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Cosine similarity implements PHP data analysis

高洛峰
Release: 2016-11-29 10:04:47
Original
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<?php
/**
 * 数据分析引擎
 * 分析向量的元素 必须和基准向量的元素一致,取最大个数,分析向量不足元素以0填补。
 * 求出分析向量与基准向量的余弦值
 * @php爱好者
 */
 
 
/**
 * 获得向量的模
 * @param unknown_type $array 传入分析数据的基准点的N维向量。|eg:array(1,1,1,1,1);
 */
function getMarkMod($arrParam){
$strModDouble = 0;
foreach($arrParam as $val){
$strModDouble += $val * $val;
}
$strMod = sqrt($strModDouble);
//是否需要保留小数点后几位
return $strMod;
}
 
/**
 * 获取标杆的元素个数
 * @param unknown_type $arrParam
 * @return number
 */
function getMarkLenth($arrParam){
$intLenth = count($arrParam);
return $intLenth;
}
/**
 * 对传入数组进行索引分配,基准点的索引必须为k,求夹角的向量索引必须为 &#39;j&#39;.
 * @param unknown_type $arrParam
 * @param unknown_type $index
 * @ruturn $arrBack
 */
function handIndex($arrParam, $index = &#39;k&#39;){
 foreach($arrParam as $key => $val){
  $in = $index.$key;
  $arrBack[$in] = $val;
 }
 return $arrBack;
}
 
/**
 *
 * @param unknown_type $arrMark标杆向量数组(索引被处理过)
 * @param unknown_type $arrAnaly 分析向量数组 (索引被处理过) |array(&#39;j0&#39;=>1,&#39;j1&#39;=>2....)
 * @param unknown_type $strMarkMod标杆向量的模
 * @param unknown_type $intLenth 向量的长度
 */
function getCosine($arrMark, $arrAnaly, $strMarkMod ,$intLenth){
$strVector = 0;
$strCosine = 0;
for($i = 0; $i < $intLenth; $i++){
$strMarkVal = $arrMark[&#39;k&#39;.$i];
$strAnalyVal = $arrAnaly[&#39;j&#39;.$i];
$strVector += $strMarkVal * $strAnalyVal;
}
$arrAnalyMod = getMarkMod($arrAnaly); //求分析向量的模
$strFenzi = $strVector;
$strFenMu = $arrAnalyMod * $strMarkMod;
$strCosine = $strFenzi / $strFenMu;
if(0 !== (int)$strFenMu){
$strCosine = $strFenzi / $strFenMu;
}
return $strCosine;
}
?>
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