{"title":"A block Toeplitz preconditioner for all-at-once systems from linear wave equations","authors":"S. Hon, S. Serra-Capizzano","doi":"10.1553/etna_vol58s177","DOIUrl":"https://doi.org/10.1553/etna_vol58s177","url":null,"abstract":". In this work, we propose a novel parallel-in-time preconditioner for an all-at-once system, arising from the numerical solution of linear wave equations. Namely, our main result concerns a block tridiagonal Toeplitz preconditioner that can be diagonalized via fast sine transforms, whose effectiveness is theoretically shown for the nonsymmetric block Toeplitz system resulting from discretizing the concerned wave equation. Our approach is to first transform the original linear system into a symmetric one and subsequently develop the desired preconditioning strategy based on the spectral symbol of the modified matrix. Various Krylov subspace methods are considered. That is, we show that the minimal polynomial of the preconditioned matrix is of low degree, which leads to fast convergence when the generalized minimal residual method is used. To fully utilize the symmetry of the modified matrix, we additionally construct an absolute-value preconditioner which is symmetric positive definite. Then, we show that the eigenvalues of the preconditioned matrix are clustered around ± 1 , which gives a convergence guarantee when the minimal residual method is employed. Numerical examples are given to support the effectiveness of our preconditioner. Our block Toeplitz preconditioner provides an alternative to the existing block circulant preconditioner proposed by McDonald, Pestana, and Wathen in [SIAM J. Sci. Comput., 40 (2018), pp. A1012–A1033], advancing the symmetrization preconditioning theory that originated from the same work.","PeriodicalId":282695,"journal":{"name":"ETNA - Electronic Transactions on Numerical Analysis","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115244648","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"${}_{delta}^{gamma}!mathbf{Phi}$-type inclusion set for eigenvalues of a tensor","authors":"Xiaoqiang Lei","doi":"10.1553/etna_vol51s262","DOIUrl":"https://doi.org/10.1553/etna_vol51s262","url":null,"abstract":"","PeriodicalId":282695,"journal":{"name":"ETNA - Electronic Transactions on Numerical Analysis","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121360308","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The bisection eigenvalue method for unitary Hessenberg matrices via their quasiseparable structure","authors":"Y. Eidelman, I. Haimovici","doi":"10.1553/etna_vol59s60","DOIUrl":"https://doi.org/10.1553/etna_vol59s60","url":null,"abstract":"","PeriodicalId":282695,"journal":{"name":"ETNA - Electronic Transactions on Numerical Analysis","volume":"76 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125146798","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A numerical method for solving systems of hypersingular integro-differential equations","authors":"M. C. De Bonis, A. Mennouni, D. Occorsio","doi":"10.1553/etna_vol58s378","DOIUrl":"https://doi.org/10.1553/etna_vol58s378","url":null,"abstract":". This paper is concerned with a collocation-quadrature method for solving systems of Prandtl’s integro-differential equations based on de la Vallée Poussin filtered interpolation at Chebyshev nodes. We prove stability and convergence in Hölder-Zygmund spaces of locally continuous functions. Some numerical tests are presented to examine the method’s efficacy.","PeriodicalId":282695,"journal":{"name":"ETNA - Electronic Transactions on Numerical Analysis","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128074755","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Preconditioned gradient iterations for the eigenproblem of definite matrix pairs","authors":"Marija Miloloza Pandur","doi":"10.1553/etna_vol51s331","DOIUrl":"https://doi.org/10.1553/etna_vol51s331","url":null,"abstract":"Preconditioned gradient iterations for large and sparse Hermitian generalized eigenvalue problems Ax = λBx, with positive definite B, are efficient methods for computing a few extremal eigenpairs. In this paper we give a unifying framework of preconditioned gradient iterations for definite generalized eigenvalue problems with indefinite B. More precisely, these iterations compute a few eigenvalues closest to the definiteness interval, which can be in the middle of the spectrum, and the corresponding eigenvectors of definite matrix pairs (A,B), that is, pairs having a positive definite linear combination. Sharp convergence theorems for the simplest variants are given. This framework includes an indefinite locally optimal block preconditioned conjugate gradient (LOBPCG) algorithm derived by Kressner, Miloloža Pandur, and Shao [Numer. Algorithms, 66 (2014), pp. 681–703]. We also give a generic algorithm for constructing new “indefinite extensions” of standard (with positive definite B) eigensolvers. Numerical experiments demonstrate the use of our algorithm for solving a product and a hyperbolic quadratic eigenvalue problem. With excellent preconditioners, the indefinite variant of LOBPCG is the most efficient method. Finally, we derive some ideas on how to use our indefinite eigensolver to compute a few eigenvalues around any spectral gap and the corresponding eigenvectors of definite matrix pairs.","PeriodicalId":282695,"journal":{"name":"ETNA - Electronic Transactions on Numerical Analysis","volume":"111 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133431607","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sai Manish Reddy Mekarthy, M. Hashemitaheri, H. Cherukuri
