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<a href="../../d4/d3e/k__nearest__neighbors_8cpp.html">Go to the documentation of this file.</a><div class="fragment"><div class="line"><a id="l00001" name="l00001"></a><span class="lineno"> 1</span></div>
<div class="line"><a id="l00011" name="l00011"></a><span class="lineno"> 11</span> </div>
<div class="line"><a id="l00012" name="l00012"></a><span class="lineno"> 12</span><span class="preprocessor">#include &lt;algorithm&gt;</span> </div>
<div class="line"><a id="l00013" name="l00013"></a><span class="lineno"> 13</span><span class="preprocessor">#include &lt;cassert&gt;</span> </div>
<div class="line"><a id="l00014" name="l00014"></a><span class="lineno"> 14</span><span class="preprocessor">#include &lt;cmath&gt;</span> </div>
<div class="line"><a id="l00015" name="l00015"></a><span class="lineno"> 15</span><span class="preprocessor">#include &lt;iostream&gt;</span> </div>
<div class="line"><a id="l00016" name="l00016"></a><span class="lineno"> 16</span><span class="preprocessor">#include &lt;numeric&gt;</span> </div>
<div class="line"><a id="l00017" name="l00017"></a><span class="lineno"> 17</span><span class="preprocessor">#include &lt;unordered_map&gt;</span> </div>
<div class="line"><a id="l00018" name="l00018"></a><span class="lineno"> 18</span><span class="preprocessor">#include &lt;vector&gt;</span> </div>
<div class="line"><a id="l00019" name="l00019"></a><span class="lineno"> 19</span></div>
<div class="line"><a id="l00024" name="l00024"></a><span class="lineno"> 24</span><span class="keyword">namespace </span><a class="code hl_namespace" href="../../d8/d77/namespacemachine__learning.html">machine_learning</a> {</div>
<div class="line"><a id="l00025" name="l00025"></a><span class="lineno"> 25</span></div>
<div class="line"><a id="l00031" name="l00031"></a><span class="lineno"> 31</span><span class="keyword">namespace </span><a class="code hl_namespace" href="../../d7/d4c/namespacek__nearest__neighbors.html">k_nearest_neighbors</a> {</div>
<div class="line"><a id="l00032" name="l00032"></a><span class="lineno"> 32</span></div>
<div class="line"><a id="l00042" name="l00042"></a><span class="lineno"> 42</span><span class="keyword">template</span> &lt;<span class="keyword">typename</span> T&gt;</div>
<div class="foldopen" id="foldopen00043" data-start="{" data-end="}">
<div class="line"><a id="l00043" name="l00043"></a><span class="lineno"><a class="line" href="../../d4/d3e/k__nearest__neighbors_8cpp.html#ad6ae16e50bb153ebaa7251d0aaa97b69"> 43</a></span><span class="keywordtype">double</span> <a class="code hl_function" href="../../d4/d3e/k__nearest__neighbors_8cpp.html#ad6ae16e50bb153ebaa7251d0aaa97b69">euclidean_distance</a>(<span class="keyword">const</span> std::vector&lt;T&gt;&amp; a, <span class="keyword">const</span> std::vector&lt;T&gt;&amp; b) {</div>
<div class="line"><a id="l00044" name="l00044"></a><span class="lineno"> 44</span> std::vector&lt;double&gt; aux;</div>
<div class="line"><a id="l00045" name="l00045"></a><span class="lineno"> 45</span> std::transform(a.begin(), a.end(), b.begin(), std::back_inserter(aux),</div>
<div class="line"><a id="l00046" name="l00046"></a><span class="lineno"> 46</span> [](T x1, T x2) { return std::pow((x1 - x2), 2); });</div>
<div class="line"><a id="l00047" name="l00047"></a><span class="lineno"> 47</span> aux.shrink_to_fit();</div>
<div class="line"><a id="l00048" name="l00048"></a><span class="lineno"> 48</span> <span class="keywordflow">return</span> std::sqrt(std::accumulate(aux.begin(), aux.end(), 0.0));</div>
<div class="line"><a id="l00049" name="l00049"></a><span class="lineno"> 49</span>}</div>
</div>
<div class="line"><a id="l00050" name="l00050"></a><span class="lineno"> 50</span></div>
