popcount64 (b[1] ^ a1) +</div>
<div class="line"><a name="l00230"></a><span class="lineno"> 230</span>  popcount64 (b[2] ^ a2) + popcount64 (b[3] ^ a3);</div>
<div class="line"><a name="l00231"></a><span class="lineno"> 231</span>  }</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> };</div>
<div class="line"><a name="l00234"></a><span class="lineno"> 234</span> </div>
<div class="line"><a name="l00235"></a><span class="lineno"><a class="line" href="structfaiss_1_1HammingComputer64.html"> 235</a></span> <span class="keyword">struct </span><a class="code" href="structfaiss_1_1HammingComputer64.html">HammingComputer64</a> {</div>
<div class="line"><a name="l00236"></a><span class="lineno"> 236</span>  uint64_t a0, a1, a2, a3, a4, a5, a6, a7;</div>
<div class="line"><a name="l00237"></a><span class="lineno"> 237</span> </div>
<div class="line"><a name="l00238"></a><span class="lineno"> 238</span>  <a class="code" href="structfaiss_1_1HammingComputer64.html">HammingComputer64</a> (<span class="keyword">const</span> uint8_t *a8, <span class="keywordtype">int</span> code_size) {</div>
<div class="line"><a name="l00239"></a><span class="lineno"> 239</span>  assert (code_size == 64);</div>
<div class="line"><a name="l00240"></a><span class="lineno"> 240</span>  <span class="keyword">const</span> uint64_t *a = (uint64_t *)a8;</div>
<div class="line"><a name="l00241"></a><span class="lineno"> 241</span>  a0 = a[0]; a1 = a[1]; a2 = a[2]; a3 = a[3];</div>
<div class="line"><a name="l00242"></a><span class="lineno"> 242</span>  a4 = a[4]; a5 = a[5]; a6 = a[6]; a7 = a[7];</div>
<div class="line"><a name="l00243"></a><span class="lineno"> 243</span>  }</div>
<div class="line"><a name="l00244"></a><span class="lineno"> 244</span> </div>
<div class="line"><a name="l00245"></a><span class="lineno"> 245</span>  <span class="keyword">inline</span> <span class="keywordtype">int</span> hamming (<span class="keyword">const</span> uint8_t *b8)<span class="keyword"> const </span>{</div>
<div class="line"><a name="l00246"></a><span class="lineno"> 246</span>  <span class="keyword">const</span> uint64_t *b = (uint64_t *)b8;</div>
<div class="line"><a name="l00247"></a><span class="lineno"> 247</span>  <span class="keywordflow">return</span> popcount64 (b[0] ^ a0) + popcount64 (b[1] ^ a1) +</div>
<div class="line"><a name="l00248"></a><span class="lineno"> 248</span>  popcount64 (b[2] ^ a2) + popcount64 (b[3] ^ a3) +</div>
<div class="line"><a name="l00249"></a><span class="lineno"> 249</span>  popcount64 (b[4] ^ a4) + popcount64 (b[5] ^ a5) +</div>
<div class="line"><a name="l00250"></a><span class="lineno"> 250</span>  popcount64 (b[6] ^ a6) + popcount64 (b[7] ^ a7);</div>
<div class="line"><a name="l00251"></a><span class="lineno"> 251</span>  }</div>
<div class="line"><a name="l00252"></a><span class="lineno"> 252</span> </div>
<div class="line"><a name="l00253"></a><span class="lineno"> 253</span> };</div>
<div class="line"><a name="l00254"></a><span class="lineno"> 254</span> </div>
<div class="line"><a name="l00255"></a><span class="lineno"><a class="line" href="structfaiss_1_1HammingComputerDefault.html"> 255</a></span> <span class="keyword">struct </span><a class="code" href="structfaiss_1_1HammingComputerDefault.html">HammingComputerDefault</a> {</div>
<div class="line"><a name="l00256"></a><span class="lineno"> 256</span>  <span class="keyword">const</span> uint8_t *a;</div>
<div class="line"><a name="l00257"></a><span class="lineno"> 257</span>  <span class="keywordtype">int</span> n;</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>  <a class="code" href="structfaiss_1_1HammingComputerDefault.html">HammingComputerDefault</a> (<span class="keyword">const</span> uint8_t *a8, <span class="keywordtype">int</span> code_size) {</div>
