def test_swinnerton_dyer_poly():
raises(ValueError, lambda: swinnerton_dyer_poly(0, x))
assert swinnerton_dyer_poly(1, x, polys=True) == Poly(x**2 - 2)
assert swinnerton_dyer_poly(1, x) == x**2 - 2
assert swinnerton_dyer_poly(2, x) == x**4 - 10*x**2 + 1
assert swinnerton_dyer_poly(
3, x) == x**8 - 40*x**6 + 352*x**4 - 960*x**2 + 576
# we only need to check that the polys arg works but
# we may as well test that the roots are correct
p = [sqrt(prime(i)) for i in range(1, 5)]
assert str([i.n(3) for i in
swinnerton_dyer_poly(4, polys=True).all_roots()]
) == str(sorted([Add(*i).n(3) for i in permute_signs(p)]))
def generate_spin_conf(n):
sample_tup = tuple(np.ones(n))
return np.asarray(list(permute_signs(sample_tup)))