{"title":"Partition-based bounds for the norm of the inverse of monotone matrices and totally non-negative matrices","authors":"Ljiljana Cvetković","doi":"10.1007/s10444-026-10355-y","DOIUrl":"https://doi.org/10.1007/s10444-026-10355-y","url":null,"abstract":"","PeriodicalId":50869,"journal":{"name":"Advances in Computational Mathematics","volume":"18 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148883439","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"An unfitted boundary algebraic equation method based on difference potentials and lattice Green’s function in 3D","authors":"Qing Xia","doi":"10.1007/s10444-026-10346-z","DOIUrl":"https://doi.org/10.1007/s10444-026-10346-z","url":null,"abstract":"","PeriodicalId":50869,"journal":{"name":"Advances in Computational Mathematics","volume":"43 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148883440","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Qing-Yang Si, Yu-Hong Ran, Jun-Gang Wang, Zong-Ze Yang
{"title":"Diagonalization-based algorithms for all-at-once systems arising from linear delay differential equations","authors":"Qing-Yang Si, Yu-Hong Ran, Jun-Gang Wang, Zong-Ze Yang","doi":"10.1007/s10444-026-10354-z","DOIUrl":"https://doi.org/10.1007/s10444-026-10354-z","url":null,"abstract":"","PeriodicalId":50869,"journal":{"name":"Advances in Computational Mathematics","volume":"12 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148883441","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yang Cao, Lu-Xin Wang, Qin-Qin Shen, Chen-Can Zhou
{"title":"Eigenvalue bounds of saddle point matrix from mixed-cell-height integrated circuit legalization problem","authors":"Yang Cao, Lu-Xin Wang, Qin-Qin Shen, Chen-Can Zhou","doi":"10.1007/s10444-026-10352-1","DOIUrl":"10.1007/s10444-026-10352-1","url":null,"abstract":"<div><p>Reformulating the mixed-cell-height integrated circuit legalization problem into a linear complementarity problem (LCP) has been proven to be a useful tool in very large-scale integrated circuit placement design. An important characteristic of such LCP is that the system matrix is a typical saddle point matrix with the (1,1) leading block being a summation of the identity matrix and a symmetric positive-semidefinite matrix. In this paper, the eigenvalue bounds of this special saddle point matrix are studied in detail. More specifically, for the real eigenvalues, the lower bound is a value larger than <span>(varvec{0})</span> and less than <span>(varvec{1})</span>, while the upper bound is less than <span>(varvec{1+4mu })</span>, where <span>(varvec{mu })</span> is the Lagrange multiplier. For the complex eigenvalues, the real parts fall within the left-closed and right-open range of <span>(varvec{frac{1}{2}})</span> to 2, while the upper bound of the modulus of the imaginary parts is less than <span>(varvec{frac{1}{2}sqrt{15}})</span>. In particular, for the case where there are only single-row-height cells, some refined bounds are derived. Finally, these theoretical findings are verified through five numerical examples.</p></div>","PeriodicalId":50869,"journal":{"name":"Advances in Computational Mathematics","volume":"52 5","pages":""},"PeriodicalIF":2.6,"publicationDate":"2026-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148837668","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Michael S. Ackermann, Ion Victor Gosea, Serkan Gugercin, Steffen W. R. Werner
{"title":"Second-order AAA algorithms for structured data-driven modeling","authors":"Michael S. Ackermann, Ion Victor Gosea, Serkan Gugercin, Steffen W. R. Werner","doi":"10.1007/s10444-026-10347-y","DOIUrl":"10.1007/s10444-026-10347-y","url":null,"abstract":"<div><p>The data-driven modeling of dynamical systems has become an essential tool for the construction of accurate computational models from real-world data. In this process, the inherent differential structures underlying the considered physical phenomena are often neglected making the reinterpretation of the learned models in a physically meaningful sense very challenging. In this work, we present three data-driven modeling approaches for the construction of dynamical systems with second-order differential structure directly from frequency domain data. Based on the second-order structured barycentric form, we extend the well-known Adaptive Antoulas-Anderson algorithm to the case of second-order systems. Depending on the available computational resources, we propose variations of the proposed method that prioritize either higher computation speed or greater modeling accuracy, and we present a theoretical analysis for the expected accuracy and performance of the proposed methods. Three numerical examples demonstrate the effectiveness of our new structured approaches in comparison to classical unstructured data-driven modeling.</p></div>","PeriodicalId":50869,"journal":{"name":"Advances in Computational Mathematics","volume":"52 5","pages":""},"PeriodicalIF":2.6,"publicationDate":"2026-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10444-026-10347-y.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148837666","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A novel penalty-based least-squares discontinuous Galerkin (LS-DG) method for time-dependent Stokes equations","authors":"Guang-an Zou, Kejia Pan, Xiaofeng Yang","doi":"10.1007/s10444-026-10349-w","DOIUrl":"10.1007/s10444-026-10349-w","url":null,"abstract":"<div><p>In this paper, a new penalty-based least-squares discontinuous Galerkin (LS-DG) framework is proposed and analyzed for the time-dependent Stokes system. A key feature of the scheme is the use of a penalty method to address the incompressibility constraint, along with the introduction of an artificial average perturbation term in the weighted least-squares functional. This approach offers three distinct advantages: first, it facilitates the proof of coercivity of the functional, ensuring the unique solvability of the method; second, it guarantees the unconditional stability of the kinetic energy at the discrete level; and third, it integrates the strengths of both the discontinuous Galerkin and least-squares methods, naturally providing a built-in residual indicator for the adaptive procedure. We rigorously establish the well-posedness and derive optimal error estimates for the proposed scheme. Finally, the accuracy, energy stability, and high efficiency of the method are demonstrated through several numerical examples, which show that it outperforms the classical DG method in terms of computational efficiency.