def grover(q, constant_1, constant_2, rot, h, grover_it, nshots=100):
"""Run the full Grover's search algorithm to find a preimage of a hash function.
Args:
q (int): number of qubits of a site in the permutation matrix.
constant_1 (int): constant that defines the hash construction.
constant_2 (int): constant that defines the hash construction.
rot (list): characterization of the rotation part of the algorithm.
h (str): hash value that one wants to find preimages of.
grover_it (int): number of Grover steps to be performed.
Returns:
result (dict): counts of the output generated by the algorithm
"""
A, B, C, D, x, ancilla, circuit, qubits = create_qc(q)
c1, c2, c3, c4 = initial_step(q, constant_1, constant_2, rot)
c = []
c.append(c1)
c.append(c2)
c.append(c3)
c.append(c4)
circuit.add(start_grover(A + B, ancilla))
for i in range(grover_it):
circuit = grover_step(q, c, circuit, A, B, C, D, x, ancilla, h, rot)
circuit.add(gates.M(*(A + B), register_name='preimages'))
result = circuit(nshots=nshots)
return result.frequencies(binary=True)
def test_thermal_relaxation_channel_repeated(backend):
initial_state = random_state(5)
c = Circuit(5)
c.add(gates.ThermalRelaxationChannel(4, t1=1.0, t2=0.6, time=0.8,
excited_population=0.8, seed=123))
final_state = c(K.cast(np.copy(initial_state)), nshots=30)
pz, p0, p1 = c.queue[0].calculate_probabilities(1.0, 0.6, 0.8, 0.8)
np.random.seed(123)
target_state = []
collapse = gates.M(4, collapse=True)
collapse.nqubits = 5
zgate, xgate = gates.Z(4), gates.X(4)
for _ in range(30):
state = K.cast(np.copy(initial_state))
if np.random.random() < pz:
state = zgate(state)
if np.random.random() < p0:
state = K.state_vector_collapse(collapse, state, [0])
if np.random.random() < p1:
state = K.state_vector_collapse(collapse, state, [0])
state = xgate(state)
target_state.append(K.copy(state))
target_state = K.stack(target_state)
K.assert_allclose(final_state, target_state)
def test_circuit_with_unmeasured_qubits(backend, accelerators):
original_backend = qibo.get_backend()
qibo.set_backend(backend)
c = models.Circuit(5, accelerators)
c.add(gates.X(4))
c.add(gates.X(2))
c.add(gates.M(0, 2))
c.add(gates.X(3))
c.add(gates.M(1, 4))
result = c(nshots=100)
target_binary_samples = np.zeros((100, 4))
target_binary_samples[:, 1] = 1
target_binary_samples[:, 3] = 1
assert_result(result, 5 * np.ones(100), target_binary_samples, {5: 100},
{"0101": 100})
qibo.set_backend(original_backend)
def test_copy_measurements(accelerators):
"""Check that ``circuit.copy()`` properly copies measurements."""
c1 = models.Circuit(6, accelerators)
c1.add([gates.X(0), gates.X(1), gates.X(3)])
c1.add(gates.M(5, 1, 3, register_name="a"))
c1.add(gates.M(2, 0, register_name="b"))
c2 = c1.copy()
r1 = c1(nshots=100)
r2 = c2(nshots=100)
np.testing.assert_allclose(r1.samples().numpy(), r2.samples().numpy())
rg1 = r1.frequencies(registers=True)
rg2 = r2.frequencies(registers=True)
assert rg1.keys() == rg2.keys()
for k in rg1.keys():
assert rg1[k] == rg2[k]
def test_multiple_measurement_gates_circuit():
"""Check multiple gates with multiple qubits each in the same circuit."""
