<?php
//Covariance Calculation
function standard_covariance($aValues,$bValues)
{
$a= (array_sum($aValues)*array_sum($bValues))/count($aValues);
$ret = array();
for($i=0;$i<count($aValues);$i++)
{
$ret[$i]=$aValues[$i]*$bValues[$i];
}
$b=(array_sum($ret)-$a)/(count($aValues)-1);
return (float) $b;
}
$aValues=array(3,4,5,7);
$bValues=array(10,11,13,14);
echo standard_covariance($aValues,$bValues);
?>
stats_covariance
(PECL stats >= 1.0.0)
stats_covariance — Computes the covariance of two data sets
Description
float stats_covariance
( array
$a
, array $b
)Warning
This function is currently not documented; only its argument list is available.
Parameters
-
a -
-
b -
Return Values
kanniprabu at gmail dot com ¶
1 month ago
