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271.
Karl Gustafson 《Numerical Linear Algebra with Applications》2003,10(4):291-315
This paper extends the relationship between the author's operator trigonometry and convergence rates and other properties of important iterative methods. A new interesting trigonometric preconditioning lemma is given. The general relationship between domain decomposition methods and the operator trigonometry is established. A new basic conceptual link between sparse approximate inverse algorithms and the operator trigonometry is observed. A new underlying fundamental inherent trigonometry of the classical successive over‐relaxation scheme is exposed. Some improved trigonometric interpretations of minimum residual schemes are mentioned. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
272.
Wolfgang Quapp 《Journal of mathematical chemistry》2004,36(4):365-379
The reaction path is an important concept of theoretical chemistry. We discuss the definition with the help of the following of the reduced gradient (RGF) [see Quapp et al., Theoret. Chem. Acc. 100 (1998) 285], also named the Newton trajectory. All the important features of the potential energy surface are definable independently of the coordinate system. We demonstrate it for the Newton trajectory. We design a numerical scheme for the RGF method including the intrinsic curvilinear metric of internal coordinates. For the path following we extend the previous method to the use of a generalized singular value decomposition (SVD). An example of the HCN isomerization pathway is discussed. 相似文献
273.
274.
Ralf R. Müller 《Entropy (Basel, Switzerland)》2021,23(5)
In 2017, Polyanskiy showed that the trade-off between power and bandwidth efficiency for massive Gaussian random access is governed by two fundamentally different regimes: low power and high power. For both regimes, tight performance bounds were found by Zadik et al., in 2019. This work utilizes recent results on the exact block error probability of Gaussian random codes in additive white Gaussian noise to propose practical methods based on iterative soft decoding to closely approach these bounds. In the low power regime, this work finds that orthogonal random codes can be applied directly. In the high power regime, a more sophisticated effort is needed. This work shows that power-profile optimization by means of linear programming, as pioneered by Caire et al. in 2001, is a promising strategy to apply. The proposed combination of orthogonal random coding and iterative soft decoding even outperforms the existence bounds of Zadik et al. in the low power regime and is very close to the non-existence bounds for message lengths around 100 and above. Finally, the approach of power optimization by linear programming proposed for the high power regime is found to benefit from power imbalances due to fading which makes it even more attractive for typical mobile radio channels. 相似文献
275.
本文采用数字散斑干涉法和栅线投影法同时测量了任意曲表面的三维位移和三维形貌,并运用数字图像处理技术分析了曲表面的三维应变场,用实验方法获得了曲表面的主应变和主方向。 相似文献
276.
We introduce a concept for the majorization order on monomials. With the help of this order, we derive a necessary condition on the positive termination of a general successive difference substitution algorithm(KSDS) for an input form f. 相似文献
277.
278.
提出了求解非线性互补问题的一个逐次逼近拟牛顿算法。在适当的假设下,证明了该算法的全局收敛性和局部超线性收敛性。 相似文献
279.
We study the optical Quantum Transition Line Shapes (QTLS) which show the absorption power and the Quantum Transition Line
Widths (QTLW) of electron-deformation potential phonon interacting systems. In order to analyze the quantum transition, we
compare the magnetic field dependencies of the QTLWand the QTLS on two transition processes, namely the intra-Landau level
transition process and the inter-Landau level transition process. We apply the Quantum Transport theory (QTR) to the system
in the confinement of electrons by square well confinement potential. We use the projected Liouville equation method with
Equilibrium Average Projection Scheme (EAPS).
相似文献
280.
Farhan Saif 《Journal of Russian Laser Research》2009,30(3):242-246
We present the recurrence phenomena of an initially localized wavepacket as a foundation to the quantum clock. Various recurrence
times in a multidimensional system serve as arms of the clock. The quantum clock so designed may provide the best precision
and make the measurement of time possible to the smallest scale. 相似文献