c = models.Circuit(4)
c.add(gates.X(1))
c.add(gates.X(2))
c.add(gates.M(0, 1))
c.add(gates.M(2))
c.add(gates.X(3))
result = c(nshots=100)
target_binary_samples = np.ones((100, 3))
target_binary_samples[:, 0] = 0
assert_results(result,
decimal_samples=3 * np.ones((100, )),
binary_samples=target_binary_samples,
decimal_frequencies={3: 100},
binary_frequencies={"011": 100})
def test_measurement_qubit_order_simple(backend, registers):
original_backend = qibo.get_backend()
qibo.set_backend(backend)
c = models.Circuit(2)
c.add(gates.X(0))
if registers:
c.add(gates.M(1, 0))
else:
c.add(gates.M(1))
c.add(gates.M(0))
result = c(nshots=100)
target_binary_samples = np.zeros((100, 2))
target_binary_samples[:, 1] = 1
assert_result(result, np.ones(100), target_binary_samples, {1: 100},
{"01": 100})
qibo.set_backend(original_backend)
def test_multiple_qubit_measurement_gate(backend):
state = np.zeros(4)
state[2] = 1
result = gates.M(0, 1)(K.cast(state), nshots=100)
target_binary_samples = np.zeros((100, 2))
target_binary_samples[:, 0] = 1
assert_result(result, 2 * np.ones((100, )), target_binary_samples,
{2: 100}, {"10": 100})
def test_gate_after_measurement_error(backend, accelerators):
c = models.Circuit(4, accelerators)
c.add(gates.X(0))
c.add(gates.M(0))
c.add(gates.X(1))
# TODO: Change this to NotImplementedError
with pytest.raises(ValueError):
c.add(gates.H(0))
def test_measurement_circuit(backend, accelerators):
c = models.Circuit(4, accelerators)
c.add(gates.X(0))
c.add(gates.M(0))
result = c(nshots=100)
assert_result(result,
np.ones((100,)), np.ones((100, 1)),
{1: 100}, {"1": 100})
def test_measurement_collapse_errors(backend):
original_backend = qibo.get_backend()
qibo.set_backend(backend)
gate = gates.M(0, 1, collapse=True)
state = np.ones(4) / 4
with pytest.raises(ValueError):
state = gate(state, nshots=100)
qibo.set_backend(original_backend)
def test_circuit_addition_with_measurements_in_both_circuits(
backend, accelerators):
original_backend = qibo.get_backend()
qibo.set_backend(backend)
c1 = models.Circuit(4, accelerators)
c1.add(gates.H(0))
c1.add(gates.H(1))
c1.add(gates.M(1, register_name="a"))
c2 = models.Circuit(4, accelerators)
c2.add(gates.X(0))
c2.add(gates.M(0, register_name="b"))
c = c1 + c2
assert len(c.measurement_gate.target_qubits) == 2
assert c.measurement_tuples == {"a": (1, ), "b": (0, )}
qibo.set_backend(original_backend)
def test_circuit_with_unmeasured_qubits(accelerators):
"""Check that unmeasured qubits are not taken into account."""
c = models.Circuit(5, accelerators)
c.add(gates.X(4))
c.add(gates.X(2))
c.add(gates.M(0, 2))
c.add(gates.X(3))
c.add(gates.M(1, 4))
result = c(nshots=100)
target_binary_samples = np.zeros((100, 4))
target_binary_samples[:, 1] = 1
target_binary_samples[:, 3] = 1
assert_results(result,
decimal_samples=5 * np.ones((100, )),
binary_samples=target_binary_samples,
decimal_frequencies={5: 100},
binary_frequencies={"0101": 100})
def test_final_state(accelerators):
"""Check that final state is logged correctly when using measurements."""
c = models.Circuit(4, accelerators)
c.add(gates.X(1))
c.add(gates.X(2))
c.add(gates.M(0, 1))
c.add(gates.M(2))
c.add(gates.X(3))
result = c(nshots=100)
logged_final_state = c.final_state.numpy()
c = models.Circuit(4, accelerators)
c.add(gates.X(1))
c.add(gates.X(2))
c.add(gates.X(3))
target_state = c().numpy()
np.testing.assert_allclose(logged_final_state, target_state)
def test_gate_after_measurement_error(accelerators):
"""Check that reusing measured qubits is not allowed."""
c = models.Circuit(2, accelerators)
c.add(gates.X(0))
c.add(gates.M(0))
c.add(gates.X(1))
# TODO: Change this to NotImplementedError
with pytest.raises(ValueError):
c.add(gates.H(0))
def test_gate_after_measurement_with_addition_error(backend, accelerators):
original_backend = qibo.get_backend()
qibo.set_backend(backend)
c = models.Circuit(4, accelerators)
c.add(gates.H(0))
c.add(gates.M(1))
# Try to add gate to qubit that is already measured
c2 = models.Circuit(4, accelerators)
c2.add(gates.H(1))
with pytest.raises(ValueError):
c += c2
# Try to add measurement to qubit that is already measured
c2 = models.Circuit(4, accelerators)
c2.add(gates.M(1, register_name="a"))
