PassManager

PassManager.append(passes, max_iteration=None, **flow_controller_conditions)

Append a Pass Set to the schedule of passes.

Parameters

• passes (Union[BasePass, List[BasePass]]) – A set of passes (a pass set) to be added to schedule. A pass set is a list of passes that are controlled by the same flow controller. If a single pass is provided, the pass set will only have that pass a single element. It is also possible to append a FlowController instance and the rest of the parameter will be ignored.
• max_iteration (Optional[int]) – max number of iterations of passes.
• flow_controller_conditions (Any) – control flow plugins.

Raises

TranspilerError – if a pass in passes is not a proper pass.

Return type

None

PassManager.draw(filename=None, style=None, raw=False)

Draw the pass manager.

This function needs pydot, which in turn needs Graphviz to be installed.

Parameters

• filename (str) – file path to save image to.
• style (dict) – keys are the pass classes and the values are the colors to make them. An example can be seen in the DEFAULT_STYLE. An ordered dict can be used to ensure a priority coloring when pass falls into multiple categories. Any values not included in the provided dict will be filled in from the default dict.
• raw (bool) – If True, save the raw Dot output instead of the image.

Returns

an in-memory representation of the pass manager, or None if no image was generated or Pillow is not installed.

Return type

Optional[PassManager]

Raises

ImportError – when nxpd or pydot not installed.

PassManager.passes()

Return a list structure of the appended passes and its options.

Return type

List[Dict[str, BasePass]]

Returns

A list of pass sets, as defined in append().

PassManager.remove(index)

Removes a particular pass in the scheduler.

Parameters

index (int) – Pass index to replace, based on the position in passes().

Raises

TranspilerError – if the index is not found.

Return type

None

PassManager.replace(index, passes, max_iteration=None, **flow_controller_conditions)

Replace a particular pass in the scheduler.

Parameters

• index (int) – Pass index to replace, based on the position in passes().
• passes (Union[BasePass, List[BasePass]]) – A pass set (as defined in qiskit.transpiler.PassManager.append()) to be added to the pass manager schedule.
• max_iteration (Optional[int]) – max number of iterations of passes.
• flow_controller_conditions (Any) – control flow plugins.

Raises

TranspilerError – if a pass in passes is not a proper pass or index not found.

Return type

None

PassManager.run(circuits, output_name=None, callback=None)

Run all the passes on the specified circuits.

Parameters

• circuits (Union[QuantumCircuit, List[QuantumCircuit]]) – Circuit(s) to transform via all the registered passes.

• output_name (Optional[str]) – The output circuit name. If None, it will be set to the same as the input circuit name.

• callback (Optional[Callable]) –

  A callback function that will be called after each pass execution. The function will be called with 5 keyword arguments:

  pass_ (Pass): the pass being run
  dag (DAGCircuit): the dag output of the pass
  time (float): the time to execute the pass
  property_set (PropertySet): the property set
  count (int): the index for the pass execution

  The exact arguments pass expose the internals of the pass manager and are subject to change as the pass manager internals change. If you intend to reuse a callback function over multiple releases be sure to check that the arguments being passed are the same.

  To use the callback feature you define a function that will take in kwargs dict and access the variables. For example:

  def callback_func(**kwargs):
      pass_ = kwargs['pass_']
      dag = kwargs['dag']
      time = kwargs['time']
      property_set = kwargs['property_set']
      count = kwargs['count']
      ...

Return type

Union[QuantumCircuit, List[QuantumCircuit]]

Returns

The transformed circuit(s).