code: public function max()
      {
          $float_max = 1 / ($this->float_sigma * sqrt(2 * pi()));
  
          if ($this->int_precision) {
              return round($float_max, $this->int_precision);
          }
  
          return $float_max;
      }
docs: Give the maximal value of the curve for the current sigma and mu.
  
  @see NormalDistribution::precision()
  @access public
  @return float