public void TestLagrange()
{
// lagrange of (0,0) (0.5,0.35) (1,1) is equal to 0.6x*x + 0.4x
Vector2[] points = { new Vector2(0, 0), new Vector2(0.5f, 0.35f), new Vector2(1, 1) };
for (double t = -10; t <= 10; t += 0.01)
{
Assert.AreEqual(0.6 * t * t + 0.4 * t, Interpolation.Lagrange(points, t), 1e-4);
}
Assert.Throws <ArgumentException>(() =>
{
Interpolation.Lagrange(null, 4);
});
Assert.Throws <ArgumentException>(() =>
{
ReadOnlySpan <Vector2> list = Array.Empty <Vector2>();
Interpolation.Lagrange(list, 4);
});
Assert.AreEqual(Interpolation.Lagrange(new[] { new Vector2(3, 4) }, 12), 4);
double[] weights = Interpolation.BarycentricWeights(points);
Assert.AreEqual(3, weights.Length);
Assert.AreEqual(2, weights[0]);
Assert.AreEqual(-4, weights[1]);
Assert.AreEqual(2, weights[2]);
}