<div class="foldopen" id="foldopen00055" data-start="{" data-end="};">
<div class="line"><a id="l00055" name="l00055"></a><span class="lineno"><a class="line" href="../../da/d94/classmachine__learning_1_1k__nearest__neighbors_1_1_knn.html"> 55</a></span><span class="keyword">class </span><a class="code hl_function" href="../../da/d94/classmachine__learning_1_1k__nearest__neighbors_1_1_knn.html#a188d29ffcefdb5900a8cd41eccd89200">Knn</a> {</div>
<div class="line"><a id="l00056" name="l00056"></a><span class="lineno"> 56</span> <span class="keyword">private</span>:</div>
<div class="line"><a id="l00057" name="l00057"></a><span class="lineno"><a class="line" href="../../da/d94/classmachine__learning_1_1k__nearest__neighbors_1_1_knn.html#a16ddc13621eec6ac5f83658b3401a581"> 57</a></span> std::vector&lt;std::vector&lt;double&gt;&gt; <a class="code hl_variable" href="../../da/d94/classmachine__learning_1_1k__nearest__neighbors_1_1_knn.html#a16ddc13621eec6ac5f83658b3401a581">X_</a>{}; </div>
<div class="line"><a id="l00058" name="l00058"></a><span class="lineno"><a class="line" href="../../da/d94/classmachine__learning_1_1k__nearest__neighbors_1_1_knn.html#a209383503fb6c03afac405a80bace964"> 58</a></span> std::vector&lt;int&gt; <a class="code hl_variable" href="../../da/d94/classmachine__learning_1_1k__nearest__neighbors_1_1_knn.html#a209383503fb6c03afac405a80bace964">Y_</a>{}; </div>
<div class="line"><a id="l00059" name="l00059"></a><span class="lineno"> 59</span> </div>
<div class="line"><a id="l00060" name="l00060"></a><span class="lineno"> 60</span> <span class="keyword">public</span>:</div>
<div class="foldopen" id="foldopen00067" data-start="{" data-end="}">
<div class="line"><a id="l00067" name="l00067"></a><span class="lineno"><a class="line" href="../../da/d94/classmachine__learning_1_1k__nearest__neighbors_1_1_knn.html#a188d29ffcefdb5900a8cd41eccd89200"> 67</a></span> <span class="keyword">explicit</span> <a class="code hl_function" href="../../da/d94/classmachine__learning_1_1k__nearest__neighbors_1_1_knn.html#a188d29ffcefdb5900a8cd41eccd89200">Knn</a>(std::vector&lt;std::vector&lt;double&gt;&gt;&amp; X, std::vector&lt;int&gt;&amp; Y)</div>
<div class="line"><a id="l00068" name="l00068"></a><span class="lineno"> 68</span> : <a class="code hl_variable" href="../../da/d94/classmachine__learning_1_1k__nearest__neighbors_1_1_knn.html#a16ddc13621eec6ac5f83658b3401a581">X_</a>(X), <a class="code hl_variable" href="../../da/d94/classmachine__learning_1_1k__nearest__neighbors_1_1_knn.html#a209383503fb6c03afac405a80bace964">Y_</a>(Y){};</div>
</div>
<div class="line"><a id="l00069" name="l00069"></a><span class="lineno"> 69</span></div>
<div class="line"><a id="l00075" name="l00075"></a><span class="lineno"><a class="line" href="../../da/d94/classmachine__learning_1_1k__nearest__neighbors_1_1_knn.html#a9f5885c40112481ae5b588fe81d7910b"> 75</a></span> <a class="code hl_function" href="../../da/d94/classmachine__learning_1_1k__nearest__neighbors_1_1_knn.html#a9f5885c40112481ae5b588fe81d7910b">Knn</a>(<span class="keyword">const</span> <a class="code hl_function" href="../../da/d94/classmachine__learning_1_1k__nearest__neighbors_1_1_knn.html#a188d29ffcefdb5900a8cd41eccd89200">Knn</a>&amp; model) = <span class="keywordflow">default</span>;</div>
<div class="line"><a id="l00076" name="l00076"></a><span class="lineno"> 76</span></div>
