Abstract The field of Quantum Computing (QC) is advancing rapidly, introducing new programming paradigms and frameworks. This rapid growth also increases the vulnerability of quantum programs (QPs) to bugs and code smells. Despite considerable research, detecting code smells in QPs remains underexplored. To bridge this gap, this paper presents QUAMET , a novel structural and semantic analysis approach designed to establish software metrics for QPs and detect quantum code smells. Structural analysis examines code structure and program architecture, focusing on rules and patterns essential for identifying code smells. Semantic analysis, utilising quantum circuit analysis and parse trees, explores the meaning of the code. The study used a publicly available LintQ dataset, which contains real-world QPs implemented with Qiskit. After thorough pre-processing, the dataset was refined to extract structural and semantic metrics, resulting in a labelled dataset of 4,102 projects. This dataset is instrumental in identifying six distinct types of code smells, reviewed by industry and academic experts. The dataset and metrics are validated using reviews and classifications, demonstrating significant advancements in detecting quantum code smells. The results highlight the importance of combining structural and semantic analyses to enhance code smell detection accuracy, providing insights into their potential impact on QPs' performance and maintainability.
Abstract The field of Quantum Computing (QC) is advancing rapidly, introducing new programming paradigms and frameworks. This rapid growth also increases the vulnerability of quantum programs (QPs) to bugs and code smells. Despite considerable research, detecting code smells in QPs remains underexplored. To bridge this gap, this paper presents QUAMET , a novel structural and semantic analysis approach designed to establish software metrics for QPs and detect quantum code smells. Structural analysis examines code structure and program architecture, focusing on rules and patterns essential for identifying code smells. Semantic analysis, utilising quantum circuit analysis and parse trees, explores the meaning of the code. The study used a publicly available LintQ dataset, which contains real-world QPs implemented with Qiskit. After thorough pre-processing, the dataset was refined to extract structural and semantic metrics, resulting in a labelled dataset of 4,102 projects. This dataset is instrumental in identifying six distinct types of code smells, reviewed by industry and academic experts. The dataset and metrics are validated using reviews and classifications, demonstrating significant advancements in detecting quantum code smells. The results highlight the importance of combining structural and semantic analyses to enhance code smell detection accuracy, providing insights into their potential impact on QPs' performance and maintainability.
As quantum computing is rising in popularity, the amount of quantum programs and the number of developers writing them are increasing rapidly. Unfortunately, writing correct quantum programs is challenging due to various subtle rules developers need to be aware of. Empirical studies show that 40–82% of all bugs in quantum software are specific to the quantum domain. Yet, existing static bug detection frameworks are mostly unaware of quantum-specific concepts, such as circuits, gates, and qubits, and hence miss many bugs. This paper presents LintQ, a comprehensive static analysis framework for detecting bugs in quantum programs. Our approach is enabled by a set of abstractions designed to reason about common concepts in quantum computing without referring to the details of the underlying quantum computing platform. Built on top of these abstractions, LintQ offers an extensible set of ten analyses that detect likely bugs, such as operating on corrupted quantum states, redundant measurements, and incorrect compositions of sub-circuits. We apply the approach to a newly collected dataset of 7,568 real-world Qiskit-based quantum programs, showing that LintQ effectively identifies various programming problems, with a precision of 91.0% in its default configuration with the six best performing analyses. Comparing to a general-purpose linter and two existing quantum-aware techniques shows that almost all problems (92.1%) found by LintQ during our evaluation are missed by prior work. LintQ hence takes an important step toward reliable software in the growing field of quantum computing.
Quantum Computing (QC) is a fast-growing field that has enhanced the emergence of new programming languages and frameworks. Furthermore, the increased availability of computational resources has also contributed to an influx in the development of quantum programs. Given that classical and QC are significantly different due to the intrinsic nature of quantum programs, several aspects of QC (e.g., performance, bugs) have been investigated, and novel approaches have been proposed. However, from a purely quantum perspective, maintenance, one of the major steps in a software development life-cycle, has not been considered by researchers yet. In this paper, we fill this gap and investigate the prevalence of code smells in quantum programs as an indicator of maintenance issues. We defined eight quantum-specific smells and validated them through a survey with 35 quantum developers. Since no tool specifically aims to detect quantum smells, we developed a tool called QSmell that supports the proposed quantum-specific smells. Finally, we conducted an empirical investigation to analyze the prevalence of quantum-specific smells in 15 open-source quantum programs. Our results showed that 11 programs (73.33%) contain at least one smell and, on average, a program has three smells. Furthermore, the long circuit is the most prevalent smell present in 53.33% of the programs.
