def test_execute(self):
ast = qasm.Qasm(
filename=self._get_resource_path('qasm/example.qasm')).parse()
dag_circuit = Unroller(ast, DAGBackend()).execute()
dag_unroller = DagUnroller(dag_circuit, DAGBackend())
unroller_dag_circuit = dag_unroller.execute()
expected_result = """\
OPENQASM 2.0;
qreg q[3];
qreg r[3];
creg c[3];
creg d[3];
U(0.5*pi,0,pi) q[2];
CX q[2],r[2];
measure r[2] -> d[2];
U(0.5*pi,0,pi) q[1];
CX q[1],r[1];
measure r[1] -> d[1];
U(0.5*pi,0,pi) q[0];
CX q[0],r[0];
measure r[0] -> d[0];
barrier q[0],q[1],q[2];
measure q[2] -> c[2];
measure q[1] -> c[1];
measure q[0] -> c[0];
"""
self.assertEqual(unroller_dag_circuit.qasm(), expected_result)
def test_dag_to_dag_expand_gates_default_basis(self):
"""Test DagUnroller.expand_gates()"""
ast = qasm.Qasm(filename=self._get_resource_path('qasm/example.qasm')).parse()
dag_circuit = Unroller(ast, DAGBackend()).execute()
dag_unroller = DagUnroller(dag_circuit, DAGBackend())
expanded_dag_circuit = dag_unroller.expand_gates()
expected_result = """\
OPENQASM 2.0;
include "qelib1.inc";
qreg q[3];
qreg r[3];
creg c[3];
creg d[3];
U(pi/2,0,pi) q[2];
CX q[2],r[2];
measure r[2] -> d[2];
U(pi/2,0,pi) q[1];
CX q[1],r[1];
measure r[1] -> d[1];
U(pi/2,0,pi) q[0];
CX q[0],r[0];
barrier q[0],q[1],q[2];
measure q[0] -> c[0];
measure q[1] -> c[1];
measure q[2] -> c[2];
measure r[0] -> d[0];
"""
expected_dag = circuit_to_dag(QuantumCircuit.from_qasm_str(expected_result))
self.assertEqual(expanded_dag_circuit, expected_dag)
def setUp(self):
qasm_filename = self._get_resource_path('qasm/example.qasm')
qasm_ast = Qasm(filename=qasm_filename).parse()
qasm_dag = Unroller(qasm_ast, DAGBackend()).execute()
qasm_json = DagUnroller(qasm_dag,
JsonBackend(qasm_dag.basis)).execute()
qr = QuantumRegister(2, 'q')
cr = ClassicalRegister(2, 'c')
qc = QuantumCircuit(qr, cr)
qc.h(qr[0])
qc.measure(qr[0], cr[0])
qc_dag = DAGCircuit.fromQuantumCircuit(qc)
qc_json = DagUnroller(qc_dag, JsonBackend(qc_dag.basis)).execute()
# create qobj
compiled_circuit1 = QobjExperiment.from_dict(qc_json)
compiled_circuit2 = QobjExperiment.from_dict(qasm_json)
self.qobj = Qobj(qobj_id='test_qobj',
config=QobjConfig(shots=2000,
memory_slots=1,
max_credits=3,
seed=1111),
experiments=[compiled_circuit1, compiled_circuit2],
header=QobjHeader(backend_name='qasm_simulator'))
self.qobj.experiments[0].header.name = 'test_circuit1'
self.qobj.experiments[1].header.name = 'test_circuit2'
self.backend = QasmSimulator()
def test_from_dag_to_json_with_basis(self):
ast = qasm.Qasm(
filename=self._get_resource_path('qasm/example.qasm')).parse()
dag_circuit = Unroller(ast, DAGBackend(["cx", "u1", "u2",
"u3"])).execute()
dag_unroller = DagUnroller(dag_circuit,
JsonBackend(["cx", "u1", "u2", "u3"]))
json_circuit = dag_unroller.execute()
expected_result = \
{'operations':
[{'qubits': [5], 'texparams': ['0', '\\pi'], 'params': [0.0, 3.141592653589793],
'name': 'u2'},
{'qubits': [5, 2], 'texparams': [], 'params': [], 'name': 'cx'},
{'qubits': [2], 'clbits': [2], 'name': 'measure'},
{'qubits': [4], 'texparams': ['0', '\\pi'], 'params': [0.0, 3.141592653589793],
'name': 'u2'},
{'qubits': [4, 1], 'texparams': [], 'params': [], 'name': 'cx'},
{'qubits': [1], 'clbits': [1], 'name': 'measure'},
{'qubits': [3], 'texparams': ['0', '\\pi'], 'params': [0.0, 3.141592653589793],
'name': 'u2'},
{'qubits': [3, 0], 'texparams': [], 'params': [], 'name': 'cx'},
{'qubits': [3, 4, 5], 'name': 'barrier'},
{'qubits': [5], 'clbits': [5], 'name': 'measure'},
{'qubits': [4], 'clbits': [4], 'name': 'measure'},
{'qubits': [3], 'clbits': [3], 'name': 'measure'},
{'qubits': [0], 'clbits': [0], 'name': 'measure'}],
'header':
{'clbit_labels': [['d', 3], ['c', 3]],
'number_of_qubits': 6,
'qubit_labels': [['r', 0], ['r', 1], ['r', 2], ['q', 0], ['q', 1], ['q', 2]],
'number_of_clbits': 6
}
}
self.assertEqual(json_circuit, expected_result)
def test_dag_to_json(self):
"""Test DagUnroller with JSON backend."""
