Abstract Least Squares Support Vector Machine (LS-SVM) is a reformulation of the Support Vector Machine(SVM) algorithm that uses a hyperplane to classify elements in a dataset, with the coefficients of the hyperplane being determined by solving a linear system of equations. A quantum algorithm, the Harrow-Hassidim-Lloyd (HHL) algorithm, has the potential to offer exponential advantages over classical algorithms for solving linear systems, although an efficient implementation is yet to be developed. The current era of quantum computing presents a series of technical challenges for implementing and executing circuits, with smaller circuits being less susceptible to noise. In response to this scenario, circuit reduction optimizations have been developed to enhance execution quality. This paper presents the process of using optimized HHL quantum circuits to generate LS-SVMs applied to the classification of pulsar candidates, where the quantum generated SVMs closely matched the performance of their classical counterparts and obtained competitive results against other Quantum Machine Learning methods even when using a real quantum device, with the optimized circuits having a significant execution speedup over the original quantum circuits.
Abstract Least Squares Support Vector Machine (LS-SVM) is a reformulation of the Support Vector Machine(SVM) algorithm that uses a hyperplane to classify elements in a dataset, with the coefficients of the hyperplane being determined by solving a linear system of equations. A quantum algorithm, the Harrow-Hassidim-Lloyd (HHL) algorithm, has the potential to offer exponential advantages over classical algorithms for solving linear systems, although an efficient implementation is yet to be developed. The current era of quantum computing presents a series of technical challenges for implementing and executing circuits, with smaller circuits being less susceptible to noise. In response to this scenario, circuit reduction optimizations have been developed to enhance execution quality. This paper presents the process of using optimized HHL quantum circuits to generate LS-SVMs applied to the classification of pulsar candidates, where the quantum generated SVMs closely matched the performance of their classical counterparts and obtained competitive results against other Quantum Machine Learning methods even when using a real quantum device, with the optimized circuits having a significant execution speedup over the original quantum circuits.
Support Vector Machine (SVM) is considered one of the main classification Machine Learning algorithms. Following the original formulation,an SVM generation has quadratic complexity, leaving room for exploring resolution methods with better performance. One way to enhance its efficiency is by utilizing Quantum Computing algorithms, such as the HHL. This work presents an automation of a Quantum Machine Learning algorithm that uses HHL to generate SVMs fixed at the origin of a two-dimensional hyperplane.
Abstract We compare two quantum approaches that use support vector machines for multi-class classification on a reduced Sloan Digital Sky Survey () dataset: the quantum kernel-based QSVM and the Harrow-Hassidim-Lloyd least-squares SVM (HHL LS-SVM). Both one-vs-rest and two-step hierarchical classification schemes were implemented. The QSVM involves angle encoding of ten features, two unitary operator blocks consisting of rotational operator gates, and a projective measurement that projects the final state to the zero state. The HHL-based method involves solving a system of linear equations using the HHL algorithm and using the solution in a support vector machine approach. The results indicate that the QSVM outperforms HHL LS-SVM in most cases. HHL LS-SVM performs somewhat competitively in selected cases, particularly when isolating galaxies (majority), however, it also performs poorly in others, especially when isolating QSOs (minority). Comparisons with classical SVMs confirm that quantum and classical methods achieve broadly similar performance, with classical models performing slightly ahead overall. Scaling analysis reveals a trade-off: QSVM performance suffers from quadratic scaling with the number of samples and features, but benefits from explicit feature representation during training, while HHL LS-SVM scales essentially constantly, with moderate fluctuations, but suffers from limited representative elements. The HHL-based method is also highly noise-sensitive. These results suggest that QSVM performs better overall under the experimental conditions considered here and is likely to be more amenable to near-term hardware execution in terms of circuit depth and structure, while the more efficient scaling of HHL LS-SVM makes it a useful option for larger datasets beyond the NISQ era.
