---
title: PassManager (v0.46)
description: API reference for qiskit.transpiler.PassManager in qiskit v0.46
source: https://eu-de.quantum.cloud.ibm.com/docs/en/api/qiskit/0.46/qiskit.transpiler.PassManager
---

# PassManager

*class* `qiskit.transpiler.PassManager(passes=(), max_iteration=1000)`

[GitHub](https://github.com/qiskit/qiskit/tree/stable/0.46/qiskit/transpiler/passmanager.py)

Bases: [`BasePassManager`](/docs/api/qiskit/0.46/qiskit.passmanager.BasePassManager "qiskit.passmanager.passmanager.BasePassManager")

Manager for a set of Passes and their scheduling during transpilation.

Initialize an empty pass manager object.

**Parameters**

- **passes** (*Task |* [*list*](https://docs.python.org/3/library/stdtypes.html#list)*\[Task]*) – A pass set to be added to the pass manager schedule.
- **max\_iteration** ([*int*](https://docs.python.org/3/library/functions.html#int)) – The maximum number of iterations the schedule will be looped if the condition is not met.

## Methods

### append

`append(passes, max_iteration=None, **flow_controller_conditions)`

Append a Pass Set to the schedule of passes.

> **Deprecated since version 0.45**
>
> Creating flow controllers with `flow_controller_conditions` keyword arguments was deprecated. Instead, you must explicitly instantiate a controller and set the controller to `passes` argument.

> **Deprecated since version 0.46**
>
> `qiskit.transpiler.passmanager.PassManager.append()`’s argument `max_iteration` is deprecated as of qiskit 0.46. It will be removed in the 1.0 release. ‘max\_iteration’ can be set in the constructor.

**Parameters**

- **passes** (*Task |* [*list*](https://docs.python.org/3/library/stdtypes.html#list)*\[Task]*) – 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 `BaseFlowController` instance and the rest of the parameter will be ignored.

- **max\_iteration** ([*int*](https://docs.python.org/3/library/functions.html#int)) – max number of iterations of passes.

- **flow\_controller\_conditions** (*Any*) –

  Dictionary of control flow plugins. Following built-in controllers are available by default:

  - do\_while: The passes repeat until the callable returns False. Corresponds to [`DoWhileController`](/docs/api/qiskit/0.46/qiskit.passmanager.DoWhileController "qiskit.passmanager.DoWhileController").
  - condition: The passes run only if the callable returns True. Corresponds to [`ConditionalController`](/docs/api/qiskit/0.46/qiskit.passmanager.ConditionalController "qiskit.passmanager.ConditionalController").

  In general, you have more control simply by creating the controller you want and passing it to [`append()`](#qiskit.transpiler.PassManager.append "qiskit.transpiler.PassManager.append").

**Raises**

[**TranspilerError**](/docs/api/qiskit/0.46/transpiler#qiskit.transpiler.TranspilerError "qiskit.transpiler.TranspilerError") – if a pass in passes is not a proper pass.

### draw

`draw(filename=None, style=None, raw=False)`

Draw the pass manager.

This function needs [pydot](https://github.com/erocarrera/pydot), which in turn needs [Graphviz](https://www.graphviz.org/) to be installed.

**Parameters**

- **filename** ([*str*](https://docs.python.org/3/library/stdtypes.html#str)) – file path to save image to.
- **style** ([*dict*](https://docs.python.org/3/library/stdtypes.html#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*](https://docs.python.org/3/library/functions.html#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](https://pypi.org/project/Pillow/) is not installed.

**Return type**

Optional\[[PassManager](#qiskit.transpiler.PassManager "qiskit.transpiler.PassManager")]

**Raises**

[**ImportError**](https://docs.python.org/3/library/exceptions.html#ImportError) – when nxpd or pydot not installed.

### passes

`passes()`

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

> **Deprecated since version 0.46**
>
> The method `qiskit.transpiler.passmanager.PassManager.passes()` is deprecated as of qiskit 0.46. It will be removed in the 1.0 release. Use .to\_flow\_controller().tasks instead. This returns a sequence of linearized base task instances in tuple format.

**Returns**

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

**Return type**

[list](https://docs.python.org/3/library/stdtypes.html#list)\[[dict](https://docs.python.org/3/library/stdtypes.html#dict)\[[str](https://docs.python.org/3/library/stdtypes.html#str), qiskit.transpiler.basepasses.BasePass]]

### remove

`remove(index)`

Removes a particular pass in the scheduler.

**Parameters**

**index** ([*int*](https://docs.python.org/3/library/functions.html#int)) – Pass index to remove, based on the position in [`passes()`](/docs/api/qiskit/0.46/transpiler_passes#module-qiskit.transpiler.passes "qiskit.transpiler.passes").

**Raises**

[**PassManagerError**](/docs/api/qiskit/0.46/passmanager#qiskit.passmanager.PassManagerError "qiskit.passmanager.PassManagerError") – If the index is not found.

### replace

`replace(index, passes, max_iteration=None, **flow_controller_conditions)`

Replace a particular pass in the scheduler.

> **Deprecated since version 0.45**
>
> Creating flow controllers with `flow_controller_conditions` keyword arguments was deprecated. Instead, you must explicitly instantiate a controller and set the controller to `passes` argument.

> **Deprecated since version 0.46**
>
> `qiskit.transpiler.passmanager.PassManager.replace()`’s argument `max_iteration` is deprecated as of qiskit 0.46. It will be removed in the 1.0 release. ‘max\_iteration’ can be set in the constructor.

**Parameters**

- **index** ([*int*](https://docs.python.org/3/library/functions.html#int)) – Pass index to replace, based on the position in passes().
- **passes** (*Task |* [*list*](https://docs.python.org/3/library/stdtypes.html#list)*\[Task]*) – A pass set to be added to the pass manager schedule.
- **max\_iteration** ([*int*](https://docs.python.org/3/library/functions.html#int)) – max number of iterations of passes.
- **flow\_controller\_conditions** (*Any*) – Dictionary of control flow plugins. See [`qiskit.transpiler.PassManager.append()`](#qiskit.transpiler.PassManager.append "qiskit.transpiler.PassManager.append") for details.

### run

`run(circuits, output_name=None, callback=None)`

Run all the passes on the specified `circuits`.

**Parameters**

- **circuits** (*\_CircuitsT*) – Circuit(s) to transform via all the registered passes.

- **output\_name** ([*str*](https://docs.python.org/3/library/stdtypes.html#str) *| None*) – The output circuit name. If `None`, it will be set to the same as the input circuit name.

- **callback** (*Callable*) –

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

  ```python
  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
  ```

  > **Note**
  >
  > Beware that the keyword arguments here are different to those used by the generic [`BasePassManager`](/docs/api/qiskit/0.46/qiskit.passmanager.BasePassManager "qiskit.passmanager.BasePassManager"). This pass manager will translate those arguments into the form described above.

  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:

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

**Returns**

The transformed circuit(s).

**Return type**

\_CircuitsT

### to\_flow\_controller

`to_flow_controller()`

Linearize this manager into a single [`FlowControllerLinear`](/docs/api/qiskit/0.46/qiskit.passmanager.FlowControllerLinear "qiskit.passmanager.FlowControllerLinear"), so that it can be nested inside another pass manager.

**Returns**

A linearized pass manager.

**Return type**

*RunningPassManager*