def test_identity_removal():
test_term = 0.25 * sX(1) * sZ(2) * sX(3) + 0.25j * sX(1) * sZ(2) * sY(3)
test_term += -0.25j * sY(1) * sZ(2) * sX(3) + 0.25 * sY(1) * sZ(2) * sY(3)
identity_term = 200 * sI(5)
new_psum, identity_term_result = remove_identity(identity_term + test_term)
assert test_term == new_psum
assert identity_term_result == identity_term
def test_group_experiments(grouping_method):
expts = [ # cf above, I removed the inner nesting. Still grouped visually
ExperimentSetting(sI(), sX(0) * sI(1)), ExperimentSetting(sI(), sI(0) * sX(1)),
ExperimentSetting(sI(), sZ(0) * sI(1)), ExperimentSetting(sI(), sI(0) * sZ(1)),
]
suite = TomographyExperiment(expts, Program(), qubits=[0, 1])
grouped_suite = group_experiments(suite, method=grouping_method)
assert len(suite) == 4
assert len(grouped_suite) == 2
def test_stabilizer_projection_ZZ():
"""
test if we project out the correct state
"""
stabilizer_state = project_stabilized_state([sZ(0) * sZ(1), sX(0) * sX(1)])
true_state = np.zeros((4, 1))
true_state[0, 0] = true_state[3, 0] = 1
true_state /= np.sqrt(2)
assert np.allclose(true_state, stabilizer_state.todense())
def test_ps_adds_pt_2():
term = ID()
b = term + 1.0
assert str(b) == "(2+0j)*I"
assert str(b + 1.0) == "(3+0j)*I"
assert str(1.0 + b) == "(3+0j)*I"
b = sX(0) + 1.0
assert str(b) == "(1+0j)*X0 + (1+0j)*I"
b = 1.0 + sX(0)
assert str(b) == "(1+0j)*I + (1+0j)*X0"
def test_ps_sub():
term = 3 * ID()
b = term - 1.0
assert str(b) == "(2+0j)*I"
assert str(b - 1.0) == "(1+0j)*I"
assert str(1.0 - b) == "(-1+0j)*I"
b = 1.0 - sX(0)
assert str(b) == "(1+0j)*I + (-1+0j)*X0"
b = sX(0) - 1.0
assert str(b) == "(1+0j)*X0 + (-1+0j)*I"
def test_sum_equality():
pauli_sum = sY(0) - sX(0)
assert pauli_sum != 2 * pauli_sum
assert pauli_sum != pauli_sum + sZ(0)
assert pauli_sum + sZ(0) != pauli_sum
assert pauli_sum != sY(1) - sX(1)
assert pauli_sum == -1.0 * sX(0) + sY(0)
assert pauli_sum == pauli_sum * 1.0
with pytest.raises(TypeError):
assert pauli_sum != 0
def test_sum_equality():
q0, q1 = QubitPlaceholder.register(2)
pauli_sum = sY(q0) - sX(q0)
assert pauli_sum != 2 * pauli_sum
assert pauli_sum != pauli_sum + sZ(q0)
assert pauli_sum + sZ(q0) != pauli_sum
assert pauli_sum != sY(q1) - sX(q1)
assert pauli_sum == -1.0 * sX(q0) + sY(q0)
assert pauli_sum == pauli_sum * 1.0
with pytest.raises(TypeError):
assert pauli_sum != 0
def test_expectation(client_configuration: QCSClientConfiguration):
wfnsim = WavefunctionSimulator(client_configuration=client_configuration)
bell = Program(H(0), CNOT(0, 1))
expects = wfnsim.expectation(bell, [sZ(0) * sZ(1), sZ(0), sZ(1), sX(0) * sX(1)])
assert expects.size == 4
np.testing.assert_allclose(expects, [1, 0, 0, 1])
pauli_sum = PauliSum([sZ(0) * sZ(1)])
expects = wfnsim.expectation(bell, pauli_sum)
assert expects.size == 1
np.testing.assert_allclose(expects, [1])
def test_ps_sub():
q0 = QubitPlaceholder()
term = 3 * ID()
b = term - 1.0
assert str(b) == "(2+0j)*I"
assert str(b - 1.0) == "(1+0j)*I"
assert str(1.0 - b) == "(-1+0j)*I"
b = 1.0 - sX(q0)
assert re.match(r"\(1\+0j\)\*I \+ \(-1\+0j\)\*Xq\d+", str(b))
b = sX(q0) - 1.0
assert re.match(r"\(1\+0j\)\*Xq\d+ \+ \(-1\+0j\)\*I", str(b))
def test_commuting_terms_indexed():
"""
Test performance of commuting_sets_by_index
"""
pauli_term_1 = PauliSum([sX(0) * sZ(1)])
pauli_term_2 = PauliSum([sX(1) * sZ(2)])
