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For optimization problems with nonlinear constraints, linearly constrained Lagrangian (LCL) methods sequentially minimize a Lagrangian function subject to linearized constraints. These methods converge rapidly near a solution but may not be…

Optimization and Control · Mathematics 2007-05-23 Michael P. Friedlander , Michael A Saunders

Connections of the conjugate gradient (CG) method with other methods in computational mathematics are surveyed, including the connections with the conjugate direction method, the subspace optimization method and the quasi-Newton method BFGS…

Numerical Analysis · Mathematics 2019-12-17 Xuping Zhang , Jiefei Yang , Ziying Liu

We consider three mathematically equivalent variants of the conjugate gradient (CG) algorithm and how they perform in finite precision arithmetic. It was shown in [{\em Behavior of slightly perturbed Lanczos and conjugate-gradient…

Numerical Analysis · Computer Science 2021-07-19 Anne Greenbaum , Hexuan Liu , Tyler Chen

Finding a good approximation of the top eigenvector of a given $d\times d$ matrix $A$ is a basic and important computational problem, with many applications. We give two different quantum algorithms that, given query access to the entries…

Quantum Physics · Physics 2024-11-15 Yanlin Chen , András Gilyén , Ronald de Wolf

In this paper we compare two methods for finding extremal eigenvalues and eigenvectors: the restarted Lanczos method and momentum accelerated power iterations. The convergence of both methods is based on ratios of Chebyshev polynomials…

Numerical Analysis · Mathematics 2026-03-03 Alessandro Barletta , Nicholas Marshall , Sara Pollock

We consider iterative methods for solving linear ill-posed problems with compact operator and right-hand side only available via noise-polluted measurements. Conjugate gradients (CG) applied to the normal equations with an appropriate…

Numerical Analysis · Mathematics 2026-02-19 Daniel Gerth , Kirk M. Soodhalter

We consider linear ill-conditioned operator equations in a Hilbert space setting. Motivated by the aggregation method, we consider approximate solutions constructed from linear combinations of Tikhonov regularization, which amounts to…

Numerical Analysis · Mathematics 2023-06-07 Stefan Kindermann , Werner Zellinger

For compact self-adjoint operators in Hilbert spaces, two algorithms are proposed to provide fully computable a posteriori error estimate for eigenfunction approximation. Both algorithms apply well to the case of tight clusters and multiple…

Numerical Analysis · Mathematics 2022-07-19 Xuefeng Liu , Tomáš Vejchodský

Composite convex optimization models arise in several applications, and are especially prevalent in inverse problems with a sparsity inducing norm and in general convex optimization with simple constraints. The most widely used algorithms…

Optimization and Control · Mathematics 2016-07-15 Vahan Hovhannisyan , Panos Parpas , Stefanos Zafeiriou

Many eigenvalue problems arising in practice are often of the generalized form $A\x=\lambda B\x$. One particularly important case is symmetric, namely $A, B$ are Hermitian and $B$ is positive definite. The standard algorithm for solving…

Quantum Physics · Physics 2021-10-20 Changpeng Shao , Jin-Peng Liu

Inverse iteration is known to be an effective method for computing eigenvectors corresponding to simple and well-separated eigenvalues. In the non-symmetric case, the solution of shifted Hessenberg systems is a central step. Existing…

Mathematical Software · Computer Science 2021-01-14 Angelika Schwarz

The eigenvalue problem of the Laplace-Beltrami operators on curved surfaces plays an essential role in the convergence analysis of the numerical simulations of some important geometric partial differential equations which involve this…

Numerical Analysis · Computer Science 2013-10-18 Sheng-Gwo Chen , Mei-Hsiu Chi , Jyh-Yang Wu

Inverse scattering has a broad applicability in quantum mechanics, remote sensing, geophysical, and medical imaging. This paper presents a robust direct reduced order model (ROM) method for solving inverse scattering problems based on an…

Numerical Analysis · Mathematics 2023-11-29 Justin Baker , Elena Cherkaev , Vladimir Druskin , Shari Moskow , Mikhail Zaslavsky

Numerical linked-cluster expansions allow one to calculate finite-temperature properties of quantum lattice models directly in the thermodynamic limit through exact solutions of small clusters. However, full diagonalization is often the…

Strongly Correlated Electrons · Physics 2019-07-17 Krishnakumar Bhattaram , Ehsan Khatami

Compared to the classical Lanczos algorithm, the $s$-step Lanczos variant has the potential to improve performance by asymptotically decreasing the synchronization cost per iteration. However, this comes at a cost. Despite being…

Numerical Analysis · Mathematics 2021-08-31 Erin Carson , Tomáš Gergelits

Jacobian and Hessian regularization aim to reduce the magnitude of the first and second-order partial derivatives with respect to neural network inputs, and they are predominantly used to ensure the adversarial robustness of image…

Machine Learning · Computer Science 2022-12-02 Chenwei Cui , Zehao Yan , Guangshen Liu , Liangfu Lu

In this paper, we develop a novel weighted Laplacian method, which is partially inspired by the theory of graph Laplacian, to study recent popular graph problems, such as multilevel graph partitioning and balanced minimum cut problem, in a…

Machine Learning · Computer Science 2020-05-20 Shijie Xu , Jiayan Fang , Xiang-Yang Li

A new algorithm to approximate Hermitian matrices by positive semidefinite Hermitian matrices based on modified Cholesky decompositions is presented. In contrast to existing algorithms, this algorithm allows to specify bounds on the…

Numerical Analysis · Mathematics 2019-12-12 Joscha Reimer

Many fields require computing the trace of the inverse of a large, sparse matrix. The typical method used for such computations is the Hutchinson method which is a Monte Carlo (MC) averaging over matrix quadratures. To improve its…

High Energy Physics - Lattice · Physics 2017-05-12 Arjun Singh Gambhir , Andreas Stathopoulos , Kostas Orginos

Benson's outer approximation algorithm and its variants are the most frequently used methods for solving linear multiobjective optimization problems. These algorithms have two intertwined components: one-dimensional linear optimization one…

Optimization and Control · Mathematics 2019-03-21 Laszlo Csirmaz