public function normF()
    {
        $f = 0;
        for ($i = 0; $i < $this->m; $i++) {
            for ($j = 0; $j < $this->n; $j++) {
                $f = hypo($f, $this->A[$i][$j]);
            }
        }
        return $f;
    }
public function normF()
    {
        $f = 0;
        for ($i = 0; $i < $this->m; $i++) {
            for ($j = 0; $j < $this->n; $j++) {
                $f = hypo($f, $this->A[$i][$j]);
            }
        }
        return $f;
    }
public function normF ( ) { $ f = 0 ; for ( $ i = 0 ; $ i < $ this -> m ; $ i ++ ) { for ( $ j = 0 ; $ j < $ this -> n ; $ j ++ ) { $ f = hypo ( $ f , $ this -> A [ $ i ] [ $ j ] ) ; } } return $ f ; }
normF
Frobenius norm
@return float Square root of the sum of all elements squared
normF Frobenius norm