pauli_term_3 = PauliSum([sX(0) * sY(3)])
commuting_set_tuples = commuting_sets_by_indices(
[pauli_term_1, pauli_term_2, pauli_term_3], check_trivial_commutation)
correct_tuples = [[(0, 0)], [(1, 0), (2, 0)]]
assert commuting_set_tuples == correct_tuples
def test_append():
expts = [
[ExperimentSetting(sI(), sX(0) * sI(1)), ExperimentSetting(sI(), sI(0) * sX(1))],
[ExperimentSetting(sI(), sZ(0) * sI(1)), ExperimentSetting(sI(), sI(0) * sZ(1))],
]
suite = TomographyExperiment(
settings=expts,
program=Program(X(0), Y(1)),
qubits=[0, 1]
)
suite.append(ExperimentSetting(sI(), sY(0) * sX(1)))
assert (len(str(suite))) > 0
def test_simulation_cnot():
"""
Test if the simulation of CNOT is accurate
:return:
"""
prog = Program().inst([H(0), CNOT(0, 1)])
qvmstab = QVM_Stabilizer(num_qubits=2)
qvmstab._apply_hadamard(prog.instructions[0])
qvmstab._apply_cnot(prog.instructions[1])
# assert that ZZ XX stabilizes a bell state
true_stabilizers = [sX(0) * sX(1), sZ(0) * sZ(1)]
test_paulis = binary_stabilizer_to_pauli_stabilizer(qvmstab.tableau[2:, :])
for idx, term in enumerate(test_paulis):
assert term == true_stabilizers[idx]
# test that CNOT does nothing to |00> state
prog = Program().inst([CNOT(0, 1)])
qvmstab = QVM_Stabilizer(num_qubits=2)
qvmstab._apply_cnot(prog.instructions[0])
true_tableau = np.array([
[1, 1, 0, 0, 0], # X1 -> X1 X2
[0, 1, 0, 0, 0], # X2 -> X2
[0, 0, 1, 0, 0], # Z1 -> Z1
[0, 0, 1, 1, 0]
]) # Z2 -> Z1 Z2
# note that Z1, Z1 Z2 still stabilizees |00>
assert np.allclose(true_tableau, qvmstab.tableau)
# test that CNOT produces 11 state after X
prog = Program().inst([H(0), S(0), S(0), H(0), CNOT(0, 1)])
qvmstab = QVM_Stabilizer(num_qubits=2)
qvmstab._apply_hadamard(prog.instructions[0])
qvmstab._apply_phase(prog.instructions[1])
qvmstab._apply_phase(prog.instructions[2])
qvmstab._apply_hadamard(prog.instructions[3])
qvmstab._apply_cnot(prog.instructions[4])
true_tableau = np.array([[1, 1, 0, 0, 0], [0, 1, 0, 0, 0], [0, 0, 1, 0, 1],
[0, 0, 1, 1, 0]])
# note that -Z1, Z1 Z2 still stabilizees |11>
assert np.allclose(true_tableau, qvmstab.tableau)
test_paulis = binary_stabilizer_to_pauli_stabilizer(
qvmstab.stabilizer_tableau())
state = project_stabilized_state(test_paulis,
qvmstab.num_qubits,
classical_state=[1, 1])
state_2 = project_stabilized_state(test_paulis, qvmstab.num_qubits)
assert np.allclose(np.array(state.todense()), np.array(state_2.todense()))
def test_max_tpb_overlap_1():
tomo_expt_settings = [ExperimentSetting(sZ(1) * sX(0), sY(2) * sY(1)),
ExperimentSetting(sX(2) * sZ(1), sY(2) * sZ(0))]
tomo_expt_program = Program(H(0), H(1), H(2))
tomo_expt_qubits = [0, 1, 2]
tomo_expt = TomographyExperiment(tomo_expt_settings, tomo_expt_program, tomo_expt_qubits)
expected_dict = {
ExperimentSetting(plusX(0) * plusZ(1) * plusX(2), sZ(0) * sY(1) * sY(2)): [
ExperimentSetting(plusZ(1) * plusX(0), sY(2) * sY(1)),
ExperimentSetting(plusX(2) * plusZ(1), sY(2) * sZ(0))
]
}
assert expected_dict == _max_tpb_overlap(tomo_expt)
def test_merge_disjoint_experiments():
sett1 = ExperimentSetting(TensorProductState(), sX(0) * sY(1))
sett2 = ExperimentSetting(plusZ(1), sY(1))
sett3 = ExperimentSetting(plusZ(0), sX(0))
sett4 = ExperimentSetting(minusX(1), sY(1))
sett5 = ExperimentSetting(TensorProductState(), sZ(2))
expt1 = Experiment(settings=[sett1, sett2], program=Program(X(1)))
