This paper studies the three-term conjugate gradient method for unconstrained optimization. The method includes the classical (two-term) conjugate gradient method and the famous Beale-Powell restart algorithm as its s...
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This paper studies the three-term conjugate gradient method for unconstrained optimization. The method includes the classical (two-term) conjugate gradient method and the famous Beale-Powell restart algorithm as its special forms. Some mild conditions are given in this paper, which ensure the global convergence of general three-term conjugate gradient methods.
For large sparse system of linear equations with the coefficient matrix with a dominant indefinite symmetric part, we present a class of splitting minimal resid- ual method, briefly called as SMINRES-method, by making...
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For large sparse system of linear equations with the coefficient matrix with a dominant indefinite symmetric part, we present a class of splitting minimal resid- ual method, briefly called as SMINRES-method, by making use of the inner/outer iteration technique. The SMINRES-method is established by first transforming the linear system into an equivalent fixed-point problem based on the symmetric/skew- symmetric splitting of the coefficient matrix, and then utilizing the minimal resid- ual (MINRES) method as the inner iterate process to get a new approximation to the original system of linear equations at each of the outer iteration step. The MINRES can be replaced by a preconditioned MINRES (PMINRES) at the inner iterate of the SMINRES method, which resulting in the so-called preconditioned splitting minimal residual (PSMINRES) method. Under suitable conditions, we prove the convergence and derive the residual estimates of the new SMINRES and PSMINRES methods. Computations show that numerical behaviours of the SMIN- RES as well as its symmetric Gauss-Seidel (SGS) iteration preconditioned variant, SGS-SMINRES, are superior to those of some standard Krylov subspace meth- ods such as CGS, CMRES and their unsymmetric Gauss-Seidel (UGS) iteration preconditioned variants UGS-CGS and UGS-GMRES.
In this paper we discuss the natural boundary element method for harmonic equation in an exterior elliptic domain. By studying the properties of the natural integral operator and the Poisson integral operator, we deve...
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In this paper we discuss the natural boundary element method for harmonic equation in an exterior elliptic domain. By studying the properties of the natural integral operator and the Poisson integral operator, we develop a numerical method to solve the natural integral equation. We also devise a fast algorithm for the solution of the corresponding system of linear equations. Finally we present some numerical results.
In this paper, based on the problems studied in [1], the discrete schemes of the coupling of FEM and BEM for the nonlinear parabolic equations are given. The existence of the approximation solution, and stability resu...
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In this paper, based on the problems studied in [1], the discrete schemes of the coupling of FEM and BEM for the nonlinear parabolic equations are given. The existence of the approximation solution, and stability results and corresponding error estimates are discussed in detail. Finally, the numerical example is provided, and numerical results show that the method is feasible and effective.
The paper presents a posteriori error estimate of FD-SD method for one- dimension time-dependent convection- dominated diffusion equation 5 which can be used to adjust space mesh. Some numerical results and an algorit...
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The paper presents a posteriori error estimate of FD-SD method for one- dimension time-dependent convection- dominated diffusion equation 5 which can be used to adjust space mesh. Some numerical results and an algorithm of adaptive finite element method based on this a posteriori error estimate are given.
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