def fallback_routine(routing: Routing, int_pairs: Set[frozenset]) -> None:
@lru_cache(maxsize=None)
def deterministic_pair(int_pairs):
int_pairs_copy = copy(set(int_pairs))
return int_pairs_copy.pop()
det_pair = deterministic_pair(frozenset(int_pairs))
hard_qb0 = routing.mapping.log2hard[list(det_pair)[0]]
hard_qb1 = routing.mapping.log2hard[list(det_pair)[1]]
shortest_path = nx.shortest_path(routing.qpu.graph, hard_qb0, hard_qb1)
routing.apply_swap(frozenset(shortest_path[:2]))
def decrease_int_pair_distance(routing: Routing, int_pairs: Set[frozenset]) -> bool:
gate_executed = False
for _ in range(routing.qpu.graph.size()):
no_swap_gate_executed = True
swap1_gate = None
for hard_qb0, hard_qb1 in routing.qpu.graph.edges():
swap_gate = frozenset((hard_qb0, hard_qb1))
if routing.layers[-1].swap_gate_applicable(swap_gate):
diff = int_pair_distance_change(routing, int_pairs, swap_gate)
if diff == 2:
routing.apply_swap(swap_gate)
gate_executed = True
no_swap_gate_executed = False
elif diff == 1:
swap1_gate = swap_gate
if no_swap_gate_executed:
if swap1_gate is not None:
routing.apply_swap(swap1_gate)
gate_executed = True
continue
else:
break
return gate_executed
class TestRouting(TestCase):
def setUp(self) -> None:
gr = nx.grid_2d_graph(2, 2)
gr.add_edge((0, 0), (1, 1))
self.qpu = Grid2dQPU(2, 2)
self.problem_instance = dimod.generators.random.uniform(gr, dimod.SPIN)
init_map = {cirq.GridQubit(*loc): loc for loc in self.problem_instance.variables}
self.initial_mapping = Mapping(self.qpu, self.problem_instance, initial_mapping=init_map)
self.routing = Routing(self.problem_instance, self.qpu, cp.deepcopy(self.initial_mapping))
def test_apply_swap(self) -> None:
self.routing.apply_swap(frozenset((cirq.GridQubit(0, 0), cirq.GridQubit(1, 0))))
self.assertEqual(self.initial_mapping.hard2log[cirq.GridQubit(0, 0)], self.routing.mapping.hard2log[cirq.GridQubit(1, 0)],
msg="application of swap gate did not update mapping")
self.assertEqual(self.initial_mapping.hard2log[cirq.GridQubit(1, 0)], self.routing.mapping.hard2log[cirq.GridQubit(0, 0)],
msg="application of swap gate did not update mapping")
self.assertTrue(self.routing.layers[0].gates[cirq.GridQubit(0, 0)][cirq.GridQubit(1, 0)]['swap'],
msg="did not add swap gate to layer")
self.routing.apply_swap(frozenset((cirq.GridQubit(0, 1), cirq.GridQubit(1, 1))))
self.assertEqual(self.initial_mapping.hard2log[cirq.GridQubit(0, 1)], self.routing.mapping.hard2log[cirq.GridQubit(1, 1)],
msg="application of swap gate did not update mapping")
self.assertEqual(self.initial_mapping.hard2log[cirq.GridQubit(1, 1)], self.routing.mapping.hard2log[cirq.GridQubit(0, 1)],
msg="application of swap gate did not update mapping")
self.assertTrue(self.routing.layers[0].gates[cirq.GridQubit(0, 1)][cirq.GridQubit(1, 1)]['swap'],
msg="did not add swap gate to layer")
self.routing.apply_swap(frozenset((cirq.GridQubit(0, 0), cirq.GridQubit(0, 1))))
self.assertTrue(self.routing.layers[1].gates[cirq.GridQubit(0, 0)][cirq.GridQubit(0, 1)]['swap'],
msg="did not add layer containing new swap gate")
self.routing.draw()
def test_apply_int(self) -> None:
self.routing.apply_int(frozenset((cirq.GridQubit(0, 0), cirq.GridQubit(1, 0))))
self.assertTrue(self.routing.layers[0].gates[cirq.GridQubit(0, 0)][cirq.GridQubit(1, 0)]['int'],
msg="did not add int gate to layer")
self.assertFalse(self.routing.remaining_interactions.has_edge(cirq.GridQubit(0, 0), cirq.GridQubit(1, 0)),
msg='interaction has not been deleted from routing.remaining_interactions')
self.routing.apply_int(frozenset((cirq.GridQubit(0, 1), cirq.GridQubit(1, 1))))
self.assertTrue(self.routing.layers[0].gates[cirq.GridQubit(0, 1)][cirq.GridQubit(1, 1)]['int'],
msg="did not add int gate to layer")
self.assertFalse(self.routing.remaining_interactions.has_edge(cirq.GridQubit(0, 1), cirq.GridQubit(1, 1)),
msg='interaction has not been deleted from routing.remaining_interactions')
self.routing.apply_int(frozenset((cirq.GridQubit(0, 0), cirq.GridQubit(0, 1))))
self.assertTrue(self.routing.layers[1].gates[cirq.GridQubit(0, 0)][cirq.GridQubit(0, 1)]['int'],
msg="did not add layer containing new int gate")
self.assertFalse(self.routing.remaining_interactions.has_edge(cirq.GridQubit(0, 0), cirq.GridQubit(0, 1)),
msg='interaction has not been deleted from routing.remaining_interactions')
def int_pair_distance_change(routing: Routing, int_pairs: Set[frozenset], swap: frozenset) -> int:
dist_before = int_pair_distance(routing, int_pairs)
routing.apply_swap(swap)
dist_after = int_pair_distance(routing, int_pairs)
routing.apply_swap(swap)
return dist_before - dist_after