<div class="line"><a id="l00080" name="l00080"></a><span class="lineno"><a class="line" href="../../da/d94/classmachine__learning_1_1k__nearest__neighbors_1_1_knn.html#a080f5b1742832a03c1cbba596a48bd1a"> 80</a></span> <a class="code hl_function" href="../../da/d94/classmachine__learning_1_1k__nearest__neighbors_1_1_knn.html#a188d29ffcefdb5900a8cd41eccd89200">Knn</a>&amp; <a class="code hl_function" href="../../da/d94/classmachine__learning_1_1k__nearest__neighbors_1_1_knn.html#a080f5b1742832a03c1cbba596a48bd1a">operator=</a>(<span class="keyword">const</span> <a class="code hl_function" href="../../da/d94/classmachine__learning_1_1k__nearest__neighbors_1_1_knn.html#a188d29ffcefdb5900a8cd41eccd89200">Knn</a>&amp; model) = <span class="keywordflow">default</span>;</div>
<div class="line"><a id="l00081" name="l00081"></a><span class="lineno"> 81</span></div>
<div class="line"><a id="l00085" name="l00085"></a><span class="lineno"><a class="line" href="../../da/d94/classmachine__learning_1_1k__nearest__neighbors_1_1_knn.html#a4b17dcf17c847f0295b60029512c120e"> 85</a></span> <a class="code hl_function" href="../../da/d94/classmachine__learning_1_1k__nearest__neighbors_1_1_knn.html#a4b17dcf17c847f0295b60029512c120e">Knn</a>(<a class="code hl_function" href="../../da/d94/classmachine__learning_1_1k__nearest__neighbors_1_1_knn.html#a188d29ffcefdb5900a8cd41eccd89200">Knn</a>&amp;&amp;) = <span class="keywordflow">default</span>;</div>
<div class="line"><a id="l00086" name="l00086"></a><span class="lineno"> 86</span></div>
<div class="line"><a id="l00090" name="l00090"></a><span class="lineno"><a class="line" href="../../da/d94/classmachine__learning_1_1k__nearest__neighbors_1_1_knn.html#ac06986d5afddc767ddba4da738f75563"> 90</a></span> <a class="code hl_function" href="../../da/d94/classmachine__learning_1_1k__nearest__neighbors_1_1_knn.html#a188d29ffcefdb5900a8cd41eccd89200">Knn</a>&amp; <a class="code hl_function" href="../../da/d94/classmachine__learning_1_1k__nearest__neighbors_1_1_knn.html#ac06986d5afddc767ddba4da738f75563">operator=</a>(<a class="code hl_function" href="../../da/d94/classmachine__learning_1_1k__nearest__neighbors_1_1_knn.html#a188d29ffcefdb5900a8cd41eccd89200">Knn</a>&amp;&amp;) = <span class="keywordflow">default</span>;</div>
<div class="line"><a id="l00091" name="l00091"></a><span class="lineno"> 91</span></div>
<div class="line"><a id="l00095" name="l00095"></a><span class="lineno"><a class="line" href="../../da/d94/classmachine__learning_1_1k__nearest__neighbors_1_1_knn.html#afe732a33112b457b738f403622d226e5"> 95</a></span> <a class="code hl_function" href="../../da/d94/classmachine__learning_1_1k__nearest__neighbors_1_1_knn.html#afe732a33112b457b738f403622d226e5">~Knn</a>() = <span class="keywordflow">default</span>;</div>
<div class="line"><a id="l00096" name="l00096"></a><span class="lineno"> 96</span></div>
<div class="foldopen" id="foldopen00103" data-start="{" data-end="}">
<div class="line"><a id="l00103" name="l00103"></a><span class="lineno"><a class="line" href="../../da/d94/classmachine__learning_1_1k__nearest__neighbors_1_1_knn.html#a62e152db014cd4de675fa906e5ef2861"> 103</a></span> <span class="keywordtype">int</span> <a class="code hl_function" href="../../da/d94/classmachine__learning_1_1k__nearest__neighbors_1_1_knn.html#a62e152db014cd4de675fa906e5ef2861">predict</a>(std::vector&lt;double&gt;&amp; sample, <span class="keywordtype">int</span> k) {</div>
<div class="line"><a id="l00104" name="l00104"></a><span class="lineno"> 104</span> std::vector&lt;int&gt; neighbors;</div>
<div class="line"><a id="l00105" name="l00105"></a><span class="lineno"> 105</span> std::vector&lt;std::pair&lt;double, int&gt;&gt; distances;</div>
<div class="line"><a id="l00106" name="l00106"></a><span class="lineno"> 106</span> <span class="keywordflow">for</span> (<span class="keywordtype">size_t</span> i = 0; i &lt; this-&gt;X_.size(); ++i) {</div>
<div class="line"><a id="l00107" name="l00107"></a><span class="lineno"> 107</span> <span class="keyword">auto</span> current = this-&gt;X_.at(i);</div>
