MCordingley\LinearAlgebra\Matrix::upper PHP Метод

    public function upper(bool $unitriangular) : self
    {
        return $this->map(function (float $element, int $i, int $j) use($unitriangular) {
            if ($unitriangular && $i === $j) {
                return 1;
            }
            return $j < $i ? 0 : $element;
        });
    }

 /**
  * @return Matrix
  */
 public function upper() : Matrix
 {
     return $this->decomposition->upper(false);
 }