def transpile_dag(dag,
basis_gates=None,
coupling_map=None,
initial_layout=None,
seed_mapper=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 (list[str]): list of basis gate names supported by the
target. Default: ['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)
}
seed_mapper (int): random seed_mapper 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
"""
# TODO: `basis_gates` will be removed after we have the unroller pass.
# TODO: `coupling_map`, `initial_layout`, `seed_mapper` removed after mapper pass.
# TODO: move this to the mapper pass
num_qubits = sum([qreg.size for qreg in dag.qregs.values()])
if num_qubits == 1 or coupling_map == "all-to-all":
coupling_map = None
if basis_gates is None:
basis_gates = ['u1', 'u2', 'u3', 'cx', 'id']
if isinstance(basis_gates, str):
warnings.warn(
"The parameter basis_gates is now a list of strings. "
"For example, this basis ['u1','u2','u3','cx'] should be used "
"instead of 'u1,u2,u3,cx'. The string format will be "
"removed after 0.9", DeprecationWarning, 2)
basis_gates = basis_gates.split(',')
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
name = dag.name
dag = Unroller(basis_gates).run(dag)
dag = BarrierBeforeFinalMeasurements().run(dag)
# if a coupling map is given compile to the map
if coupling_map:
logger.info("pre-mapping properties: %s", dag.properties())
# Insert swap gates
coupling = CouplingMap(coupling_map)
logger.info("initial layout: %s", initial_layout)
dag, final_layout = swap_mapper(dag,
coupling,
initial_layout,
trials=20,
seed=seed_mapper)
logger.info("final layout: %s", final_layout)
# Expand swaps
dag = Decompose(SwapGate).run(dag)
# Change cx directions
dag = CXDirection(coupling).run(dag)
# Simplify cx gates
dag = CXCancellation().run(dag)
# Unroll to the basis
dag = Unroller(['u1', 'u2', 'u3', 'id', 'cx']).run(dag)
# Simplify single qubit gates
dag = Optimize1qGates().run(dag)
logger.info("post-mapping properties: %s", dag.properties())
dag.name = name
return dag
def transpile_dag(dag,
basis_gates=None,
coupling_map=None,
initial_layout=None,
seed_mapper=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 (list[str]): list of basis gate names supported by the
target. Default: ['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 (Layout or None): A layout object
seed_mapper (int): random seed_mapper 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
"""
# TODO: `basis_gates` will be removed after we have the unroller pass.
# TODO: `coupling_map`, `initial_layout`, `seed_mapper` removed after mapper pass.
# TODO: move this to the mapper pass
num_qubits = sum([qreg.size for qreg in dag.qregs.values()])
if num_qubits == 1:
coupling_map = None
if basis_gates is None:
basis_gates = ['u1', 'u2', 'u3', 'cx', 'id']
if isinstance(basis_gates, str):
warnings.warn(
"The parameter basis_gates is now a list of strings. "
"For example, this basis ['u1','u2','u3','cx'] should be used "
"instead of 'u1,u2,u3,cx'. The string format will be "
"removed after 0.9", DeprecationWarning, 2)
basis_gates = basis_gates.split(',')
if initial_layout is None:
initial_layout = Layout.generate_trivial_layout(*dag.qregs.values())
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
name = dag.name
dag = Unroller(basis_gates).run(dag)
dag = BarrierBeforeFinalMeasurements().run(dag)
# if a coupling map is given compile to the map
if coupling_map:
logger.info("pre-mapping properties: %s", dag.properties())
coupling = CouplingMap(coupling_map)
# Extend and enlarge the the dag/layout with ancillas using the full coupling map
logger.info("initial layout: %s", initial_layout)
pass_ = ExtendLayout(coupling)
pass_.property_set['layout'] = initial_layout
pass_.run(dag)
initial_layout = pass_.property_set['layout']
pass_ = EnlargeWithAncilla(initial_layout)
dag = pass_.run(dag)
initial_layout = pass_.property_set['layout']
logger.info("initial layout (ancilla extended): %s",
initial_layout)
# temporarily build old-style layout dict
# (TODO: remove after transition to StochasticSwap pass)
virtual_qubits = initial_layout.get_virtual_bits()
initial_layout = {(v[0].name, v[1]): ('q', initial_layout[v])
for v in virtual_qubits}
# Swap mapper
dag, final_layout = swap_mapper(dag,
coupling,
initial_layout,
trials=20,
seed=seed_mapper)
logger.info("final layout: %s", final_layout)
# Expand swaps
dag = Decompose(SwapGate).run(dag)
# Change cx directions
dag = CXDirection(coupling).run(dag)
# Unroll to the basis
dag = Unroller(['u1', 'u2', 'u3', 'id', 'cx']).run(dag)
# Simplify single qubit gates and CXs
pm_4_optimization = PassManager()
pm_4_optimization.append(
[Optimize1qGates(),
CXCancellation(),
DAGFixedPoint()],
do_while=lambda property_set: not property_set[
'dag_fixed_point'])
dag = transpile_dag(dag, pass_manager=pm_4_optimization)
dag.name = name
return dag