共查询到20条相似文献,搜索用时 15 毫秒
1.
Summary. We consider a piecewise constant finite element approximation to the convolution Volterra equation problem of the second
kind: find such that in a time interval . An a posteriori estimate of the error measured in the norm is developed and used to provide a time step selection criterion for an adaptive solution algorithm. Numerical examples
are given for problems in which is of a form typical in viscoelasticity theory.
Received March 5, 1998 / Revised version received November 30, 1998 / Published online December 6, 1999 相似文献
2.
Summary. In this paper, we study finite volume schemes for the nonhomogeneous scalar conservation law with initial condition . The source term may be either stiff or nonstiff. In both cases, we prove error estimates between the approximate solution given by a finite volume scheme (the scheme is totally explicit in the nonstiff case, semi-implicit in the stiff case) and the entropy solution. The order of these estimates is in space-time -norm (h denotes the size of the mesh). Furthermore, the error estimate does not depend on the stiffness of the source term in the stiff case. Received October 21, 1999 / Published online February 5, 2001 相似文献
3.
Summary. We present an approximate-inertial-manifold-based postprocess to enhance Chebyshev or Legendre spectral Galerkin methods.
We prove that the postprocess improves the order of convergence of the Galerkin solution, yielding the same accuracy as the
nonlinear Galerkin method. Numerical experiments show that the new method is computationally more efficient than Galerkin
and nonlinear Galerkin methods. New approximation results for Chebyshev polynomials are presented.
Received January 5, 1998 / Revised version received September 7, 1999 / Published online June 8, 2000 相似文献
4.
On one approach to a posteriori error estimates for evolution problems solved by the method of lines 总被引:2,自引:0,他引:2
Summary. In this paper, we describe a new technique for a posteriori error estimates suitable to parabolic and hyperbolic equations
solved by the method of lines. One of our goals is to apply known estimates derived for elliptic problems to evolution equations.
We apply the new technique to three distinct problems: a general nonlinear parabolic problem with a strongly monotonic elliptic
operator, a linear nonstationary convection-diffusion problem, and a linear second order hyperbolic problem. The error is
measured with the aid of the -norm in the space-time cylinder combined with a special time-weighted energy norm. Theory as well as computational results
are presented.
Received September 2, 1999 / Revised version received March 6, 2000 / Published online March 20, 2001 相似文献
5.
Interpolation error-based a posteriori error estimation for two-point boundary value problems and parabolic equations in one space dimension 总被引:1,自引:0,他引:1
Peter K. Moore 《Numerische Mathematik》2001,90(1):149-177
Summary. I derive a posteriori error estimates for two-point boundary value problems and parabolic equations in one dimension based on interpolation error
estimates. The interpolation error estimates are obtained from an extension of the error formula for the Lagrange interpolating
polynomial in the case of symmetrically-spaced interpolation points. From this formula pointwise and seminorm a priori estimates of the interpolation error are derived. The interpolant in conjunction with the a priori estimates is used to obtain asymptotically exact a posteriori error estimates of the interpolation error. These a posteriori error estimates are extended to linear two-point boundary problems and parabolic equations. Computational results demonstrate
the convergence of a posteriori error estimates and their effectiveness when combined with an hp-adaptive code for solving parabolic systems.
Received April 17, 2000 / Revised version received September 25, 2000 / Published online May 30, 2001 相似文献
6.
Summary. Using a slightly different discretization scheme in time and adapting the approach in Nochetto et al. (1998) for analysing the time discretization error in the backward Euler method, we improve on the error bounds derived in (i) Barrett and Blowley (1998) and (ii) Barrett and Blowey (1999c) for a fully practical piecewise linear finite element approximation of a model for phase separation of a multi-component alloy with a concentration dependent mobility matrix and (i) a logarithmic free energy, and (ii) a non-smooth free energy (the deep quench limit); respectively. Moreover, the improved error bound in the deep quench limit is optimal. Numerical experiments with three components illustrating the above error bounds are also presented. Received June 28, 1999 / Revised version received December 3, 1999 / Published online November 8, 2000 相似文献
7.
K. Segeth 《Numerische Mathematik》1999,83(3):455-475
Summary. Convergence of a posteriori error estimates to the true error for the semidiscrete finite element method of lines is shown
for a nonlinear parabolic initial-boundary value problem.
Received June 15, 1997 / Revised version received May 15, 1998 / Published online: June 29, 1999 相似文献
8.
Summary.
An error
bound is proved for a fully practical piecewise linear finite
element approximation, using a backward Euler time
discretization, of the Cahn-Hilliard equation with a logarithmic
free energy.
Received October 12, 1994 相似文献
9.
Summary. Interpolation with translates of a basis function is a common process in approximation theory. The most elementary form of
the interpolant consists of a linear combination of all translates by interpolation points of a single basis function. Frequently,
low degree polynomials are added to the interpolant. One of the significant features of this type of interpolant is that it
is often the solution of a variational problem. In this paper we concentrate on developing a wide variety of spaces for which
a variational theory is available. For each of these spaces, we show that there is a natural choice of basis function. We
also show how the theory leads to efficient ways of calculating the interpolant and to new error estimates.
Received December 10, 1996 / Revised version received August 29, 1997 相似文献
10.
Georgios E. Zouraris 《Numerische Mathematik》1997,77(1):123-142
Summary. We analyze a class of algebraically stable Runge–Kutta/standard Galerkin methods for inhomogeneous linear parabolic equations,
with time–dependent coefficients, under Neumann boundary conditions, and derive an error bound of provided is bounded.
