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Traditional numerical methods for calculating matrix eigenvalues are prohibitively expensive for high-dimensional problems. Iterative random sparsification methods allow for the estimation of a single dominant eigenvalue at reduced cost by…

Numerical Analysis · Mathematics 2023-10-03 Samuel M. Greene , Robert J. Webber , Timothy C. Berkelbach , Jonathan Weare

The numerical solution of the generalized eigenvalue problem for a singular matrix pencil is challenging due to the discontinuity of its eigenvalues. Classically, such problems are addressed by first extracting the regular part through the…

Numerical Analysis · Mathematics 2024-07-17 Daniel Kressner , Bor Plestenjak

A QR factorization of a tall and skinny matrix with n columns can be represented as a reduction. The operation used along the reduction tree has in input two n-by-n upper triangular matrices and in output an n-by-n upper triangular matrix…

Numerical Analysis · Mathematics 2010-02-24 Julien Langou

We propose a new way of visualising the dynamics of iterative eigenvalue algorithms such as the QR algorithm, over the important special case of PSD (positive semi-definite) matrices. Many subtle and important properties of such algorithms…

Numerical Analysis · Mathematics 2022-04-04 Ran Gutin

This paper describes efficient algorithms for computing rank-revealing factorizations of matrices that are too large to fit in RAM, and must instead be stored on slow external memory devices such as solid-state or spinning disk hard drives…

Mathematical Software · Computer Science 2020-03-05 Nathan Heavner , Per-Gunnar Martinsson , Gregorio Quintana-Ortí

An efficient algorithm for computing eigenvectors of a matrix of integers by exact computation is proposed. The components of calculated eigenvectors are expressed as polynomials in the eigenvalue to which the eigenvector is associated, as…

Numerical Analysis · Mathematics 2019-02-19 Shinichi Tajima , Katsuyoshi Ohara , Akira Terui

The QZ algorithm for computing eigenvalues and eigenvectors of a matrix pencil $A - \lambda B$ requires that the matrices first be reduced to Hessenberg-triangular (HT) form. The current method of choice for HT reduction relies entirely on…

Numerical Analysis · Mathematics 2018-05-31 Zvonimir Bujanović , Lars Karlsson , Daniel Kressner

We present a general quantum circuit design for finding eigenvalues of non-unitary matrices on quantum computers using the iterative phase estimation algorithm. In particular, we show how the method can be used for the simulation of…

Quantum Physics · Physics 2013-11-01 Anmer Daskin , Ananth Grama , Sabre Kais

This paper proposes a novel matrix quantization method, Binary Quadratic Quantization (BQQ). In contrast to conventional first-order quantization approaches, such as uniform quantization and binary coding quantization, that approximate…

Computer Vision and Pattern Recognition · Computer Science 2025-10-22 Kyo Kuroki , Yasuyuki Okoshi , Thiem Van Chu , Kazushi Kawamura , Masato Motomura

We present a new algorithm for solving an eigenvalue problem for a real symmetric arrowhead matrix. The algorithm computes all eigenvalues and all components of the corresponding eigenvectors with high relative accuracy in $O(n^{2})$…

Numerical Analysis · Mathematics 2014-05-30 Nevena Jakovcevic Stor , Ivan Slapnicar , Jesse L. Barlow

This paper describes a set of rational filtering algorithms to compute a few eigenvalues (and associated eigenvectors) of non-Hermitian matrix pencils. Our interest lies in computing eigenvalues located inside a given disk, and the proposed…

Numerical Analysis · Mathematics 2021-03-10 Vassilis Kalantzis , Yuanzhe Xi , Lior Horesh

In the iterative solution of dense linear systems from boundary integral equations or systems involving kernel matrices, the main challenges are the expensive matrix-vector multiplication and the storage cost which are usually tackled by…

Numerical Analysis · Mathematics 2018-11-13 Xin Xing , Edmond Chow

The efficient and accurate QR decomposition for matrices with hierarchical low-rank structures, such as HODLR and hierarchical matrices, has been challenging. Existing structure-exploiting algorithms are prone to numerical instability as…

Numerical Analysis · Mathematics 2018-09-28 Daniel Kressner , Ana Susnjara

In this work, we present a method to exponentiate non-sparse indefinite low-rank matrices on a quantum computer. Given an operation for accessing the elements of the matrix, our method allows singular values and associated singular vectors…

Quantum Physics · Physics 2018-01-31 Patrick Rebentrost , Adrian Steffens , Seth Lloyd

An algorithm is proposed to convert arbitrary unitary matrix to a sequence of $X$ gates and fully controlled $R_y, R_z$ and $R_1$ gates. This algorithm is used to generate Q# implementation for arbitrary unitary matrix. Some optimizations…

Quantum Physics · Physics 2025-01-15 Dmytro Fedoriaka

Continuous representation of words is a standard component in deep learning-based NLP models. However, representing a large vocabulary requires significant memory, which can cause problems, particularly on resource-constrained platforms.…

Computation and Language · Computer Science 2020-01-24 Siyu Liao , Jie Chen , Yanzhi Wang , Qinru Qiu , Bo Yuan

Quantum machine learning (QML) leverages quantum states for data encoding, with key approaches being explicit models that use parameterized quantum circuits and implicit models that use quantum kernels. Implicit models often have lower…

Quantum Physics · Physics 2025-12-08 Akimoto Nakayama , Hayata Morisaki , Kosuke Mitarai , Hiroshi Ueda , Keisuke Fujii

In this work, we present a quantum neighborhood preserving embedding and a quantum local discriminant embedding for dimensionality reduction and classification. We demonstrate that these two algorithms have an exponential speedup over their…

Quantum Physics · Physics 2020-03-23 Jin-Min Liang , Shu-Qian Shen , Ming Li , Lei Li

We propose the variational quantum singular value decomposition based on encoding the elements of the considered { $N\times N$} matrix into the state of a quantum system of appropriate dimension. This method doesn't use the expansion of…

Quantum Physics · Physics 2025-08-05 Alexander I. Zenchuk , Wentao Qi , Junde Wu

The numerical solution of singular eigenvalue problems is complicated by the fact that small perturbations of the coefficients may have an arbitrarily bad effect on eigenvalue accuracy. However, it has been known for a long time that such…

Numerical Analysis · Mathematics 2023-01-10 Daniel Kressner , Ivana Šain Glibić