QUBIKOS – QUantum Benchmark wIth Known-Optimal SWAP Counts

QUBIKOS is a benchmarking tool designed to evaluate quantum layout synthesis tools by generating quantum circuits with a known optimal number of SWAP operations.

📌 Overview

QUBIKOS generates benchmark circuits that respect a given hardware topology and ensure the minimal number of SWAP gates needed is known. This allows for an accurate assessment of SWAP insertion efficiency in quantum compilers and layout synthesis tools.

⚙️ How to Use

Generate QUBIKOS Benchmark with QUBIKOS.py

To generate a benchmark circuit, provide a device coupling graph — a list of tuples like [(0, 1), (1, 2)], where each number is a physical qubit and each tuple denotes a connection between them. Physical qubits should be labeled from 0 to n-1.

Example

from QUBIKOS import *

benchmark_circuit, compiled_circuit = generate_qubikos_circuit(
    "benchmark.qasm",         # Output QASM file for the benchmark circuit
    "compiled.qasm",          # Output QASM file for the compiled circuit with SWAPs
    [(0, 1), (1, 2)],          # Coupling graph
    2,                         # Known optimal number of SWAPs (minimum is 1)
    50,                        # Number of two-qubit gates
    10                         # Number of single-qubit gates
)

• benchmark.qasm: File where the benchmark circuit will be written.
• compiled.qasm: File for the compiled circuit with inserted SWAP gates.
• Coupling graph: Describes the hardware connectivity.
• The function returns two QuantumCircuit objects (benchmark_circuit and compiled_circuit).

⚠️ Note: If the number of two-qubit gates is too small to satisfy the construction constraints, the output circuit may contain more two-qubit gates than specified.

📄 Citation

If you use QUBIKOS in your research, please cite the following paper:

@misc{ping2025assessingquantumlayoutsynthesis,
      title={Assessing Quantum Layout Synthesis Tools via Known Optimal-SWAP Cost Benchmarks}, 
      author={Shuohao Ping and Wan-Hsuan Lin and Daniel Bochen Tan and Jason Cong},
      year={2025},
      eprint={2502.08839},
      archivePrefix={arXiv},
      primaryClass={quant-ph},
      url={https://arxiv.org/abs/2502.08839}, 
}

🔗 Resources

• arXiv:2502.08839 – Full paper on the QUBIKOS methodology and benchmark analysis.