如何计算几何平均值（pascal或php）

Question

I wanna solve this problem with your support. Assume that, there is an array in variable named $ar, and exist 5 numbers in this array, so i want to calculate geometric average of these numbers through Pascal or PHP programming language. How can i do ?

Answer 1

Here is PHP version:

function geometric_average($a) {  
   foreach($a as $i=>$n) $mul = $i == 0 ? $n : $mul*$n;  
   return pow($mul,1/count($a));  
}

//usage
echo geometric_average(array(2,8)); //Output-> 4