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1.
一种迭代格式的有限元并行算法   总被引:1,自引:0,他引:1  
本文提出了一种求解有限元方程的迭代格式的并行算法.该方法在线性代数方程迭代解法的基础上,引进并行运算步骤;并且运用加权残数方法,通过选择适当的权函数,推导了该并行算法的有限元基本格式.该方法在西安交通大学BLXSI-6400并行计算机上程序实现.计算结果表明它能有效地提高运算速度,减少计算时间,是一种有效的求解大型结构有限元方程的并行算法.  相似文献   

2.
改进伪并行遗传算法求解作业车间调度问题   总被引:1,自引:0,他引:1  
针对遗传算法在求解极复杂优化问题中出现的过早收敛、执行效率差的缺点,提出了一种改进的伪并行遗传算法.该算法将并行进化与串行搜索相结合,提高了算法的收敛速度.同时该算法通过种群因子控制伪并行算法中的各子种群的规模,不仅保证了搜索过程中勘探和开采的平衡,克服过早收敛,而且减少了计算的复杂性,特别是在处理复杂优化问题上具有较高的性能.实验结果证明了该算法的有效性.  相似文献   

3.
并行迭代算法的有效性的度量参数   总被引:2,自引:0,他引:2  
1.引言对于理想化的并行计算机模型山,一个并行算法的加速定义为初二万/几一地小,效率定义为Ea二Sa/a二万/(aTa)二Va/(aVI),其中a为并行计算机的等效处理机数目,乃为已知最快的串行算法在单处理机上的运行时间,凡是所讨论的并行算法使用。个处理机的运行时间,VI为单个处理机求解问题的运算速度,而Va为0个处理机求解问题的运算速度.曼尼和几分别反映了算法并行性对计算时间改进的程度以及并行计算机处理能力发挥的程度,因此,它们是度量并行算法的有效性的重要参数.另外两个与之相人的重要参数分别为冗余度尼二几周l…  相似文献   

4.
并行求解初边值问题的有限差分方法研究   总被引:2,自引:0,他引:2  
一近二十年间,随着各类并行处理机和向量计算机的问世。出现了对数值分析方法的一种新的分类法:串行算法和并行算法。在传统的串行计算机上使用的算法称为串行算法;适合于在并行计算机或向量计算机上使用的算法称为并行算法。目前由于有愈来愈多的并行机投入使用,并行算法的研究在国内外受到了普遍重视。本文概述适合于并行计算的求解扩散方程的有限差分方法研究的部分情况,其中包括作者的近期工作,希望能作为引玉之砖,引起大家的兴趣和关心。我们研究如下扩散方程的有限差分方法。  相似文献   

5.
针对扩散问题提出了一类带有加权系数的隐格式,采用分组显式和区域分解思想,又构造了若干分组显式格式.结合初边值条件,建立了求解扩散问题的一种多子域并行算法.虽然格式是隐式的,但在算法实现过程中可显式且并行地计算,这样避免了求解线性方程组的复杂性.并且当加权系数1≤θ≤2.4时,格式是无条件稳定的;0θ1时,趋向于1的方向,格式也是无条件稳定的;θ=2时,算法收敛的最快,收敛速率接近于2.通过数值试验证明此类隐格式和并行算法是有效的,计算速度快,精确度高,易于实现并行.  相似文献   

6.
§1.引言 Schwarz算法也称为区域分裂法.是近代的数学物理方程求解方法的基础.随着计算技术的进步以及巨型并行计算机的出现,区域分裂法被用来作为建立并行算法的基础Schwarz算法是区域分裂法的迭代解法的总称.现在美苏等国也在研究区域分裂法的直接解法.当然,那只是对离散问题的.  相似文献   

7.
本文介绍一套求解复杂流体模拟和优化控制问题的高可扩展并行算法.该算法基于非结构化网格,结合了加稳定化项的有限元空间离散方法、全隐的时间离散格式、多物理场全耦合的求解算法、区域分解算法及求解非线性系统的Newton-Krylov-Schwarz算法等多套先进算法.利用该算法,本文对多个实际工程应用中流体模拟和优化设计问题进行了测试,数值结果显示,该算法对本文研究的几类问题,具有很好的收敛性和并行可扩展性,当使用8192个处理器核求解规模超过两千万个网格单元的问题时,仍然具有超过40%的并行效率.  相似文献   

8.
1.引言 由于高性能并行计算机的出现和并行计算的推动,十多年来,抛物型方程有限差分并行算法设计与分析一直受到关注. D.J.Evalns和A.R.B.Abdullah(1983,[1,2]利用Saul’yev非对称格式对常系数抛物方程设计了AGE(交替分组显格式)算法,并用矩阵分析的方法证明了该算法的无条件稳定性.该算法有明显的并行性,倍受推崇,且计算的实践([8],[9])表明它对变系数的抛物方程也是可行的,但稳定性的分析成为一个难点.张宝琳([3])在一维情  相似文献   

9.
解无约束极小问题的一个并行共轭方向法   总被引:2,自引:0,他引:2  
具有并行运算能力的计算机出现,促进了计算方法中的并行算法的发展,因为它是提高计算速度的一个新的重要方面。 1970年Chazan,Miranker在文[1]中,对于无约束极小问题  相似文献   

