As quantum computing evolves, the need for quantum software measurement techniques has increased. Functional Size Measurement (FSM) has been adopted to measure quantum Software in three different approaches based on COSMIC ISO 19761. We examine the proposed approaches by analyzing the measurement results of their application on Shor’s and Grover’s algorithms. A comparative analysis reveals the strengths and limitations of each approach, emphasizing the need for continued refinement. The insights gained from this study are critical for developing a more unified approach for quantum software and pave the way to a standardized approach.
As quantum computing evolves, the need for quantum software measurement techniques has increased. Functional Size Measurement (FSM) has been adopted to measure quantum Software in three different approaches based on COSMIC ISO 19761. We examine the proposed approaches by analyzing the measurement results of their application on Shor’s and Grover’s algorithms. A comparative analysis reveals the strengths and limitations of each approach, emphasizing the need for continued refinement. The insights gained from this study are critical for developing a more unified approach for quantum software and pave the way to a standardized approach.
Quantum computing promises to offer significant computational advantages over classical computing, leveraging principles such as superposition and entanglement. This necessitates effective metrics and measurement techniques for evaluating quantum systems, aiding in their development and performance optimization. However, due to fundamental differences in computing paradigms, and current immaturity of quantum software abstractions, classical software and hardware metrics may not directly apply to quantum computing, where the distinction between software and hardware can still be somewhat indiscernible compared to classical computing. This paper provides a comprehensive review of existing quantum software and hardware metrics in the scientific literature, highlighting key challenges in the field. Additionally, it investigates the application of Functional Size Measurement (FSM) based on COSMIC ISO 19761 to measure quantum software. Three FSM approaches are analyzed by applying them to Shor’s and Grover’s algorithms, with measurement results compared to assess their effectiveness. A comparative analysis highlights the strengths and limitations of each approach, emphasizing the need for further refinement. The insights from this study contribute to the advancement of quantum metrics, especially software metrics and measurement, paving the way for the development of a unified and standardized approach to quantum software measurement and assessment.
The rapid evolution of quantum computing has led to growing interest in the development of systematic approaches to assess and manage quantum software. Among these, functional size measurement (FSM) offers a promising pathway for establishing metrics that can support project estimation, benchmarking, and quality assessment. This paper provides an overview of emerging efforts in quantum software functional size measurement with a focus on key concepts, challenges, and motivations. First, we examine the foundational principles of quantum computing in relation to the existing FSM methods, identifying both compatibilities and unique constraints. Building on this, we discuss the challenges that arise when applying FSM to quantum software, including the hardware-coupled nature of functionality, evolving semantics of data and measurement abstractions, gaps in tooling and standardization, and evolving role of FSM across the Noisy Intermediate-Scale Quantum (NISQ) and future faulttolerant eras. We then outline community-driven initiatives, such as the COSMIC Quantum Software Taskforce and the Fall 2024 Workshop, which highlight the increasing demand for structured measurement practices. By articulating these issues, this paper aims to present initial research efforts for quantum software functional size measurement and stimulate further exploration of measurement approaches that are both theoretically grounded and practically applicable in quantum software engineering.
Quantum engineering seeks to exploit quantum information to build, among others, computing, cybersecurity, and metrology technologies. Quantum Software Engineering (QSE) focuses on the information processing side of these technologies. Historically, quantum (software) engineering has focused on development in controlled research environments and 'in the small'. As the field progresses, we should expect to see more large-scale quantum systems to be deployed as 'real-world' products and services. An essential tool in (classical) software engineering and development has been software size metrics. Calculating/estimating the size of a piece of software, to be developed or pre-existing, is an essential step in its engineering. Quantum software will be no different. Here we introduce Q-COSMIC, a technique for measuring the functional size of quantum software, based on the well-regarded COSMIC standard (ISO/IEC19761) for classical software
Rapid growth in quantum computing has created an urgent need to adapt traditional software engineering methodologies. Among these methodological challenges, software size measurement plays a central role in project estimation, quality assurance, and software engineering management. However, there is no consolidated understanding of how it should be applied to quantum software systems. This paper presents the first systematic literature review on quantum software size measurement, synthesizing existing approaches, and identifying key research gaps. An analysis of 16 studies shows that size measures span multiple abstraction levels, with most research focusing on adapting classical metrics, such as Lines of Code (LOC) and functional size, to quantum software systems. LOC continues to be used for sizing quantum code, while COSMIC Function Points (ISO 19761) have been extended to capture data movements in quantum components, enabling their application at the requirement, code, and circuit levels. At the specification and architectural design levels, the proposed measures include counts of quantum classes and methods as well as lines of architectural specifications. At the circuit level, quantum-specific constructs, such as qubits, gates, and measurements, are also incorporated. Additionally, software structure metrics, including cyclomatic complexity and Halstead metrics, are used to measure quantum software at both the code and design levels. Research output has grown since 2024, and is driven by academic groups, with minimal industrial participation. However, most metrics remain conceptual, lack empirical validation, and are not integrated into development life cycles, highlighting the immaturity and fragmentation of current proposals and the need for standardized frameworks.
As quantum computing has progressed toward fault-tolerant implementations, quantum error correction (QEC) for quantum hardware and software has become a dominant concern. While conventional QEC measurements, such as qubit overhead, code distance, and error thresholds, quantify physical resource costs, they do not capture the software-level functionality introduced by error detection, correction, and fault-tolerant gate protocols. This study investigated the QEC contribution to the functional size of quantum software and demonstrated that this contribution can be systematically measured using the COSMIC Functional Size Measurement method. A gate-level sizing approach, known as Gates’ Occurrences, was used to quantify functional user requirements (FUR) associated with QEC processes, including logical encoding, syndrome extraction, and recovery operations. A prototype measurement tool, implemented in Qiskit (Version 0.7.2), enables the automated calculation of COSMIC Function Points (CFP) from annotated circuit representations. Case studies involving Bell state preparation, Grover’s search algorithm, and 15-to-1 magic state distillation revealed that QEC-related functionality can account for 70–85% of the total functional size, even under simplified encoding assumptions. The results underscore the importance of QEC for the functional size of quantum software. These findings offer a reproducible foundation for functional sizing and future fault-tolerant quantum applications.
With the growth of quantum computing hardware technology, more developers are becoming involved in the design and development of quantum algorithms, leading to the creation of practical applications that align with real-world needs through the combination of quantum hardware and software. Among quantum algorithms, the most well-known include Grover’s algorithm and Shor’s algorithm. Grover’s algorithm can quickly provide search results, making it highly valuable for search-related applications. In light of this, this study primarily examines the theoretical usability of Grover’s algorithm and explores its limitations. Additionally, on the practical side, this research implements Grover’s algorithm using IBM Quantum Computing and the IBM Qiskit package. By comparing simulation results with those obtained from execution on real quantum computers, the study discusses the current limitations of quantum computing hardware technology.