<div class="line"><a name="l00260"></a><span class="lineno"> 260</span>  a = a8;</div>
<div class="line"><a name="l00261"></a><span class="lineno"> 261</span>  n = code_size;</div>
<div class="line"><a name="l00262"></a><span class="lineno"> 262</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>  <span class="keywordtype">int</span> hamming (<span class="keyword">const</span> uint8_t *b8)<span class="keyword"> const </span>{</div>
<div class="line"><a name="l00265"></a><span class="lineno"> 265</span>  <span class="keywordtype">int</span> accu = 0;</div>
<div class="line"><a name="l00266"></a><span class="lineno"> 266</span>  <span class="keywordflow">for</span> (<span class="keywordtype">int</span> i = 0; i < n; i++)</div>
<div class="line"><a name="l00267"></a><span class="lineno"> 267</span>  accu += popcount64 (a[i] ^ b8[i]);</div>
<div class="line"><a name="l00268"></a><span class="lineno"> 268</span>  <span class="keywordflow">return</span> accu;</div>
<div class="line"><a name="l00269"></a><span class="lineno"> 269</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> };</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> </div>
<div class="line"><a name="l00274"></a><span class="lineno"><a class="line" href="structfaiss_1_1HammingComputerM8.html"> 274</a></span> <span class="keyword">struct </span><a class="code" href="structfaiss_1_1HammingComputerM8.html">HammingComputerM8</a> {</div>
<div class="line"><a name="l00275"></a><span class="lineno"> 275</span>  <span class="keyword">const</span> uint64_t *a;</div>
<div class="line"><a name="l00276"></a><span class="lineno"> 276</span>  <span class="keywordtype">int</span> n;</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>  <a class="code" href="structfaiss_1_1HammingComputerM8.html">HammingComputerM8</a> (<span class="keyword">const</span> uint8_t *a8, <span class="keywordtype">int</span> code_size) {</div>
<div class="line"><a name="l00279"></a><span class="lineno"> 279</span>  assert (code_size % 8 == 0);</div>
<div class="line"><a name="l00280"></a><span class="lineno"> 280</span>  a = (uint64_t *)a8;</div>
<div class="line"><a name="l00281"></a><span class="lineno"> 281</span>  n = code_size / 8;</div>
<div class="line"><a name="l00282"></a><span class="lineno"> 282</span>  }</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>  <span class="keywordtype">int</span> hamming (<span class="keyword">const</span> uint8_t *b8)<span class="keyword"> const </span>{</div>
<div class="line"><a name="l00285"></a><span class="lineno"> 285</span>  <span class="keyword">const</span> uint64_t *b = (uint64_t *)b8;</div>
<div class="line"><a name="l00286"></a><span class="lineno"> 286</span>  <span class="keywordtype">int</span> accu = 0;</div>
<div class="line"><a name="l00287"></a><span class="lineno"> 287</span>  <span class="keywordflow">for</span> (<span class="keywordtype">int</span> i = 0; i < n; i++)</div>
<div class="line"><a name="l00288"></a><span class="lineno"> 288</span>  accu += popcount64 (a[i] ^ b[i]);</div>
<div class="line"><a name="l00289"></a><span class="lineno"> 289</span>  <span class="keywordflow">return</span> accu;</div>
<div class="line"><a name="l00290"></a><span class="lineno"> 290</span>  }</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> };</div>
<div class="line"><a name="l00293"></a><span class="lineno"> 293</span> </div>
<div class="line"><a name="l00294"></a><span class="lineno"> 294</span> <span class="comment">// very inefficient...</span></div>
<div class="line"><a name="l00295"></a><span class="lineno"><a class="line" href="structfaiss_1_1HammingComputerM4.html"> 295</a></span> <span class="keyword">struct </span><a class="code" href="structfaiss_1_1HammingComputerM4.html">HammingComputerM4</a> {</div>
<div class="line"><a name="l00296"></a><span class="lineno"> 296</span>  <span class="keyword">const</span> uint32_t *a;</div>
