stats_harmonic_mean

(PECL stats >= 1.0.0)

stats_harmonic_mean値の配列の調和平均を返す

説明

stats_harmonic_mean ( array $a ) : number

a に含まれる値の調和平均を返します。

パラメータ

a

入力配列

返り値

a に含まれる値の調和平均。 a が空の場合、または、配列ではない場合は FALSE を返します。

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User Contributed Notes 1 note

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4
Daniel Morris (www.danielxmorris.com)
11 years ago
I wrote this to calculate harmonic averages in my shares program.  Hopefully this can help someone who doesn't want to use PECL.  The function accepts an unlimited number of arguments without the need to place them into an array, which is better than the way the PECL extension handles the function.

<?php

/**
*  @author    Daniel Morris
*/
function harmonic () {
   
$num_args = func_num_args ();
    for (
$i = 0; $i < $num_args; $i++) {
       
$sum += 1 / func_get_arg ($i);
    }
    return
$num_args / $sum;
}

// Tests

echo harmonic (1, 2, 3, 4, 5);
echo
harmonic (-1, 3, 4, 10293);
echo
harmonic (-1, -2, -3, -4, -5);

//  2.1897810218978
//  -9.6022389365052
//  -2.1897810218978 

?>
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