---
title: utils (latest version)
description: API reference for qiskit_fermions.transpiler.passes.utils in the latest version of qiskit-fermions
source: https://eu-de.quantum.cloud.ibm.com/docs/en/api/qiskit-fermions/transpiler-passes-utils
---

# Transpiler Pass Utilities

Several convenience functions are provided to simplify the implementation of common operations during the implementation of custom transpiler passes.

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| [`map_node_single_register`](/docs/api/qiskit-fermions/transpiler-passes-utils-map-node-single-register#qiskit_fermions.transpiler.passes.utils.map_node_single_register "qiskit_fermions.transpiler.passes.utils.map_node_single_register")(in\_node, f2q\_layout) | Map the single fermionic mode register acted upon by the circuit operation. |