def test_polynomial_interpolates_to_itself(self):
def f(x): return 4*x**3 + 2*x + 1
x_knots = [x for x in range(-2,2)]
p = newton.interpolation_polynomial([(x,f(x)) for x in x_knots])
self.assertEqual(p(0.5), f(0.5))
def test_zero_degree_polynomial(self):
"""Are zero degree (constant) polynomials handled correctly?"""
# f(x) = 2
p, p_str = newton.interpolation_polynomial([(0,2)], get_string=True)
self.assertEqual(p(-3.14), 2)
self.assertEqual(p_str, 'p(x) = 2')
def test_known_points_equal_themselves(self):
# f(x) = 2x
x_knots = range(1,5)
p = newton.interpolation_polynomial([(x,2*x) for x in x_knots])
for x in x_knots:
self.assertEqual(p(x), 2*x)