public static function geometric( $values, $accuracy = NULL )
	{
		Deprecation::getInstance()
			->setErrorVersion( '0.8.5' )
			->setExceptionVersion( '0.9' )
			->message( sprintf(
				'Please use %s (%s) instead',
				'public library "CeusMedia/Math"',
			 	'https://packagist.org/packages/ceus-media/math'
			) );
		$product	= 1;
		foreach( $values as $value )
			$product	*= $value;
		$result	= pow( $product, 1 / count( $values ) );
		if( $accuracy >= 0 )
			$result	= round( $result, $accuracy );
		return $result;
	}