def test_sample_heavy_set_with_parity():
"""Test that we correctly sample a circuit's heavy set with a parity map"""
sampler = Mock(spec=cirq.Simulator)
# Construct a result that returns [1, 0, 1, 0] for the physical qubit
# measurement, and [0, 1, 1, 0] for the ancilla qubit measurement. The first
# bitstring "10" is valid and heavy. The second "01" is valid and not
# heavy. The third and fourth bitstraings "11" and "00" are not valid and
# dropped.
result = cirq.TrialResult.from_single_parameter_set(
params=cirq.ParamResolver({}),
measurements={
'0': np.array([[1], [0]]),
'1': np.array([[0], [1]]),
'2': np.array([[1], [1]]),
'3': np.array([[0], [0]])
})
sampler.run = MagicMock(return_value=result)
circuit = cirq.Circuit(cirq.measure(*cirq.LineQubit.range(4)))
compilation_result = CompilationResult(
circuit=circuit,
mapping={q: q
for q in cirq.LineQubit.range(4)},
parity_map={
cirq.LineQubit(0): cirq.LineQubit(1),
cirq.LineQubit(2): cirq.LineQubit(3)
})
probability = cirq.contrib.quantum_volume.sample_heavy_set(
compilation_result, [1], sampler=sampler, repetitions=1)
# The first output is in the heavy set. The second one isn't, but it is
# dropped.
assert probability == .5
def test_sample_heavy_set():
"""Test that we correctly sample a circuit's heavy set"""
sampler = Mock(spec=cirq.Simulator)
# Construct a result that returns "1", "2", "3", "0"
result = cirq.TrialResult.from_single_parameter_set(
params=cirq.ParamResolver({}),
measurements={'mock': np.array([[0, 1], [1, 0], [1, 1], [0, 0]])})
sampler.run = MagicMock(return_value=result)
circuit = cirq.Circuit(cirq.measure(*cirq.LineQubit.range(2)))
compilation_result = CompilationResult(circuit=circuit,
mapping={},
parity_map={})
probability = cirq.contrib.quantum_volume.sample_heavy_set(
compilation_result, [1, 2, 3], sampler=sampler, repetitions=10)
# The first 3 of our outputs are in the heavy set, and then the rest are
# not.
assert probability == .75