---
title: Optimize1qGates (v2.1)
description: API reference for qiskit.transpiler.passes.Optimize1qGates in qiskit v2.1
source: https://quantum.cloud.ibm.com/docs/en/api/qiskit/2.1/qiskit.transpiler.passes.Optimize1qGates
---

# Optimize1qGates

*class* `qiskit.transpiler.passes.Optimize1qGates(*args, **kwargs)`

[GitHub](https://github.com/Qiskit/qiskit/tree/stable/2.1/qiskit/transpiler/passes/optimization/optimize_1q_gates.py#L34-L364)

Bases: [`TransformationPass`](/docs/api/qiskit/2.1/qiskit.transpiler.TransformationPass "qiskit.transpiler.basepasses.TransformationPass")

Optimize chains of single-qubit u1, u2, u3 gates by combining them into a single gate.

Optimize1qGates initializer.

**Parameters**

- **basis** ([*list*](https://docs.python.org/3/library/stdtypes.html#list)*\[*[*str*](https://docs.python.org/3/library/stdtypes.html#str)*]*) – Basis gates to consider, e.g. \[‘u3’, ‘cx’]. For the effects of this pass, the basis is the set intersection between the basis parameter and the set \{‘u1’,’u2’,’u3’, ‘u’, ‘p’}.
- **eps** ([*float*](https://docs.python.org/3/library/functions.html#float)) – EPS to check against
- **target** ([*Target*](/docs/api/qiskit/2.1/qiskit.transpiler.Target "qiskit.transpiler.Target")) – The [`Target`](/docs/api/qiskit/2.1/qiskit.transpiler.Target "qiskit.transpiler.Target") representing the target backend, if both `basis` and `target` are specified then this argument will take precedence and `basis` will be ignored.

## 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

### compose\_u3

*static* `compose_u3(theta1, phi1, lambda1, theta2, phi2, lambda2)`

[GitHub](https://github.com/Qiskit/qiskit/tree/stable/2.1/qiskit/transpiler/passes/optimization/optimize_1q_gates.py#L326-L339)

Return a triple theta, phi, lambda for the product.

**u3(theta, phi, lambda)**

\= u3(theta1, phi1, lambda1).u3(theta2, phi2, lambda2) = Rz(phi1).Ry(theta1).Rz(lambda1+phi2).Ry(theta2).Rz(lambda2) = Rz(phi1).Rz(phi’).Ry(theta’).Rz(lambda’).Rz(lambda2) = u3(theta’, phi1 + phi’, lambda2 + lambda’)

Return theta, phi, lambda.

### execute

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

[GitHub](https://github.com/Qiskit/qiskit/tree/stable/2.1/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/2.1/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 caller 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/2.1/qiskit.passmanager.PassManagerState "qiskit.passmanager.compilation_status.PassManagerState")]

### name

`name()`

[GitHub](https://github.com/Qiskit/qiskit/tree/stable/2.1/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/2.1/qiskit/transpiler/passes/optimization/optimize_1q_gates.py#L54-L324)

Run the Optimize1qGates pass on dag.

**Parameters**

**dag** ([*DAGCircuit*](/docs/api/qiskit/2.1/qiskit.dagcircuit.DAGCircuit "qiskit.dagcircuit.DAGCircuit")) – the DAG to be optimized.

**Returns**

the optimized DAG.

**Return type**

[DAGCircuit](/docs/api/qiskit/2.1/qiskit.dagcircuit.DAGCircuit "qiskit.dagcircuit.DAGCircuit")

**Raises**

[**TranspilerError**](/docs/api/qiskit/2.1/transpiler#qiskit.transpiler.TranspilerError "qiskit.transpiler.TranspilerError") – if `YZY` and `ZYZ` angles do not give same rotation matrix.

### update\_status

`update_status(state, run_state)`

[GitHub](https://github.com/Qiskit/qiskit/tree/stable/2.1/qiskit/transpiler/basepasses.py#L182-L190)

Update workflow status.

**Parameters**

- **state** ([*PassManagerState*](/docs/api/qiskit/2.1/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/2.1/qiskit.passmanager.PassManagerState "qiskit.passmanager.compilation_status.PassManagerState")

### yzy\_to\_zyz

*static* `yzy_to_zyz(xi, theta1, theta2, eps=1e-09)`

[GitHub](https://github.com/Qiskit/qiskit/tree/stable/2.1/qiskit/transpiler/passes/optimization/optimize_1q_gates.py#L341-L364)

Express a Y.Z.Y single qubit gate as a Z.Y.Z gate.

Solve the equation

$$
$$

Ry(theta1).Rz(xi).Ry(theta2) = Rz(phi).Ry(theta).Rz(lambda)

for theta, phi, and lambda.

Return a solution theta, phi, and lambda.