186,994 research outputs found
gander n: gander river boat
No full textganderWe had two Gander River boats, special craft which look like big canoes. They are built especially for running the Lower Gander River, to carry 'sports' and their guides to the salmon pools below Glenwood. Fitted with a motor, these boats can carry a big load easily and safely.G. M. Story JUL. 13 1988WK PRINTED ITEMDNE SupUsed SupUsed Sup1Used Su
TeamWorker: An agent-based support system for mobile task execution
No full textTraditional workflow management systems are considered insufficiently flexible to support autonomous job management via close team working. This paper proposes a multi-agent system approach to enhancing existing workflow management systems to enable team-based job management in the field of telecommunications service provision and maintenance. This paper adopts a component-based approach and explains how applications can be developed by customising the generic components provided by a multi-agent systems framework
How to Best Choose the Outer Coarse Mesh in the Domain Decomposition Method of Bank and Jimack
No full textIn Ciaramella et al. (2020) we defined a new partition of unity for the Bank–Jimack domain decomposition method in 1D and proved that with the new partition of unity, the Bank–Jimack method is an optimal Schwarz method in 1D and thus converges in two iterations for two subdomains: it becomes a direct solver, and this independently of the outer coarse mesh one uses! In this paper, we show that the Bank–Jimack method in 2D is an optimized Schwarz method and its convergence behavior depends on the structure of the outer coarse mesh each subdomain is using. For an equally spaced coarse mesh its convergence behavior is not as good as the convergence behavior of optimized Schwarz. However, if a stretched coarse mesh is used, then the Bank–Jimack method becomes faster then optimized Schwarz with Robin or Ventcell transmission conditions. Our analysis leads to a conjecture stating that the convergence factor of the Bank–Jimack method with overlap L and m geometrically stretched outer coarse mesh cells is [Formula: see text]
Analysis of the parallel Schwarz method for growing chains of fixed-sized subdomains: Part III. ETNA - Electronic Transactions on Numerical Analysis
No full textIn the ddCOSMO solvation model for the numerical simulation ofmolecules (chains of atoms), the unusual observation was made thatthe associated Schwarz domain-decomposition method converges independentlyof the number of subdomains (atoms) and this without coarsecorrection, i.e., the one-level Schwarz method is scalable.We analyzed this unusual property for the simplified caseof a rectangular molecule and square subdomains using Fourier analysis,leading to robust convergence estimates in the -norm and lateralso for chains of subdomains represented by disks using maximumprinciple arguments, leading to robust convergence estimates in. A convergence analysis in the more natural-setting proving convergence independently of the number ofsubdomains was, however, missing. We close this gap in this paperusing tools from the theory of alternating projection methodsand estimates introduced by P.-L. Lions for the study of domaindecomposition methods. We prove that robust convergenceindependently of the number of subdomains is possible also in and show furthermore that even for certain two-dimensional domainswith holes, Schwarz methods can be scalable without coarse-space corrections.As a by-product, we review some of the results of P.-L. Lions[On the Schwarz alternating method. I, in DomainDecomposition Methods for Partial Differential Equations, SIAM,Philadelphia, 1988, pp. 1-42]and in some cases provide simpler proofs
The Domain Decomposition Method of Bank and Jimack as an Optimized Schwarz Method
No full textIn 2001 Randolph E. Bank and Peter K. Jimack [1] introduced a new domain decomposition method for the adaptive solution of elliptic partial differential equations, see also [2]
Optimized Schwarz Methods for Advection Diffusion Equations in Bounded Domains
No full textOptimized Schwarz methods use better transmission conditions than the classical Dirichlet conditions that were used by Schwarz. These transmission conditions are optimized for the physical problem that needs to be solved to lead to fast convergence. The opimization is typically performed in the geometrically simplified setting of two unbounded subdomains using Fourier transforms. Recent studies for both homogeneous and heterogeneous domain decomposition methods indicate that the geometry of the physical domain has actually an influence on this opimization process. We study here this influence for an advection diffusion equation in a bounded domain using separation of variables. We provide theoretical results for the min-max problems characterizing the optimized transmission conditions. Our numerical experiments show significant improvements of the new transmission conditions which take the geometry into account, especially for strong tangential advection. </p
Linear and nonlinear substructured Restricted Additive Schwarz iterations and preconditioning
No full textIterative substructuring Domain Decomposition (DD) methods have been extensively studied, and they are usually associated with nonoverlapping decompositions. It is less known that classical overlapping DD methods can also be formulated in substructured form, i.e., as iterative methods acting on variables defined exclusively on the interfaces of the overlapping domain decomposition. We call such formulations substructured domain decomposition methods. We introduce here a substructured version of Restricted Additive Schwarz (RAS) which we call SRAS. We show that RAS and SRAS are equivalent when used as iterative solvers, as they produce the same iterates, while they are substantially different when used as preconditioners for GMRES. We link the volume and substructured Krylov spaces and show that the iterates are different by deriving the least squares problems solved at each GMRES iteration. When used as iterative solvers, SRAS presents computational advantages over RAS, as it avoids computations with matrices and vectors at the volume level. When used as preconditioners, SRAS has the further advantage of allowing GMRES to store smaller vectors and perform orthogonalization in a lower dimensional space. We then consider nonlinear problems, and we introduce SRASPEN (Substructured Restricted Additive Schwarz Preconditioned Exact Newton), where SRAS is used as a preconditioner for Newton’s method. In contrast to the linear case, we prove that Newton’s method applied to the preconditioned volume and substructured formulation produces the same iterates in the nonlinear case. Next, we introduce two-level versions of nonlinear SRAS and SRASPEN. Finally, we validate our theoretical results with numerical experiments.CSQ
On the nonlinear Dirichlet-Neumann method and preconditioner for Newton's method
No full textThe Dirichlet-Neumann (DN) method has been extensively studied for linear partial differential equations, while little attention has been devoted to the nonlinear case. In this paper, we analyze the DN method both as a nonlinear iterative method and as a preconditioner for Newton's method. We discuss the nilpotent property and prove that under special conditions, there exists a relaxation parameter such that the DN method converges quadratically. We further prove that the convergence of Newton's method preconditioned by the DN method is independent of the relaxation parameter. Our numerical experiments further illustrate the mesh independent convergence of the DN method and compare it with other standard nonlinear preconditioners.CSQ
GANDER: a Platform for Exploration of Gaze-driven Assistance in Code Review - Supplementary Material
No full text<p>Supplementary material for the paper "GANDER: a Platform for Exploration of Gaze-driven Assistance in Code Review"</p>
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