def test_sample_from_wavefunction_fails_for_invalid_n_samples(n_samples):
n_qubits = 4
amplitudes = [0] * (2**n_qubits)
amplitudes[1] = 1
wavefunction = Wavefunction(amplitudes)
with pytest.raises(AssertionError):
sample_from_wavefunction(wavefunction, n_samples)
def run_circuit_and_measure(self, circuit, **kwargs):
"""
Method for executing the circuit and measuring the outcome.
Args:
circuit (core.circuit.Circuit): quantum circuit to be executed.
"""
wavefunction = self.get_wavefunction(circuit)
return sample_from_wavefunction(wavefunction, self.n_samples)
def test_sample_from_wavefunction_list():
n_qubits = 4
expected_bitstring = (0, 0, 0, 1)
amplitudes = [0] * (2**n_qubits)
amplitudes[1] = 1 # |0001> will be measured in all cases.
wavefunction = Wavefunction(amplitudes)
sample = set(sample_from_wavefunction(wavefunction, 500))
assert len(sample) == 1
assert sample.pop() == expected_bitstring
def test_sample_from_wavefunction_column_vector():
n_qubits = 4
expected_bitstring = (0, 0, 0, 1)
amplitudes = np.array([0] * (2**n_qubits)).reshape(2**n_qubits, 1)
amplitudes[1] = 1 # |0001> will be measured in all cases.
wavefunction = Wavefunction(amplitudes)
sample = set(sample_from_wavefunction(wavefunction, 500))
assert len(sample) == 1
assert sample.pop() == expected_bitstring
def test_sample_from_wavefunction_list():
n_qubits = 4
# NOTE: our indexing places the state of qubit i at the ith index of the tuple. Hence |01> will result in
# the tuple (1, 0)
expected_bitstring = (1, 0, 0, 0)
amplitudes = [0] * (2**n_qubits)
amplitudes[1] = 1 # |0001> will be measured in all cases.
wavefunction = Wavefunction(amplitudes)
sample = set(sample_from_wavefunction(wavefunction, 500))
assert len(sample) == 1
assert sample.pop() == expected_bitstring
def run_circuit_and_measure(self, circuit, **kwargs):
"""
Run a circuit and measure a certain number of bitstrings
Args:
circuit (zquantum.core.circuit.Circuit): the circuit to prepare the state
n_samples (int): the number of bitstrings to sample
Returns:
a list of bitstrings (a list of tuples)
"""
wavefunction = self.get_wavefunction(circuit)
bitstrings = sample_from_wavefunction(wavefunction, self.n_samples)
return Measurements(bitstrings)
def test_sample_from_wavefunction():
wavefunction = create_random_wavefunction(4)
samples = sample_from_wavefunction(wavefunction, 10000)
sampled_dict = Counter(samples)
sampled_probabilities = []
for num in range(len(wavefunction)):
bitstring = format(num, "b")
while len(bitstring) < wavefunction.n_qubits:
bitstring = "0" + bitstring
measurement = convert_bitstrings_to_tuples([bitstring])[0]
sampled_probabilities.append(sampled_dict[measurement] / 10000)
probabilities = wavefunction.probabilities()
for sampled_prob, exact_prob in zip(sampled_probabilities, probabilities):
assert np.allclose(sampled_prob, exact_prob, atol=0.01)
def run_circuit_and_measure(self,
circuit: Circuit,
n_samples: Optional[int] = None,
**kwargs):
"""
Run a circuit and measure a certain number of bitstrings
Args:
circuit: the circuit to prepare the state
n_samples: the number of bitstrings to sample
Returns:
The measured bitstrings.
"""
if n_samples is None:
n_samples = self.n_samples
wavefunction = self.get_wavefunction(circuit)
bitstrings = sample_from_wavefunction(wavefunction, n_samples)
return Measurements(bitstrings)
def test_sample_from_wavefunction():
wavefunction = create_random_wavefunction(4)
samples = sample_from_wavefunction(wavefunction, 10000)
sampled_dict = Counter(samples)
sampled_probabilities = []
for num in range(len(wavefunction)**2):
bitstring = format(num, "b")
while len(bitstring) < len(wavefunction):
bitstring = "0" + bitstring
# NOTE: our indexing places the state of qubit i at the ith index of the tuple. Hence |01> will result in
# the tuple (1, 0)
bitstring = bitstring[::-1]
measurement = convert_bitstrings_to_tuples([bitstring])[0]
sampled_probabilities.append(sampled_dict[measurement] / 10000)
probabilities = wavefunction.probabilities()
for sampled_prob, exact_prob in zip(sampled_probabilities, probabilities):
assert np.allclose(sampled_prob, exact_prob, atol=0.01)
def run_circuit_and_measure(
self,
circuit: Circuit,
n_samples: int,
symbol_map: Optional[Dict[Symbol, Any]] = {},
) -> Measurements:
"""Run a circuit and measure a certain number of bitstrings
Args:
circuit: the circuit to prepare the state
n_samples: the number of bitstrings to sample
"""
wavefunction = self.get_wavefunction(circuit).bind(
symbol_map=symbol_map)
if circuit.free_symbols:
raise ValueError(
"Cannot sample from circuit with symbolic parameters.")
bitstrings = sample_from_wavefunction(wavefunction, n_samples,
self._seed)
return Measurements(bitstrings)
def run_circuit_and_measure(self,
circuit: Circuit,
n_samples: Optional[int] = None,
**kwargs):
"""
Run a circuit and measure a certain number of bitstrings
Args:
circuit: the circuit to prepare the state
n_samples: the number of bitstrings to sample
Returns:
The measured bitstrings.
"""
if n_samples is None:
if self.n_samples is None:
raise ValueError(
"n_samples needs to be specified either as backend attribute or as an function argument."
)
else:
n_samples = self.n_samples
wavefunction = self.get_wavefunction(circuit)
bitstrings = sample_from_wavefunction(wavefunction, n_samples)
return Measurements(bitstrings)
def run_circuit_and_measure(self, circuit, **kwargs):
wavefunction = self.get_wavefunction(circuit)
return Measurements(
sample_from_wavefunction(wavefunction, self.n_samples))