stats_rand_gen_normal

(PECL stats >= 1.0.0)

stats_rand_gen_normalGenerates a single random deviate from a normal distribution

Açıklama

stats_rand_gen_normal(float $av, float $sd): float

Returns a random deviate from the normal distribution with mean, av, and standard deviation, sd.

Bağımsız Değişkenler

av

The mean of the normal distribution

sd

The standard deviation of the normal distribution

Dönen Değerler

A random deviate

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KEINOS
4 years ago
Alternative of "stats_rand_gen_normal()".

<?php
/**
* "Box–Muller transform" based random deviate generator.
*
* @ref https://en.wikipedia.org/wiki/Box%E2%80%93Muller_transform
*
* @param float|int $av Average/Mean
* @param float|int $sd Standard deviation
* @return float
*/
if (! function_exists('stats_rand_gen_normal')) {
function
stats_rand_gen_normal($av, $sd): float
{
$x = mt_rand() / mt_getrandmax();
$y = mt_rand() / mt_getrandmax();

return
sqrt(-2 * log($x)) * cos(2 * pi() * $y) * $sd + $av;
}
}
?>
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