private void GetQR(double[,] matrixB, double[,] Q, double [,] R)
        {
            for (int i = 0; i < N; i++)
                Q[i, 0] = matrixB[i, 0];

            R[0, 0] = 1;
            var sum = 0.0;
            for (int k = 0; k < N; k++)
            {
                for (int i = 0; i < N; i++)
                {
                    sum += matrixB[i, k] * matrixB[i, k];
                }
                R[k, k] = Math.Sqrt(sum);
                sum = 0;
                for (int i = 0; i < N; i++)
                    Q[i, k] = matrixB[i, k] / R[k, k];

                for (int j = k; j < N; j++)
                {
                    for (int i = 0; i < N; i++)
                    {
                        sum += Q[i, k] * matrixB[i, j];
                    }
                    R[k, j] = sum;
                    sum = 0;
                    for (int i = 0; i < N; i++)
                        matrixB[i, j] = matrixB[i, j] - Q[i, k] * R[k, j];
                }
            }
        }