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<a href="StatsHelper_8java.html">Go to the documentation of this file.</a><div class="fragment"><div class="line"><a name="l00001"></a><span class="lineno"> 1</span>&#160;<span class="comment">// Copyright 2014 Cloudera Inc.</span></div>
<div class="line"><a name="l00002"></a><span class="lineno"> 2</span>&#160;<span class="comment">//</span></div>
<div class="line"><a name="l00003"></a><span class="lineno"> 3</span>&#160;<span class="comment">// Licensed under the Apache License, Version 2.0 (the &quot;License&quot;);</span></div>
<div class="line"><a name="l00004"></a><span class="lineno"> 4</span>&#160;<span class="comment">// you may not use this file except in compliance with the License.</span></div>
<div class="line"><a name="l00005"></a><span class="lineno"> 5</span>&#160;<span class="comment">// You may obtain a copy of the License at</span></div>
<div class="line"><a name="l00006"></a><span class="lineno"> 6</span>&#160;<span class="comment">//</span></div>
<div class="line"><a name="l00007"></a><span class="lineno"> 7</span>&#160;<span class="comment">// http://www.apache.org/licenses/LICENSE-2.0</span></div>
<div class="line"><a name="l00008"></a><span class="lineno"> 8</span>&#160;<span class="comment">//</span></div>
<div class="line"><a name="l00009"></a><span class="lineno"> 9</span>&#160;<span class="comment">// Unless required by applicable law or agreed to in writing, software</span></div>
<div class="line"><a name="l00010"></a><span class="lineno"> 10</span>&#160;<span class="comment">// distributed under the License is distributed on an &quot;AS IS&quot; BASIS,</span></div>
<div class="line"><a name="l00011"></a><span class="lineno"> 11</span>&#160;<span class="comment">// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.</span></div>
<div class="line"><a name="l00012"></a><span class="lineno"> 12</span>&#160;<span class="comment">// See the License for the specific language governing permissions and</span></div>
<div class="line"><a name="l00013"></a><span class="lineno"> 13</span>&#160;<span class="comment">// limitations under the License.</span></div>
<div class="line"><a name="l00014"></a><span class="lineno"> 14</span>&#160;</div>
<div class="line"><a name="l00015"></a><span class="lineno"> 15</span>&#160;<span class="keyword">package </span>com.cloudera.impala.util;</div>
<div class="line"><a name="l00016"></a><span class="lineno"> 16</span>&#160;</div>
<div class="line"><a name="l00028"></a><span class="lineno"><a class="line" href="classcom_1_1cloudera_1_1impala_1_1util_1_1StatsHelper_3_01T_01extends_01Number_01_4.html"> 28</a></span>&#160;<span class="keyword">public</span> <span class="keyword">class </span>StatsHelper&lt;T <span class="keyword">extends</span> Number&gt; {</div>
<div class="line"><a name="l00029"></a><span class="lineno"> 29</span>&#160;</div>
<div class="line"><a name="l00030"></a><span class="lineno"><a class="line" href="classcom_1_1cloudera_1_1impala_1_1util_1_1StatsHelper_3_01T_01extends_01Number_01_4.html#a6959f173e586b92038cf4e26a3c7f524"> 30</a></span>&#160; <span class="keyword">private</span> <span class="keywordtype">long</span> count_ = 0;</div>
<div class="line"><a name="l00031"></a><span class="lineno"> 31</span>&#160;</div>
<div class="line"><a name="l00032"></a><span class="lineno"> 32</span>&#160; <span class="comment">// Current mean</span></div>
<div class="line"><a name="l00033"></a><span class="lineno"><a class="line" href="classcom_1_1cloudera_1_1impala_1_1util_1_1StatsHelper_3_01T_01extends_01Number_01_4.html#abe12c9dce8e9cbc2c18d9776bf270a08"> 33</a></span>&#160; <span class="keyword">private</span> <span class="keywordtype">double</span> mean_ = 0.0d;</div>
