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991.
研究具有一般形式的凸二次-线性双层规划问题。讨论了这类双层规划问题的DC规划等价形式,利用DC规划共轭对偶理论,提出了凸二次-线性双层规划的共轭对偶规划,并给出相应的对偶性质。 相似文献
992.
H. Egger 《Numerical Linear Algebra with Applications》2007,14(3):183-196
The conjugate gradient method applied to the normal equations (CGNE ) is known as efficient method for the solution of non‐symmetric linear equations. By stopping the iteration according to a discrepancy principle, CGNE can be turned into a regularization method, and thus can be applied to the solution of inverse, in particular, ill‐posed problems. We show that CGNE for inverse problems can be further accelerated by preconditioning in Hilbert scales, derive (optimal) convergence rates with respect to data noise, and give tight bounds on the iteration numbers. The theoretical results are illustrated by numerical tests. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
993.
研究了一类线性椭圆型分布参数最优控制问题的数值解算法.得到最优控制对应的最优性方程组,在凸性条件下,证明了最优控制的唯一存在性问题.将最优控制问题化为以控制函数和状态函数为局中人的递阶式(Stackelberg)非合作对策问题,其平衡点是最优控制的解.进一步得到求平衡点的边界元共轭梯度算法.最后,研究算法中边界元离散的误差估计,以算例验证该算法. 相似文献
994.
提出一类求解无约束最优化问题的混合共轭梯度算法,新算法有机地结合了DY算法和HS算法的优点,并采用非单调线搜索技术在较弱条件下证明了算法的全局收敛性.数值实验表明新算法具有良好的计算效能. 相似文献
995.
996.
In this study, the discretized finite volume form of the two-dimensional, incompressible Navier-Stokes equations is solved using both a frozen coefficient and a full Newton non-linear iteration. The optimal method is a combination of these two techniques. The linearized equations are solved using a conjugate-gradient-like method (CGSTAB). Various types of preconditioning are developed. Completely general sparse matrix methods are used. Investigations are carried out to determine the effect of finite volume cell anisotropy on the preconditioner. Numerical results are given for several test problems. 相似文献
997.
C. Beoni 《Journal of Optimization Theory and Applications》1986,49(3):375-387
This paper deals with an extention of Fenchel duality theory to fractional extremum problems, i.e., problems having a fractional objective function. The main result is obtained by regarding the classic Fenchel theorem as a decomposition property for the extremum of a sum of functions into a sum of extrema of functions, and then by extending it to the case where the addition is replaced by the quotient. This leads to a generalization of the classic concept of conjugate function. Several remarks are made about the conceivable further generalizations to other kinds of decomposition. 相似文献
998.
J. L. Nazareth 《Mathematical Programming》1986,35(1):97-109
The traditional development of conjugate gradient (CG) methods emphasizes notions of conjugacy and the minimization of quadratic functions. The associated theory of conjugate direction methods, strictly a branch of numerical linear algebra, is both elegant and useful for obtaining insight into algorithms for nonlinear minimization. Nevertheless, it is preferable that favorable behavior on a quadratic be a consquence of a more general approach, one which fits in more naturally with Newton and variable metric methods. We give new CG algorithms along these lines and discuss some of their properties, along with some numerical supporting evidence.I acknowledge partial support by ONR Contract #N00014-76-C-0013 at the Center for Pure & Applied Mathematics, University of California, Berkeley in the dissemination of this article. 相似文献
999.
Patrizia Scafato 《Tetrahedron》2004,60(40):8801-8806
The preparation of a new phosphoramidite starting from (R)-BINOL and a biphenylamine is presented. In such a compound the chirality is due only to atropisomerism and this molecule possesses a flexible biphenylamine residue. Therefore it can work as a tropos catalyst. The catalytic efficiency of this new phosphoramidite has been tested in some asymmetric conjugate additions of dialkylzinc reagents to α,β-enones and compared with that of an analogous already known non-tropos ligand. Interestingly, while comparable results were obtained in the addition of ZnEt2 to chalcone and cyclohexenone, in the case of the addition of ZnMe2 to (E)-cyclopentadec-2-en-1-one, the new ligand provides (−)-muscone, a valuable ingredient of the perfume industry, in 84% ee, while the non-tropos ligand gives a much lower (57%) ee value. 相似文献
1000.
Yakambram Pedduri 《Tetrahedron letters》2008,49(41):6009-6012
General and robust synthesis of highly functionalized tetrahydrofuran ring was accomplished with activated propargyl alcohol and reactive Michael acceptors in the presence of catalytic Bu3P. 相似文献