Received June 25, 1994 / Revised version received February 26, 1996 相似文献
11.
Summary. The perfectly matched layer (PML) is an efficient tool to simulate propagation phenomena in free space on unbounded domain.
In this paper we consider a new type of absorbing layer for Maxwell's equations and the linearized Euler equations which is
also valid for several classes of first order hyperbolic systems. The definition of this layer appears as a slight modification
of the PML technique. We show that the associated Cauchy problem is well-posed in suitable spaces. This theory is finally
illustrated by some numerical results. It must be underlined that the discretization of this layer leads to a new discretization
of the classical PML formulation.
Received May 5, 2000 / Published online November 15, 2001 相似文献
12.
Summary. We give the asymptotic formula for the error in cardinal interpolation. We generalize the Mazur Orlicz Theorem for periodic
function.
Received February 22, 1999 / Revised version received October 15, 1999 / Published online March 20, 2001 相似文献
13.
Summary. Suppose one approximates an invariant subspace of an
matrix in
which in not necessarily
self--adjoint. Suppose
that one also has an approximation for the corresponding eigenvalues. We
consider the question of how good the approximations are. Specifically, we
develop bounds on the angle between the approximating subspace and the
invariant subspace itself.
These bounds are functions
of the following three terms: (1) the residual of the approximations; (2)
singular--value separation in an associated matrix; and (3) the goodness
of the approximations to the eigenvalues.
Received December 1, 1992 / Revised version received October 20,
1993 相似文献
14.
The global error of numerical approximations for symmetric positive systems in the sense of Friedrichs is decomposed into
a locally created part and a propagating component. Residual-based two-sided local a posteriori error bounds are derived for
the locally created part of the global error. These suggest taking the -norm as well as weaker, dual norms of the computable residual as local error indicators. The dual graph norm of the residual
is further bounded from above and below in terms of the norm of where h is the local mesh size. The theoretical results are illustrated by a series of numerical experiments.
Received January 10, 1997 / Revised version received March 5, 1998 相似文献
15.
Christian Kanzow 《Numerische Mathematik》1998,80(4):557-577
Summary. We consider a quadratic programming-based method for nonlinear complementarity problems which allows inexact solutions of
the quadratic subproblems. The main features of this method are that all iterates stay in the feasible set and that the method
has some strong global and local convergence properties. Numerical results for all complementarity problems from the MCPLIB
test problem collection are also reported.
Received February 24, 1997 / Revised version received September 5, 1997 相似文献
16.
Summary. In this paper we are interested in two phase flow problems in porous media. We use a Dual Mesh Method to discretize this
problem with finite volume schemes. In a simplified case (elliptic - hyperbolic system) we prove the convergence of approximate
solutions to the exact solutions. We use the Dual Mesh Method in physically complex problems (heterogeneous cases with non
constant total mobility). We validate numerically the Dual Mesh Method on practical examples by computing error estimates
for different test-cases.
Received March 21, 1997 / Revised version received October 13, 1997 相似文献
17.
A numerically stable, structure preserving method for computing the eigenvalues of real Hamiltonian or symplectic pencils 总被引:3,自引:0,他引:3
A new method is presented for the numerical computation of the generalized eigenvalues of real Hamiltonian or symplectic
pencils and matrices. The method is numerically backward stable and preserves the structure (i.e., Hamiltonian or symplectic).
In the case of a Hamiltonian matrix the method is closely related to the square reduced method of Van Loan, but in contrast
to that method which may suffer from a loss of accuracy of order , where is the machine precision, the new method computes the eigenvalues to full possible accuracy.
Received April 8, 1996 / Revised version received December 20, 1996 相似文献
18.
Silvia Bertoluzza 《Numerische Mathematik》1997,78(1):1-20
Summary. In this paper we derive an interior estimate for the Galerkin method with wavelet-type basis. Such an estimate follows from
interior Galerkin equations which are common to a class of methods used in the solution of elliptic boundary value problems.
We show that the error in an interior domain can be estimated with the best order of accuracy possible, provided the solution is sufficiently regular in a slightly larger domain, and that an estimate of the same order exists for the error in a weaker
norm (measuring the effects from outside the domain ). Examples of the application of such an estimate are given for different problems.
Received May 17, 1995 / Revised version received April 26, 1996 相似文献
19.
Walter Gautschi 《Numerische Mathematik》2001,87(4):791-792
Summary. A formula for the efficient evaluation of the (truncated) cardinal series is known to be numerically unstable near the interpolation abscissae. Here it is shown how the series can be evaluated in an entirely stable manner. Received February 14, 2000 / Published online October 16, 2000 相似文献
20.
A posteriori error estimate for finite volume approximations to singularly perturbed nonlinear convection-diffusion equations 总被引:1,自引:0,他引:1
Mario Ohlberger 《Numerische Mathematik》2001,87(4):737-761
Summary. This paper is devoted to the study of a posteriori and a priori error estimates for the scalar nonlinear convection diffusion equation . The estimates for the error between the exact solution and an upwind finite volume approximation to the solution are derived
in the -norm in the situation, where the diffusion parameter is smaller or comparable to the mesh size. Numerical experiments underline the theoretical results.
Received February 25, 1999 / Revised version received July 6, 1999 / Published online August 2, 2000 相似文献