Fisher.php

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<?php
 
namespace PhpOffice\PhpSpreadsheet\Calculation\Statistical\Distributions;
 
use PhpOffice\PhpSpreadsheet\Calculation\Exception;
use PhpOffice\PhpSpreadsheet\Calculation\Functions;
 
class Fisher
{
    public static function distribution($value)
    {
        $value = Functions::flattenSingleValue($value);
 
        try {
            DistributionValidations::validateFloat($value);
        } catch (Exception $e) {
            return $e->getMessage();
        }
 
        if (($value <= -1) || ($value >= 1)) {
            return Functions::NAN();
        }
 
        return 0.5 * log((1 + $value) / (1 - $value));
    }
 
    public static function inverse($probability)
    {
        $probability = Functions::flattenSingleValue($probability);
 
        try {
            DistributionValidations::validateFloat($probability);
        } catch (Exception $e) {
            return $e->getMessage();
        }
 
        return (exp(2 * $probability) - 1) / (exp(2 * $probability) + 1);
    }
}