expt2 = Experiment(settings=[sett3, sett4], program=Program(Z(0)))
expt3 = Experiment(settings=[sett5], program=Program())
merged_expt = merge_disjoint_experiments([expt1, expt2, expt3])
assert len(merged_expt) == 2
def test_diagonal_basis_commutes():
x_term = sX(0) * sX(1)
z1_term = sZ(1)
z0_term = sZ(0)
z0z1_term = sZ(0) * sZ(1)
assert not diagonal_basis_commutes(x_term, z1_term)
assert not diagonal_basis_commutes(z0z1_term, x_term)
assert diagonal_basis_commutes(z1_term, z0_term)
assert diagonal_basis_commutes(z0z1_term, z0_term)
assert diagonal_basis_commutes(z0z1_term, z1_term)
assert diagonal_basis_commutes(z0z1_term, sI(1))
assert diagonal_basis_commutes(z0z1_term, sI(2))
assert diagonal_basis_commutes(z0z1_term, sX(5) * sY(7))
def test_experiment_deser(tmpdir):
expts = [
[ExperimentSetting(sI(), sX(0) * sI(1)), ExperimentSetting(sI(), sI(0) * sX(1))],
[ExperimentSetting(sI(), sZ(0) * sI(1)), ExperimentSetting(sI(), sI(0) * sZ(1))],
]
suite = TomographyExperiment(
settings=expts,
program=Program(X(0), Y(1)),
qubits=[0, 1]
)
to_json(f'{tmpdir}/suite.json', suite)
suite2 = read_json(f'{tmpdir}/suite.json')
assert suite == suite2
def test_rowsum_phase_accumulator():
"""
Test the accuracy of the phase accumulator. This subroutine keeps track of the power that $i$ is raised to
when multiplying two PauliTerms together. PauliTerms are now composed of multi single-qubit Pauli's.
The formula is phase_accumulator(h, i) = 2 * rh + 2 * ri + \sum_{j}^{n}g(x_{ij}, z_{ij}, x_{hj}, z_{hj}
The returned value is presented mod 4.
notice that since r_h indicates +1 or -1 this corresponds to i^{0} or i^{2}. Given r_{h/i} takes on {0, 1} then
we need to multiply by 2 get the correct power of $i$ for the Pauli Term to account for multiplication.
In order to test we will generate random elements of P_{n} and then multiply them together keeping track of the
$i$ power. We will then compare this to the phase_accumulator subroutine.
We have to load in the stabilizer into an empty qvmstab object because the subroutine needs a tableau as a reference
"""
num_qubits = 2
pauli_terms = [sX(0) * sX(1), sZ(0) * sZ(1)]
stab_mat = pauli_stabilizer_to_binary_stabilizer(pauli_terms)
qvmstab = QVM_Stabilizer(num_qubits=num_qubits)
qvmstab.tableau[num_qubits:, :] = stab_mat
exp_on_i = qvmstab._rowsum_phase_accumulator(2, 3)
assert exp_on_i == 2
num_qubits = 2
pauli_terms = [sZ(0) * sI(1), sZ(0) * sZ(1)]
stab_mat = pauli_stabilizer_to_binary_stabilizer(pauli_terms)
qvmstab = QVM_Stabilizer(num_qubits=num_qubits)
qvmstab.tableau[num_qubits:, :] = stab_mat
exp_on_i = qvmstab._rowsum_phase_accumulator(2, 3)
assert exp_on_i == 0
# now try generating random valid elements from 2-qubit group
for _ in range(100):
num_qubits = 6
pauli_terms = []
for _ in range(num_qubits):
pauli_terms.append(
reduce(lambda x, y: x * y, [
pauli_subgroup[x](idx) for idx, x in enumerate(
np.random.randint(1, 4, num_qubits))
]))
stab_mat = pauli_stabilizer_to_binary_stabilizer(pauli_terms)
qvmstab = QVM_Stabilizer(num_qubits=num_qubits)
qvmstab.tableau[num_qubits:, :] = stab_mat
p_on_i = qvmstab._rowsum_phase_accumulator(num_qubits, num_qubits + 1)
coeff_test = pauli_terms[1] * pauli_terms[0]
assert np.isclose(coeff_test.coefficient, (1j)**p_on_i)
def test_expectation(forest: ForestConnection):
