def set_polynomial_degree(self):
"""Set fitting function to be polynomial based on given degree."""
degree = int(self.polynomial_degree_input.value)
self.fitting_function = polynomial(degree)
if degree == 1:
self.fitting_function_syntax.value = "a[0] + a[1] * x"
else:
self.fitting_function_syntax.value = "a[0] + a[1] * x + " + " + ".join(
[f"a[{i}] * x ^ {i}" for i in range(2, degree + 1)])
def case_polynomial_1():
return dict(
func=polynomial(1),
func_name="linear",
title="Linear",
n=2,
syntax="a[0] + a[1] * x",
a=np.array([-7, 2]),
x=np.arange(5),
y=[-7, -5, -3, -1, 1],
x_derivatives=[2, 2, 2, 2, 2],
a_derivatives=[[1, 0], [1, 1], [1, 2], [1, 3], [1, 4]],
)
def case_polynomial_3():
return dict(
func=polynomial(3),
func_name="polynomial_3",
title="Polynomial 3",
syntax="a[0] + a[1] * x + a[2] * x ^ 2 + a[3] * x ^ 3",
n=4,
a=np.array([3, 4, -2, 1]),
x=np.arange(5),
y=[3, 6, 11, 24, 51],
x_derivatives=[4, 3, 8, 19, 36],
a_derivatives=[
[1, 0, 0, 0],
[1, 1, 1, 1],
[1, 2, 4, 8],
[1, 3, 9, 27],
[1, 4, 16, 64],
],
)
def test_initialize_polynomial_with_negative_degree_raises_error():
with pytest.raises(FittingFunctionLoadError,
match="^n must be positive, got -1$"):
polynomial(-1)
def test_initialize_polynomial_with_0_degree_raises_error():
with pytest.raises(FitFunctionLoadError,
match="^n must be positive, got 0$"):
polynomial(0)