public void GetPolynomCoefficients2()
{
double[] xx = { 1, 2, 3, 4 };
double[] yy = { 6, 9, 2, 5, };
double[] d = { 6, 3, -5, 10 / 3d };
var p = new Polynom(d[0]);
var p1 = new Polynom(-xx[0], 1);
var pp1 = d[1] * p1;
p += pp1;
var p2 = new Polynom(-xx[1], 1);
p += d[2] * p1 * p2;
var p3 = new Polynom(-xx[2], 1);
p += d[3] * p1 * p2 * p3;
var expected_coefficients = p.Coefficients;
var actual_coefficients = Newton.GetPolynomCoefficients(xx, yy);
var actual_coefficients2 = Lagrange.GetPolynomCoefficients(xx, yy);
const double accuracy = 7.106e-15;
Assert.That.Collection(actual_coefficients).IsEqualTo(expected_coefficients, accuracy);
}
public void GetPolynomCoefficients()
{
double[] xx =
{
-3 / 2d,
-3 / 4d,
0,
3 / 4d,
3 / 2d
};
double[] yy =
{
-14.1014,
-0.931596,
0,
0.931596,
14.1014
};
double[] expected_coefficients =
{
-1.7763568394002505E-15,
-1.4774737777777762,
0,
4.834847604938271,
0
};
var actual_coefficients = Newton.GetPolynomCoefficients(xx, yy);
Assert.That.Collection(actual_coefficients).IsEqualTo(expected_coefficients);
// Сравнение с первоисточником в англо.википедии https://en.wikipedia.org/wiki/Newton_polynomial
double[] expected_wikipedia_coefficients =
{
-0.00005,
-1.4775,
0.00001,
4.8348,
0
};
const double accuracy = 5.1e-5;
Assert.That.Collection(actual_coefficients)
.IsEqualTo(expected_wikipedia_coefficients, accuracy);
}
