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1.
On the two classes of high‐order convergent methods of approximate inverse preconditioners for solving linear systems 下载免费PDF全文
Suzan C. Buranay Dervis Subasi Ovgu C. Iyikal 《Numerical Linear Algebra with Applications》2017,24(6)
Two classes of methods for approximate matrix inversion with convergence orders p =3?2k +1 (Class 1) and p =5?2k ?1 (Class 2), k ≥1 an integer, are given based on matrix multiplication and matrix addition. These methods perform less number of matrix multiplications compared to the known hyperpower method or p th‐order method for the same orders and can be used to construct approximate inverse preconditioners for solving linear systems. Convergence, error, and stability analyses of the proposed classes of methods are provided. Theoretical results are justified with numerical results obtained by using the proposed methods of orders p =7,13 from Class 1 and the methods with orders p =9,19 from Class 2 to obtain polynomial preconditioners for preconditioning the biconjugate gradient (BICG) method for solving well‐ and ill‐posed problems. From the literature, methods with orders p =8,16 belonging to a family developed by the effective representation of the p th‐order method for orders p =2k , k is integer k ≥1, and other recently given high‐order convergent methods of orders p =6,7,8,12 for approximate matrix inversion are also used to construct polynomial preconditioners for preconditioning the BICG method to solve the considered problems. Numerical comparisons are given to show the applicability, stability, and computational complexity of the proposed methods by paying attention to the asymptotic convergence rates. It is shown that the BICG method converges very quickly when applied to solve the preconditioned system. Therefore, the cost of constructing these preconditioners is amortized if the preconditioner is to be reused over several systems of same coefficient matrix with different right sides. 相似文献
2.
This paper concerns classification by Boolean functions. We investigate the classification accuracy obtained by standard classification techniques on unseen points (elements of the domain, {0,1}n, for some n) that are similar, in particular senses, to the points that have been observed as training observations. Explicitly, we use a new measure of how similar a point x∈{0,1}n is to a set of such points to restrict the domain of points on which we offer a classification. For points sufficiently dissimilar, no classification is given. We report on experimental results which indicate that the classification accuracies obtained on the resulting restricted domains are better than those obtained without restriction. These experiments involve a number of standard data-sets and classification techniques. We also compare the classification accuracies with those obtained by restricting the domain on which classification is given by using the Hamming distance. 相似文献
3.
The γ-hydroxypropyl-functionalised diiron dithiolate complex [Fe2(CO)6(μ-SCH2CH2CH2OH)2] is prepared upon thermolysis of Fe3(CO)12 and HO(CH2)3SH and further reaction with dppm (dppm = Ph2PCH2PPh2) affords [Fe2(CO)4(μ-dppm)(μ-SCH2CH2CH2OH)2]. From the reaction of Fe3(CO)12 with dppm(S2) a minor product is the tetrairon cluster, [{Fe2(CO)6(μ-SCH2CH2CH2OH)}2(μ4-S)], the mode of formation of which is unclear. It has been crystallographically characterised and adopts a μ4-S bridged double butterfly structure which is compared with other crystallographically characterised complexes of this type.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
4.
A discrete function f defined on Zn is said to be logconcave if for , , . A more restrictive notion is strong unimodality. Following Barndorff-Nielsen [O. Barndorff-Nielsen, Unimodality and exponential families, Commun. Statist. 1 (1973) 189-216] a discrete function is called strongly unimodal if there exists a convex function such that if . In this paper sufficient conditions that ensure the strong unimodality of a multivariate discrete distribution, are given. Examples of strongly unimodal multivariate discrete distributions are presented. 相似文献
5.
New complexes cis-[M(CO)4-DABRd] (M = Cr(I), Mo(II) and fac-[M(CO)3-SAT] (M = Cr(III), Mo(IV)) have been synthesized by the photochemical reactions of cis-[(η4-NBD)M(CO)4] (NBD is norbornadiene; M=Cr, Mo) with 5-(4-dimethylaminobenzylidene) rhodanine (DABRd) and salicylidene-3-amino-1,2,4-triazole
(SAT) ligands and characterized by elemental analysis, FT-IR and 1H NMR spectroscopy, and mass spectrometry. The spectroscopic studies show that the DABRd ligand acts as a bidentate ligand
coordinating via both NH-(S)C=S sulfur donor atoms in I and II and SAT ligand behaves as a tridentate ligand coordinating via its all imine nitrogen-C=N-donor atoms in III and IV to the metal center.
