共查询到20条相似文献,搜索用时 239 毫秒
1.
基于传统的Wolfe线搜索,提出了一种新的非精确线搜索.在无需限制参数σ≤1/2的情况下(即盯的取值范围扩展至0<σ<1),证明了FR算法的全局收敛性.数值实验表明了这种线搜索下的FR算法的有效性. 相似文献
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大步长非单调线搜索规则的Lampariello修正对角稀疏拟牛顿算法的全局收敛性 总被引:3,自引:0,他引:3
本文在ZhangH.C.的非单调线搜索规则基础上,结合ShiZ.J.大步长线搜索技巧提出了新的大步长的非单调线搜索规则,设计了求解无约束最优化问题的大步长非单调线搜索规则的Lampariello修正对角稀疏拟牛顿算法,在△f(x)一致连续的条件下给出了算法的全局收敛性和超线性收敛性分析.数值例子表明算法是有效的,适合求解大规模问题. 相似文献
4.
本文在Zhang
H.C.的非单调线搜索规则的基础上,设计了求解无约束最优化问题的新的非单调线搜索BFGS算法,在一定
的条件下证明了算法的线性收敛性和超线性收敛性分析.数值例子表明算法是有效的. 相似文献
5.
一类新的非单调记忆梯度法及其全局收敛性 总被引:1,自引:0,他引:1
在非单调Armijo线搜索的基础上提出一种新的非单调线搜索,研究了一类在该线搜索下的记忆梯度法,在较弱条件下证明了其全局收敛性。与非单调Armijo线搜索相比,新的非单调线搜索在每次迭代时可以产生更大的步长,从而使目标函数值充分下降,降低算法的计算量。 相似文献
6.
本文研究了大规模无约束优化问题,提出了一个基于改进的FR共轭参数公式的共轭梯度法.不依赖于任何线搜索准则,算法所产生的搜索方向总是充分下降的.在标准Wolfe线搜索准则下,获得了新算法的全局收敛性.最后,对所提出的算法进行了初步数值实验,其结果表明所改进的方法是有效的. 相似文献
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文章结合非单调信赖域方法和非单调线搜索技术提出了一类新的无约束优化算法.与传统的非单调信赖与算法相比,此算法在每步都采用非单调Wolfe线搜索得到下一个迭代点,信赖域半径由子问题的近似解和线搜索的步长调节,这样得到的新算法不仅不需重解子问题,而且在每步迭代保证目标函数的近似海赛矩阵的正定性,在一定条件下证明了算法具有全局收敛性和Q-二次收敛性.数值试验表明算法是十分有效的. 相似文献
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为了确保变尺度算法在“坏条件”下的收敛性,本文提出对原算法的线搜索方向作适当地调整的方法,并且证明了带调整线搜索方向的Broyden类算法,无论线搜索是否精确,它对连接可微函数是收敛的,对一致凸函数是Q-超线性收敛的。 相似文献
11.
Jogi Henna 《Annals of the Institute of Statistical Mathematics》2005,57(4):655-664
An estimator of the number of components of a finite mixture ofk-dimensional distributions is given on the basis of a one-dimensional independent random sample obtained by a transformation
of ak-dimensional independent random sample. A consistency of the estimator is shown. Some simulation results are given in a case
of finite mixtures of two-dimensional normal distributions. 相似文献
12.
N/Kbe a Galois extension of number fields with finite Galois group G.We describe a new approach for constructing invariants of the G-module structure of the K groups of the ring of integers of N in the Grothendieck group of finitely generated projective Z[G]modules. In various cases we can relate these classes, and their function field counterparts, to the root number class of Fröhlich and Cassou-Noguès. 相似文献
13.
Piotr Je¸drzejewicz 《代数通讯》2013,41(4):1500-1508
Let A be a UFD of characteristic p > 0, let 𝒵 be a set of some eigenvectors of a derivation of A. We prove, under some additional assumptions, a necessary and sufficient condition for 𝒵 to be a p-basis of the minimal ring of constants containing 𝒵. The main preparatory result is the unique decomposition theorem with respect to a factor from a given subalgebra containing Ap. 相似文献
14.
有资格限制的指派问题的求解方法 总被引:3,自引:0,他引:3
在实际的指派工作中,常会遇到某个人有没有资格去承担某项工作的问题,因此,本建立了有资格限制的指派问题的数学模型。在此数学模型中,将效益矩阵转化为判定矩阵,由此给出了判定此种指派问题是否有解的方法;在有解的情况下,进一步将效益矩阵转化为求解矩阵,从而将有资格限制的指派问题化为传统的指派问题来求解。最后给出了一个数值例子来说明这样的处理方法是有效的。 相似文献
15.
We study the nilpotency of the sums of all coefficients of some sorts of products of polynomials over reversible, IFP, and NI rings, and introduce an SCN ring as a generalization. We characterize SCN rings in relation with related ring properties, and also provide several useful properties and ring extensions of SCN rings. 相似文献
16.
Rodney Y. Sharp 《Proceedings of the American Mathematical Society》2003,131(10):3009-3017
It is a well-known result of M. Brodmann that if is an ideal of a commutative Noetherian ring , then the set of associated primes of the -th power of is constant for all large . This paper is concerned with the following question: given a prime ideal of which is known to be in for all large integers , can one identify a term of the sequence beyond which will subsequently be an ever-present? This paper presents some results about convergence of sequences of sets of associated primes of graded components of finitely generated graded modules over a standard positively graded commutative Noetherian ring; those results are then applied to the above question.
17.
Let L be the Euclidean functional with p-th power-weighted edges. Examples include the sum of the p-th power-weighted lengths of the edges in minimal spanning trees, traveling salesman tours, and minimal matchings. Motivated
by the works of Steele, Redmond and Yukich (Ann. Appl. Probab. 4, 1057–1073, 1994, Stoch. Process. Appl. 61, 289–304, 1996) have shown that for n i.i.d. sample points {X
1,…,X
n
} from [0,1]
d
, L({X
1,…,X
n
})/n
(d−p)/d
converges a.s. to a finite constant. Here we bound the rate of convergence of EL({X
1,…,X
n
})/n
(d−p)/d
.
Y. Koo supported by the BK21 project of the Department of Mathematics, Sungkyunkwan University.
S. Lee supported by the BK21 project of the Department of Mathematics, Yonsei University. 相似文献
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Imme P. van den Berg 《Logic and Analysis》2008,1(2):153-185
One method to determine the asymptotics of particular solutions of a difference equation is by solving an associated asymptotic
functional equation. Here we study the behaviour of the solutions in an asymptotic neighbourhood of such individual solutions.
We identify several types of attraction and repulsion, which range from almost orthogonality to almost parallelness. Necessary
and sufficient conditions for these types of behaviour are given. 相似文献