def place_line(self, device: 'cirq_google.GridDevice', length: int) -> GridQubitLineTuple:
"""Runs line sequence search.
Args:
device: Chip description.
length: Required line length.
Returns:
Linear sequences found on the chip.
Raises:
ValueError: If search algorithm passed on initialization is not
recognized.
"""
if not device.metadata.qubit_set:
return GridQubitLineTuple()
start: GridQubit = cast(GridQubit, min(device.metadata.qubit_set))
sequences: List[LineSequence] = []
greedy_search: Dict[str, List[GreedySequenceSearch]] = {
'minimal_connectivity': [_PickFewestNeighbors(device, start)],
'largest_area': [_PickLargestArea(device, start)],
'best': [_PickFewestNeighbors(device, start), _PickLargestArea(device, start)],
}
algos = greedy_search.get(self.algorithm)
if algos is None:
raise ValueError(f"Unknown greedy search algorithm {self.algorithm}")
for algorithm in algos:
sequences.append(algorithm.get_or_search())
return GridQubitLineTuple.best_of(sequences, length)
def test_largest_sequence_search_traverses_grid():
q00 = cirq.GridQubit(0, 0)
q10 = cirq.GridQubit(1, 0)
q11 = cirq.GridQubit(1, 1)
q20 = cirq.GridQubit(2, 0)
q30 = cirq.GridQubit(3, 0)
q40 = cirq.GridQubit(4, 0)
q41 = cirq.GridQubit(4, 1)
q42 = cirq.GridQubit(4, 2)
q50 = cirq.GridQubit(5, 0)
qubits = [q00, q10, q11, q20, q30, q40, q50, q41, q42]
device = _create_device(qubits)
search = greedy._PickLargestArea(device, q20)
# + + +-+-+ +
# |
# + +
# |
# +
assert search._choose_next_qubit(q20, {q20}) == q30
assert search._choose_next_qubit(q30, {q20, q30}) == q40
assert search._choose_next_qubit(q40, {q20, q30, q40}) == q41
assert search._choose_next_qubit(q41, {q20, q30, q40, q41}) == q42
assert search._choose_next_qubit(q42, {q20, q30, q40, q41, q42}) is None
method = greedy.GreedySequenceSearchStrategy('largest_area')
assert method.place_line(device, 7) == GridQubitLineTuple(
[q00, q10, q20, q30, q40, q41, q42])
with pytest.raises(NotFoundError):
_ = method.place_line(device, 8)
def test_greedy_search_method_returns_longest():
q00 = cirq.GridQubit(0, 0)
q10 = cirq.GridQubit(1, 0)
device = _create_device([q00, q10])
length = 1
method = greedy.GreedySequenceSearchStrategy()
assert method.place_line(device, length) == GridQubitLineTuple([q00])
def test_line_placement_str():
q00 = cirq.GridQubit(0, 0)
q01 = cirq.GridQubit(0, 1)
q02 = cirq.GridQubit(0, 2)
placement = GridQubitLineTuple([q00, q01, q02])
assert (str(placement).strip() == """
q(0, 0)━━q(0, 1)━━q(0, 2)
""".strip())
def test_line_placement_to_str():
q00 = cirq.GridQubit(0, 0)
q01 = cirq.GridQubit(0, 1)
q02 = cirq.GridQubit(0, 2)
q10 = cirq.GridQubit(1, 0)
q11 = cirq.GridQubit(1, 1)
placement = GridQubitLineTuple([q02, q01, q00, q10, q11])
assert (str(placement).strip() == """
q(0, 0)━━q(0, 1)━━q(0, 2)
┃
q(1, 0)━━q(1, 1)
""".strip())
def test_greedy_search_method_calls_minimal_only(minimal, largest):
q00 = cirq.GridQubit(0, 0)
q01 = cirq.GridQubit(0, 1)
device = _create_device([q00, q01])
length = 2
sequence = [q00, q01]
minimal.return_value.get_or_search.return_value = sequence
method = greedy.GreedySequenceSearchStrategy('minimal_connectivity')
assert method.place_line(device, length) == GridQubitLineTuple(sequence)
largest.return_value.get_or_search.assert_not_called()
minimal.return_value.get_or_search.assert_called_once_with()
def place_line(self, device: 'cirq_google.XmonDevice', length: int) -> GridQubitLineTuple:
"""Runs line sequence search.
Args:
device: Chip description.
length: Required line length.
Returns:
List of linear sequences on the chip found by simulated annealing
method.
"""
seqs = AnnealSequenceSearch(device, self.seed).search(self.trace_func)
return GridQubitLineTuple.best_of(seqs, length)
def test_greedy_search_method_returns_empty_when_empty():
device = _create_device([])
length = 0
method = greedy.GreedySequenceSearchStrategy()
assert method.place_line(device, length) == GridQubitLineTuple()
def test_best_of_gets_longest_needs_minimum():
q00 = cirq.GridQubit(0, 0)
q01 = cirq.GridQubit(0, 1)
assert GridQubitLineTuple.best_of([[]], 0) == ()
assert GridQubitLineTuple.best_of([[], [q00]], 0) == ()
assert GridQubitLineTuple.best_of([[q00], []], 0) == ()
assert GridQubitLineTuple.best_of([[], [q00]], 1) == (q00, )
assert GridQubitLineTuple.best_of([[q00], []], 1) == (q00, )
assert GridQubitLineTuple.best_of([[q00, q01], [q00]], 1) == (q00, )
assert GridQubitLineTuple.best_of([[q00, q01], [q00]], 2) == (q00, q01)
assert GridQubitLineTuple.best_of([[q00, q01]], 2) == (q00, q01)
assert GridQubitLineTuple.best_of([], 0) == ()
with pytest.raises(NotFoundError):
_ = GridQubitLineTuple.best_of([[]], 1)
with pytest.raises(NotFoundError):
_ = GridQubitLineTuple.best_of([[q00]], 2)
