def test_entangled_permute(self):
dims = [2, 2, 2]
a = qu.bell_state(0) & qu.up()
assert_allclose(qu.mutinf_subsys(a, dims, 0, 1), 2.)
b = qu.permute(a, dims, [1, 2, 0])
assert_allclose(qu.mutinf_subsys(b, dims, 0, 1), 0., atol=1e-12)
assert_allclose(qu.mutinf_subsys(b, dims, 0, 2), 2.)
def test_mutinf_subsys_pure(self):
p = rand_ket(2**7)
dims = (2**3, 2**4)
# exact
mi0 = mutual_information(p, dims, sysa=0)
mi1 = mutinf_subsys(p, dims, sysa=0, sysb=1, approx_thresh=1e30)
assert_allclose(mi1, mi0)
# approx
mi2 = mutinf_subsys(p, dims, sysa=0, sysb=1, approx_thresh=1)
assert_allclose(mi1, mi2, rtol=5e-2)
def test_mutinf_subsys(self):
p = qu.rand_ket(2**9)
dims = (2**3, 2**2, 2**4)
# exact
rho_ab = qu.ptr(p, dims, [0, 2])
mi0 = qu.mutual_information(rho_ab, [8, 16])
mi1 = qu.mutinf_subsys(p, dims, sysa=0, sysb=2, approx_thresh=1e30)
assert_allclose(mi1, mi0)
# approx
mi2 = qu.mutinf_subsys(p, dims, sysa=0, sysb=2, approx_thresh=1)
assert_allclose(mi1, mi2, rtol=0.1)