{"title":"A combined finite element and machine learning approach for the prediction of specific cutting forces and maximum tool temperatures in machining","authors":"Sai Manish Reddy Mekarthy, M. Hashemitaheri, H. Cherukuri","doi":"10.1553/etna_vol56s66","DOIUrl":"https://doi.org/10.1553/etna_vol56s66","url":null,"abstract":"","PeriodicalId":282695,"journal":{"name":"ETNA - Electronic Transactions on Numerical Analysis","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133117692","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Additive Schwarz preconditioners for a localized orthogonal decomposition method","authors":"S. C. Brenner, J. C. Garay, L. Sung","doi":"10.1553/ETNA_VOL54S234","DOIUrl":"https://doi.org/10.1553/ETNA_VOL54S234","url":null,"abstract":"We investigate a variant of the localized orthogonal decomposition method (Henning and Peterseim, [Multiscale Model. Simul., 11 (2013), pp. 1149–1175] and Målqvist and Peterseim, [Math. Comp., 83 (2014), pp. 2583–2603]) for elliptic problems with rough coefficients. The construction of the basis of the multiscale finite element space is based on domain decomposition techniques, which is motivated by the recent work of Kornhuber, Peterseim, and Yserentant [Math. Comp., 87 (2018), pp. 2765–2774]. We also design and analyze additive Schwarz domain decomposition preconditioners for the resulting discrete problems.","PeriodicalId":282695,"journal":{"name":"ETNA - Electronic Transactions on Numerical Analysis","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114720976","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A time-stepping finite element method for a time-fractional partial differential equation of hidden-memory space-time variable order","authors":"Xiangcheng Zheng, Hong Wang","doi":"10.1553/etna_vol55s652","DOIUrl":"https://doi.org/10.1553/etna_vol55s652","url":null,"abstract":". We analyze a time-stepping finite element method for a time-fractional partial differential equation with hidden-memory space-time variable order. Due to the coupling of the space-dependent variable order with the finite element formulation and the hidden memory, the variable fractional order cannot be split from the space and destroys the monotonicity in the time-stepping discretization. Because of these difficulties, the numerical analysis of a fully-discrete finite element method of the proposed model remained untreated in the literature. We develop an alternative analysis to address these issues and to prove an optimal-order error estimate of the fully-discrete finite element scheme without any assumption on the regularity of the true solution and perform numerical experiments to substantiate the theoretical findings.","PeriodicalId":282695,"journal":{"name":"ETNA - Electronic Transactions on Numerical Analysis","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121470820","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Robust BDDC algorithms for finite volume element methods","authors":"Ya Su, Xuemin Tu, Yingxiang Xu","doi":"10.1553/etna_vol58s66","DOIUrl":"https://doi.org/10.1553/etna_vol58s66","url":null,"abstract":". The balancing domain decomposition by constraints (BDDC) method is applied to the linear system arising from the finite volume element method (FVEM) discretization of a scalar elliptic equation. The FVEMs share nice features of both finite element and finite volume methods and are flexible for complicated geometries with good conservation properties. However, the resulting linear system usually is asymmetric. The generalized minimal residual (GMRES) method is used to accelerate convergence. The proposed BDDC methods allow for jumps of the coefficient across subdomain interfaces. When jumps of the coefficient appear inside subdomains, the BDDC algorithms adaptively choose the primal variables deriving from the eigenvectors of some local generalized eigenvalue problems. The adaptive BDDC algorithms with advanced deluxe scaling can ensure good performance with highly discontinuous coefficients. A convergence analysis of the BDDC method with a preconditioned GMRES iteration is provided, and several numerical experiments confirm the theoretical estimate.","PeriodicalId":282695,"journal":{"name":"ETNA - Electronic Transactions on Numerical Analysis","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127045813","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}