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141.
A new algorithm to compute the Legendre–Fenchel transform is proposed and investigated. The so-called Linear-time Legendre
Transform (LLT) improves all previously known Fast Legendre Transform algorithms by reducing their log-linear worst-case time
complexity to linear. Since the algorithm amounts to computing several convex hulls and sorting, any convex hull algorithm
well-suited for a particular problem gives a corresponding LLT algorithm. After justifying the convergence of the Discrete
Legendre Transform to the Legendre–Fenchel transform, an extended computation time complexity analysis is given and confirmed
by numerical tests. Finally, the LLT is illustrated with several examples and a LLT MATLAB package is described.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
142.
Asymptotic expansions in the two limitsx → + ∞ andx → 0+ are obtained for the Mehler-Fock transform
相似文献
143.
144.
We discuss the impact of modal filtering in Legendre spectral methods, both on accuracy and stability. For the former, we derive sufficient conditions on the filter to recover high order accuracy away from points of discontinuity. Computational results confirm that less strict necessary conditions appear to be adequate. We proceed to discuss a instability mechanism in polynomial spectral methods and prove that filtering suffices to ensure stability. The results are illustrated by computational experiments.
145.
1.IntroductionThereismuchliteratureconcerningnumericalsolutionsofNavier-Stokesequations,e.g.,see[1--4].FOrsemi-periodicproblems,someauthorusedcombinedFOurierspectralfinitedifferenceandFOurierspectral--finiteelementapproximations(see[5--8]).Influiddyn... 相似文献
146.
刘西民 《纯粹数学与应用数学》1998,14(2):93-97
引入并研究了3-Sasakian流形的3-C-全实子流形,借助了第二基本形式的长度,给出了单位球面S^4m+3-C-全实子流形的一个Pinching定理。 相似文献
147.
By virtue of the density operator's P-representation in the coherent state representation, we derive a new quantum mechanical photon counting distribution formula. As its application, we calculate photon counting distributions for some given light fields. It is found that the pure squeezed state's photon counting distribution is related to the Legendre function, which is a new result. 相似文献
148.
In this paper, a hybrid method based on the collocation and Newton-Kantorovich methods is used for solving the nonlinear singular Thomas-Fermi equation. At first, by using the Newton-Kantorovich method, the nonlinear problem is converted to a sequence of linear differential equations, and then, the fractional order of rational Legendre functions are introduced and used for solving linear differential equations at each iteration based on the collocation method. Moreover, the boundary conditions of the problem by using Ritz method without domain truncation method are satisfied. In the end, the obtained results compare with other published in the literature to show the performance of the method, and the amounts of residual error are very small, which indicates the convergence of the method. 相似文献
149.
Given a closed connected manifold smoothly immersed in a complete noncompact Riemannian manifold with nonnegative sectional curvature, we estimate the intrinsic diameter of the submanifold in terms of its mean curvature field integral. On the other hand, for a compact convex surface with boundary smoothly immersed in a complete noncompact Riemannian manifold with nonnegative sectional curvature, we can estimate its intrinsic diameter in terms of its mean curvature field integral and the length of its boundary. These results are supplements of previous work of Topping, Wu-Zheng and Paeng. 相似文献
150.
Roughly speaking, an ideal immersion of a Riemannian manifold into a real space form is an isometric immersion which produces the least possible amount of tension from the ambient space at each point of the submanifold. The main purpose of this paper is to completely classify all non-minimal ideal submanifolds of real space forms with type number . 相似文献
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