<div class="line"><a name="l00297"></a><span class="lineno"> 297</span>  <span class="keywordtype">int</span> n;</div>
<div class="line"><a name="l00298"></a><span class="lineno"> 298</span> </div>
<div class="line"><a name="l00299"></a><span class="lineno"> 299</span>  <a class="code" href="structfaiss_1_1HammingComputerM4.html">HammingComputerM4</a> (<span class="keyword">const</span> uint8_t *a4, <span class="keywordtype">int</span> code_size) {</div>
<div class="line"><a name="l00300"></a><span class="lineno"> 300</span>  assert (code_size % 4 == 0);</div>
<div class="line"><a name="l00301"></a><span class="lineno"> 301</span>  a = (uint32_t *)a4;</div>
<div class="line"><a name="l00302"></a><span class="lineno"> 302</span>  n = code_size / 4;</div>
<div class="line"><a name="l00303"></a><span class="lineno"> 303</span>  }</div>
<div class="line"><a name="l00304"></a><span class="lineno"> 304</span>  <span class="keywordtype">int</span> hamming (<span class="keyword">const</span> uint8_t *b8)<span class="keyword"> const </span>{</div>
<div class="line"><a name="l00305"></a><span class="lineno"> 305</span>  <span class="keyword">const</span> uint32_t *b = (uint32_t *)b8;</div>
<div class="line"><a name="l00306"></a><span class="lineno"> 306</span>  <span class="keywordtype">int</span> accu = 0;</div>
<div class="line"><a name="l00307"></a><span class="lineno"> 307</span>  <span class="keywordflow">for</span> (<span class="keywordtype">int</span> i = 0; i < n; i++)</div>
<div class="line"><a name="l00308"></a><span class="lineno"> 308</span>  accu += popcount64 (a[i] ^ b[i]);</div>
<div class="line"><a name="l00309"></a><span class="lineno"> 309</span>  <span class="keywordflow">return</span> accu;</div>
<div class="line"><a name="l00310"></a><span class="lineno"> 310</span>  }</div>
<div class="line"><a name="l00311"></a><span class="lineno"> 311</span> </div>
<div class="line"><a name="l00312"></a><span class="lineno"> 312</span> };</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">/***************************************************************************</span></div>
<div class="line"><a name="l00315"></a><span class="lineno"> 315</span> <span class="comment"> * Equivalence with a template class when code size is known at compile time</span></div>
<div class="line"><a name="l00316"></a><span class="lineno"> 316</span> <span class="comment"> **************************************************************************/</span></div>
<div class="line"><a name="l00317"></a><span class="lineno"> 317</span> </div>
<div class="line"><a name="l00318"></a><span class="lineno"> 318</span> <span class="comment">// default template</span></div>
<div class="line"><a name="l00319"></a><span class="lineno"> 319</span> <span class="keyword">template</span><<span class="keywordtype">int</span> CODE_SIZE></div>
<div class="line"><a name="l00320"></a><span class="lineno"><a class="line" href="structfaiss_1_1HammingComputer.html"> 320</a></span> <span class="keyword">struct </span><a class="code" href="structfaiss_1_1HammingComputer.html">HammingComputer</a>: <a class="code" href="structfaiss_1_1HammingComputerM8.html">HammingComputerM8</a> {</div>
<div class="line"><a name="l00321"></a><span class="lineno"> 321</span>  <a class="code" href="structfaiss_1_1HammingComputer.html">HammingComputer</a> (<span class="keyword">const</span> uint8_t *a, <span class="keywordtype">int</span> code_size):</div>
<div class="line"><a name="l00322"></a><span class="lineno"> 322</span>  <a class="code" href="structfaiss_1_1HammingComputerM8.html">HammingComputerM8</a>(a, code_size) {}</div>
<div class="line"><a name="l00323"></a><span class="lineno"> 323</span> };</div>
<div class="line"><a name="l00324"></a><span class="lineno"> 324</span> </div>