<div class="line"><a name="l00034"></a><span class="lineno"> 34</span>&#160;</div>
<div class="line"><a name="l00035"></a><span class="lineno"> 35</span>&#160; <span class="comment">// Sum of the square differences from the mean</span></div>
<div class="line"><a name="l00036"></a><span class="lineno"><a class="line" href="classcom_1_1cloudera_1_1impala_1_1util_1_1StatsHelper_3_01T_01extends_01Number_01_4.html#a2ff8af93ec6d1b983b21925e5f5496d0"> 36</a></span>&#160; <span class="keyword">private</span> <span class="keywordtype">double</span> m2_ = 0.0d;</div>
<div class="line"><a name="l00037"></a><span class="lineno"> 37</span>&#160;</div>
<div class="line"><a name="l00038"></a><span class="lineno"><a class="line" href="classcom_1_1cloudera_1_1impala_1_1util_1_1StatsHelper_3_01T_01extends_01Number_01_4.html#a3134cb1e0b43f1110f8ebb8b9f08c88d"> 38</a></span>&#160; <span class="keyword">public</span> <span class="keywordtype">void</span> <a class="code" href="classcom_1_1cloudera_1_1impala_1_1util_1_1StatsHelper_3_01T_01extends_01Number_01_4.html#a3134cb1e0b43f1110f8ebb8b9f08c88d">addSample</a>(T val) {</div>
<div class="line"><a name="l00039"></a><span class="lineno"> 39</span>&#160; ++count_;</div>
<div class="line"><a name="l00040"></a><span class="lineno"> 40</span>&#160; mean_ += (val.doubleValue() - mean_) / count_;</div>
<div class="line"><a name="l00041"></a><span class="lineno"> 41</span>&#160; m2_ += Math.pow(val.doubleValue() - mean_, 2);</div>
<div class="line"><a name="l00042"></a><span class="lineno"> 42</span>&#160; }</div>
<div class="line"><a name="l00043"></a><span class="lineno"> 43</span>&#160;</div>
<div class="line"><a name="l00044"></a><span class="lineno"><a class="line" href="classcom_1_1cloudera_1_1impala_1_1util_1_1StatsHelper_3_01T_01extends_01Number_01_4.html#ab6cdf2708f54eac828982d1ad9ad12e1"> 44</a></span>&#160; <span class="keyword">public</span> <span class="keywordtype">long</span> <a class="code" href="classcom_1_1cloudera_1_1impala_1_1util_1_1StatsHelper_3_01T_01extends_01Number_01_4.html#ab6cdf2708f54eac828982d1ad9ad12e1">count</a>() { <span class="keywordflow">return</span> count_; }</div>
<div class="line"><a name="l00045"></a><span class="lineno"> 45</span>&#160;</div>
<div class="line"><a name="l00046"></a><span class="lineno"><a class="line" href="classcom_1_1cloudera_1_1impala_1_1util_1_1StatsHelper_3_01T_01extends_01Number_01_4.html#a8fc9c062319b661deb202eb09570c10f"> 46</a></span>&#160; <span class="keyword">public</span> <span class="keywordtype">double</span> <a class="code" href="classcom_1_1cloudera_1_1impala_1_1util_1_1StatsHelper_3_01T_01extends_01Number_01_4.html#a8fc9c062319b661deb202eb09570c10f">mean</a>() {</div>
<div class="line"><a name="l00047"></a><span class="lineno"> 47</span>&#160; <span class="keywordflow">return</span> count_ &gt; 0 ? mean_ : 0.0;</div>
<div class="line"><a name="l00048"></a><span class="lineno"> 48</span>&#160; }</div>
<div class="line"><a name="l00049"></a><span class="lineno"> 49</span>&#160;</div>
<div class="line"><a name="l00050"></a><span class="lineno"><a class="line" href="classcom_1_1cloudera_1_1impala_1_1util_1_1StatsHelper_3_01T_01extends_01Number_01_4.html#a683be0b322cfa2c74ccf4b059ea1a682"> 50</a></span>&#160; <span class="keyword">public</span> <span class="keywordtype">double</span> <a class="code" href="classcom_1_1cloudera_1_1impala_1_1util_1_1StatsHelper_3_01T_01extends_01Number_01_4.html#a683be0b322cfa2c74ccf4b059ea1a682">variance</a>() {</div>
<div class="line"><a name="l00051"></a><span class="lineno"> 51</span>&#160; <span class="keywordflow">return</span> count_ &gt; 1 ? m2_ / (count_ - 1) : 0.0d;</div>