ast = qasm.Qasm(filename=self._get_resource_path('qasm/example.qasm')).parse()
dag_circuit = Unroller(ast, DAGBackend()).execute()
dag_unroller = DagUnroller(dag_circuit, JsonBackend())
json_circuit = dag_unroller.execute()
expected_result = {
'operations':
[
{'qubits': [5], 'texparams': ['0.5 \\pi', '0', '\\pi'],
'name': 'U', 'params': [1.5707963267948966, 0.0, 3.141592653589793]},
{'name': 'CX', 'qubits': [5, 2]},
{'clbits': [2], 'name': 'measure', 'qubits': [2]},
{'qubits': [4], 'texparams': ['0.5 \\pi', '0', '\\pi'], 'name': 'U',
'params': [1.5707963267948966, 0.0, 3.141592653589793]},
{'name': 'CX', 'qubits': [4, 1]},
{'clbits': [1], 'name': 'measure', 'qubits': [1]},
{'qubits': [3], 'texparams': ['0.5 \\pi', '0', '\\pi'], 'name': 'U',
'params': [1.5707963267948966, 0.0, 3.141592653589793]},
{'name': 'CX', 'qubits': [3, 0]},
{'name': 'barrier', 'qubits': [3, 4, 5]},
{'clbits': [5], 'name': 'measure', 'qubits': [5]},
{'clbits': [4], 'name': 'measure', 'qubits': [4]},
{'clbits': [3], 'name': 'measure', 'qubits': [3]},
{'clbits': [0], 'name': 'measure', 'qubits': [0]}
],
'header':
{
'memory_slots': 6,
'qubit_labels': [['r', 0], ['r', 1], ['r', 2], ['q', 0], ['q', 1], ['q', 2]],
'n_qubits': 6, 'clbit_labels': [['d', 3], ['c', 3]]
}
}
self.assertEqual(json_circuit, expected_result)
def _circuit_from_qasm(qasm):
from qiskit.unroll import Unroller
from qiskit.unroll import DAGBackend
from qiskit.converters import dag_to_circuit
ast = qasm.parse()
dag = Unroller(ast, DAGBackend()).execute()
return dag_to_circuit(dag)
def test_from_ast_to_dag(self):
"""Test Unroller.execute()"""
ast = qasm.Qasm(
filename=self._get_resource_path('qasm/example.qasm')).parse()
dag_circuit = Unroller(ast, DAGBackend()).execute()
expected_result = """\
OPENQASM 2.0;
include "qelib1.inc";
qreg q[3];
qreg r[3];
creg c[3];
creg d[3];
h q[0];
h q[1];
h q[2];
cx q[0],r[0];
cx q[1],r[1];
cx q[2],r[2];
barrier q[0],q[1],q[2];
measure q[0] -> c[0];
measure q[1] -> c[1];
measure q[2] -> c[2];
measure r[0] -> d[0];
measure r[1] -> d[1];
measure r[2] -> d[2];
"""
expected_dag = DAGCircuit.fromQuantumCircuit(
QuantumCircuit.from_qasm_str(expected_result))
self.assertEqual(dag_circuit, expected_dag)
def test_dag_to_dag_expand_gates_custom_basis(self):
"""Test DagUnroller.expand_gates() to a gate basis."""