<div class="line"><a name="l00325"></a><span class="lineno"> 325</span> <span class="preprocessor">#define SPECIALIZED_HC(CODE_SIZE) \</span></div>
<div class="line"><a name="l00326"></a><span class="lineno"> 326</span> <span class="preprocessor"> template<> struct HammingComputer<CODE_SIZE>: \</span></div>
<div class="line"><a name="l00327"></a><span class="lineno"> 327</span> <span class="preprocessor"> HammingComputer ## CODE_SIZE { \</span></div>
<div class="line"><a name="l00328"></a><span class="lineno"> 328</span> <span class="preprocessor"> HammingComputer (const uint8_t *a): \</span></div>
<div class="line"><a name="l00329"></a><span class="lineno"> 329</span> <span class="preprocessor"> HammingComputer ## CODE_SIZE(a, CODE_SIZE) {} \</span></div>
<div class="line"><a name="l00330"></a><span class="lineno"> 330</span> <span class="preprocessor"> }</span></div>
<div class="line"><a name="l00331"></a><span class="lineno"> 331</span> <span class="preprocessor"></span></div>
<div class="line"><a name="l00332"></a><span class="lineno"> 332</span> SPECIALIZED_HC(4);</div>
<div class="line"><a name="l00333"></a><span class="lineno"> 333</span> SPECIALIZED_HC(8);</div>
<div class="line"><a name="l00334"></a><span class="lineno"> 334</span> SPECIALIZED_HC(16);</div>
<div class="line"><a name="l00335"></a><span class="lineno"> 335</span> SPECIALIZED_HC(20);</div>
<div class="line"><a name="l00336"></a><span class="lineno"> 336</span> SPECIALIZED_HC(32);</div>
<div class="line"><a name="l00337"></a><span class="lineno"> 337</span> SPECIALIZED_HC(64);</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> <span class="preprocessor">#undef SPECIALIZED_HC</span></div>
<div class="line"><a name="l00340"></a><span class="lineno"> 340</span> <span class="preprocessor"></span></div>
<div class="line"><a name="l00341"></a><span class="lineno"> 341</span> </div>
<div class="line"><a name="l00342"></a><span class="lineno"> 342</span> <span class="comment">/***************************************************************************</span></div>
<div class="line"><a name="l00343"></a><span class="lineno"> 343</span> <span class="comment"> * generalized Hamming = number of bytes that are different between</span></div>
<div class="line"><a name="l00344"></a><span class="lineno"> 344</span> <span class="comment"> * two codes.</span></div>
<div class="line"><a name="l00345"></a><span class="lineno"> 345</span> <span class="comment"> ***************************************************************************/</span></div>
<div class="line"><a name="l00346"></a><span class="lineno"> 346</span> </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="keyword">inline</span> <span class="keywordtype">int</span> generalized_hamming_64 (uint64_t a) {</div>
<div class="line"><a name="l00349"></a><span class="lineno"> 349</span>  a |= a >> 1;</div>
<div class="line"><a name="l00350"></a><span class="lineno"> 350</span>  a |= a >> 2;</div>
<div class="line"><a name="l00351"></a><span class="lineno"> 351</span>  a |= a >> 4;</div>
<div class="line"><a name="l00352"></a><span class="lineno"> 352</span>  a &= 0x0101010101010101UL;</div>
<div class="line"><a name="l00353"></a><span class="lineno"> 353</span>  <span class="keywordflow">return</span> popcount64 (a);</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> </div>
<div class="line"><a name="l00356"></a><span class="lineno"> 356</span> </div>
<div class="line"><a name="l00357"></a><span class="lineno"><a class="line" href="structfaiss_1_1GenHammingComputer8.html"> 357</a></span> <span class="keyword">struct </span><a class="code" href="structfaiss_1_1GenHammingComputer8.html">GenHammingComputer8</a> {</div>
