In this paper, based on the natural boundary reduction suggested by Feng and Yu,an overlapping domain decomposition method for harmonic boundary value problerns on the unbounded sector domain or the unbounded cracked ...
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In this paper, based on the natural boundary reduction suggested by Feng and Yu,an overlapping domain decomposition method for harmonic boundary value problerns on the unbounded sector domain or the unbounded cracked domain is discussed. The numerical examples show that this discrete Schwarz iteration is geometric *** the convergence rate of this method is independent of the finite element mesh size,but dependent on the frequency of the exact solution and the overlaPping degree of thesubdomains.
A predictor-correct interior point method is presented for solving convex quadraticprogramming problem with box constraints in this paper. Actually, the method isequivalent to solve a system of equations-the first ord...
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A predictor-correct interior point method is presented for solving convex quadraticprogramming problem with box constraints in this paper. Actually, the method isequivalent to solve a system of equations-the first order optimality conditions of theproblem by decomposing one Newton step with one simplified Newton step, and hasa nice convergent property with high order. Moreover, the center direction generatedby introducing the barrier parameter is used to correct the descent Newton directionsuch that the search direction which consists of the center and Newton direction avoidshitting the board of the feasible region. Therefore, the iterative sequence generated bythe algorithm is remained inside of the feasible region and converges to the optimalsolution. The numerical results for a group of test problems are also given, and haveshown that the algorithm works very efficiently.
In this paper we present a set of absorbing boundary conditions based on the higher order approximations of one-way wave equations. By introducing new functions, these absorbing boundary conditions are put into the fo...
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In this paper we present a set of absorbing boundary conditions based on the higher order approximations of one-way wave equations. By introducing new functions, these absorbing boundary conditions are put into the form of systems of lower order partial differential equations. The stability of initial boundary value problems with these type of boundary conditions is discussed. The energy estimates for their solutions are obtained.
Do-loop unrolling is an effective technique for improving performance of applicistion programs. This paper presents a method for unrolling nested Fortran DO-loops using the m4 macro language. m4 is a macro processor w...
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Do-loop unrolling is an effective technique for improving performance of applicistion programs. This paper presents a method for unrolling nested Fortran DO-loops using the m4 macro language. m4 is a macro processor widely available on UNIX platforms. By using carefully designed m4 macros, Do-loop unrolling becomes much simpler. More over, with this method, code can be written for general ullrolling parameters, allowing the program to be easily tuned bn different computers to reach optimal performance.
Asynchronous parallel multisplitting nonlinear symmetric Gauss-Seidel methods are established for the system of nonlinear equations , withA, B∈L(Rn) being matrices of particular properties, being diagonal and continu...
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Asynchronous parallel multisplitting nonlinear symmetric Gauss-Seidel methods are established for the system of nonlinear equations , withA, B∈L(Rn) being matrices of particular properties, being diagonal and continuous mappings, and b ∈Rn a known vector. The establishments of these new methods are according to the principle of sufficiently using the delayed information and are concerning about the concrete characteristics of the multiprocessor systems. Therefore, they have considerably higher parallel computingefficiency. The global convergenge as well as the asymptotic convergence rates of these new methods are investigated in detail under suitable conditions.
In this paper the natural boundary reduction, suggested by Feng and Yu[1], is applied to deal with the three-dimensional problems. By expansion in spherical harmonics, we obtain the natural integral equations of harmo...
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In this paper the natural boundary reduction, suggested by Feng and Yu[1], is applied to deal with the three-dimensional problems. By expansion in spherical harmonics, we obtain the natural integral equations of harmonic problems over interior and exterior spherical domains. Meanwhile, we develop a numerical method for sloving these equations. Some numerical examples are also given to illustrate our method.
In using the methods given by [1] to compute the hypersingular integrals on interval,one should select the mesh carefully in such a way that singular point falls near the center of a subinterval. A numerical method gi...
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In using the methods given by [1] to compute the hypersingular integrals on interval,one should select the mesh carefully in such a way that singular point falls near the center of a subinterval. A numerical method given in this paper might solve this problem. This new method is very simple, easy to be implemented, and above all, notaffected by the location of singular point.
This paper deals with parallel implemeatation on distributed memory systemsof a pressure-correction projection scheme for the unsteady incompressible NavierStokes equations, the CNMT2 scheme (i.e., the Crank-Nickolson...
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This paper deals with parallel implemeatation on distributed memory systemsof a pressure-correction projection scheme for the unsteady incompressible NavierStokes equations, the CNMT2 scheme (i.e., the Crank-Nickolson Modified Temamscheme Ⅱ), presented in [1, 2]. The key point of this work is to study parallelizationof the fast Poisson solver [2] and analyse its parallel efficiency. Various techniques,such as pipelining and canon cyclic algorithm, were used to ensure good parallel performance and scalability of the algorithm. The algorithm has been implemented using MPI message passing environment and numerical tests have been carried out on various computers, including the home made Dawn-1000 MPP system and workstation clusters.
In this paper, we propose a new definition of symplectic multistep methods. This definition differs from the old ones in that it is given via the one step method defined directly on M which is corresponding to the m s...
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In this paper, we propose a new definition of symplectic multistep methods. This definition differs from the old ones in that it is given via the one step method defined directly on M which is corresponding to the m step scheme defined on M while the old definitions are given out by defining a corresponding one step method on M × M ×…× M = Mm with a set of new variables. The new definition gives out a steptransition operator g: M → M. Under our new definition, the Leap-frog method is symplectic only for linear Hamiltonian systems. The transition operator g will be constructed via continued fractions and rational approximations.
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