def test_qc_joint_expectation(forest):
device = NxDevice(nx.complete_graph(2))
qc = QuantumComputer(
name="testy!", qam=QVM(connection=forest), device=device, compiler=DummyCompiler()
)
# |01> state program
p = Program()
p += RESET()
p += X(0)
p.wrap_in_numshots_loop(10)
# ZZ experiment
sz = ExperimentSetting(
in_state=sZ(0) * sZ(1), out_operator=sZ(0) * sZ(1), additional_expectations=[[0], [1]]
)
e = Experiment(settings=[sz], program=p)
results = qc.experiment(e)
# ZZ expectation value for state |01> is -1
assert np.isclose(results[0].expectation, -1)
assert np.isclose(results[0].std_err, 0)
assert results[0].total_counts == 40
# Z0 expectation value for state |01> is -1
assert np.isclose(results[0].additional_results[0].expectation, -1)
assert results[0].additional_results[1].total_counts == 40
# Z1 expectation value for state |01> is 1
assert np.isclose(results[0].additional_results[1].expectation, 1)
assert results[0].additional_results[1].total_counts == 40
def test_qc_expectation_larger_lattice(forest):
device = NxDevice(nx.complete_graph(4))
qc = QuantumComputer(name='testy!',
qam=QVM(connection=forest),
device=device,
compiler=DummyCompiler())
q0 = 2
q1 = 3
# bell state program
p = Program()
p += RESET()
p += H(q0)
p += CNOT(q0, q1)
p.wrap_in_numshots_loop(10)
# XX, YY, ZZ experiment
sx = ExperimentSetting(in_state=sZ(q0) * sZ(q1),
out_operator=sX(q0) * sX(q1))
sy = ExperimentSetting(in_state=sZ(q0) * sZ(q1),
out_operator=sY(q0) * sY(q1))
sz = ExperimentSetting(in_state=sZ(q0) * sZ(q1),
out_operator=sZ(q0) * sZ(q1))
e = TomographyExperiment(settings=[sx, sy, sz], program=p)
results = qc.experiment(e)
# XX expectation value for bell state |00> + |11> is 1
assert np.isclose(results[0].expectation, 1)
assert np.isclose(results[0].std_err, 0)
assert results[0].total_counts == 40
# YY expectation value for bell state |00> + |11> is -1
assert np.isclose(results[1].expectation, -1)
assert np.isclose(results[1].std_err, 0)
assert results[1].total_counts == 40
# ZZ expectation value for bell state |00> + |11> is 1
assert np.isclose(results[2].expectation, 1)
assert np.isclose(results[2].std_err, 0)
assert results[2].total_counts == 40
def test_qc_expectation_on_qvm_that_requires_executable(forest):
# regression test for https://github.com/rigetti/forest-tutorials/issues/2
device = NxDevice(nx.complete_graph(2))
qc = QuantumComputer(
name="testy!",
qam=QVM(connection=forest, requires_executable=True),
device=device,
compiler=DummyCompiler(),
)
p = Program()
theta = p.declare("theta", "REAL")
p += RESET()
p += RY(theta, 0)
p.wrap_in_numshots_loop(10000)
sx = ExperimentSetting(in_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