<div class="line"><a name="l00358"></a><span class="lineno"> 358</span>  uint64_t a0;</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>  <a class="code" href="structfaiss_1_1GenHammingComputer8.html">GenHammingComputer8</a> (<span class="keyword">const</span> uint8_t *a, <span class="keywordtype">int</span> code_size) {</div>
<div class="line"><a name="l00361"></a><span class="lineno"> 361</span>  assert (code_size == 8);</div>
<div class="line"><a name="l00362"></a><span class="lineno"> 362</span>  a0 = *(uint64_t *)a;</div>
<div class="line"><a name="l00363"></a><span class="lineno"> 363</span>  }</div>
<div class="line"><a name="l00364"></a><span class="lineno"> 364</span> </div>
<div class="line"><a name="l00365"></a><span class="lineno"> 365</span>  <span class="keyword">inline</span> <span class="keywordtype">int</span> hamming (<span class="keyword">const</span> uint8_t *b)<span class="keyword"> const </span>{</div>
<div class="line"><a name="l00366"></a><span class="lineno"> 366</span>  <span class="keywordflow">return</span> generalized_hamming_64 (*(uint64_t *)b ^ a0);</div>
<div class="line"><a name="l00367"></a><span class="lineno"> 367</span>  }</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> };</div>
<div class="line"><a name="l00370"></a><span class="lineno"> 370</span> </div>
<div class="line"><a name="l00371"></a><span class="lineno"> 371</span> </div>
<div class="line"><a name="l00372"></a><span class="lineno"><a class="line" href="structfaiss_1_1GenHammingComputer16.html"> 372</a></span> <span class="keyword">struct </span><a class="code" href="structfaiss_1_1GenHammingComputer16.html">GenHammingComputer16</a> {</div>
<div class="line"><a name="l00373"></a><span class="lineno"> 373</span>  uint64_t a0, a1;</div>
<div class="line"><a name="l00374"></a><span class="lineno"> 374</span>  <a class="code" href="structfaiss_1_1GenHammingComputer16.html">GenHammingComputer16</a> (<span class="keyword">const</span> uint8_t *a8, <span class="keywordtype">int</span> code_size) {</div>
<div class="line"><a name="l00375"></a><span class="lineno"> 375</span>  assert (code_size == 16);</div>
<div class="line"><a name="l00376"></a><span class="lineno"> 376</span>  <span class="keyword">const</span> uint64_t *a = (uint64_t *)a8;</div>
<div class="line"><a name="l00377"></a><span class="lineno"> 377</span>  a0 = a[0]; a1 = a[1];</div>
<div class="line"><a name="l00378"></a><span class="lineno"> 378</span>  }</div>
<div class="line"><a name="l00379"></a><span class="lineno"> 379</span> </div>
<div class="line"><a name="l00380"></a><span class="lineno"> 380</span>  <span class="keyword">inline</span> <span class="keywordtype">int</span> hamming (<span class="keyword">const</span> uint8_t *b8)<span class="keyword"> const </span>{</div>
<div class="line"><a name="l00381"></a><span class="lineno"> 381</span>  <span class="keyword">const</span> uint64_t *b = (uint64_t *)b8;</div>
<div class="line"><a name="l00382"></a><span class="lineno"> 382</span>  <span class="keywordflow">return</span> generalized_hamming_64 (b[0] ^ a0) +</div>
<div class="line"><a name="l00383"></a><span class="lineno"> 383</span>  generalized_hamming_64 (b[1] ^ a1);</div>
<div class="line"><a name="l00384"></a><span class="lineno"> 384</span>  }</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> };</div>
<div class="line"><a name="l00387"></a><span class="lineno"> 387</span> </div>
<div class="line"><a name="l00388"></a><span class="lineno"><a class="line" href="structfaiss_1_1GenHammingComputer32.html"> 388</a></span> <span class="keyword">struct </span><a class="code" href="structfaiss_1_1GenHammingComputer32.html">GenHammingComputer32</a> {</div>
<div class="line"><a name="l00389"></a><span class="lineno"> 389</span>  uint64_t a0, a1, a2, a3;</div>
<div class="line"><a name="l00390"></a><span class="lineno"> 390</span> </div>
