stats_rand_gen_normal

    (PECL stats >= 1.0.0)

    stats_rand_gen_normal — Generates a single random deviate from a normal distribution

    Опис

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

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

    Параметри

    av

    The mean of the normal distribution

    sd

    The standard deviation of the normal distribution

    Значення, що повертаються

    A random deviate

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    User Contributed Notes 1 note

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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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