ast = qasm.Qasm(
filename=self._get_resource_path('qasm/example.qasm')).parse()
dag_circuit = Unroller(ast, DAGBackend()).execute()
dag_unroller = DagUnroller(dag_circuit, DAGBackend())
expanded_dag_circuit = dag_unroller.expand_gates(
basis=["cx", "u1", "u2", "u3"])
expected_result = """\
OPENQASM 2.0;
qreg q[3];
qreg r[3];
creg c[3];
creg d[3];
gate u2(phi,lambda) q
{
U((pi/2),phi,lambda) q;
}
gate h a
{
u2(0,pi) a;
}
gate cx c,t
{
CX c,t;
}
u2(0,pi) q[2];
cx q[2],r[2];
measure r[2] -> d[2];
u2(0,pi) q[1];
cx q[1],r[1];
measure r[1] -> d[1];
u2(0,pi) q[0];
cx q[0],r[0];
barrier q[0],q[1],q[2];
measure q[0] -> c[0];
measure q[1] -> c[1];
measure q[2] -> c[2];
measure r[0] -> d[0];
"""
self.assertEqual(expanded_dag_circuit.qasm(), expected_result)
def setUp(self):
self.seed = 88
self.backend = QasmSimulatorPy()
backend_basis = self.backend.configuration().basis_gates
qasm_filename = self._get_resource_path('qasm/example.qasm')
qasm_ast = Qasm(filename=qasm_filename).parse()
qasm_dag = Unroller(qasm_ast, DAGBackend()).execute()
qasm_dag = DagUnroller(qasm_dag, DAGBackend(backend_basis)).expand_gates()
qasm_json = DagUnroller(qasm_dag, JsonBackend(qasm_dag.basis)).execute()
compiled_circuit = QobjExperiment.from_dict(qasm_json)
compiled_circuit.header.name = 'test'
self.qobj = Qobj(
qobj_id='test_sim_single_shot',
config=QobjConfig(
shots=1024, memory_slots=6,
max_credits=3, seed=self.seed
),
experiments=[compiled_circuit],
header=QobjHeader(backend_name='qasm_simulator_py')
)
def qasm_to_dag_circuit(qasm_string, basis_gates='u1,u2,u3,cx,id'):
"""
Convert an OPENQASM text string to a DAGCircuit.
Args:
qasm_string (str): OPENQASM2.0 circuit string.
basis_gates (str): QASM gates to unroll circuit to.
Returns:
A DAGCircuit object of the unrolled QASM circuit.
"""
program_node_circuit = qiskit.qasm.Qasm(data=qasm_string).parse()
dag_circuit = Unroller(program_node_circuit,
DAGBackend(basis_gates.split(","))).execute()
return dag_circuit
def _circuit_from_qasm(qasm):
from qiskit.unroll import Unroller
from qiskit.unroll import DAGBackend
ast = qasm.parse()
dag = Unroller(ast, DAGBackend()).execute()
circuit = QuantumCircuit()
for qreg in dag.qregs.values():
circuit.add_register(qreg)
for creg in dag.cregs.values():
circuit.add_register(creg)
graph = dag.multi_graph
for node in nx.topological_sort(graph):
n = graph.nodes[node]
if n['type'] == 'op':
n['op'].circuit = circuit
if 'condition' in n and n['condition']:
circuit._attach(n['op'].c_if(*n['condition']))
else:
circuit._attach(n['op'])
return circuit
def transpile(dag,
basis_gates='u1,u2,u3,cx,id',
coupling_map=None,
initial_layout=None,
get_layout=False,
format='dag',
seed=None,
pass_manager=None):
"""Transform a dag circuit into another dag circuit (transpile), through
consecutive passes on the dag.
Args:
dag (DAGCircuit): dag circuit to transform via transpilation
basis_gates (str): a comma separated string for the target basis gates
coupling_map (list): A graph of coupling::
[
[control0(int), target0(int)],
[control1(int), target1(int)],
]
eg. [[0, 2], [1, 2], [1, 3], [3, 4]}
initial_layout (dict): A mapping of qubit to qubit::
{
("q", start(int)): ("q", final(int)),
...
}
eg.
{
("q", 0): ("q", 0),
("q", 1): ("q", 1),
("q", 2): ("q", 2),
("q", 3): ("q", 3)
}
get_layout (bool): flag for returning the final layout after mapping
format (str): The target format of the compilation:
{'dag', 'json', 'qasm'}
seed (int): random seed for the swap mapper
pass_manager (PassManager): pass manager instance for the transpilation process
If None, a default set of passes are run.