# The forest fixture (argument) to this test is to ensure this is
# skipped when a forest web api key is unavailable. You could also
# pass it to the constructor of WavefunctionSimulator() but it is not
# necessary.
wfnsim = WavefunctionSimulator()
bell = Program(H(0), CNOT(0, 1))
expects = wfnsim.expectation(bell, [sZ(0) * sZ(1), sZ(0), sZ(1), sX(0) * sX(1)])
assert expects.size == 4
np.testing.assert_allclose(expects, [1, 0, 0, 1])
pauli_sum = PauliSum([sZ(0) * sZ(1)])
expects = wfnsim.expectation(bell, pauli_sum)
assert expects.size == 1
np.testing.assert_allclose(expects, [1])
def test_check_commutation_trivial_grouping():
"""
Check grouping of trivial terms
"""
commuting_set_one = sX(0) * sZ(1) + sY(2)
commuting_set_two = PauliSum([sX(1)])
hamiltonian = commuting_set_one + commuting_set_two
commuting_sets = commuting_sets_trivial(hamiltonian)
for comm_set in commuting_sets:
if len(comm_set) == 2:
true_set = set(map(lambda x: x.id(), commuting_set_one.terms))
assert set(map(lambda x: x.id(), comm_set)) == true_set
elif len(comm_set) == 1:
true_set = set(map(lambda x: x.id(), commuting_set_two.terms))
assert set(map(lambda x: x.id(), comm_set)) == true_set
def test_group_experiments(grouping_method):
expts = [ # cf above, I removed the inner nesting. Still grouped visually
ExperimentSetting(TensorProductState(),
sX(0) * sI(1)),
ExperimentSetting(TensorProductState(),
sI(0) * sX(1)),
ExperimentSetting(TensorProductState(),
sZ(0) * sI(1)),
ExperimentSetting(TensorProductState(),
sI(0) * sZ(1)),
]
suite = Experiment(expts, Program())
grouped_suite = group_settings(suite, method=grouping_method)
assert len(suite) == 4
assert len(grouped_suite) == 2
def test_experiment_deser(tmpdir):
expts = [
[
ExperimentSetting(TensorProductState(), sX(0) * sI(1)),
ExperimentSetting(TensorProductState(), sI(0) * sX(1)),
],
[
ExperimentSetting(TensorProductState(), sZ(0) * sI(1)),
ExperimentSetting(TensorProductState(), sI(0) * sZ(1)),
],
]
suite = Experiment(settings=expts, program=Program(X(0), Y(1)))
to_json(f"{tmpdir}/suite.json", suite)
suite2 = read_json(f"{tmpdir}/suite.json")
assert suite == suite2
def test_experiment_result():
er = ExperimentResult(
setting=ExperimentSetting(sX(0), sZ(0)),
expectation=0.9,
stddev=0.05,
)
assert str(er) == '(1+0j)*X0→(1+0j)*Z0: 0.9 +- 0.05'
def test_measure_observables(forest):
expts = [
ExperimentSetting(sI(), o1 * o2)
for o1, o2 in itertools.product([sI(0), sX(0), sY(0), sZ(0)], [sI(1), sX(1), sY(1), sZ(1)])
]
suite = TomographyExperiment(expts, program=Program(X(0), CNOT(0, 1)), qubits=[0, 1])
assert len(suite) == 4 * 4
gsuite = group_experiments(suite)
assert len(gsuite) == 3 * 3 # can get all the terms with I for free in this case
qc = get_qc('2q-qvm')
for res in measure_observables(qc, gsuite, n_shots=10_000):
if res.setting.out_operator in [sI(), sZ(0), sZ(1), sZ(0) * sZ(1)]:
assert np.abs(res.expectation) > 0.9
else:
assert np.abs(res.expectation) < 0.1
def test_qc_expectation_on_qvm(client_configuration: QCSClientConfiguration, dummy_compiler: DummyCompiler):
# regression test for https://github.com/rigetti/forest-tutorials/issues/2
qc = QuantumComputer(name="testy!", qam=QVM(client_configuration=client_configuration), compiler=dummy_compiler)
p = Program()
theta = p.declare("theta", "REAL")
p += RESET()
p += RY(theta, 0)
p.wrap_in_numshots_loop(10000)
sx = ExperimentSetting(in_state=_pauli_to_product_state(sZ(0)), out_operator=sX(0))
e = Experiment(settings=[sx], program=p)
thetas = [-np.pi / 2, 0.0, np.pi / 2]
results = []