<div class="line"><a name="l00391"></a><span class="lineno"> 391</span>  <a class="code" href="structfaiss_1_1GenHammingComputer32.html">GenHammingComputer32</a> (<span class="keyword">const</span> uint8_t *a8, <span class="keywordtype">int</span> code_size) {</div>
<div class="line"><a name="l00392"></a><span class="lineno"> 392</span>  assert (code_size == 32);</div>
<div class="line"><a name="l00393"></a><span class="lineno"> 393</span>  <span class="keyword">const</span> uint64_t *a = (uint64_t *)a8;</div>
<div class="line"><a name="l00394"></a><span class="lineno"> 394</span>  a0 = a[0]; a1 = a[1]; a2 = a[2]; a3 = a[3];</div>
<div class="line"><a name="l00395"></a><span class="lineno"> 395</span>  }</div>
<div class="line"><a name="l00396"></a><span class="lineno"> 396</span> </div>
<div class="line"><a name="l00397"></a><span class="lineno"> 397</span>  <span class="keyword">inline</span> <span class="keywordtype">int</span> hamming (<span class="keyword">const</span> uint8_t *b8)<span class="keyword"> const </span>{</div>
<div class="line"><a name="l00398"></a><span class="lineno"> 398</span>  <span class="keyword">const</span> uint64_t *b = (uint64_t *)b8;</div>
<div class="line"><a name="l00399"></a><span class="lineno"> 399</span>  <span class="keywordflow">return</span> generalized_hamming_64 (b[0] ^ a0) +</div>
<div class="line"><a name="l00400"></a><span class="lineno"> 400</span>  generalized_hamming_64 (b[1] ^ a1) +</div>
<div class="line"><a name="l00401"></a><span class="lineno"> 401</span>  generalized_hamming_64 (b[2] ^ a2) +</div>
<div class="line"><a name="l00402"></a><span class="lineno"> 402</span>  generalized_hamming_64 (b[3] ^ a3);</div>
<div class="line"><a name="l00403"></a><span class="lineno"> 403</span>  }</div>
<div class="line"><a name="l00404"></a><span class="lineno"> 404</span> </div>
<div class="line"><a name="l00405"></a><span class="lineno"> 405</span> };</div>
<div class="line"><a name="l00406"></a><span class="lineno"> 406</span> </div>
<div class="line"><a name="l00407"></a><span class="lineno"><a class="line" href="structfaiss_1_1GenHammingComputerM8.html"> 407</a></span> <span class="keyword">struct </span><a class="code" href="structfaiss_1_1GenHammingComputerM8.html">GenHammingComputerM8</a> {</div>
<div class="line"><a name="l00408"></a><span class="lineno"> 408</span>  <span class="keyword">const</span> uint64_t *a;</div>
<div class="line"><a name="l00409"></a><span class="lineno"> 409</span>  <span class="keywordtype">int</span> n;</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>  <a class="code" href="structfaiss_1_1GenHammingComputerM8.html">GenHammingComputerM8</a> (<span class="keyword">const</span> uint8_t *a8, <span class="keywordtype">int</span> code_size) {</div>
<div class="line"><a name="l00412"></a><span class="lineno"> 412</span>  assert (code_size % 8 == 0);</div>
<div class="line"><a name="l00413"></a><span class="lineno"> 413</span>  a = (uint64_t *)a8;</div>
<div class="line"><a name="l00414"></a><span class="lineno"> 414</span>  n = code_size / 8;</div>
<div class="line"><a name="l00415"></a><span class="lineno"> 415</span>  }</div>
<div class="line"><a name="l00416"></a><span class="lineno"> 416</span> </div>
<div class="line"><a name="l00417"></a><span class="lineno"> 417</span>  <span class="keywordtype">int</span> hamming (<span class="keyword">const</span> uint8_t *b8)<span class="keyword"> const </span>{</div>
<div class="line"><a name="l00418"></a><span class="lineno"> 418</span>  <span class="keyword">const</span> uint64_t *b = (uint64_t *)b8;</div>
<div class="line"><a name="l00419"></a><span class="lineno"> 419</span>  <span class="keywordtype">int</span> accu = 0;</div>
<div class="line"><a name="l00420"></a><span class="lineno"> 420</span>  <span class="keywordflow">for</span> (<span class="keywordtype">int</span> i = 0; i < n; i++)</div>