Otherwise, the passes defined in it will run.
If contains no passes in it, no dag transformations occur.
Returns:
DAGCircuit: transformed dag
DAGCircuit, dict: transformed dag along with the final layout on backend qubits
Raises:
TranspilerError: if the format is not valid.
"""
# TODO: `basis_gates` will be removed after we have the unroller pass.
# TODO: `coupling_map`, `initial_layout`, `get_layout`, `seed` removed after mapper pass.
# TODO: move this to the mapper pass
num_qubits = sum(dag.qregs.values())
if num_qubits == 1 or coupling_map == "all-to-all":
coupling_map = None
final_layout = None
if pass_manager:
# run the passes specified by the pass manager
# TODO return the property set too. See #1086
dag = pass_manager.run_passes(dag)
else:
# default set of passes
# TODO: move each step here to a pass, and use a default passmanager below
basis = basis_gates.split(',') if basis_gates else []
dag_unroller = DagUnroller(dag, DAGBackend(basis))
dag = dag_unroller.expand_gates()
# if a coupling map is given compile to the map
if coupling_map:
logger.info("pre-mapping properties: %s", dag.property_summary())
# Insert swap gates
coupling = Coupling(coupling_list2dict(coupling_map))
removed_meas = remove_last_measurements(dag)
logger.info("measurements moved: %s", removed_meas)
logger.info("initial layout: %s", initial_layout)
dag, final_layout, last_layout = swap_mapper(dag,
coupling,
initial_layout,
trials=20,
seed=seed)
logger.info("final layout: %s", final_layout)
# Expand swaps
dag_unroller = DagUnroller(dag, DAGBackend(basis))
dag = dag_unroller.expand_gates()
# Change cx directions
dag = direction_mapper(dag, coupling)
# Simplify cx gates
cx_cancellation(dag)
# Simplify single qubit gates
dag = optimize_1q_gates(dag)
return_last_measurements(dag, removed_meas, last_layout)
logger.info("post-mapping properties: %s", dag.property_summary())
# choose output format
# TODO: do we need all of these formats, or just the dag?
if format == 'dag':
compiled_circuit = dag
elif format == 'json':
# FIXME: JsonBackend is wrongly taking an ordered dict as basis, not list
dag_unroller = DagUnroller(dag, JsonBackend(dag.basis))
compiled_circuit = dag_unroller.execute()
elif format == 'qasm':
compiled_circuit = dag.qasm()
else:
raise TranspilerError('unrecognized circuit format')
if get_layout:
return compiled_circuit, final_layout
return compiled_circuit
def optimize_1q_gates(circuit):
"""Simplify runs of single qubit gates in the QX basis.
Return a new circuit that has been optimized.
"""
qx_basis = ["u1", "u2", "u3", "cx", "id"]
dag_unroller = DagUnroller(circuit, DAGBackend(qx_basis))
unrolled = dag_unroller.expand_gates()
runs = unrolled.collect_runs(["u1", "u2", "u3", "id"])
for run in runs:
qname = unrolled.multi_graph.node[run[0]]["qargs"][0]
right_name = "u1"
right_parameters = (N(0), N(0), N(0)) # (theta, phi, lambda)
for current_node in run:
nd = unrolled.multi_graph.node[current_node]
assert nd["condition"] is None, "internal error"
assert len(nd["qargs"]) == 1, "internal error"
assert nd["qargs"][0] == qname, "internal error"
left_name = nd["name"]
assert left_name in ["u1", "u2", "u3", "id"], "internal error"
if left_name == "u1":
left_parameters = (N(0), N(0), nd["params"][0])
elif left_name == "u2":
left_parameters = (sympy.pi / 2, nd["params"][0], nd["params"][1])
elif left_name == "u3":
left_parameters = tuple(nd["params"])
else:
left_name = "u1" # replace id with u1
left_parameters = (N(0), N(0), N(0))
# Compose gates
name_tuple = (left_name, right_name)
if name_tuple == ("u1", "u1"):
# u1(lambda1) * u1(lambda2) = u1(lambda1 + lambda2)
right_parameters = (N(0), N(0), right_parameters[2] +
left_parameters[2])
elif name_tuple == ("u1", "u2"):
# u1(lambda1) * u2(phi2, lambda2) = u2(phi2 + lambda1, lambda2)
right_parameters = (sympy.pi / 2, right_parameters[1] +
left_parameters[2], right_parameters[2])
elif name_tuple == ("u2", "u1"):
# u2(phi1, lambda1) * u1(lambda2) = u2(phi1, lambda1 + lambda2)
right_name = "u2"
right_parameters = (sympy.pi / 2, left_parameters[1],
right_parameters[2] + left_parameters[2])
elif name_tuple == ("u1", "u3"):
# u1(lambda1) * u3(theta2, phi2, lambda2) =
# u3(theta2, phi2 + lambda1, lambda2)
right_parameters = (right_parameters[0], right_parameters[1] +