10.
拟蝴蝶算法     
D.J.Evans于[1~3]中提出了一类求解线性方程组的并行算法,即蝴蝶算法.可是,直接蝴蝶法,回代过程不是并行的;间接蝴蝶法,因矩阵求逆的工作量很大,故块蝴蝶法的SOR型算法不易于并行化.为解决这些问题,我们对原算法做了改造,并称改造后的方法为拟蝴蝶方法.  相似文献   

11.
本文利用对称化原理,讨论了一种只需在子区域上计算两个完全独立子问题就可得到原问题解的对称区域分裂法,并用此方法求解线性算子方程和线性透射问题.此方法可作为并行算法在MIMD计算机上使用.  相似文献   

12.
采用并行计算的思想,在单台计算机上应用自适应的伪并行遗传算法,求解了双准则三维运输问题,最后通过实验验证该方法可产生适合需求的解,同时体现了该算法有较快的收敛速度.  相似文献   

13.
The branch-and-bound method is one of most efficient search algorithms. However, parallel decomposition of this method is difficult even on architectures with common memory, not to mention distributed systems. The paper describes an algorithm for solution of the problems that can be solved with the branch-and-bound method on a distributed computer system. The results of testing of the proposed algorithm via solution of the chess-game problem are presented.  相似文献   

14.
In this article, the supersonic flow of a viscous heat-conducting gas near bodies of complex shape is simulated on a parallel computing system. Kinetically consistent difference schemes are used in the calculation, as they easily adapt to distributed-memory multiprocessor computer architectures. The parallel implementation of the kinetically consistent algorithm has been coded in the language Norma.  相似文献   

15.
Based on the variational formulation and penalty method, we have considered the Neumann parallel scheme of the domain decomposition method for the solution of problems of one-sided contact between three-dimensional elastic bodies. We have shown the existence and uniqueness of a solution of the variational problem with penalty and convergence in the penalty parameter. The convergence of this scheme has been proved, and the optimal value of iteration parameter has been determined.  相似文献   

16.
A broad class of problems involving the optimal control of robot arms can be formulated as dynamic programming problems whose structure is particularly attractive for parallel processing. For certain simple cost functions the dynamic programming formulation reduces to determining the shortest path through a network. This algorithm has been implemented on a Floating Point Systems' T-20 hypercube computer. An analysis of the performance of the algorithm provides several important insights into the interplay between problem size and the number of processors in a parallel computer. The results also underscore the potential for parallel computers in real-time control applications.This work was supported in part by the Office of Naval Research, Contract N 00014-86-K-0693.  相似文献   

17.
The "branch-and-bound" algorithm for the exact solution of a three-machine scheduling problem proposed by Lomnicki has been generalized to the case of an arbitrary number of machines (under the assumption of an identical order on all the machines) and it has been adapted for an electronic computer. The flow chart of this algorithm used in the programming of calculations has been given and the efficiency of the method has been illustrated by some experimental evaluations of optimum job sequencing.  相似文献   

18.
Recent research in parallel numerical computation has tended to focus on the algorithmic level. Less attention has been given to the programming level where algorithm is matched, to some extent, to computer architecture. This two-part paper presents a three-level approach to parallel programming which distinguishes between mathematical algorithm, program and computer architecture. In part I, we motivate our approach by a case study using the Ada language. In part II, a mathematical concept of parallel algorithm is introduced in terms of partial orders. This serves as the basis of a theory of parallel computation which makes possible a precise semantics and a precise criterion of complexity of parallel programs. It also suggests some notation for specifying parallel numerical algorithms. To illustrate the ideas presented in part II, we concentrate here on parallel numerical computations which have vector spaces as their central data type and which are intended to be executed on a multi-processor system. The Ada language, with its task constructs, allows one to program computer algorithms to be executed on multi-processor systems, rather than on vector (pipelined) architectures. To provide a concrete example of the general problem of programming parallel numerical algorithms for multi-processor computers, we do a case study of how Ada can be used to program the solution of a system of linear equations on such computers. The case study includes an analysis of complexity which addresses the cost of data movement and process control/synchronization as well as the usual arithmetic complexity.Dedicated to Peter Naur on the occasion of his 60th birthdayThis research was partially supported by NSF Grants DCR-8406290 & CCR-8712192.  相似文献   

19.
This paper describes a collection of parallel optimal control algorithms which are suitable for implementation on an advanced computer with the facility for large-scale parallel processing. Specifically, a parallel nongradient algorithm and a parallel variablemetric algorithm are used to search for the initial costate vector that defines the solution to the optimal control problem. To avoid the computational problems sometimes associated with simultaneous forward integration of both the state and costate equations, a parallel shooting procedure based upon partitioning of the integration interval is considered. To further speed computations, parallel integration methods are proposed. Application of this all-parallel procedure to a forced Van der Pol system indicates that convergence time is significantly less than that required by highly efficient serial procedures.This research was supported in part by the Air Force Office of Scientific Research, Air Force Systems Command, USAF, under Grant No. AFOSR-77-3418.  相似文献   

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