if (Q < 0) {
        double tmp_p = -p / 3.0;
        var sqrt_Q = new Complex(Q, 0);
        sqrt_Q = Complex.Sqrt(sqrt_Q);

        var tmp_A = new Complex(-q / 2.0, sqrt_Q.Imaginary);
        var tmp_B = new Complex(-q / 2.0, -sqrt_Q.Imaginary);

        var A_compl = Muavr(tmp_A);
        var B_compl = Muavr(tmp_B);

        double y1 = (((-Complex.Add(A_compl / 2.0, B_compl / 2.0)) +
          Complex.Multiply(Complex.ImaginaryOne, (Complex.Subtract(A_compl / 2.0, B_compl / 2.0) * Math.Sqrt(3.0))))).Real;
        complexArr[0] = (y1 - (b / (3.0 * a)));

        double y3 = (((-Complex.Add(A_compl / 2.0, B_compl / 2.0)) -
          Complex.Multiply(Complex.ImaginaryOne, (Complex.Subtract(A_compl / 2.0, B_compl / 2.0) * Math.Sqrt(3.0))))).Real;
        complexArr[2] = (y3 - (b / (3.0 * a)));

        double y2 = (Complex.Add(A_compl, B_compl)).Real;
        complexArr[1] = y2 - (b / (3.0 * a));
      }