left_parameters[2], right_parameters[2])
elif name_tuple == ("u3", "u1"):
# u3(theta1, phi1, lambda1) * u1(lambda2) =
# u3(theta1, phi1, lambda1 + lambda2)
right_name = "u3"
right_parameters = (left_parameters[0], left_parameters[1],
right_parameters[2] + left_parameters[2])
elif name_tuple == ("u2", "u2"):
# Using Ry(pi/2).Rz(2*lambda).Ry(pi/2) =
# Rz(pi/2).Ry(pi-2*lambda).Rz(pi/2),
# u2(phi1, lambda1) * u2(phi2, lambda2) =
# u3(pi - lambda1 - phi2, phi1 + pi/2, lambda2 + pi/2)
right_name = "u3"
right_parameters = (sympy.pi - left_parameters[2] -
right_parameters[1], left_parameters[1] +
sympy.pi / 2, right_parameters[2] +
sympy.pi / 2)
elif name_tuple[1] == "nop":
right_name = left_name
right_parameters = left_parameters
else:
# For composing u3's or u2's with u3's, use
# u2(phi, lambda) = u3(pi/2, phi, lambda)
# together with the qiskit.mapper.compose_u3 method.
right_name = "u3"
# Evaluate the symbolic expressions for efficiency
left_parameters = tuple(map(lambda x: x.evalf(), list(left_parameters)))
right_parameters = tuple(map(lambda x: x.evalf(), list(right_parameters)))
right_parameters = compose_u3(left_parameters[0],
left_parameters[1],
left_parameters[2],
right_parameters[0],
right_parameters[1],
right_parameters[2])
# Why evalf()? This program:
# OPENQASM 2.0;
# include "qelib1.inc";
# qreg q[2];
# creg c[2];
# u3(0.518016983430947*pi,1.37051598592907*pi,1.36816383603222*pi) q[0];
# u3(1.69867232277986*pi,0.371448347747471*pi,0.461117217930936*pi) q[0];
# u3(0.294319836336836*pi,0.450325871124225*pi,1.46804720442555*pi) q[0];
# measure q -> c;
# took >630 seconds (did not complete) to optimize without
# calling evalf() at all, 19 seconds to optimize calling
# evalf() AFTER compose_u3, and 1 second to optimize
# calling evalf() BEFORE compose_u3.
# 1. Here down, when we simplify, we add f(theta) to lambda to
# correct the global phase when f(theta) is 2*pi. This isn't
# necessary but the other steps preserve the global phase, so
# we continue in that manner.
# 2. The final step will remove Z rotations by 2*pi.
# 3. Note that is_zero is true only if the expression is exactly
# zero. If the input expressions have already been evaluated
# then these final simplifications will not occur.
# TODO After we refactor, we should have separate passes for
# exact and approximate rewriting.
# Y rotation is 0 mod 2*pi, so the gate is a u1
if (right_parameters[0] % (2 * sympy.pi)).is_zero \
and right_name != "u1":
right_name = "u1"
right_parameters = (0, 0, right_parameters[1] +
right_parameters[2] +
right_parameters[0])
# Y rotation is pi/2 or -pi/2 mod 2*pi, so the gate is a u2
if right_name == "u3":
# theta = pi/2 + 2*k*pi
if ((right_parameters[0] - sympy.pi / 2) % (2 * sympy.pi)).is_zero:
right_name = "u2"
right_parameters = (sympy.pi / 2, right_parameters[1],
right_parameters[2] +
(right_parameters[0] - sympy.pi / 2))
# theta = -pi/2 + 2*k*pi
if ((right_parameters[0] + sympy.pi / 2) % (2 * sympy.pi)).is_zero:
right_name = "u2"
right_parameters = (sympy.pi / 2, right_parameters[1] +
sympy.pi, right_parameters[2] -
sympy.pi + (right_parameters[0] +
sympy.pi / 2))
# u1 and lambda is 0 mod 2*pi so gate is nop (up to a global phase)
if right_name == "u1" and (right_parameters[2] % (2 * sympy.pi)).is_zero:
right_name = "nop"
# Simplify the symbolic parameters
right_parameters = tuple(map(sympy.simplify, list(right_parameters)))
# Replace the data of the first node in the run
new_params = []
if right_name == "u1":
new_params = [right_parameters[2]]
if right_name == "u2":
new_params = [right_parameters[1], right_parameters[2]]
if right_name == "u3":
new_params = list(right_parameters)
nx.set_node_attributes(unrolled.multi_graph, name='name',
values={run[0]: right_name})
# params is a list of sympy symbols
nx.set_node_attributes(unrolled.multi_graph, name='params',
values={run[0]: new_params})
# Delete the other nodes in the run
for current_node in run[1:]:
unrolled._remove_op_node(current_node)
if right_name == "nop":
unrolled._remove_op_node(run[0])
return unrolled
def swap_mapper(circuit_graph, coupling_graph,
initial_layout=None,
basis="cx,u1,u2,u3,id", trials=20, seed=None):
"""Map a DAGCircuit onto a CouplingGraph using swap gates.