The article was submitted by the authors in English. 相似文献
6.
Subasi Abdussamet Manay Eyuphan Elbas Seyma Sahin Bayram 《Journal of Thermal Analysis and Calorimetry》2021,145(5):2451-2465
Journal of Thermal Analysis and Calorimetry - An experimental research was performed to examine the effect of hydrodynamically and thermally developing distilled water-based SiO $$_2$$ nanofluid... 相似文献
7.
Glasses are known to exhibit quantitative universalities at low temperatures, the most striking of which is the ultrasonic attenuation coefficient Q?1. In this work we develop a theory of coupled generic blocks with a certain randomness property to show that universality emerges essentially due to the interactions between elastic blocks, regardless of their microscopic nature. 相似文献
8.
Dervis Gok 《Journal of heterocyclic chemistry》2019,56(12):3343-3353
A simple and easy synthesis of 2‐(3‐nitro‐phenyl)‐quinazoline‐4‐carboxylic acid ( 3 ) has been successfully developed through a one‐pot three‐component condensation reaction of (2‐amino‐phenyl)‐oxo‐acetic acid sodium salt ( 1 ) obtained from the hydrolysis of isatin with ammonium acetate and 3‐nitrobenzaldehyde. Some novel quinazoline‐ester derivatives 4‐7 were then obtained by the reaction between the new compound 3 and various alcohols. Then, quinazoline‐amide derivatives 10‐14 were synthesized from the reaction of various amines and 2‐(3‐nitro‐phenyl)‐quinazoline‐4‐carbonyl chloride ( 8 ), obtained by the reaction of compound 3 with SOCl2. Finally, some novel quinazoline‐azo derivatives 17‐19 were synthesized by the coupling reaction between β‐dicarbonyl compounds and the novel amino‐quinazoline derivative compound 15 , obtained by reduction of nitro‐quinazoline derivative compound 11 . Thus, a new series of quinazoline‐4‐carboxylic acid, ester, amide, and azo derivatives was synthesized and fully characterized by 1H NMR, 13C NMR, IR, and mass spectrometry analysis. 相似文献
9.
A powerful and efficient algorithm for numerical function optimization: artificial bee colony (ABC) algorithm 总被引:36,自引:0,他引:36
Swarm intelligence is a research branch that models the population of interacting agents or swarms that are able to self-organize.
An ant colony, a flock of birds or an immune system is a typical example of a swarm system. Bees’ swarming around their hive
is another example of swarm intelligence. Artificial Bee Colony (ABC) Algorithm is an optimization algorithm based on the
intelligent behaviour of honey bee swarm. In this work, ABC algorithm is used for optimizing multivariable functions and the
results produced by ABC, Genetic Algorithm (GA), Particle Swarm Algorithm (PSO) and Particle Swarm Inspired Evolutionary Algorithm
(PS-EA) have been compared. The results showed that ABC outperforms the other algorithms. 相似文献
10.
Anthony Birri Graeme Hogarth Elif Subasi 《Journal of organometallic chemistry》2007,692(12):2448-2455
Allyl-palladium dithiocarbamate complexes, [Pd(allyl)(S2CNR2)], have been prepared from the addition of dithiocarbamate salts to [Pd(allyl)(μ-Cl)]2 and TGA and DSC studies have been carried out in order to assess their potential as MOCVD precursors to palladium sulfides. For comparison [(η3-C4H7)Pd(S2PPh2)] and [Pd(S2CNMeR)2] (R = Bu, Hex) have also been prepared and tested as precursors. The unsymmetrical dithiocarbamate complex, [(η3-C3H5)Pd(S2CNMeHex)], which has a melting point of 65 °C was selected as the best single source precursor and thin films of predominantly Pd2.8S were deposited on glass slides. The crystal structures of [(η3-C4H7)Pd(S2CNMe2)], [(η3-C4H7)Pd(S2CNPr2)], [(η3-C4H7)Pd(S2PPh2)] and [Pd(S2CNMeBu)2] are reported. All except [(η3-C4H7)Pd(S2CNPr2)] show weak intermolecular S?H or Pd?H interactions. 相似文献