<div class="line"><a id="l00108" name="l00108"></a><span class="lineno"> 108</span> <span class="keyword">auto</span> label = this-&gt;Y_.at(i);</div>
<div class="line"><a id="l00109" name="l00109"></a><span class="lineno"> 109</span> <span class="keyword">auto</span> distance = <a class="code hl_function" href="../../d4/d3e/k__nearest__neighbors_8cpp.html#ad6ae16e50bb153ebaa7251d0aaa97b69">euclidean_distance</a>(current, sample);</div>
<div class="line"><a id="l00110" name="l00110"></a><span class="lineno"> 110</span> distances.emplace_back(distance, label);</div>
<div class="line"><a id="l00111" name="l00111"></a><span class="lineno"> 111</span> }</div>
<div class="line"><a id="l00112" name="l00112"></a><span class="lineno"> 112</span> std::sort(distances.begin(), distances.end());</div>
<div class="line"><a id="l00113" name="l00113"></a><span class="lineno"> 113</span> <span class="keywordflow">for</span> (<span class="keywordtype">int</span> i = 0; i &lt; k; i++) {</div>
<div class="line"><a id="l00114" name="l00114"></a><span class="lineno"> 114</span> <span class="keyword">auto</span> label = distances.at(i).second;</div>
<div class="line"><a id="l00115" name="l00115"></a><span class="lineno"> 115</span> neighbors.push_back(label);</div>
<div class="line"><a id="l00116" name="l00116"></a><span class="lineno"> 116</span> }</div>
<div class="line"><a id="l00117" name="l00117"></a><span class="lineno"> 117</span> std::unordered_map&lt;int, int&gt; frequency;</div>
<div class="line"><a id="l00118" name="l00118"></a><span class="lineno"> 118</span> <span class="keywordflow">for</span> (<span class="keyword">auto</span> neighbor : neighbors) {</div>
<div class="line"><a id="l00119" name="l00119"></a><span class="lineno"> 119</span> ++frequency[neighbor];</div>
<div class="line"><a id="l00120" name="l00120"></a><span class="lineno"> 120</span> }</div>
<div class="line"><a id="l00121" name="l00121"></a><span class="lineno"> 121</span> std::pair&lt;int, int&gt; predicted;</div>
<div class="line"><a id="l00122" name="l00122"></a><span class="lineno"> 122</span> predicted.first = -1;</div>
<div class="line"><a id="l00123" name="l00123"></a><span class="lineno"> 123</span> predicted.second = -1;</div>
<div class="line"><a id="l00124" name="l00124"></a><span class="lineno"> 124</span> <span class="keywordflow">for</span> (<span class="keyword">auto</span>&amp; kv : frequency) {</div>
<div class="line"><a id="l00125" name="l00125"></a><span class="lineno"> 125</span> <span class="keywordflow">if</span> (kv.second &gt; predicted.second) {</div>
<div class="line"><a id="l00126" name="l00126"></a><span class="lineno"> 126</span> predicted.second = kv.second;</div>
<div class="line"><a id="l00127" name="l00127"></a><span class="lineno"> 127</span> predicted.first = kv.first;</div>
<div class="line"><a id="l00128" name="l00128"></a><span class="lineno"> 128</span> }</div>
<div class="line"><a id="l00129" name="l00129"></a><span class="lineno"> 129</span> }</div>
<div class="line"><a id="l00130" name="l00130"></a><span class="lineno"> 130</span> <span class="keywordflow">return</span> predicted.first;</div>
<div class="line"><a id="l00131" name="l00131"></a><span class="lineno"> 131</span> }</div>
</div>
<div class="line"><a id="l00132" name="l00132"></a><span class="lineno"> 132</span>};</div>
</div>
<div class="line"><a id="l00133" name="l00133"></a><span class="lineno"> 133</span>} <span class="comment">// namespace k_nearest_neighbors</span></div>
<div class="line"><a id="l00134" name="l00134"></a><span class="lineno"> 134</span>} <span class="comment">// namespace machine_learning</span></div>
<div class="line"><a id="l00135" name="l00135"></a><span class="lineno"> 135</span></div>