Quantum computing has become an active research field in recent years, as its applications in fields such as cryptography, optimization, and materials science are promising. Along with these developments, challenges and opportunities exist in the field of Quantum Software Engineering, as the development of frameworks and higher-level abstractions has attracted practitioners from diverse backgrounds. Unlike initial quantum frameworks based on the circuit model, recent frameworks and libraries leverage higher-level abstractions for creating quantum programs. This paper presents an empirical study of 985 Jupyter Notebooks from 80 open-source projects to investigate how quantum patterns are applied in practice. Our work involved two main stages. First, we built a knowledge base from three quantum computing frameworks (Qiskit, PennyLane, and Classiq). This process led us to identify and document 9 new patterns that refine and extend the existing quantum computing pattern catalog. Second, we developed a reusable semantic search tool to automatically detect these patterns across our large-scale dataset, providing a practitioner-focused analysis. Our results show that developers use patterns in three levels: from foundational circuit utilities, to common algorithmic primitives (e.g., Amplitude Amplification), up to domain-specific applications for finance and optimization. This indicates a maturing field where developers are increasingly using high-level building blocks to solve real-world problems.
Abstract Quantum computing is a promising field that can solve complex problems beyond traditional computers’ capabilities. Developing high-quality quantum software applications, called quantum software engineering, has recently gained attention. However, quantum software development faces challenges related to code quality. A recent study found that many open-source quantum programs are affected by quantum-specific code smells, with long circuit being the most common. While the study provided relevant insights into the prevalence of code smells in quantum circuits, it did not explore the potential effect of transpilation, a necessary step for executing quantum computer programs, on the emergence of code smells. Indeed, transpilation might alter those characteristics employed to detect the presence of a smell on a circuit. To address this limitation, we present a new study investigating the impact of transpilation on quantum-specific code smells and how different target gate sets affect the results. We conducted experiments on 17 open-source quantum programs alongside a set of 100 synthetic circuits. We found that transpilation can significantly alter the metrics that are used to detect code smells, even into previously smell-free circuits, with the long circuit smell being the most susceptible to transpilation. Furthermore, the choice of the gate set significantly influences the presence and severity of code smells in transpiled circuits, highlighting the need for careful gate set selection to mitigate their impact. These findings have implications for circuit optimization and high-quality quantum software development. Further research is needed to understand the consequences of code smells and their potential impact on quantum computations, considering the characteristics and constraints of different gate sets and hardware platforms.
Quantum computing has become an active research field in recent years, as its applications in fields such as cryptography, optimization, and materials science are promising. Along with these developments, challenges and opportunities exist in the field of Quantum Software Engineering, as the development of frameworks and higher-level abstractions has attracted practitioners from diverse backgrounds. Unlike initial quantum frameworks based on the circuit model, recent frameworks and libraries leverage higher-level abstractions for creating quantum programs. This paper presents an empirical study of 985 Jupyter Notebooks from 80 open-source projects to investigate how quantum patterns are applied in practice. Our work involved two main stages. First, we built a knowledge base from three quantum computing frameworks (Qiskit, PennyLane, and Classiq). This process led us to identify and document nine new patterns that refine and extend the existing quantum computing pattern catalog. Second, we developed a reusable semantic search tool to automatically detect these patterns across our large-scale dataset, providing a practitioner-focused analysis. Our results show that developers use patterns in three levels: from foundational circuit utilities, to common algorithmic primitives (e.g., Amplitude Amplification), up to domain-specific applications for finance and optimization. This indicates a maturing field where developers are increasingly using high-level building blocks to solve real-world problems.
Abstract Quantum computing holds great promise for solving complex problems that classical computing cannot address, with applications in various industries and sectors. However, developing efficient quantum software remains a challenge. Quantum software engineering (QSE) has emerged to address this, adapting classical software engineering practices for quantum systems. Design patterns, widely used in classical software, can provide reusable solutions for common quantum development issues, but their use in quantum software remains underexplored. This paper presents an empirical study investigating the use of design patterns in 2610 Qiskit programs from GitHub. Using the QCPD Tool to detect four design patterns (initialization, superposition, entanglement, and oracle) and QMetrics to compute software metrics, the study creates a dataset linking patterns with code characteristics. Three research questions guide the study: RQ1 examines the prevalence of design patterns in quantum software, RQ2 explores the relationship between design patterns and code metrics, and RQ3 analyzes the combinations of patterns that occur together. The findings provide insights into quantum software development, offering developers practical guidance on applying specific patterns. The results contribute to QSE by revealing key relationships between patterns and metrics, which can inform future research and tool development. These findings support improved performance, maintainability, and scalability, fostering the broader adoption of quantum computing.