def test_pauli_reconstruct(self):
p1 = qu.rand_rho(4)
names_cffs = qu.pauli_decomp(p1, mode='c')
pr = sum(
qu.kron(*(qu.pauli(s) for s in name)) * names_cffs["".join(name)]
for name in itertools.product('IXYZ', repeat=2))
assert_allclose(pr, p1)
def test_pauli_decomp_singlet(self, qtype):
p = qu.singlet(qtype=qtype)
names_cffs = qu.pauli_decomp(p, mode='cp')
assert_allclose(names_cffs['II'], 0.25)
assert_allclose(names_cffs['ZZ'], -0.25)
assert_allclose(names_cffs['YY'], -0.25)
assert_allclose(names_cffs['ZZ'], -0.25)
for name in itertools.permutations('IXYZ', 2):
assert_allclose(names_cffs["".join(name)], 0.0)
def test_multisubsystem(self):
qu.seed_rand(42)
dims = [2, 2, 2]
IIX = qu.ikron(qu.rand_herm(2), dims, 2)
dcmp = qu.pauli_decomp(IIX, mode='c')
for p, x in dcmp.items():
if x == 0j:
assert (p[0] != 'I') or (p[1] != 'I')
else:
assert p[0] == p[1] == 'I'
K = qu.rand_iso(3 * 4, 4).reshape(3, 4, 4)
KIIXK = qu.kraus_op(IIX, K, dims=dims, where=[0, 2])
dcmp = qu.pauli_decomp(KIIXK, mode='c')
for p, x in dcmp.items():
if x == 0j:
assert p[1] != 'I'
else:
assert p[1] == 'I'