<div class="foldopen" id="foldopen00140" data-start="{" data-end="}">
<div class="line"><a id="l00140" name="l00140"></a><span class="lineno"><a class="line" href="../../d4/d3e/k__nearest__neighbors_8cpp.html#aa8dca7b867074164d5f45b0f3851269d"> 140</a></span><span class="keyword">static</span> <span class="keywordtype">void</span> <a class="code hl_function" href="../../d4/d3e/k__nearest__neighbors_8cpp.html#aa8dca7b867074164d5f45b0f3851269d">test</a>() {</div>
<div class="line"><a id="l00141" name="l00141"></a><span class="lineno"> 141</span> std::cout &lt;&lt; <span class="stringliteral">&quot;------- Test 1 -------&quot;</span> &lt;&lt; std::endl;</div>
<div class="line"><a id="l00142" name="l00142"></a><span class="lineno"> 142</span> std::vector&lt;std::vector&lt;double&gt;&gt; X1 = {{0.0, 0.0}, {0.25, 0.25},</div>
<div class="line"><a id="l00143" name="l00143"></a><span class="lineno"> 143</span> {0.0, 0.5}, {0.5, 0.5},</div>
<div class="line"><a id="l00144" name="l00144"></a><span class="lineno"> 144</span> {1.0, 0.5}, {1.0, 1.0}};</div>
<div class="line"><a id="l00145" name="l00145"></a><span class="lineno"> 145</span> std::vector&lt;int&gt; Y1 = {1, 1, 1, 1, 2, 2};</div>
<div class="line"><a id="l00146" name="l00146"></a><span class="lineno"> 146</span> <span class="keyword">auto</span> model1 = <a class="code hl_class" href="../../da/d94/classmachine__learning_1_1k__nearest__neighbors_1_1_knn.html">machine_learning::k_nearest_neighbors::Knn</a>(X1, Y1);</div>
<div class="line"><a id="l00147" name="l00147"></a><span class="lineno"> 147</span> std::vector&lt;double&gt; sample1 = {1.2, 1.2};</div>
<div class="line"><a id="l00148" name="l00148"></a><span class="lineno"> 148</span> std::vector&lt;double&gt; sample2 = {0.1, 0.1};</div>
<div class="line"><a id="l00149" name="l00149"></a><span class="lineno"> 149</span> std::vector&lt;double&gt; sample3 = {0.1, 0.5};</div>
<div class="line"><a id="l00150" name="l00150"></a><span class="lineno"> 150</span> std::vector&lt;double&gt; sample4 = {1.0, 0.75};</div>
<div class="line"><a id="l00151" name="l00151"></a><span class="lineno"> 151</span> assert(model1.predict(sample1, 2) == 2);</div>
<div class="line"><a id="l00152" name="l00152"></a><span class="lineno"> 152</span> assert(model1.predict(sample2, 2) == 1);</div>
<div class="line"><a id="l00153" name="l00153"></a><span class="lineno"> 153</span> assert(model1.predict(sample3, 2) == 1);</div>
<div class="line"><a id="l00154" name="l00154"></a><span class="lineno"> 154</span> assert(model1.predict(sample4, 2) == 2);</div>
<div class="line"><a id="l00155" name="l00155"></a><span class="lineno"> 155</span> std::cout &lt;&lt; <span class="stringliteral">&quot;... Passed&quot;</span> &lt;&lt; std::endl;</div>
<div class="line"><a id="l00156" name="l00156"></a><span class="lineno"> 156</span> std::cout &lt;&lt; <span class="stringliteral">&quot;------- Test 2 -------&quot;</span> &lt;&lt; std::endl;</div>
<div class="line"><a id="l00157" name="l00157"></a><span class="lineno"> 157</span> std::vector&lt;std::vector&lt;double&gt;&gt; X2 = {</div>
<div class="line"><a id="l00158" name="l00158"></a><span class="lineno"> 158</span> {0.0, 0.0, 0.0}, {0.25, 0.25, 0.0}, {0.0, 0.5, 0.0}, {0.5, 0.5, 0.0},</div>
<div class="line"><a id="l00159" name="l00159"></a><span class="lineno"> 159</span> {1.0, 0.5, 0.0}, {1.0, 1.0, 0.0}, {1.0, 1.0, 1.0}, {1.5, 1.5, 1.0}};</div>
<div class="line"><a id="l00160" name="l00160"></a><span class="lineno"> 160</span> std::vector&lt;int&gt; Y2 = {1, 1, 1, 1, 2, 2, 3, 3};</div>
