---
title: MCXSynthesis1CleanB95 (v1.3)
description: API reference for qiskit.transpiler.passes.synthesis.hls_plugins.MCXSynthesis1CleanB95 in qiskit v1.3
source: https://eu-de.quantum.cloud.ibm.com/docs/en/api/qiskit/1.3/qiskit.transpiler.passes.synthesis.hls_plugins.MCXSynthesis1CleanB95
---

# MCXSynthesis1CleanB95

*class* `qiskit.transpiler.passes.synthesis.hls_plugins.MCXSynthesis1CleanB95`

[GitHub](https://github.com/Qiskit/qiskit/tree/stable/1.3/qiskit/transpiler/passes/synthesis/hls_plugins.py#L1027-L1072)

Bases: [`HighLevelSynthesisPlugin`](/docs/api/qiskit/1.3/qiskit.transpiler.passes.synthesis.plugin.HighLevelSynthesisPlugin "qiskit.transpiler.passes.synthesis.plugin.HighLevelSynthesisPlugin")

Synthesis plugin for a multi-controlled X gate based on the paper by Barenco et al. (1995).

See \[1] for details.

This plugin name is :`mcx.1_clean_b95` which can be used as the key on an [`HLSConfig`](/docs/api/qiskit/1.3/qiskit.transpiler.passes.HLSConfig "qiskit.transpiler.passes.HLSConfig") object to use this method with [`HighLevelSynthesis`](/docs/api/qiskit/1.3/qiskit.transpiler.passes.HighLevelSynthesis "qiskit.transpiler.passes.HighLevelSynthesis").

For a multi-controlled X gate with $k\ge 5$ control qubits this synthesis method requires a single additional clean auxiliary qubit. The synthesized circuit consists of $k + 2$ qubits and at most $16 * k - 8$ CX gates.

The plugin supports the following plugin-specific options:

- num\_clean\_ancillas: The number of clean auxiliary qubits available.

**References**

1. Barenco et. al., Phys.Rev. A52 3457 (1995), [arXiv:quant-ph/9503016](https://arxiv.org/abs/quant-ph/9503016)

## Methods

### run

`run(high_level_object, coupling_map=None, target=None, qubits=None, **options)`

[GitHub](https://github.com/Qiskit/qiskit/tree/stable/1.3/qiskit/transpiler/passes/synthesis/hls_plugins.py#L1049-L1072)

Run synthesis for the given MCX gate.