---
title: UnrollCustomDefinitions (v2.3)
description: API reference for qiskit.transpiler.passes.UnrollCustomDefinitions in qiskit v2.3
source: https://eu-de.quantum.cloud.ibm.com/docs/en/api/qiskit/2.3/qiskit.transpiler.passes.UnrollCustomDefinitions
---

# UnrollCustomDefinitions

*class* `qiskit.transpiler.passes.UnrollCustomDefinitions(*args, **kwargs)`

[GitHub](https://github.com/Qiskit/qiskit/tree/stable/2.3/qiskit/transpiler/passes/basis/unroll_custom_definitions.py#L22-L110)

Bases: [`TransformationPass`](/docs/api/qiskit/2.3/qiskit.transpiler.TransformationPass "qiskit.transpiler.basepasses.TransformationPass")

Unrolls instructions with custom definitions.

Unrolls instructions with custom definitions.

**Parameters**

- **equivalence\_library** ([*EquivalenceLibrary*](/docs/api/qiskit/2.3/qiskit.circuit.EquivalenceLibrary "qiskit.circuit.EquivalenceLibrary")) – The equivalence library which will be used by the BasisTranslator pass. (Instructions in this library will not be unrolled by this pass.)

- **basis\_gates** (*Optional\[*[*list*](https://docs.python.org/3/library/stdtypes.html#list)*\[*[*str*](https://docs.python.org/3/library/stdtypes.html#str)*]]*) – Target basis names to unroll to, e.g. `['u3', 'cx']`. Ignored if `target` is also specified.

- **target** (*Optional\[*[*Target*](/docs/api/qiskit/2.3/qiskit.transpiler.Target "qiskit.transpiler.Target")*]*) –

  **The [`Target`](/docs/api/qiskit/2.3/qiskit.transpiler.Target "qiskit.transpiler.Target") object corresponding to the compilation**

  target. When specified, any argument specified for `basis_gates` is ignored.

  **min\_qubits (int): The minimum number of qubits for operations in the input**

  dag to translate.

## Attributes

### is\_analysis\_pass

Check if the pass is an analysis pass.

If the pass is an AnalysisPass, that means that the pass can analyze the DAG and write the results of that analysis in the property set. Modifications on the DAG are not allowed by this kind of pass.

### is\_transformation\_pass

Check if the pass is a transformation pass.

If the pass is a TransformationPass, that means that the pass can manipulate the DAG, but cannot modify the property set (but it can be read).

## Methods

### execute

`execute(passmanager_ir, state, callback=None)`

[GitHub](https://github.com/Qiskit/qiskit/tree/stable/2.3/qiskit/transpiler/basepasses.py#L161-L180)

Execute optimization task for input Qiskit IR.

**Parameters**

- **passmanager\_ir** ([*Any*](https://docs.python.org/3/library/typing.html#typing.Any)) – Qiskit IR to optimize.
- **state** ([*PassManagerState*](/docs/api/qiskit/2.3/qiskit.passmanager.PassManagerState "qiskit.passmanager.compilation_status.PassManagerState")) – State associated with workflow execution by the pass manager itself.
- **callback** ([*Callable*](https://docs.python.org/3/library/collections.abc.html#collections.abc.Callable) *| None*) – A callback function which is called per execution of optimization task.

**Returns**

Optimized Qiskit IR and state of the workflow.

**Return type**

[tuple](https://docs.python.org/3/library/stdtypes.html#tuple)\[[*Any*](https://docs.python.org/3/library/typing.html#typing.Any), [qiskit.passmanager.compilation\_status.PassManagerState](/docs/api/qiskit/2.3/qiskit.passmanager.PassManagerState "qiskit.passmanager.compilation_status.PassManagerState")]

### name

`name()`

[GitHub](https://github.com/Qiskit/qiskit/tree/stable/2.3/qiskit/passmanager/base_tasks.py#L68-L70)

Name of the pass.

**Return type**

[str](https://docs.python.org/3/library/stdtypes.html#str)

### run

`run(dag)`

[GitHub](https://github.com/Qiskit/qiskit/tree/stable/2.3/qiskit/transpiler/passes/basis/unroll_custom_definitions.py#L46-L110)

Run the UnrollCustomDefinitions pass on dag.

**Parameters**

**dag** ([*DAGCircuit*](/docs/api/qiskit/2.3/qiskit.dagcircuit.DAGCircuit "qiskit.dagcircuit.DAGCircuit")) – input dag

**Raises**

- [**QiskitError**](/docs/api/qiskit/2.3/exceptions#qiskit.exceptions.QiskitError "qiskit.exceptions.QiskitError") – if unable to unroll given the basis due to undefined
- **decomposition rules**\*\* (****such as a bad basis****) or \*\***excessive recursion.** –

**Returns**

output unrolled dag

**Return type**

[DAGCircuit](/docs/api/qiskit/2.3/qiskit.dagcircuit.DAGCircuit "qiskit.dagcircuit.DAGCircuit")

### update\_status

`update_status(state, run_state)`

[GitHub](https://github.com/Qiskit/qiskit/tree/stable/2.3/qiskit/transpiler/basepasses.py#L182-L190)

Update workflow status.

**Parameters**

- **state** ([*PassManagerState*](/docs/api/qiskit/2.3/qiskit.passmanager.PassManagerState "qiskit.passmanager.compilation_status.PassManagerState")) – Pass manager state to update.
- **run\_state** (*RunState*) – Completion status of current task.

**Returns**

Updated pass manager state.

**Return type**

[*PassManagerState*](/docs/api/qiskit/2.3/qiskit.passmanager.PassManagerState "qiskit.passmanager.compilation_status.PassManagerState")