<div class="line"><a id="l00161" name="l00161"></a><span class="lineno"> 161</span> <span class="keyword">auto</span> model2 = <a class="code hl_class" href="../../da/d94/classmachine__learning_1_1k__nearest__neighbors_1_1_knn.html">machine_learning::k_nearest_neighbors::Knn</a>(X2, Y2);</div>
<div class="line"><a id="l00162" name="l00162"></a><span class="lineno"> 162</span> std::vector&lt;double&gt; sample5 = {1.2, 1.2, 0.0};</div>
<div class="line"><a id="l00163" name="l00163"></a><span class="lineno"> 163</span> std::vector&lt;double&gt; sample6 = {0.1, 0.1, 0.0};</div>
<div class="line"><a id="l00164" name="l00164"></a><span class="lineno"> 164</span> std::vector&lt;double&gt; sample7 = {0.1, 0.5, 0.0};</div>
<div class="line"><a id="l00165" name="l00165"></a><span class="lineno"> 165</span> std::vector&lt;double&gt; sample8 = {1.0, 0.75, 1.0};</div>
<div class="line"><a id="l00166" name="l00166"></a><span class="lineno"> 166</span> assert(model2.predict(sample5, 2) == 2);</div>
<div class="line"><a id="l00167" name="l00167"></a><span class="lineno"> 167</span> assert(model2.predict(sample6, 2) == 1);</div>
<div class="line"><a id="l00168" name="l00168"></a><span class="lineno"> 168</span> assert(model2.predict(sample7, 2) == 1);</div>
<div class="line"><a id="l00169" name="l00169"></a><span class="lineno"> 169</span> assert(model2.predict(sample8, 2) == 3);</div>
<div class="line"><a id="l00170" name="l00170"></a><span class="lineno"> 170</span> std::cout &lt;&lt; <span class="stringliteral">&quot;... Passed&quot;</span> &lt;&lt; std::endl;</div>
<div class="line"><a id="l00171" name="l00171"></a><span class="lineno"> 171</span> std::cout &lt;&lt; <span class="stringliteral">&quot;------- Test 3 -------&quot;</span> &lt;&lt; std::endl;</div>
<div class="line"><a id="l00172" name="l00172"></a><span class="lineno"> 172</span> std::vector&lt;std::vector&lt;double&gt;&gt; X3 = {{0.0}, {1.0}, {2.0}, {3.0},</div>
<div class="line"><a id="l00173" name="l00173"></a><span class="lineno"> 173</span> {4.0}, {5.0}, {6.0}, {7.0}};</div>
<div class="line"><a id="l00174" name="l00174"></a><span class="lineno"> 174</span> std::vector&lt;int&gt; Y3 = {1, 1, 1, 1, 2, 2, 2, 2};</div>
<div class="line"><a id="l00175" name="l00175"></a><span class="lineno"> 175</span> <span class="keyword">auto</span> model3 = <a class="code hl_class" href="../../da/d94/classmachine__learning_1_1k__nearest__neighbors_1_1_knn.html">machine_learning::k_nearest_neighbors::Knn</a>(X3, Y3);</div>
<div class="line"><a id="l00176" name="l00176"></a><span class="lineno"> 176</span> std::vector&lt;double&gt; sample9 = {0.5};</div>
<div class="line"><a id="l00177" name="l00177"></a><span class="lineno"> 177</span> std::vector&lt;double&gt; sample10 = {2.9};</div>
<div class="line"><a id="l00178" name="l00178"></a><span class="lineno"> 178</span> std::vector&lt;double&gt; sample11 = {5.5};</div>
<div class="line"><a id="l00179" name="l00179"></a><span class="lineno"> 179</span> std::vector&lt;double&gt; sample12 = {7.5};</div>
<div class="line"><a id="l00180" name="l00180"></a><span class="lineno"> 180</span> assert(model3.predict(sample9, 3) == 1);</div>
<div class="line"><a id="l00181" name="l00181"></a><span class="lineno"> 181</span> assert(model3.predict(sample10, 3) == 1);</div>
<div class="line"><a id="l00182" name="l00182"></a><span class="lineno"> 182</span> assert(model3.predict(sample11, 3) == 2);</div>
<div class="line"><a id="l00183" name="l00183"></a><span class="lineno"> 183</span> assert(model3.predict(sample12, 3) == 2);</div>
<div class="line"><a id="l00184" name="l00184"></a><span class="lineno"> 184</span> std::cout &lt;&lt; <span class="stringliteral">&quot;... Passed&quot;</span> &lt;&lt; std::endl;</div>
<div class="line"><a id="l00185" name="l00185"></a><span class="lineno"> 185</span>}</div>
</div>
