def test_cycle_basis_multiple_roots_same_cycles(self):
res = sorted(sorted(x) for x in retworkx.cycle_basis(self.graph, 0))
self.assertEqual(res, [[0, 1, 2, 3], [0, 1, 6, 7, 8], [0, 3, 4, 5]])
res = sorted(sorted(x) for x in retworkx.cycle_basis(self.graph, 1))
self.assertEqual(res, [[0, 1, 2, 3], [0, 1, 6, 7, 8], [0, 3, 4, 5]])
res = sorted(sorted(x) for x in retworkx.cycle_basis(self.graph, 9))
self.assertEqual(res, [[0, 1, 2, 3], [0, 1, 6, 7, 8], [0, 3, 4, 5]])
def vacuum_operator(fer_op):
"""Use the stabilizers to find the vacuum state in bravyi_kitaev_fast.
Args:
fer_op (FermionicOperator): the fermionic operator in the second quantized form
Returns:
WeightedPauliOperator: the qubit operator
"""
edge_list = bravyi_kitaev_fast_edge_list(fer_op)
num_qubits = edge_list.shape[1]
vac_operator = WeightedPauliOperator(paulis=[[1.0, Pauli.from_label('I' * num_qubits)]])
graph = retworkx.PyGraph()
graph.extend_from_edge_list(list(map(tuple, edge_list.transpose())))
stabs = np.asarray(retworkx.cycle_basis(graph))
for stab in stabs:
a_op = WeightedPauliOperator(paulis=[[1.0, Pauli.from_label('I' * num_qubits)]])
stab = np.asarray(stab)
for i in range(np.size(stab)):
a_op = a_op * edge_operator_aij(edge_list, stab[i], stab[(i + 1) % np.size(stab)]) * 1j
# a_op.scaling_coeff(1j)
a_op += WeightedPauliOperator(paulis=[[1.0, Pauli.from_label('I' * num_qubits)]])
vac_operator = vac_operator * a_op * np.sqrt(2)
# vac_operator.scaling_coeff()
return vac_operator
def test_cycle_basis_disconnected_graphs(self):
self.graph.add_nodes_from(["A", "B", "C"])
self.graph.add_edges_from_no_data([(10, 11), (10, 12), (11, 12)])
cycles = retworkx.cycle_basis(self.graph, 9)
res = sorted(sorted(x) for x in cycles[:-1]) + [sorted(cycles[-1])]
self.assertEqual(
res, [[0, 1, 2, 3], [0, 1, 6, 7, 8], [0, 3, 4, 5], [10, 11, 12]])
def test_cycle_basis(self):
graph = retworkx.PyGraph()
graph.add_nodes_from(list(range(6)))
graph.add_edges_from_no_data([(0, 1), (0, 3), (0, 5), (1, 2), (2, 3),
(3, 4), (4, 5)])
res = sorted(sorted(c) for c in retworkx.cycle_basis(graph, 0))
self.assertEqual([[0, 1, 2, 3], [0, 3, 4, 5]], res)
def test_equal_distance_graph(self):
n = 3
graph = retworkx.PyGraph()
graph.add_nodes_from(range(n + 5))
graph.add_edges_from([
(n, n + 1, 0.5),
(n, n + 2, 0.5),
(n + 1, n + 2, 0.5),
(n, n + 3, 0.5),
(n + 1, n + 4, 0.5),
])
graph.add_edges_from([(i, n + 2, 2) for i in range(n)])
terminals = list(range(5)) + [n + 3, n + 4]
tree = retworkx.steiner_tree(graph, terminals, weight_fn=float)
# Assert no cycle
self.assertEqual(retworkx.cycle_basis(tree), [])
expected_edges = [
(3, 4, 0.5),
(4, 5, 0.5),
(3, 6, 0.5),
(4, 7, 0.5),
(0, 5, 2),
(1, 5, 2),
(2, 5, 2),
]
self.assertEqual(tree.weighted_edge_list(), expected_edges)
def stabilizers(fer_op):
""" stabilizers """
edge_list = bravyi_kitaev_fast_edge_list(fer_op)
num_qubits = edge_list.shape[1]
graph = retworkx.PyGraph()
graph.extend_from_edge_list(list(map(tuple, edge_list.transpose())))
stabs = np.asarray(retworkx.cycle_basis(graph))
stabilizer_ops = []
for stab in stabs:
a_op = WeightedPauliOperator(paulis=[[1.0, Pauli.from_label('I' * num_qubits)]])
stab = np.asarray(stab)
for i in range(np.size(stab)):
a_op = a_op * edge_operator_aij(edge_list, stab[i], stab[(i + 1) % np.size(stab)]) * 1j
stabilizer_ops.append(a_op)
return stabilizer_ops
def test_self_loop(self):
self.graph.add_edge(1, 1, None)
res = sorted(sorted(c) for c in retworkx.cycle_basis(self.graph, 0))
self.assertEqual([[0, 1, 2, 3], [0, 1, 6, 7, 8], [0, 3, 4, 5], [1]],
res)
def test_invalid_types(self):
digraph = retworkx.PyDiGraph()
with self.assertRaises(TypeError):
retworkx.cycle_basis(digraph)