with pytest.raises(ValueError):
c += c2
qibo.set_backend(original_backend)
def test_state_probabilities_errors():
from qibo import gates
state = states.VectorState.zero_state(3)
mgate = gates.M(0)
qubits = [0]
with pytest.raises(ValueError):
probs = state.probabilities()
with pytest.raises(ValueError):
probs = state.probabilities(qubits, mgate)
def test_measurement_gate(backend, n, nshots):
original_backend = qibo.get_backend()
qibo.set_backend(backend)
state = np.zeros(4)
state[-n] = 1
result = gates.M(0)(state, nshots=nshots)
assert_result(result, n * np.ones(nshots), n * np.ones((nshots, 1)),
{n: nshots}, {str(n): nshots})
qibo.set_backend(original_backend)
def test_state_probabilities(backend, state_type, use_gate):
state = getattr(states, state_type).plus_state(4)
if use_gate:
from qibo import gates
mgate = gates.M(0, 1)
probs = state.probabilities(measurement_gate=mgate)
else:
probs = state.probabilities(qubits=[0, 1])
target_probs = np.ones((2, 2)) / 4
K.assert_allclose(probs, target_probs)
def test_measurement_result_parameters_multiple_qubits(backend):
initial_state = random_state(4)
K.set_seed(123)
c = models.Circuit(4)
output = c.add(gates.M(0, 1, 2, collapse=True))
c.add(gates.RY(1, theta=np.pi * output[0] / 5))
c.add(gates.RX(3, theta=np.pi * output[2] / 3))
result = c(initial_state=np.copy(initial_state))
K.set_seed(123)
collapse = gates.M(0, 1, 2, collapse=True)
target_state = collapse(K.cast(np.copy(initial_state)))
# not including in coverage because outcomes are probabilistic and may
# not occur for the CI run
if int(collapse.result.outcome(0)): # pragma: no cover
target_state = gates.RY(1, theta=np.pi / 5)(target_state)
if int(collapse.result.outcome(2)): # pragma: no cover
target_state = gates.RX(3, theta=np.pi / 3)(target_state)
K.assert_allclose(result, target_state)
def test_measurement_result_parameters_random(backend, accelerators):
test_device = K.cpu_devices[0] if accelerators else K.default_device
initial_state = random_state(4)
set_device_seed(123, accelerators)
c = models.Circuit(4, accelerators)
output = c.add(gates.M(1, collapse=True))
c.add(gates.RY(0, theta=np.pi * output / 5))
c.add(gates.RX(2, theta=np.pi * output / 4))
result = c(initial_state=np.copy(initial_state))
assert len(output.frequencies()) == 1
set_device_seed(123, accelerators)
with K.device(test_device):
collapse = gates.M(1, collapse=True)
target_state = collapse(K.cast(np.copy(initial_state)))
if int(collapse.result.outcome()):
target_state = gates.RY(0, theta=np.pi / 5)(target_state)
target_state = gates.RX(2, theta=np.pi / 4)(target_state)
K.assert_allclose(result, target_state)
def test_measurement_compiled_circuit(backend):
from qibo import K
if K.is_custom:
# use native gates because custom gates do not support compilation
pytest.skip("Custom backend does not support compilation.")
c = models.Circuit(2)
c.add(gates.X(0))
c.add(gates.M(0))
c.add(gates.M(1))
c.compile()
result = c(nshots=100)
target_binary_samples = np.zeros((100, 2))
target_binary_samples[:, 0] = 1
assert_result(result, 2 * np.ones((100, )), target_binary_samples,
{2: 100}, {"10": 100})
target_state = np.zeros_like(c.final_state)
target_state[2] = 1
K.assert_allclose(c.final_state, target_state)
def test_post_measurement_bitflips_on_circuit(backend, accelerators, i, probs):
"""Check bitflip errors on circuit measurements."""
K.set_seed(123)
c = models.Circuit(5, accelerators=accelerators)
c.add([gates.X(0), gates.X(2), gates.X(3)])
c.add(gates.M(0, 1, p0={0: probs[0], 1: probs[1]}))
c.add(gates.M(3, p0=probs[2]))
result = c(nshots=30).frequencies(binary=False)
if K.name == "qibojit" and K.op.get_backend() == "cupy": # pragma: no cover
# cupy is not tested by CI!
targets = [{5: 30}, {5: 12, 7: 7, 6: 5, 4: 3, 1: 2, 2: 1},
{2: 10, 6: 5, 5: 4, 0: 3, 7: 3, 1: 2, 3: 2, 4: 1}]
elif K.name == "numpy" or K.name == "qibojit":
targets = [{5: 30}, {5: 18, 4: 5, 7: 4, 1: 2, 6: 1},
{4: 8, 2: 6, 5: 5, 1: 3, 3: 3, 6: 2, 7: 2, 0: 1}]
else:
targets = [{5: 30}, {5: 16, 7: 10, 6: 2, 3: 1, 4: 1},
{3: 6, 5: 6, 7: 5, 2: 4, 4: 3, 0: 2, 1: 2, 6: 2}]
assert result == targets[i]
def test_measurement_gate2():
"""Check that measurement gate works when called on the state |11>."""