<div class="line"><a id="l00186" name="l00186"></a><span class="lineno"> 186</span></div>
<div class="foldopen" id="foldopen00191" data-start="{" data-end="}">
<div class="line"><a id="l00191" name="l00191"></a><span class="lineno"><a class="line" href="../../d4/d3e/k__nearest__neighbors_8cpp.html#ae66f6b31b5ad750f1fe042a706a4e3d4"> 191</a></span><span class="keywordtype">int</span> <a class="code hl_function" href="../../d4/d3e/k__nearest__neighbors_8cpp.html#ae66f6b31b5ad750f1fe042a706a4e3d4">main</a>() {</div>
<div class="line"><a id="l00192" name="l00192"></a><span class="lineno"> 192</span> <a class="code hl_function" href="../../d4/d3e/k__nearest__neighbors_8cpp.html#aa8dca7b867074164d5f45b0f3851269d">test</a>(); <span class="comment">// run self-test implementations</span></div>
<div class="line"><a id="l00193" name="l00193"></a><span class="lineno"> 193</span> <span class="keywordflow">return</span> 0;</div>
<div class="line"><a id="l00194" name="l00194"></a><span class="lineno"> 194</span>}</div>
</div>
<div class="ttc" id="aclassmachine__learning_1_1k__nearest__neighbors_1_1_knn_html"><div class="ttname"><a href="../../da/d94/classmachine__learning_1_1k__nearest__neighbors_1_1_knn.html">machine_learning::k_nearest_neighbors::Knn</a></div><div class="ttdoc">K-Nearest Neighbors (Knn) class using Euclidean distance as distance metric.</div><div class="ttdef"><b>Definition</b> <a href="#l00055">k_nearest_neighbors.cpp:55</a></div></div>
<div class="ttc" id="aclassmachine__learning_1_1k__nearest__neighbors_1_1_knn_html_a080f5b1742832a03c1cbba596a48bd1a"><div class="ttname"><a href="../../da/d94/classmachine__learning_1_1k__nearest__neighbors_1_1_knn.html#a080f5b1742832a03c1cbba596a48bd1a">machine_learning::k_nearest_neighbors::Knn::operator=</a></div><div class="ttdeci">Knn &amp; operator=(const Knn &amp;model)=default</div></div>
<div class="ttc" id="aclassmachine__learning_1_1k__nearest__neighbors_1_1_knn_html_a16ddc13621eec6ac5f83658b3401a581"><div class="ttname"><a href="../../da/d94/classmachine__learning_1_1k__nearest__neighbors_1_1_knn.html#a16ddc13621eec6ac5f83658b3401a581">machine_learning::k_nearest_neighbors::Knn::X_</a></div><div class="ttdeci">std::vector&lt; std::vector&lt; double &gt; &gt; X_</div><div class="ttdoc">attributes vector</div><div class="ttdef"><b>Definition</b> <a href="#l00057">k_nearest_neighbors.cpp:57</a></div></div>
<div class="ttc" id="aclassmachine__learning_1_1k__nearest__neighbors_1_1_knn_html_a188d29ffcefdb5900a8cd41eccd89200"><div class="ttname"><a href="../../da/d94/classmachine__learning_1_1k__nearest__neighbors_1_1_knn.html#a188d29ffcefdb5900a8cd41eccd89200">machine_learning::k_nearest_neighbors::Knn::Knn</a></div><div class="ttdeci">Knn(std::vector&lt; std::vector&lt; double &gt; &gt; &amp;X, std::vector&lt; int &gt; &amp;Y)</div><div class="ttdoc">Construct a new Knn object.</div><div class="ttdef"><b>Definition</b> <a href="#l00067">k_nearest_neighbors.cpp:67</a></div></div>
<div class="ttc" id="aclassmachine__learning_1_1k__nearest__neighbors_1_1_knn_html_a209383503fb6c03afac405a80bace964"><div class="ttname"><a href="../../da/d94/classmachine__learning_1_1k__nearest__neighbors_1_1_knn.html#a209383503fb6c03afac405a80bace964">machine_learning::k_nearest_neighbors::Knn::Y_</a></div><div class="ttdeci">std::vector&lt; int &gt; Y_</div><div class="ttdoc">labels vector</div><div class="ttdef"><b>Definition</b> <a href="#l00058">k_nearest_neighbors.cpp:58</a></div></div>
<div class="ttc" id="aclassmachine__learning_1_1k__nearest__neighbors_1_1_knn_html_a4b17dcf17c847f0295b60029512c120e"><div class="ttname"><a href="../../da/d94/classmachine__learning_1_1k__nearest__neighbors_1_1_knn.html#a4b17dcf17c847f0295b60029512c120e">machine_learning::k_nearest_neighbors::Knn::Knn</a></div><div class="ttdeci">Knn(Knn &amp;&amp;)=default</div></div>
