共查询到20条相似文献,搜索用时 15 毫秒
1.
We study the dynamic critical behavior of the worm algorithm for the two- and three-dimensional Ising models, by Monte Carlo simulation. The autocorrelation functions exhibit an unusual three-time-scale behavior. As a practical matter, the worm algorithm is slightly more efficient than the Swendsen-Wang algorithm for simulating the two-point function of the three-dimensional Ising model. 相似文献
2.
An algorithm is presented for computing the topological entropy of a piecewise monotone map of the interval having three monotone pieces. The accuracy of the algorithm is discussed and some graphs of the topological entropy obtained using the algorithm are displayed. Some of the ideas behind the algorithm have application to piecewise monotone functions with more than three monotone pieces. 相似文献
3.
N. A. Yavorovskii Yu. N. Isaev Ya. I. Kornev M. B. Haskel'berg B. N. Chen 《Russian Physics Journal》2003,46(10):955-961
An algorithm (method) of determining the parameters of the two-pole equivalent electric circuit for an electric discharge is described in the present paper. The algorithm (method) is based on a solution of the ill-posed inverse problem of determining a kernel of the Duhamel integral for the first-order Fredholm integral equation. The fast Fourier transform (FFT) algorithm used to solve this problem reduces significantly the execution time of the algorithm. Examples of solving model problems for first- and second-order electric equivalent circuits are presented which demonstrate the universality and efficiency of the suggested algorithm. 相似文献
4.
In this paper, we present a hybrid genetic-hierarchical algorithm for the solution of the quadratic assignment problem. The main distinguishing aspect of the proposed algorithm is that this is an innovative hybrid genetic algorithm with the original, hierarchical architecture. In particular, the genetic algorithm is combined with the so-called hierarchical (self-similar) iterated tabu search algorithm, which serves as a powerful local optimizer (local improvement algorithm) of the offspring solutions produced by the crossover operator of the genetic algorithm. The results of the conducted computational experiments demonstrate the promising performance and competitiveness of the proposed algorithm. 相似文献
5.
A new algorithm for the numerical solution of the Zakharov equations is presented. This algorithm is explicit and it is second-order accurate. The convergence of the algorithm is demonstrated by numerically solving the Zakharov equations for several test cases. 相似文献
6.
On a recent attempt to define the interpretation basis in the many worlds interpretation of quantum mechanics 总被引:1,自引:0,他引:1
David Deutsch's 1985 algorithm to determine the preferred product structure and basis in the many worlds interpretation is examined. His heuristic argument for the conditions appearing in the algorithm is found wanting. The question of the existence and uniqueness of a final solution to his algorithm is discussed. The algorithm is shown to be inadequate to account for certain types of measurement which are, at least in principle, possible. 相似文献
7.
We investigate a common used algorithm [Phys. Rev. E 64 (2001) 016132] to calculate the betweenness centrality for all vertices. The inaccurateness of that algorithm is pointed out and a corrected algorithm, also with O(MN) time complexity, is given. In addition, the comparison of calculating results for these two algorithm aiming at the protein interaction network of yeast is shown. 相似文献
8.
The increase of the monotonic convergence rate is an important issue for iterative Fourier-transform algorithms. However, the steepest monotonic convergence of the iterative Fourier-transform algorithm does not always promise an optimal solution in the design of a diffractive optical element. The optimal nonmonotonic convergence of the iterative Fourier-transform algorithm is investigated by employing a microgenetic algorithm. The proposed hybrid scheme of the iterative Fourier-transform algorithm and the microgenetic algorithm show nonmonotonic convergence, and this results in a superior design. 相似文献
9.
10.
Relations between different functional algorithms for solving the inverse scattering problem are analyzed. It is shown that
the Rose algorithm does not provide a unique solution, but can be used as a means to improve the interference resistance in
reconstruction algorithms that provide unique restoration of scatterer characteristics. The possibility of unique reconstruction
of refractive-absorbing scatterers by the modified Rose algorithm, which includes the Sokhotsky equation, is illustrated.
Results of numeric simulation of the Novikov-Grinevich-Manakov algorithm, which is efficient in reconstructing two-dimensional
acoustic refractive-absorbing scatterers of actually arbitrary shape and strength, are presented. The algorithm rigorously
allows for multiple scattering effects. It is promising for tomography-like application problems and features a sufficiently
high interference resistance. 相似文献
11.
12.
提出了一种三维矩阵的奇异值分解算法,该法适合处理具有三维矩阵数据的模式识别和分类模型等领域实际问题,该算法与二维矩阵奇异值分解算法类似,通过求解约束条件极值问题获得,该算法与已有的三线性分解算法比较,相对简单,计算速度快,适合处理数据量大的实际问题,该算法也很容易推广到更高维阵列的光谱数据。 相似文献
13.
We study the typical (median) value of the minimum gap in the quantum version of the exact cover problem using quantum Monte Carlo simulations, in order to understand the complexity of the quantum adiabatic algorithm for much larger sizes than before. For a range of sizes N< or =128, where the classical Davis-Putnam algorithm shows exponential median complexity, the quantum adiabatic algorithm shows polynomial median complexity. The bottleneck of the algorithm is an isolated avoided-crossing point of a Landau-Zener type (collision between the two lowest energy levels only). 相似文献
14.