# Verify that multiple calls to qc.experiment with the same experiment backed by a QVM that
# requires_exectutable does not raise an exception.
for theta in thetas:
results.append(qc.experiment(e, memory_map={"theta": [theta]}))
assert np.isclose(results[0][0].expectation, -1.0, atol=0.01)
assert np.isclose(results[0][0].std_err, 0)
assert results[0][0].total_counts == 20000
# bounds on atol and std_err here are a little loose to try and avoid test flakiness.
assert np.isclose(results[1][0].expectation, 0.0, atol=0.1)
assert results[1][0].std_err < 0.01
assert results[1][0].total_counts == 20000
assert np.isclose(results[2][0].expectation, 1.0, atol=0.01)
assert np.isclose(results[2][0].std_err, 0)
assert results[2][0].total_counts == 20000
def test_for_negative_probabilities():
# trivial program to do state tomography on
prog = Program(I(0))
# make TomographyExperiment
expt_settings = [ExperimentSetting(zeros_state([0]), pt) for pt in [sI(0), sX(0), sY(0), sZ(0)]]
experiment_1q = TomographyExperiment(settings=expt_settings, program=prog)
# make a quantum computer object
device = NxDevice(nx.complete_graph(1))
qc_density = QuantumComputer(
name="testy!",
qam=PyQVM(n_qubits=1, quantum_simulator_type=ReferenceDensitySimulator),
device=device,
compiler=DummyCompiler(),
)
# initialize with a pure state
initial_density = np.array([[1.0, 0.0], [0.0, 0.0]])
qc_density.qam.wf_simulator.density = initial_density
try:
list(measure_observables(qc=qc_density, tomo_experiment=experiment_1q, n_shots=3000))
except ValueError as e:
# the error is from np.random.choice by way of self.rs.choice in ReferenceDensitySimulator
assert str(e) != "probabilities are not non-negative"
# initialize with a mixed state
initial_density = np.array([[0.9, 0.0], [0.0, 0.1]])
qc_density.qam.wf_simulator.density = initial_density
try:
list(measure_observables(qc=qc_density, tomo_experiment=experiment_1q, n_shots=3000))
except ValueError as e:
assert str(e) != "probabilities are not non-negative"
def benchmarker():
try:
bm = get_benchmarker(timeout=2)
bm.apply_clifford_to_pauli(Program(I(0)), sX(0))
return bm
except (RequestException, TimeoutError) as e:
return pytest.skip("This test requires a running local benchmarker endpoint (ie quilc): {}"
.format(e))
def test_stats_from_measurements():
d_results = {0: np.array([0] * 10), 1: np.array([1] * 10)}
setting = ExperimentSetting(TensorProductState(), sZ(0) * sX(1))
n_shots = 1000
obs_mean, obs_var = _stats_from_measurements(d_results, setting, n_shots)
assert obs_mean == -1.0
assert obs_var == 0.0
def test_tomo_experiment_pre_grouped():
expts = [
[ExperimentSetting(sI(), sX(0) * sI(1)), ExperimentSetting(sI(), sI(0) * sX(1))],
[ExperimentSetting(sI(), sZ(0) * sI(1)), ExperimentSetting(sI(), sI(0) * sZ(1))],
]
suite = TomographyExperiment(
settings=expts,
program=Program(X(0), Y(1)),
qubits=[0, 1]
)
assert len(suite) == 2 # number of groups
for es1, es2 in zip(expts, suite):
for e1, e2 in zip(es1, es2):
assert e1 == e2
prog_str = str(suite).splitlines()[0]
assert prog_str == 'X 0; Y 1'
def test_experiment_result_compat():
er = ExperimentResult(
setting=ExperimentSetting(sX(0), sZ(0)),
expectation=0.9,
stddev=0.05,
total_counts=100,
)
assert str(er) == 'X0_0→(1+0j)*Z0: 0.9 +- 0.05'
def test_is_identity():
pt1 = -1.5j * sI(2)
pt2 = 1.5 * sX(1) * sZ(2)
assert is_identity(pt1)
assert is_identity(pt2 + (-1 * pt2) + sI(0))
assert not is_identity(0 * pt1)
assert not is_identity(pt2 + (-1 * pt2))
from pyquil.paulis import ID, sX, sY, sZ
from pyquil import *
from pyquil.gates import H
import pyquil.paulis as pl
# Pauli term takes an operator "X", "Y", "Z", or "I"; a qubit to act on, and
# an optional coefficient.
a = 1 * ID()
b = -0.75 * sX(0) * sY(1) * sZ(3)
c = (5-2j) * sZ(1) * sX(2)
# Construct a sum of Pauli terms.
sigma = a + b + c
print("sigma = {}".format(sigma))
p = Program()
p.inst(pl.exponentiate_commuting_pauli_sum(sigma))
print(p)