Args:
circuit_graph (DAGCircuit): input DAG circuit
coupling_graph (CouplingGraph): coupling graph to map onto
initial_layout (dict): dict from qubits of circuit_graph to qubits
of coupling_graph (optional)
basis (str): basis string specifying basis of output DAGCircuit
trials (int): number of trials.
seed (int): initial seed.
Returns:
DAGCircuit: object containing a circuit equivalent to
circuit_graph that respects couplings in coupling_graph, and
a layout dict mapping qubits of circuit_graph into qubits
of coupling_graph. The layout may differ from the initial_layout
if the first layer of gates cannot be executed on the
initial_layout. Finally, returned is the final layer qubit
permutation that is needed to add measurements back in.
Raises:
MapperError: if there was any error during the mapping or with the
parameters.
"""
if circuit_graph.width() > coupling_graph.size():
raise MapperError("Not enough qubits in CouplingGraph")
# Schedule the input circuit
layerlist = list(circuit_graph.layers())
logger.debug("schedule:")
for i, v in enumerate(layerlist):
logger.debug(" %d: %s", i, v["partition"])
if initial_layout is not None:
# Check the input layout
circ_qubits = circuit_graph.get_qubits()
coup_qubits = coupling_graph.get_qubits()
qubit_subset = []
for k, v in initial_layout.items():
qubit_subset.append(v)
if k not in circ_qubits:
raise MapperError("initial_layout qubit %s[%d] not in input "
"DAGCircuit" % (k[0], k[1]))
if v not in coup_qubits:
raise MapperError("initial_layout qubit %s[%d] not in input "
"CouplingGraph" % (v[0], v[1]))
else:
# Supply a default layout
qubit_subset = coupling_graph.get_qubits()
qubit_subset = qubit_subset[0:circuit_graph.width()]
initial_layout = {a: b for a, b in
zip(circuit_graph.get_qubits(), qubit_subset)}
# Find swap circuit to preceed to each layer of input circuit
layout = initial_layout.copy()
layout_max_index = max(map(lambda x: x[1]+1, layout.values()))
# Construct an empty DAGCircuit with one qreg "q"
# and the same set of cregs as the input circuit
dagcircuit_output = DAGCircuit()
dagcircuit_output.add_qreg("q", layout_max_index)
for name, size in circuit_graph.cregs.items():
dagcircuit_output.add_creg(name, size)
# Make a trivial wire mapping between the subcircuits
# returned by swap_mapper_layer_update and the circuit
# we are building
identity_wire_map = {}
for j in range(layout_max_index):
identity_wire_map[("q", j)] = ("q", j)
for name, size in circuit_graph.cregs.items():
for j in range(size):
identity_wire_map[(name, j)] = (name, j)
first_layer = True # True until first layer is output
logger.debug("initial_layout = %s", layout)
# Iterate over layers
for i, layer in enumerate(layerlist):
# Attempt to find a permutation for this layer
success_flag, best_circ, best_d, best_layout, trivial_flag \
= layer_permutation(layer["partition"], layout,
qubit_subset, coupling_graph, trials, seed)
logger.debug("swap_mapper: layer %d", i)
logger.debug("swap_mapper: success_flag=%s,best_d=%s,trivial_flag=%s",
success_flag, str(best_d), trivial_flag)
# If this fails, try one gate at a time in this layer
if not success_flag:
logger.debug("swap_mapper: failed, layer %d, "
"retrying sequentially", i)
serial_layerlist = list(layer["graph"].serial_layers())
# Go through each gate in the layer
for j, serial_layer in enumerate(serial_layerlist):
success_flag, best_circ, best_d, best_layout, trivial_flag \