<div class="line"><a name="l00052"></a><span class="lineno"> 52</span>&#160; }</div>
<div class="line"><a name="l00053"></a><span class="lineno"> 53</span>&#160;</div>
<div class="line"><a name="l00054"></a><span class="lineno"><a class="line" href="classcom_1_1cloudera_1_1impala_1_1util_1_1StatsHelper_3_01T_01extends_01Number_01_4.html#af59a232c958fa580f78d1e689d18de90"> 54</a></span>&#160; <span class="keyword">public</span> <span class="keywordtype">double</span> <a class="code" href="classcom_1_1cloudera_1_1impala_1_1util_1_1StatsHelper_3_01T_01extends_01Number_01_4.html#af59a232c958fa580f78d1e689d18de90">stddev</a>() {</div>
<div class="line"><a name="l00055"></a><span class="lineno"> 55</span>&#160; <span class="keywordflow">return</span> Math.sqrt(variance());</div>
<div class="line"><a name="l00056"></a><span class="lineno"> 56</span>&#160; }</div>
<div class="line"><a name="l00057"></a><span class="lineno"> 57</span>&#160;}</div>
<div class="ttc" id="classcom_1_1cloudera_1_1impala_1_1util_1_1StatsHelper_3_01T_01extends_01Number_01_4_html_a683be0b322cfa2c74ccf4b059ea1a682"><div class="ttname"><a href="classcom_1_1cloudera_1_1impala_1_1util_1_1StatsHelper_3_01T_01extends_01Number_01_4.html#a683be0b322cfa2c74ccf4b059ea1a682">com.cloudera.impala.util.StatsHelper&lt; T extends Number &gt;.variance</a></div><div class="ttdeci">double variance()</div><div class="ttdef"><b>Definition:</b> <a href="StatsHelper_8java_source.html#l00050">StatsHelper.java:50</a></div></div>
<div class="ttc" id="classcom_1_1cloudera_1_1impala_1_1util_1_1StatsHelper_3_01T_01extends_01Number_01_4_html_af59a232c958fa580f78d1e689d18de90"><div class="ttname"><a href="classcom_1_1cloudera_1_1impala_1_1util_1_1StatsHelper_3_01T_01extends_01Number_01_4.html#af59a232c958fa580f78d1e689d18de90">com.cloudera.impala.util.StatsHelper&lt; T extends Number &gt;.stddev</a></div><div class="ttdeci">double stddev()</div><div class="ttdef"><b>Definition:</b> <a href="StatsHelper_8java_source.html#l00054">StatsHelper.java:54</a></div></div>
<div class="ttc" id="classcom_1_1cloudera_1_1impala_1_1util_1_1StatsHelper_3_01T_01extends_01Number_01_4_html_a8fc9c062319b661deb202eb09570c10f"><div class="ttname"><a href="classcom_1_1cloudera_1_1impala_1_1util_1_1StatsHelper_3_01T_01extends_01Number_01_4.html#a8fc9c062319b661deb202eb09570c10f">com.cloudera.impala.util.StatsHelper&lt; T extends Number &gt;.mean</a></div><div class="ttdeci">double mean()</div><div class="ttdef"><b>Definition:</b> <a href="StatsHelper_8java_source.html#l00046">StatsHelper.java:46</a></div></div>
<div class="ttc" id="classcom_1_1cloudera_1_1impala_1_1util_1_1StatsHelper_3_01T_01extends_01Number_01_4_html_a3134cb1e0b43f1110f8ebb8b9f08c88d"><div class="ttname"><a href="classcom_1_1cloudera_1_1impala_1_1util_1_1StatsHelper_3_01T_01extends_01Number_01_4.html#a3134cb1e0b43f1110f8ebb8b9f08c88d">com.cloudera.impala.util.StatsHelper&lt; T extends Number &gt;.addSample</a></div><div class="ttdeci">void addSample(T val)</div><div class="ttdef"><b>Definition:</b> <a href="StatsHelper_8java_source.html#l00038">StatsHelper.java:38</a></div></div>
<div class="ttc" id="classcom_1_1cloudera_1_1impala_1_1util_1_1StatsHelper_3_01T_01extends_01Number_01_4_html_ab6cdf2708f54eac828982d1ad9ad12e1"><div class="ttname"><a href="classcom_1_1cloudera_1_1impala_1_1util_1_1StatsHelper_3_01T_01extends_01Number_01_4.html#ab6cdf2708f54eac828982d1ad9ad12e1">com.cloudera.impala.util.StatsHelper&lt; T extends Number &gt;.count</a></div><div class="ttdeci">long count()</div><div class="ttdef"><b>Definition:</b> <a href="StatsHelper_8java_source.html#l00044">StatsHelper.java:44</a></div></div>
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