def test_pure(self):
rho = qu.up(qtype='dop')
psi = qu.purify(rho)
assert abs(qu.concurrence(psi)) < 1e-14
def test_bell_states(self, qtype, bs):
p = qu.bell_state(bs, qtype=qtype)
assert qu.concurrence(p) > 1.0 - 1e-14
def test_subsystem(self):
p = qu.rand_rho(2**4)
e = qu.concurrence(p, [2, 2, 2, 2], 1, 2)
assert 0 <= e <= 1
def test_entanglement(self, p):
rho = werner_state(p)
assert concurrence(rho) > 1e-14
