def test_prefactor_vacuum():
"""test the correct prefactor of 0.5 is calculated for a vacuum state"""
Q = np.identity(2)
beta = np.zeros([2])
res = prefactor(Means(beta), Covmat(Q))
ex = 1
assert np.allclose(res, ex)
def test_prefactor_TMS():
"""test the correct prefactor of 0.5 is calculated for a TMS state"""
q = np.fliplr(np.diag([2.0] * 4))
np.fill_diagonal(q, np.sqrt(2))
Q = np.fliplr(q)
beta = np.zeros([4])
res = prefactor(Means(beta), Covmat(Q))
ex = 0.5
assert np.allclose(res, ex)
def test_prefactor_with_displacement():
"""test the correct prefactor of 0.5 is calculated for a TMS state"""
q = np.fliplr(np.diag([2.0] * 4))
np.fill_diagonal(q, np.sqrt(2))
Q = np.fliplr(q)
Qinv = np.linalg.inv(Q)
vect = 1.2 * np.ones([2]) + 1j * np.ones(2)
beta = np.concatenate([vect, vect.conj()])
res = prefactor(Means(beta), Covmat(Q), hbar=2)
ex = np.exp(-0.5 * beta @ Qinv @ beta.conj()) / np.sqrt(np.linalg.det(Q))
assert np.allclose(res, ex)