<div class="line"><a name="l00421"></a><span class="lineno"> 421</span>  accu += generalized_hamming_64 (a[i] ^ b[i]);</div>
<div class="line"><a name="l00422"></a><span class="lineno"> 422</span>  <span class="keywordflow">return</span> accu;</div>
<div class="line"><a name="l00423"></a><span class="lineno"> 423</span>  }</div>
<div class="line"><a name="l00424"></a><span class="lineno"> 424</span> </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> </div>
<div class="line"><a name="l00427"></a><span class="lineno"> 427</span> <span class="comment"></span></div>
<div class="line"><a name="l00428"></a><span class="lineno"> 428</span> <span class="comment">/** generalized Hamming distances (= count number of code bytes that</span></div>
<div class="line"><a name="l00429"></a><span class="lineno"> 429</span> <span class="comment"> are the same) */</span></div>
<div class="line"><a name="l00430"></a><span class="lineno"> 430</span> <span class="keywordtype">void</span> <a class="code" href="namespacefaiss.html#ae81da42f6f40356f7525917b3acb54c8">generalized_hammings_knn</a> (</div>
<div class="line"><a name="l00431"></a><span class="lineno"> 431</span>  <a class="code" href="structfaiss_1_1HeapArray.html">int_maxheap_array_t</a> * ha,</div>
<div class="line"><a name="l00432"></a><span class="lineno"> 432</span>  <span class="keyword">const</span> uint8_t * a,</div>
<div class="line"><a name="l00433"></a><span class="lineno"> 433</span>  <span class="keyword">const</span> uint8_t * b,</div>
<div class="line"><a name="l00434"></a><span class="lineno"> 434</span>  <span class="keywordtype">size_t</span> nb,</div>
<div class="line"><a name="l00435"></a><span class="lineno"> 435</span>  <span class="keywordtype">size_t</span> code_size,</div>
<div class="line"><a name="l00436"></a><span class="lineno"> 436</span>  <span class="keywordtype">int</span> ordered = <span class="keyword">true</span>);</div>
<div class="line"><a name="l00437"></a><span class="lineno"> 437</span> </div>
<div class="line"><a name="l00438"></a><span class="lineno"> 438</span> </div>
<div class="line"><a name="l00439"></a><span class="lineno"> 439</span> </div>
<div class="line"><a name="l00440"></a><span class="lineno"> 440</span> </div>
<div class="line"><a name="l00441"></a><span class="lineno"> 441</span> } <span class="comment">// namespace faiss</span></div>
<div class="line"><a name="l00442"></a><span class="lineno"> 442</span> </div>
<div class="line"><a name="l00443"></a><span class="lineno"> 443</span> </div>
<div class="line"><a name="l00444"></a><span class="lineno"> 444</span> </div>
<div class="line"><a name="l00445"></a><span class="lineno"> 445</span> </div>
<div class="line"><a name="l00446"></a><span class="lineno"> 446</span> <span class="preprocessor">#endif </span><span class="comment">/* FAISS_hamming_h */</span><span class="preprocessor"></span></div>
<div class="ttc" id="structfaiss_1_1HammingComputerM4_html"><div class="ttname"><a href="structfaiss_1_1HammingComputerM4.html">faiss::HammingComputerM4</a></div><div class="ttdef"><b>Definition:</b> <a href="hamming_8h_source.html#l00295">hamming.h:295</a></div></div>
<div class="ttc" id="structfaiss_1_1HammingComputer_html"><div class="ttname"><a href="structfaiss_1_1HammingComputer.html">faiss::HammingComputer</a></div><div class="ttdef"><b>Definition:</b> <a href="hamming_8h_source.html#l00320">hamming.h:320</a></div></div>
<div class="ttc" id="structfaiss_1_1HammingComputer20_html"><div class="ttname"><a href="structfaiss_1_1HammingComputer20.html">faiss::HammingComputer20</a></div><div class="ttdef"><b>Definition:</b> <a href="hamming_8h_source.html#l00201">hamming.h:201</a></div></div>
<div class="ttc" id="structfaiss_1_1GenHammingComputer16_html"><div class="ttname"><a href="structfaiss_1_1GenHammingComputer16.html">faiss::GenHammingComputer16</a></div><div class="ttdef"><b>Definition:</b> <a href="hamming_8h_source.html#l00372">hamming.h:372</a></div></div>
