---
title: PropagateLocalPauliNode (latest version)
description: API reference for samplomatic.samplex.nodes.PropagateLocalPauliNode in the latest version of samplomatic
source: https://eu-de.quantum.cloud.ibm.com/docs/en/api/samplomatic/auto/samplex-nodes-propagate-local-pauli-node
---

# PropagateLocalPauliNode

*class* `samplomatic.samplex.nodes.PropagateLocalPauliNode(op_name: str, register_name: str, subsystem_idxs: Sequence[Sequence[int]], *, lookup_table: ndarray | None = None)`

[GitHub](https://github.com/Qiskit/samplomatic/tree/main/samplomatic/samplex/nodes/propagate_local_pauli_node.py#L37-L121)

Bases: [`EvaluationNode`](/docs/api/samplomatic/auto/samplex-nodes-evaluation-node "samplomatic.samplex.nodes.evaluation_node.EvaluationNode")

A node that propagates a Pauli register past a gate.

Only Paulis from the commutant of the gate generators (those that commute with the gate for any angle) are allowed through. Non-commutant Paulis trigger a runtime error.

**Parameters**

- **register\_name** – The name of the Pauli register to propagate.
- **subsystem\_idxs** – The subsystems in the register specified as a 2D array where the left-most axes is over subsystems and the right-most axes is over indices in the subsystem.
- **op\_name** – The name of the gate operation.

**Attributes Summary**

|                                                                                                                                                                                  |                                              |
| -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------- |
| [`outgoing_register_type`](#samplomatic.samplex.nodes.PropagateLocalPauliNode.outgoing_register_type "samplomatic.samplex.nodes.PropagateLocalPauliNode.outgoing_register_type") | The virtual gate type of outgoing registers. |

**Methods Summary**

|                                                                                                                                                         |                                                                                  |
| ------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------- |
| [`evaluate`](#samplomatic.samplex.nodes.PropagateLocalPauliNode.evaluate "samplomatic.samplex.nodes.PropagateLocalPauliNode.evaluate")(registers, \*\_) | Evaluate this node.                                                              |
| [`get_style`](#samplomatic.samplex.nodes.PropagateLocalPauliNode.get_style "samplomatic.samplex.nodes.PropagateLocalPauliNode.get_style")()             | Return the style of this node when plotted.                                      |
| [`reads_from`](#samplomatic.samplex.nodes.PropagateLocalPauliNode.reads_from "samplomatic.samplex.nodes.PropagateLocalPauliNode.reads_from")()          | Return a manifest of which virtual register values this node needs to read from. |
| [`writes_to`](#samplomatic.samplex.nodes.PropagateLocalPauliNode.writes_to "samplomatic.samplex.nodes.PropagateLocalPauliNode.writes_to")()             | Return a manifest of which virtual register values this node needs to write to.  |

**Attributes Documentation**

### outgoing\_register\_type

**Methods Documentation**

### evaluate

`evaluate(registers, *_)`

[GitHub](https://github.com/Qiskit/samplomatic/tree/main/samplomatic/samplex/nodes/propagate_local_pauli_node.py#L76-L88)

Evaluate this node.

**Parameters**

- **registers** – At least those registers needed by this node to read from or write to.
- **parameter\_values** – Parameter values to use during evaluation.

**Raises**

[**SamplexRuntimeError**](/docs/api/samplomatic/auto/exceptions-samplex-runtime-error "samplomatic.exceptions.SamplexRuntimeError") – If the number of parameter values received does not equal the number required by this node.

### get\_style

`get_style()`

[GitHub](https://github.com/Qiskit/samplomatic/tree/main/samplomatic/samplex/nodes/propagate_local_pauli_node.py#L114-L121)

Return the style of this node when plotted.

### reads\_from

`reads_from()`

[GitHub](https://github.com/Qiskit/samplomatic/tree/main/samplomatic/samplex/nodes/propagate_local_pauli_node.py#L90-L96)

Return a manifest of which virtual register values this node needs to read from.

### writes\_to

`writes_to()`

[GitHub](https://github.com/Qiskit/samplomatic/tree/main/samplomatic/samplex/nodes/propagate_local_pauli_node.py#L98-L104)

Return a manifest of which virtual register values this node needs to write to.