共查询到20条相似文献,搜索用时 69 毫秒
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用n-1个单参数李群求n阶自治系统的首次积分 总被引:1,自引:1,他引:0
在一般条件下,对n阶自治系统给出利用系统所接受的n-1个独立单参数李群的生成元计算首次积分的方法,并给出方程组有满足条件的非零解的充要条件. 相似文献
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一个求解线性不等式约束的非线性规划的广义梯度投影内点 … 总被引:1,自引:0,他引:1
基于内点算法思想,利用广义投影技术设计了求解带线性不等式约束和非负约束的非线性规划的广义梯度投影内点算法,并了算法的收敛性质,数值例子表明算法是有效的。 相似文献
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讨论带非线性不等式和等式约束的最优化问题,借助强次可行方向法和半罚函数的思想,给出了问题的一个新的广义投影强次可行方向法.该算法的一个重要特性是有限次迭代后,迭代点落入半罚问题的可行域.在适当的条件下证明了算法的全局收敛性和强收敛性.数值实验表明算法是有效的. 相似文献
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Stein Krogstad 《BIT Numerical Mathematics》2003,43(1):107-122
A low complexity Lie group method for numerical integration of ordinary differential equations on the orthogonal Stiefel manifold is presented. Based on the quotient space representation of the Stiefel manifold we provide a representation of the tangent space suitable for Lie group methods. According to this representation a special type of generalized polar coordinates (GPC) is defined and used as a coordinate map. The GPC maps prove to adapt well to the Stiefel manifold. For the n×k matrix representation of the Stiefel manifold the arithmetic complexity of the method presented is of order nk
2, and for nk this leads to huge savings in computation time compared to ordinary Lie group methods. Numerical experiments compare the method to a standard Lie group method using the matrix exponential, and conclude that on the examples presented, the methods perform equally on both accuracy and maintaining orthogonality. 相似文献
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约束优化问题的一个变尺度投影算法的全局收敛性 总被引:3,自引:1,他引:2
叶留青 《数学的实践与认识》2004,34(2):115-117
利用投影算子 PxΩ 建立了求解问题 ( P)的变尺度投影算法 ,并讨论了算法的全局收敛性 . 相似文献
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In this paper we mainly concern the persistence of invariant tori in generalized Hamiltonian systems. Here the generalized Hamiltonian systems refer to the systems which may admit a distinct number of action and angle variables. In particular, system under consideration can be odd dimensional. Under the Riissmann type non-degenerate condition, we proved that the majority of the lower-dimension invariant tori of the integrable systems in generalized Hamiltonian system are persistent under small perturbation. The surviving lower-dimensional tori might be elliptic, hyperbolic, or of mixed type. 相似文献
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本文给出三体在—般情形下的伴随李群系与守恒量,并在特殊的力势函数下求出了三体扩展的伴随李群系,进一步利用这个扩展的伴随李群系求出除10个经典守恒外的更多守恒量. 相似文献
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This paper develops convergence theory of the gradient projection method by Calamai and Moré (Math. Programming, vol. 39, 93–116, 1987) which, for minimizing a continuously differentiable optimization problem min{f(x) : x } where is a nonempty closed convex set, generates a sequence xk+1 = P(xk – k f(xk)) where the stepsize k > 0 is chosen suitably. It is shown that, when f(x) is a pseudo-convex (quasi-convex) function, this method has strong convergence results: either xk x* and x* is a minimizer (stationary point); or xk arg min{f(x) : x } = , and f(xk) inf{f(x) : x }. 相似文献
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With the help of a Lie algebra,two kinds of Lie algebras with the forms of blocks are introduced for generating nonlinear integrable and bi-integrable couplings.For illustrating the application of the Lie algebras,an integrable Hamiltonian system is obtained,from which some reduced evolution equations are presented.Finally,Hamiltonian structures of nonlinear integrable and bi-integrable couplings of the integrable Hamiltonian system are furnished by applying the variational identity.The approach presented in the paper can also provide nonlinear integrable and bi-integrable couplings of other integrable system. 相似文献
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Allanus H. Tsoi 《Journal of Theoretical Probability》1993,6(4):693-698
LetG be a Lie group ofd×d matrices and be theLLie algebra ofG. We choose some Euclidean norm on , and an orthonormal basis (D
1,...D
m
) relative to it. Let
be the corresponding left invariant vector fields onG. In this paper we derive an integration by parts formula for aG-valued Brownian motion corresponding to the Laplacian
. 相似文献
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In this paper we prove the persistence of hyperbolic invariant tori in generalized Hamiltonian systems, which may admit a distinct number of action and angle variables. The systems under consideration can be odd dimensional in tangent direction. Our results generalize the well-known results of Graff and Zehnder in standard Hamiltonians. In our case the unperturbed Hamiltonian systems may be degenerate. We also consider the persistence problem of hyperbolic tori on sub manifolds. 相似文献