<div class="ttc" id="structfaiss_1_1GenHammingComputer8_html"><div class="ttname"><a href="structfaiss_1_1GenHammingComputer8.html">faiss::GenHammingComputer8</a></div><div class="ttdef"><b>Definition:</b> <a href="hamming_8h_source.html#l00357">hamming.h:357</a></div></div>
<div class="ttc" id="structfaiss_1_1HammingComputer8_html"><div class="ttname"><a href="structfaiss_1_1HammingComputer8.html">faiss::HammingComputer8</a></div><div class="ttdef"><b>Definition:</b> <a href="hamming_8h_source.html#l00169">hamming.h:169</a></div></div>
<div class="ttc" id="structfaiss_1_1HammingComputer64_html"><div class="ttname"><a href="structfaiss_1_1HammingComputer64.html">faiss::HammingComputer64</a></div><div class="ttdef"><b>Definition:</b> <a href="hamming_8h_source.html#l00235">hamming.h:235</a></div></div>
<div class="ttc" id="namespacefaiss_html_ae81da42f6f40356f7525917b3acb54c8"><div class="ttname"><a href="namespacefaiss.html#ae81da42f6f40356f7525917b3acb54c8">faiss::generalized_hammings_knn</a></div><div class="ttdeci">void generalized_hammings_knn(int_maxheap_array_t *ha, const uint8_t *a, const uint8_t *b, size_t nb, size_t code_size, int ordered)</div><div class="ttdef"><b>Definition:</b> <a href="hamming_8cpp_source.html#l00639">hamming.cpp:639</a></div></div>
<div class="ttc" id="structfaiss_1_1HammingComputer16_html"><div class="ttname"><a href="structfaiss_1_1HammingComputer16.html">faiss::HammingComputer16</a></div><div class="ttdef"><b>Definition:</b> <a href="hamming_8h_source.html#l00184">hamming.h:184</a></div></div>
<div class="ttc" id="structfaiss_1_1HammingComputer4_html"><div class="ttname"><a href="structfaiss_1_1HammingComputer4.html">faiss::HammingComputer4</a></div><div class="ttdef"><b>Definition:</b> <a href="hamming_8h_source.html#l00155">hamming.h:155</a></div></div>
<div class="ttc" id="structfaiss_1_1GenHammingComputerM8_html"><div class="ttname"><a href="structfaiss_1_1GenHammingComputerM8.html">faiss::GenHammingComputerM8</a></div><div class="ttdef"><b>Definition:</b> <a href="hamming_8h_source.html#l00407">hamming.h:407</a></div></div>
<div class="ttc" id="structfaiss_1_1HeapArray_html"><div class="ttname"><a href="structfaiss_1_1HeapArray.html">faiss::HeapArray</a></div><div class="ttdef"><b>Definition:</b> <a href="Heap_8h_source.html#l00350">Heap.h:350</a></div></div>
<div class="ttc" id="namespacefaiss_html_ac0b4dc73a8470d61f510396dc460ca18"><div class="ttname"><a href="namespacefaiss.html#ac0b4dc73a8470d61f510396dc460ca18">faiss::hammings_knn</a></div><div class="ttdeci">void hammings_knn(int_maxheap_array_t *ha, const uint8_t *a, const uint8_t *b, size_t nb, size_t ncodes, int order)</div><div class="ttdef"><b>Definition:</b> <a href="hamming_8cpp_source.html#l00474">hamming.cpp:474</a></div></div>
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<div class="ttc" id="structfaiss_1_1GenHammingComputer32_html"><div class="ttname"><a href="structfaiss_1_1GenHammingComputer32.html">faiss::GenHammingComputer32</a></div><div class="ttdef"><b>Definition:</b> <a href="hamming_8h_source.html#l00388">hamming.h:388</a></div></div>
<div class="ttc" id="structfaiss_1_1HammingComputerDefault_html"><div class="ttname"><a href="structfaiss_1_1HammingComputerDefault.html">faiss::HammingComputerDefault</a></div><div class="ttdef"><b>Definition:</b> <a href="hamming_8h_source.html#l00255">hamming.h:255</a></div></div>
<div class="ttc" id="structfaiss_1_1HammingComputerM8_html"><div class="ttname"><a href="structfaiss_1_1HammingComputerM8.html">faiss::HammingComputerM8</a></div><div class="ttdef"><b>Definition:</b> <a href="hamming_8h_source.html#l00274">hamming.h:274</a></div></div>
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