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Showing 1 to 20 of 38 for “"nonsymmetric"”.
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Energy methods for nonsymmetric nonlocal operators
… driven by nonlocal operators associated with nonsymmetric bilinear forms. In contrast to the symmetric case, nonsymmetric nonlocal operators have not yet been studied systematically. Our main results contain Hölder regularity estimates, full Harnack inequalities, and two-sided heat kernel …
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Solution of Nonsymmetric Systems of Equations on a Multiprocessor
We consider the iterative solution of large sparse linear systems of equations arising from elliptic and parabolic partial differential equations in two and three space dimensions. Specifically, we focus our attention on non-symmetric systems of equations whose eigenvalues lie on both sides of the …
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Techniques for handling nonsymmetric cones in interior point algorithms
… cones that are not symmetric. Algorithms for nonsymmetric cones have been implemented in significantly fewer solvers. Practically efficient, self-concordant barrier functions have not been previously suggested for many useful nonsymmetric cones. For the nonsymmetric cones with known barriers, …
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Approximation of the Scattering Amplitude using Nonsymmetric Saddle Point Matrices
<p>In this thesis we look at iterative methods for solving the primal (<strong>A</strong>x = b) and dual (<strong>A</strong><em><sup><strong>T </strong></sup></em>y = g) systems of linear equations to approximate the scattering amplitude defined by g<em><sup><strong>T</strong></sup></em>x …
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On a posteriori finite element bound procedures for nonsymmetric Eigenvalue problems
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mathematics, 1999.
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Preconditioned iterative methods for highly sparse, nonsymmetric, unstructured linear algebra problems
… Ax = b in which A is large, highly sparse, nonsymmetric, and unstructured. Several iterative methods which are applicable to nonsymmetric and indefinite problems are applied to a suite of test problems derived from simulations of actual bipolar circuits and to a viscous flow problem. Methods …
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An Iterative Method for Solving Nonsymmetric Linear Systems With Dynamic Estimation of Parameters
Made available in DSpace on 2014-12-14T13:09:27Z (GMT). No. of bitstreams: 1 7606854.pdf: 4599366 bytes, checksum: a872f24ed765aff02aa6956ccbf8c8e6 (MD5) Previous issue date: 1975
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On the Use of Arnoldi and Golub-Kahan Bases to Solve Nonsymmetric Ill-Posed Inverse Problems
Iterative Krylov subspace methods have proven to be efficient tools for solving linear systems of equations. In the context of ill-posed inverse problems, they tend to exhibit semiconvergence behavior making it difficult detect ``inverted noise" and stop iterations before solutions become …
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Partially-Symmetric Macdonald Polynomials
Nonsymmetric Macdonald polynomials can be symmetrized in all their variables to obtain the (symmetric) Macdonald polynomials. We generalize this process, symmetrizing the nonsymmetric Macdonald polynomials in only the first k out of n variables. The resulting partially-symmetric Macdonald …
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Restarting the Lanczos algorithm for large eigenvalue problems and linear equations.
… Restarted versions of both the symmetric and nonsymmetric Lanczos algorithms are given. For the symmetric case, we give a method called Lan-DR that simultaneously solves linear equations and computes eigenvalues and eigenvectors. The use of approximate eigenvectors deflates eigenvalues. …
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Torricelli's Law and the Turn-Up Number
… turn-up number of 1. That allows us to construct nonsymmetric clepsydra.</p>
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Accelerating the Jacobi Iteration for Solving Linear Systems of Equations using Theory, Machine Learning, and High Performance Computing
… provide acceleration for both symmetric and nonsymmetric linear systems of equations. In the symmetric case, a data informed heuristic is developed to aid scheme selection in a practical implementation without user intervention. Secondly, we develop a high-performance GPU implementation of …
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Row Projection Methods for Linear Systems
… An implementation approach is presented for nonsymmetric matrices arising from the seven point centered difference operator applied to three dimensional elliptic partial differential equations. This approach allows large scale parallelism in the computations, requires only a few extra vector …
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Investigation of nonlinear crack tip deformation including the effects of unsymmetric spatial variations of material properties
… techniques of focusing attention on the nonsymmetric deformation fields around a crack tip in a non-uniform yield strength varying material. Each analysis independently shows that the material non-uniformities alter stress and strain distributions drastically and that a statically …
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Domain decomposition and high order discretization of elliptic partial differential equations
… variable PDE coefficients generally result in a nonsymmetric A, and less is known about the use of preconditioned Krylov subspace iterative methods for the solution of nonsymmetric systems. The use of the high order accurate discretization together with a domain decomposition based preconditioner …
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A Modified Preconditioned Conjugate Gradient Method for Approximating the Scattering Amplitude
… derive a conjugate gradient-like iteration for a nonsymmetric saddle point matrix that is constructed to have a real positive spectrum. We investigate the use of Schur Complement preconditioners with block-diagonal factorization to speed up the convergence of our method and compare the results to …
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Efficient Solution of Large Sparse Eigenvalue Problems in Microelectronic Simulation
… which is essentially the same for symmetric, nonsymmetric, and complex nonhermitian matrices, is adapted to a specific problem by two subroutines which encapsulate the problem-specific definition of energy, plus the discretization and matrix-vector multiply routines. We adapt the algorithm to …
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Studies on quadratic matrix equations and riccati differential equations associated with regular m-matrices
… are studied by transforming the equation into a nonsymmetric algebraic Riccati equation for which the four coe cient matrices form a regular M-matrix. We also discuss the initial value problem for a matrix Riccati di erential equation associated with a regular M-matrix. We show that for suitable …
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Parallel Domain Decomposition Preconditioning for the Adaptive Finite Element Solution of Elliptic Problems in Three Dimensions
… suitable for symmetric problems but also for nonsymmetric and convection-dominated elliptic problems. This generalization, in the absence of theoretical or mathematical background, is based on empirical observations. Moreover, it turns out to be more effective and robust than the original …
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Dynamic analysis of composite beams using shear-deformable finite elements
… and orthotropic layers in symmetric and nonsymmetric configurations can be accomodated. In addition, the elements can impose a kinematic constraint on the entire beam or on individual layers within the beam. This study refers to elements which employ the latter approach as ""stacked …
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