</p></div>","PeriodicalId":50869,"journal":{"name":"Advances in Computational Mathematics","volume":"52 5","pages":""},"PeriodicalIF":2.6,"publicationDate":"2026-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10444-026-10349-w.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148837665","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"How to induce regularization in linear models: a guide to reparametrizing gradient flow","authors":"Hung-Hsu Chou, Johannes Maly, Dominik Stöger","doi":"10.1007/s10444-026-10350-3","DOIUrl":"10.1007/s10444-026-10350-3","url":null,"abstract":"<div><p>In this work, we analyze the relation between reparametrizations of gradient flow and the induced implicit bias in linear models, which encompass various basic regression tasks. In particular, we study how reparametrization, loss function, and link function influence the convergence behavior and implicit bias of gradient flow. Our results provide conditions under which the implicit bias can be well-described and convergence of the flow is guaranteed. We furthermore show how to use these insights for designing reparametrization functions that lead to specific implicit biases which are closely connected to <span>(ell _p)</span>- or trigonometric regularizers.</p></div>","PeriodicalId":50869,"journal":{"name":"Advances in Computational Mathematics","volume":"52 5","pages":""},"PeriodicalIF":2.6,"publicationDate":"2026-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10444-026-10350-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148837667","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A class of improved randomized Gauss-Seidel methods based on the leverage scores for the parameter estimation of TAR model","authors":"Zhang-Yang Xu, Ju-Li Zhang","doi":"10.1007/s10444-026-10353-0","DOIUrl":"10.1007/s10444-026-10353-0","url":null,"abstract":"<div><p>In this work, an aggregation leverage score (ALS) sketching method for matrix compression is proposed, drawing inspiration from the weighted leverage score (WLS) sketching method. The ALS method is then combined with the randomized Gauss-Seidel (RGS) method to perform parameter estimation for the TAR model, and a detailed convergence analysis is derived and presented. Furthermore, we develop a leverage randomized block Gauss-Seidel (LRBGS) method by incorporating block leverage scores and a relaxation parameter into the randomized block Gauss-Seidel (RBGS) method, and the corresponding convergence analysis is also given. Finally, the ALS method is integrated with the LRBGS method, yielding the aggregation leverage randomized block Gauss-Seidel (A-LRBGS) method for TAR model parameter estimation. Numerical experiments indicate that the ALS-RGS method and the A-LRBGS method exhibit efficiency in both parameter estimation and prediction for the TAR model.</p></div>","PeriodicalId":50869,"journal":{"name":"Advances in Computational Mathematics","volume":"52 5","pages":""},"PeriodicalIF":2.6,"publicationDate":"2026-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148837661","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"High order regularization of nearly singular surface integrals","authors":"J. Thomas Beale, Svetlana Tlupova","doi":"10.1007/s10444-026-10344-1","DOIUrl":"10.1007/s10444-026-10344-1","url":null,"abstract":"<div><p>Solutions of partial differential equations can often be written as surface integrals having a kernel related to a singular fundamental solution. Special methods are needed to evaluate the integral accurately at points on or near the surface. Here, we derive formulas to regularize the integrals with high accuracy, using analysis from [6], so that a standard quadrature can be used without special care near the singularity. We treat single or double layer integrals for harmonic functions or for Stokes flow. The nearly singular case, evaluation at points close to the surface, can be needed when surfaces are close to each other, or to find values at grid points near a surface. We derive formulas for regularized kernels with error <span>(O(delta ^p))</span> where <span>(delta )</span> is the smoothing radius and <span>(p = 3)</span>, 5, 7. With spacing <i>h</i> in the quadrature, we choose <span>(delta )</span> proportional to <span>(h^q)</span> with <span>(q<1)</span> so that the discretization error is controlled as <span>(h rightarrow 0)</span>. We see the predicted order of convergence <span>(O(h^{pq}))</span> in various examples. Values at all grid points can be obtained from those near the surface in an efficient manner suggested in [20]. With this technique, we obtain high-order accurate grid values for a harmonic function determined by interfacial conditions and for the pressure and velocity in Stokes flow around a translating spheroid.</p></div>","PeriodicalId":50869,"journal":{"name":"Advances in Computational Mathematics","volume":"52 5","pages":""},"PeriodicalIF":2.6,"publicationDate":"2026-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148837688","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Block-randomized stochastic methods for tensor ring decomposition","authors":"Yajie Yu, Hanyu Li, Jingchun Zhou","doi":"10.1007/s10444-026-10333-4","DOIUrl":"10.1007/s10444-026-10333-4","url":null,"abstract":"<div><p>Tensor ring (TR) decomposition is a simple but effective tensor network for analyzing and interpreting latent patterns of tensors. In this work, we first propose a doubly randomized optimization framework for computing TR decomposition. It can be regarded as a sensible mix of randomized block coordinate descent and stochastic gradient descent, and hence functions in a double-random manner and can achieve lightweight updates and a small memory footprint. Further, to improve the convergence, especially for ill-conditioned problems, we propose a scaled version of the framework that can be viewed as an adaptive preconditioned or diagonally scaled variant. Four different probability distributions for selecting the mini-batch and the adaptive strategy for determining the step size are also provided. Finally, we present the theoretical properties and numerical performance of our proposed methods.</p></div>","PeriodicalId":50869,"journal":{"name":"Advances in Computational Mathematics","volume":"52 5","pages":""},"PeriodicalIF":2.6,"publicationDate":"2026-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148837632","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}