Investigating Retargetability Claims for Quantum Compilers

TL;DR

The paper tackles the challenge of retargetability for quantum software across diverse hardware backends in the NISQ era by proposing a multi-dimensional evaluation framework that combines a metric-based assessment with a practical user study. It defines four core metric dimensions—Compilation Strategy Flexibility, Standardization Compliance, Community and Ecosystem Integration, and Device-Agnostic Compiler Architecture—plus a fifth dimension assessing Documentation and API Quality, aggregating results with an equal-weighted scheme: $s_{total} = w_1 s_1 + w_2 s_2 + w_3 s_3 + w_4 s_4 + w_5 s_5$ with $w_i = 0.2$. Applying this methodology to Tket, Qiskit, and ProjectQ, the study finds Tket to have the highest retargetability, followed closely by Qiskit, while ProjectQ lags due to documentation and standardization gaps. These findings provide actionable guidance for quantum software developers in selecting backends and identify concrete areas for improvement in compiler design. The work also proposes an extension to include additional retargetable frameworks such as Weaver as the field standardizes further.

Abstract

In the NISQ-era, there is a wide variety of hardware manufacturers building quantum computers. Each of these companies may choose different approaches and hardware architectures for their machines. This poses a problem for quantum software engineering, as the retargetability of quantum programs across different hardware platforms becomes a non-trivial challenge. In response to this problem, various retargetable quantum compilers have been presented in the scientific literature. These promise the ability to compile software for different hardware platforms, enabling retargetability for quantum software. In this paper, we develop and apply a metric by which the retargetability of the quantum compilers can be assessed. We develop and run a study to analyze key aspects regarding the retargetability of the compilers Tket, Qiskit, and ProjectQ. Our findings indicate that Tket demonstrates the highest level of retargetability, closely followed by Qiskit, while ProjectQ lags behind. These results provide insights for quantum software developers in selecting appropriate compilers for their use-cases, and highlight areas for improvement in quantum compilers.

Figures (1)

• Figure 1: Retargetability scores for all dimensions represented as a spider diagram