= layer_permutation(serial_layer["partition"],
layout, qubit_subset, coupling_graph,
trials, seed)
logger.debug("swap_mapper: layer %d, sublayer %d", i, j)
logger.debug("swap_mapper: success_flag=%s,best_d=%s,"
"trivial_flag=%s",
success_flag, str(best_d), trivial_flag)
# Give up if we fail again
if not success_flag:
raise MapperError("swap_mapper failed: " +
"layer %d, sublayer %d" % (i, j) +
", \"%s\"" %
serial_layer["graph"].qasm(
no_decls=True,
aliases=layout))
# If this layer is only single-qubit gates,
# and we have yet to see multi-qubit gates,
# continue to the next inner iteration
if trivial_flag and first_layer:
logger.debug("swap_mapper: skip to next sublayer")
continue
# Update the record of qubit positions for each inner iteration
layout = best_layout
# Update the QASM
dagcircuit_output.compose_back(
swap_mapper_layer_update(j,
first_layer,
best_layout,
best_d,
best_circ,
serial_layerlist),
identity_wire_map)
# Update initial layout
if first_layer:
initial_layout = layout
first_layer = False
else:
# Update the record of qubit positions for each iteration
layout = best_layout
# Update the QASM
dagcircuit_output.compose_back(
swap_mapper_layer_update(i,
first_layer,
best_layout,
best_d,
best_circ,
layerlist),
identity_wire_map)
# Update initial layout
if first_layer:
initial_layout = layout
first_layer = False
# This is the final layout that we need to correctly replace
# any measurements that needed to be removed before the swap
last_layout = layout
# If first_layer is still set, the circuit only has single-qubit gates
# so we can use the initial layout to output the entire circuit
if first_layer:
layout = initial_layout
for i, layer in enumerate(layerlist):
dagcircuit_output.compose_back(layer["graph"], layout)
# Parse openqasm_output into DAGCircuit object
dag_unrrolled = DagUnroller(dagcircuit_output,
DAGBackend(basis.split(",")))
dagcircuit_output = dag_unrrolled.expand_gates()
return dagcircuit_output, initial_layout, last_layout
def transpile(dag_circuit,
basis_gates='u1,u2,u3,cx,id',
coupling_map=None,
initial_layout=None,
get_layout=False,
format='dag',
seed=None,
pass_manager=None):
"""Transform a dag circuit into another dag circuit (transpile), through
consecutive passes on the dag.
Args:
dag_circuit (DAGCircuit): dag circuit to transform via transpilation
basis_gates (str): a comma seperated string for the target basis gates
coupling_map (list): A graph of coupling::
[
[control0(int), target0(int)],
[control1(int), target1(int)],
]
eg. [[0, 2], [1, 2], [1, 3], [3, 4]}
initial_layout (dict): A mapping of qubit to qubit::
{
("q", start(int)): ("q", final(int)),
...
}
eg.
{
("q", 0): ("q", 0),
("q", 1): ("q", 1),
("q", 2): ("q", 2),
("q", 3): ("q", 3)
}
get_layout (bool): flag for returning the layout
format (str): The target format of the compilation:
{'dag', 'json', 'qasm'}
seed (int): random seed for simulators
pass_manager (PassManager): pass manager instance for the tranpilation process
If None, a default set of passes are run.
Otherwise, the passes defined in it will run.
If contains no passes in it, no dag transformations occur.
Returns:
object: If get_layout == False, the compiled circuit in the specified
format. If get_layout == True, a tuple is returned, with the
second element being the layout.
Raises:
TranspilerError: if the format is not valid.