<div class="ttc" id="aclassmachine__learning_1_1k__nearest__neighbors_1_1_knn_html_a62e152db014cd4de675fa906e5ef2861"><div class="ttname"><a href="../../da/d94/classmachine__learning_1_1k__nearest__neighbors_1_1_knn.html#a62e152db014cd4de675fa906e5ef2861">machine_learning::k_nearest_neighbors::Knn::predict</a></div><div class="ttdeci">int predict(std::vector&lt; double &gt; &amp;sample, int k)</div><div class="ttdoc">Classify sample.</div><div class="ttdef"><b>Definition</b> <a href="#l00103">k_nearest_neighbors.cpp:103</a></div></div>
<div class="ttc" id="aclassmachine__learning_1_1k__nearest__neighbors_1_1_knn_html_a9f5885c40112481ae5b588fe81d7910b"><div class="ttname"><a href="../../da/d94/classmachine__learning_1_1k__nearest__neighbors_1_1_knn.html#a9f5885c40112481ae5b588fe81d7910b">machine_learning::k_nearest_neighbors::Knn::Knn</a></div><div class="ttdeci">Knn(const Knn &amp;model)=default</div></div>
<div class="ttc" id="aclassmachine__learning_1_1k__nearest__neighbors_1_1_knn_html_ac06986d5afddc767ddba4da738f75563"><div class="ttname"><a href="../../da/d94/classmachine__learning_1_1k__nearest__neighbors_1_1_knn.html#ac06986d5afddc767ddba4da738f75563">machine_learning::k_nearest_neighbors::Knn::operator=</a></div><div class="ttdeci">Knn &amp; operator=(Knn &amp;&amp;)=default</div></div>
<div class="ttc" id="aclassmachine__learning_1_1k__nearest__neighbors_1_1_knn_html_afe732a33112b457b738f403622d226e5"><div class="ttname"><a href="../../da/d94/classmachine__learning_1_1k__nearest__neighbors_1_1_knn.html#afe732a33112b457b738f403622d226e5">machine_learning::k_nearest_neighbors::Knn::~Knn</a></div><div class="ttdeci">~Knn()=default</div><div class="ttdoc">Destroy the Knn object.</div></div>
<div class="ttc" id="ak__nearest__neighbors_8cpp_html_aa8dca7b867074164d5f45b0f3851269d"><div class="ttname"><a href="../../d4/d3e/k__nearest__neighbors_8cpp.html#aa8dca7b867074164d5f45b0f3851269d">test</a></div><div class="ttdeci">static void test()</div><div class="ttdoc">Self-test implementations.</div><div class="ttdef"><b>Definition</b> <a href="#l00140">k_nearest_neighbors.cpp:140</a></div></div>
<div class="ttc" id="ak__nearest__neighbors_8cpp_html_ad6ae16e50bb153ebaa7251d0aaa97b69"><div class="ttname"><a href="../../d4/d3e/k__nearest__neighbors_8cpp.html#ad6ae16e50bb153ebaa7251d0aaa97b69">machine_learning::k_nearest_neighbors::euclidean_distance</a></div><div class="ttdeci">double euclidean_distance(const std::vector&lt; T &gt; &amp;a, const std::vector&lt; T &gt; &amp;b)</div><div class="ttdoc">Compute the Euclidean distance between two vectors.</div><div class="ttdef"><b>Definition</b> <a href="#l00043">k_nearest_neighbors.cpp:43</a></div></div>
<div class="ttc" id="ak__nearest__neighbors_8cpp_html_ae66f6b31b5ad750f1fe042a706a4e3d4"><div class="ttname"><a href="../../d4/d3e/k__nearest__neighbors_8cpp.html#ae66f6b31b5ad750f1fe042a706a4e3d4">main</a></div><div class="ttdeci">int main()</div><div class="ttdoc">Main function.</div><div class="ttdef"><b>Definition</b> <a href="#l00191">k_nearest_neighbors.cpp:191</a></div></div>
<div class="ttc" id="anamespacek__nearest__neighbors_html"><div class="ttname"><a href="../../d7/d4c/namespacek__nearest__neighbors.html">k_nearest_neighbors</a></div><div class="ttdoc">Functions for the [K-Nearest Neighbors algorithm] (https://en.wikipedia.org/wiki/K-nearest_neighbors_...</div></div>
<div class="ttc" id="anamespacemachine__learning_html"><div class="ttname"><a href="../../d8/d77/namespacemachine__learning.html">machine_learning</a></div><div class="ttdoc">A* search algorithm</div></div>
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