Support vector machine (SVM) is a particularly powerful and flexible supervised learning model that analyzes data for both classification and regression, whose usual algorithm complexity scales polynomially with the dimension of data space and the number of data points. To tackle the big data challenge, a quantum SVM algorithm was proposed, which is claimed to achieve exponential speedup for least squares SVM (LS-SVM). Here, inspired by the quantum SVM algorithm, we present a quantum-inspired classical algorithm for LS-SVM. In our approach, an improved fast sampling technique, namely indirect sampling, is proposed for sampling the kernel matrix and classifying. We first consider the LS-SVM with a linear kernel, and then discuss the generalization of our method to nonlinear kernels. Theoretical analysis shows our algorithm can make classification with arbitrary success probability in logarithmic runtime of both the dimension of data space and the number of data points for low rank, low condition number, and high dimensional data matrix, matching the runtime of the quantum SVM.
Quantum Support Vector Machines (QSVM) play a vital role in using quantum resources for supervised machine learning tasks, such as classification. However, current methods are strongly limited in terms of scalability on Noisy Intermediate Scale Quantum (NISQ) devices. In this work, we propose a novel approach called the Variational Quantum Linear Solver (VQLS) enhanced QSVM. This is built upon our idea of utilizing the variational quantum linear solver to solve system of linear equations of a Least Squares-SVM on a NISQ device. The implementation of our approach is evaluated by an extensive series of numerical experiments with the Iris dataset, which consists of three distinct iris plant species. Based on this, we explore the effectiveness of our algorithm by constructing a classifier capable of classification in a feature space ranging from one to seven dimensions. Furthermore, we exploit both classical and quantum computing for various subroutines of our algorithm, and effectively mitigate challenges associated with the implementation. These include significant improvement in the trainability of the variational ansatz and notable reductions in run-time for cost calculations. Based on the numerical experiments, our approach exhibits the capability of identifying a separating hyperplane in an 8-dimensional feature space. Moreover, it consistently demonstrated strong performance across various instances with the same dataset.
Quantum Support Vector Machines (QSVM) play a vital role in using quantum resources for supervised machine learning tasks, such as classification. However, current methods are strongly limited in terms of scalability on Noisy Intermediate Scale Quantum (NISQ) devices. In this work, we propose a novel approach called the Variational Quantum Linear Solver (VQLS) enhanced QSVM. This is built upon our idea of utilizing the variational quantum linear solver to solve system of linear equations of a least squares-SVM on a NISQ device. The implementation of our approach is evaluated by an extensive series of numerical experiments with the Iris dataset, which consists of three distinct iris plant species. Based on this, we explore the practicality and effectiveness of our algorithm by constructing a classifier capable of classification in a feature space ranging from one to seven dimensions. Furthermore, by strategically exploiting both classical and quantum computing for various subroutines of our algorithm, we effectively mitigate practical challenges associated with the implementation. These include significant improvement in the trainability of the variational ansatz and notable reductions in run-time for cost calculations. Based on the numerical experiments, our approach exhibits the capability of identifying a separating hyperplane in an 8-dimensional feature space. Moreover, it consistently demonstrated strong performance across various instances with the same dataset.
The current development of Support Vector Machines (SVM) has reached a bottleneck, with issues such as long training times and weak interpretability when dealing with large-scale, multi-dimensional data. This paper introduces the concept of Quantum Support Vector Machines (QSVM) and achieves efficient solutions through quantum algorithms such as the HHL algorithm. The research designs a computational architecture that combines classical and quantum computing, utilizing the Pauli decomposition of Hermitian matrices to simulate the quantum simulation of Hamiltonian quantities and implementing the quantum simulation of unitary operators. Based on the conclusions, a complete quantum linear solver circuit is designed, achieving exponential growth in computational complexity. Experiments using the Iris dataset demonstrate the excellent classification performance of QSVM, which outperform classical SVM in classification accuracy, computational time complexity, and memory requirements. More efficient quantum mapping algorithms and quantum circuit optimization methods are implemented, providing new ideas and methods for the application of SVM to large-scale datasets.