state = np.zeros(4)
state[-1] = 1
result = gates.M(1)(state, nshots=100)
assert_results(result,
decimal_samples=np.ones((100, )),
binary_samples=np.ones((100, 1)),
decimal_frequencies={1: 100},
binary_frequencies={"1": 100})
def test_measurement_circuit(backend, accelerators):
original_backend = qibo.get_backend()
qibo.set_backend(backend)
c = models.Circuit(4, accelerators)
c.add(gates.X(0))
c.add(gates.M(0))
result = c(nshots=100)
assert_result(result, np.ones((100, )), np.ones((100, 1)), {1: 100},
{"1": 100})
qibo.set_backend(original_backend)
def test_circuit_copy_with_measurements(backend, accelerators):
original_backend = qibo.get_backend()
qibo.set_backend(backend)
c1 = models.Circuit(6, accelerators)
c1.add([gates.X(0), gates.X(1), gates.X(3)])
c1.add(gates.M(5, 1, 3, register_name="a"))
c1.add(gates.M(2, 0, register_name="b"))
c2 = c1.copy()
r1 = c1(nshots=100)
r2 = c2(nshots=100)
np.testing.assert_allclose(r1.samples(), r2.samples())
rg1 = r1.frequencies(registers=True)
rg2 = r2.frequencies(registers=True)
assert rg1.keys() == rg2.keys()
for k in rg1.keys():
assert rg1[k] == rg2[k]
qibo.set_backend(original_backend)
def measure_payoff(q, ancilla):
"""Measurement gates needed to measure the expected payoff and perform post-selection
Args:
q (list): quantum register encoding the asset's price in the unary bases.
ancilla (int): qubit that encodes the payoff of the options.
Returns:
generator that yields the measurement gates to recover the expected payoff.
"""
yield gates.M(*(q + [ancilla]), register_name='payoff')
def test_pauli_error(backend, density_matrix, nshots):
pauli = PauliError(0, 0.2, 0.3)
noise = NoiseModel()
noise.add(pauli, gates.X, 1)
noise.add(pauli, gates.CNOT)
noise.add(pauli, gates.Z, (0,1))
circuit = Circuit(3, density_matrix=density_matrix)
circuit.add(gates.CNOT(0,1))
circuit.add(gates.Z(1))
circuit.add(gates.X(1))
circuit.add(gates.X(2))
circuit.add(gates.Z(2))
circuit.add(gates.M(0, 1, 2))
target_circuit = Circuit(3, density_matrix=density_matrix)
target_circuit.add(gates.CNOT(0,1))
target_circuit.add(gates.PauliNoiseChannel(0, 0, 0.2, 0.3))
target_circuit.add(gates.PauliNoiseChannel(1, 0, 0.2, 0.3))
target_circuit.add(gates.Z(1))
target_circuit.add(gates.PauliNoiseChannel(1, 0, 0.2, 0.3))
target_circuit.add(gates.X(1))
target_circuit.add(gates.PauliNoiseChannel(1, 0, 0.2, 0.3))
target_circuit.add(gates.X(2))
target_circuit.add(gates.Z(2))
target_circuit.add(gates.M(0, 1, 2))
initial_psi = random_density_matrix(3) if density_matrix else random_state(3)
np.random.seed(123)
K.set_seed(123)
final_state = noise.apply(circuit)(initial_state=np.copy(initial_psi), nshots=nshots)
final_state_samples = final_state.samples() if nshots else None
np.random.seed(123)
K.set_seed(123)
target_final_state = target_circuit(initial_state=np.copy(initial_psi), nshots=nshots)
target_final_state_samples = target_final_state.samples() if nshots else None
if nshots is None:
K.assert_allclose(final_state, target_final_state)
else:
K.assert_allclose(final_state_samples, target_final_state_samples)
def test_construct_unitary_errors(backend):
qibo.set_backend(backend)
gate = gates.M(0)
with pytest.raises(ValueError):
matrix = gate.unitary
pairs = list((i, i + 1) for i in range(0, 5, 2))
theta = 2 * np.pi * np.random.random(6)
gate = gates.VariationalLayer(range(6), pairs, gates.RY, gates.CZ, theta)
with pytest.raises(ValueError):
matrix = gate.unitary
def test_measurement_gate_errors(backend):
gate = gates.M(0)
# attempting to use `controlled_by`
with pytest.raises(NotImplementedError):
gate.controlled_by(1)
# attempting to construct unitary
with pytest.raises(ValueError):
matrix = gate.matrix
# calling on bad state
with pytest.raises(TypeError):
gate("test", 100)
def test_circuit_addition_with_measurements(backend):
c = models.Circuit(2)
c.add(gates.H(0))
c.add(gates.H(1))
meas_c = models.Circuit(2)
c.add(gates.M(0, 1))
c += meas_c
assert len(c.measurement_gate.target_qubits) == 2
assert c.measurement_tuples == {"register0": (0, 1)}
