共查询到18条相似文献,搜索用时 828 毫秒
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将复杂组合体亚音速气动力特性串行算法改造成并行算法,并在PAN95并行机上进行了数值试验。试验表明,并行计算不仅缩短了计时,而且可增加到18000个面元,计算结果与实验结果吻合较好。 相似文献
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隐格式并行求解是计算流体力学并行算法研究的难点,本文针对分布式存储并行处理系统,在异构编程PVM环境下,采用"局部隐"方法,使用发送/接收数据结构和自动剖分等技术,有效地实现了对飞行器亚跨超声速流气动力数值模拟串行程序的并行化改造,保证了并行计算结果与串行结果的一致性.该方法具有简单实用、并行效率高以及并行程序可移植性好和应用前景广泛等特点. 相似文献
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给出了一种适用于混合网格的并行无矩阵GMRES+LU-SGS隐式时间格式。首先采用LU-SGS方法迭代若干步以获得一个合适的初场,然后切换到GMRES方法在每一时间步内近似求解,并将LU-SGS方法作为其预处理器。为加速收敛,将CFL数随着残差的降低逐步放大;为减少存储量和计算量,通量Jacobian采用无矩阵处理。在保证与串行执行一致的前提下,采用基于共享内存的OpenMP方法实现了并行计算,并通过对网格的分组避免了内存争夺。算例验证表明,方法极大地提高了计算收敛效率,并行结果与串行结果完全一致,计算结果与实验结果吻合较好。 相似文献
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基于串行网格划分软件METIS与并行化消息传递编程接口( MPICH2)对现有串行自适应程序进行简单的并行化改造,给出了一种三维可压缩无粘流数值模拟的并行自适应方法。首先利用单个进程调用METIS,串行划分网格;然后对所有进程并行计算以获得初始网格下的流场解;再次利用单个进程对整个流场运用自适应方法进行局部网格加密并调用METIS串行划分网格;最后全部进程在流场初始解的基础上继续并行计算,以获得自适应网格下的流场解。数值模拟算例验证了此方法的可靠性与高效性。 相似文献
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经典的集中式多传感器多目标跟踪算法通常计算量较大,经常难以满足系统的实时性要求,工程上实现起来比较困难,为进一步扩大集中式多传感器的应用范围,使其在对算法实时性要求较高、跟踪精度要求较小的实际场合中广泛应用。文章基于最近邻域思想,研究了并行处理结构的集中式多传感器最近邻域算法,并从算法跟踪精度、实时性、有效跟踪率3个方面对其与经典的顺序多传感器联合概率数据互联算法进行了仿真比较。经仿真验证,并行处理结构的集中式多传感器最近邻域算法实时性提高了60%以上,且在跟踪背景杂波适中的情况下能够有效跟踪目标。 相似文献
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Deergha Rao K.. Sridhar G. 《IEEE transactions on aerospace and electronic systems》1995,31(3):1193-1198
A new approach using a multilayered feed forward neural network for pulse compression is presented. The 13 element Barker code was used as the signal code. In training this network, the extended Kalman filtering (EKF)-based learning algorithm which has faster convergence speed than the conventional backpropagation (BP) algorithm was used. This approach has yielded output peak signal to sidelobe ratios which are much superior to those obtained with the BP algorithm. Further, for use of this neural network for real time processing, parallel implementation of the EKF-based learning algorithm is indispensable. Therefore, parallel implementation has also been developed 相似文献
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A design method is proposed for a class of nonparametric truncated sequential detectors. These detectors test nonparametric statistics against two parallel linear boundaries with an abrupt truncation at some sample size. The proposed method obtains the asymptotic relative efficiencies (ARE) of these tests with respect to their corresponding fixed-sample-size (FSS) tests in terms of some parameters of the tests. There parameters are then chosen to optimize the ARE. This (asymptotically) optimal set of parameters is used to design the thresholds of the sequential tests. Numerical results are obtained and design examples are presented, using the sum of the signs of the observations as the test statistic. The method can be used for nonparametric sequential detectors and for robust and parametric sequential detectors as well 相似文献
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A parallel square-root algorithm and its systolic array implementation are proposed for performing modified extended Kalman filtering (MEKF). The proposed parallel square-root algorithm is designed based on the singular value decomposition (SVD) and the Faddeev algorithm, and a very large scale integration (VLSI) systolic array architecture is developed for its implementation. Compared to other square root Kalman filtering algorithms, the proposed method is more numerically stable. The VLSI architecture described has good parallel and pipelining characteristics in applying to the MEKF and achieves higher efficiency. For n -dimensional state vector estimations, the proposed architecture consists of O (2n 2) processing elements and uses O ((s +17)n ) time-steps for a complete iteration at each instant, in contrast to the complexity of O ((s +6) n 3) time-steps for a sequential implementation, where s ≈log n 相似文献
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许多非定常无粘流体力学问题的数值模拟都需要利用Euler方程组来进行计算,而由于在隐格式下,所选取的时间步长可以比在显格式下时大得多,所以隐格式越来越受到重视,其中隐式LU分解是最常用的方法之一。对三维Euler方程组,采用隐式LU分解进行计算时,网格点所在的各个对角阵面之间存在数据依赖关系,本文分析了采用区域分解且边界上用显格式代替隐格式进行计算的高效性,在长方体建筑物内的爆炸模拟表明,在有112个CPU的某MPP巨型机上,并行计算效率超过60%。本文还分析了计算结果与串行计算时的差异,以及利用区域重叠减小这种差异的方法,同时考虑了对处理器进行合理的逻辑组织,将计算网格映射到处理器网格,以最大限度减少通信开销的方法。文中最后以一个爆炸毁伤的例子实际说明了所述方法的可行性与高效性。 相似文献
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基于集群系统(CLUSTER),在Linux和MPI并行环境下,研究了带制退器的复杂膛口流场三维数值模拟并行算法。计算网格是三维多区结构化网格,数值格式采用Jameson格式及LU隐式分解方法。针对流场的复杂拓扑结构,建立分区信息文件记录各分区的相关信息,并提出了通过合并相邻网格分区的方法均衡各个进程的负载,提高程序的并行效率。在处理需要通讯的信息时,设计了自定义数据类型和"设置中间参数"相结合的方法,并通过动态分配内存减少了程序对计算机系统资源的占用。数值实验表明,本文设计的算法可以适应拓扑结构较复杂的流场,并能取得理想的并行效率,将有助于制退器性能的研究。 相似文献