S.M. Abrarov B.M. Quine R.K. Jagpal 《Journal of Quantitative Spectroscopy & Radiative Transfer》2009,110(6-7):376-383
A simple interpolating algorithm for rapid calculation of the Voigt function with high accuracy is presented. It can utilize any existing rapid algorithm as a subprogram for the pre-computation of the selected points. Such approach is particularly efficient for massive input arrays and, compared to the Wells algorithm, accelerates the computation, improves the accuracy, and increases the input vector size by factors greater than 35, 7, and 10, respectively. The calculated results were compared with exponential and arctangent expansion approximations of the Voigt function. It is found that the relative error in the Wells algorithm slightly exceeds the supposed accuracy of 10?5. 相似文献
15.
从两量子位核磁共振量子处理器物理模型出发,利用Raedt小组提出的自旋-1/2代数理论,根据量子控制非门的定义及Grover量子算法原理,介绍了量子控制非门的4种不同脉冲序列及两量子位Grover量子算法的两种不同脉冲序列的设计过程,通过数值求解含时薛定谔方程模拟量子控制非门和两量子位Grover量子算法,等价于执行量... 相似文献
16.
Lacunarity is a measure of how data fills space. It complements fractal dimension, which measures how much space is filled. Many researchers use the gliding box algorithm to calculate lacunarity. This paper introduces a fast algorithm for making this calculation. This algorithm is akin to fast box-counting algorithms used by some researchers to estimate fractal dimension. A simplified gliding box measure equation, along with key pseudo code implementations for the algorithm, are presented. Applications for the gliding box lacunarity measure have ranged from biological community modelling to target detection. 相似文献
17.
A method for calorimeter-signal processing intended for deriving input signals for the neutral trigger is considered. An algorithm for digitizing signals is described in detail, along with a simulation of its operation. A brief account of data obtained in tests of a prototype of the signal-processing module that employs the developed algorithm is given. 相似文献
18.
This paper deals with the particle-mesh probability density function (PDF) method. It shows how an existing but less precise pressure algorithm for the stand-alone method can be improved. The present algorithm is able to handle the general case of an unsteady three-dimensional turbulent reacting flow. The transport equation of the joint PDF of velocity and composition is solved with a particle method. Open boundary conditions are realized and for statistical reasons a simple but effective particle splitting procedure is applied. Based on a simple configuration, the properties of the presented improved pressure algorithm are analysed. It is shown which numerical condition must be taken care of so that the algorithm is able to correct the particle positions such that the normalization condition is fulfilled as accurately as specified. To verify the algorithm the combustion of a methane–air mixture enclosed in an open simulation volume is calculated. It is shown that the simple particle splitting algorithm works very effectively in the studied case. The behaviour of the improved pressure algorithm is examined by different calculations. To analyse the convergence of the algorithm, the particle number per cell and the grid spacing are varied. To demonstrate the accuracy, a statistically stationary inflow/outflow configuration is used and the numerical solution is compared to an analytical one. For a less symmetric test case, the previous unsteady combustion problem is simulated, including an additional mean velocity in one direction. The presented improved pressure algorithm provides the opportunity to calculate unsteady three-dimensional turbulent reacting flows with a stand-alone method, and offers an alternative to the complex hybrid finite-volume/particle PDF method. 相似文献
19.
一种用于光束整形的衍射光学元件设计算法 总被引:3,自引:1,他引:2
在光束整形衍射光学元件的设计中,为同时减小输出光束的均方根误差和顶部不均匀度值,提出了模糊控制迭代算法(IAFC)。在盖师贝格-撒克斯通(Gerchberg-Saxton,G-S)算法的基础上,提出了平滑修正法,可有效改善输出光束的顶部均匀度,但却增大了均方根误差值。模糊控制迭代算法依据模糊控制理论,通过有效结合盖师贝格-撒克斯通算法和平滑修正法来同时降低均方根误差和顶部不均匀度值。计算机设计的结果表明,利用模糊控制迭代算法可以得到非常理想的输出光束,其均方根误差和顶部不均匀度值分别为0.75%和0.46%,能量转换效率可达94.91%。为光束整形衍射光学元件的设计提供了一种有效的新算法。 相似文献
20.
Olofsson T 《Ultrasonics》2004,42(1-9):969-975
The received signal in ultrasonic pulse-echo inspection can be modeled as a convolution between an impulse response, or prototype, and the reflection sequence that is the impulse characteristic of the inspected object. Deconvolution aims at approximately inverting this process to improve the time resolution so that the overlap between echoes from closely spaced reflectors becomes small. For the relatively high contrast reflection sequences often found in non-destructive testing applications, semi-sparse deconvolution algorithms will typically yield better results than the classical Wiener filter solution. However, this requires a prototype that is a good representative for all echo responses found in the signals. Since, in practice, the prototype is often chosen by the operator directly from the inspection data, the prototype may incidentally be a bad representative for modeling the echoes for the remaining part of the object. Because of the sensitivity to deviations in the prototype this can yield deconvolution results with poor reproducibility. This paper presents a new semi-sparse deconvolution algorithm that is robust to deviations in the prototype. The new robust algorithm is based on a modification of an earlier presented non-robust semi-sparse algorithm. The robustness is obtained by including a stochastic model of the variations in the prototypes to the signal model when deriving the algorithm. Experiments performed using simulated data verify that the robust algorithm is less sensitive to deviations in the prototypes compared to the non-robust version of the algorithm and show that the proposed algorithm yields better estimates than its non-robust version and the Wiener filter in scenarios for which the algorithm was derived. Results using real ultrasonic data further show that the algorithm can be useful in practical scenarios where similar deconvolution results are required from slightly different echoes. 相似文献