"""
final_layout = None
if pass_manager:
# run the passes specified by the pass manager
for pass_ in pass_manager.passes():
pass_.run(dag_circuit)
else:
# default set of passes
# TODO: move each step here to a pass, and use a default passmanager below
basis = basis_gates.split(',') if basis_gates else []
dag_unroller = DagUnroller(dag_circuit, DAGBackend(basis))
dag_circuit = dag_unroller.expand_gates()
# if a coupling map is given compile to the map
if coupling_map:
logger.info("pre-mapping properties: %s",
dag_circuit.property_summary())
# Insert swap gates
coupling = Coupling(coupling_list2dict(coupling_map))
logger.info("initial layout: %s", initial_layout)
dag_circuit, final_layout = swap_mapper(dag_circuit,
coupling,
initial_layout,
trials=20,
seed=seed)
logger.info("final layout: %s", final_layout)
# Expand swaps
dag_unroller = DagUnroller(dag_circuit, DAGBackend(basis))
dag_circuit = dag_unroller.expand_gates()
# Change cx directions
dag_circuit = direction_mapper(dag_circuit, coupling)
# Simplify cx gates
cx_cancellation(dag_circuit)
# Simplify single qubit gates
dag_circuit = optimize_1q_gates(dag_circuit)
logger.info("post-mapping properties: %s",
dag_circuit.property_summary())
# choose output format
# TODO: do we need all of these formats, or just the dag?
if format == 'dag':
compiled_circuit = dag_circuit
elif format == 'json':
# FIXME: JsonBackend is wrongly taking an ordered dict as basis, not list
dag_unroller = DagUnroller(dag_circuit, JsonBackend(dag_circuit.basis))
compiled_circuit = dag_unroller.execute()
elif format == 'qasm':
compiled_circuit = dag_circuit.qasm()
else:
raise TranspilerError('unrecognized circuit format')
if get_layout:
return compiled_circuit, final_layout
return compiled_circuit
def compile(quantum_circuit, basis_gates='u1,u2,u3,cx,id', coupling_map=None,
initial_layout=None, get_layout=False, format='dag'):
"""Compile the circuit.
This builds the internal "to execute" list which is list of quantum
circuits to run on different backends.
Args:
quantum_circuit (QuantumCircuit): circuit to compile
basis_gates (str): a comma seperated string and are the base gates,
which by default are: u1,u2,u3,cx,id
coupling_map (list): A graph of coupling::
[
[control0(int), target0(int)],
[control1(int), target1(int)],
]
eg. [[0, 2], [1, 2], [1, 3], [3, 4]}
initial_layout (dict): A mapping of qubit to qubit::
{
("q", start(int)): ("q", final(int)),
...
}
eg.
{
("q", 0): ("q", 0),
("q", 1): ("q", 1),
("q", 2): ("q", 2),
("q", 3): ("q", 3)
}
get_layout (bool): flag for returning the layout.
format (str): The target format of the compilation:
{'dag', 'json', 'qasm'}
Returns:
object: If get_layout == False, the compiled circuit in the specified
format. If get_layout == True, a tuple is returned, with the
second element being the layout.
Raises:
QISKitCompilerError: if the format is not valid.
"""
compiled_dag_circuit = DAGCircuit.fromQuantumCircuit(quantum_circuit)
basis = basis_gates.split(',') if basis_gates else []
dag_unroller = DagUnroller(compiled_dag_circuit, DAGBackend(basis))
compiled_dag_circuit = dag_unroller.expand_gates()
final_layout = None
# if a coupling map is given compile to the map
if coupling_map:
logger.info("pre-mapping properties: %s",
compiled_dag_circuit.property_summary())
# Insert swap gates
coupling = mapper.Coupling(mapper.coupling_list2dict(coupling_map))
logger.info("initial layout: %s", initial_layout)
compiled_dag_circuit, final_layout = mapper.swap_mapper(
compiled_dag_circuit, coupling, initial_layout, trials=20, seed=13)
logger.info("final layout: %s", final_layout)
# Expand swaps
dag_unroller = DagUnroller(compiled_dag_circuit, DAGBackend(basis))
compiled_dag_circuit = dag_unroller.expand_gates()
# Change cx directions
compiled_dag_circuit = mapper.direction_mapper(compiled_dag_circuit, coupling)
# Simplify cx gates
mapper.cx_cancellation(compiled_dag_circuit)
# Simplify single qubit gates
compiled_dag_circuit = mapper.optimize_1q_gates(compiled_dag_circuit)
logger.info("post-mapping properties: %s",
compiled_dag_circuit.property_summary())
# choose output format
if format == 'dag':
compiled_circuit = compiled_dag_circuit
elif format == 'json':
dag_unroller = DagUnroller(compiled_dag_circuit,
JsonBackend(list(compiled_dag_circuit.basis.keys())))
compiled_circuit = dag_unroller.execute()
elif format == 'qasm':
compiled_circuit = compiled_dag_circuit.qasm()
else:
raise QISKitCompilerError('unrecognized circuit format')
if get_layout:
return compiled_circuit, final_layout
return compiled_circuit
