共查询到20条相似文献，搜索用时 15 毫秒
1.
This paper describes an implementation of a highly scalable parallel computational facility with high speedup efficiency using relatively low-cost hardware, which consists of a cluster of desktop personal computers (PCs) connected via a 10-Gigabit Ethernet. Two-levels of parallelization were implemented. Communication between different PCs was achieved using message passing interface (MPI) protocol. Domain decomposition was automated and based on element numbering. Domain continuity was assured largely by re-numbering the elements using a “front squasher” code prior to decomposition. Within each PC, the shared memory parallelization was implemented using either the open-multiprocessing (OpenMP) or the MPI protocol. Analysis of three different problems with number of degrees-of-freedom ranging from about 129,000 to about 2,260,000 shows a speedup efficiency generally above 70%. Super-linear speedup was achieved in several of the cases examined in this study, with the hybrid MPI-OpenMP approach generally performing better compared to the pure MPI method for parallelization. The results demonstrate the feasibility of acquiring a parallel computing facility with relatively modest outlay that is within the reach of consulting or engineering offices. 相似文献
2.
This study reports a Graphics Processing Unit (GPU)-based parallelization of the Distinct Lattice Spring Model (DLSM) for geomechanics simulation. The DLSM is a newly developed numerical model for rock dynamics problems, i.e., dynamic failure and wave propagation. Despite its applicability, one of the drawbacks of this model is the high computational load for practical simulations. To tackle this problem, a GPU with a Compute Unified Device Architecture (CUDA) is adopted to parallelize the DLSM code. The performance of the GPU DLSM code is tested on two computers equipped with modern GPU cards. The results show that significant performance improvements are gained from GPU parallelization of the DLSM code (the maximum speed up achieved was 23×). 相似文献
3.
为提高重力及重力梯度数据的正演效率,笔者引入基于MPI (Message Passing Interface)和OpenMP (Open Multi-Processing)的并行计算,通过对比分析不同数据规模的网格数和模型体个数对并行效率和加速比的影响,得出随着正演数据规模的增加,并行效率和加速比均得到提高。同时对比了基于MPI和基于OpenMP的两种并行方式的性能,结果表明,重力及重力梯度数据正演的并行计算中MPI的提速能力优于OpenMP,且在较大规模数据的正演计算中基于MPI的并行效率优于基于OpenMP的并行效率。 相似文献
4.
Implementation of a coupled plastic damage distinct lattice spring model for dynamic crack propagation in geomaterials 
下载免费PDF全文
下载免费PDF全文 This paper studies dynamic crack propagation by employing the distinct lattice spring model (DLSM) and 3‐dimensional (3D) printing technique. A damage‐plasticity model was developed and implemented in a 2D DLSM. Applicability of the damage‐plasticity DLSM was verified against analytical elastic solutions and experimental results for crack propagation. As a physical analogy, dynamic fracturing tests were conducted on 3D printed specimens using the split Hopkinson pressure bar. The dynamic stress intensity factors were recorded, and crack paths were captured by a high‐speed camera. A parametric study was conducted to find the influences of the parameters on cracking behaviors, including initial and peak fracture toughness, crack speed, and crack patterns. Finally, selection of parameters for the damage‐plasticity model was determined through the comparison of numerical predictions and the experimentally observed cracking features. 相似文献
5.
A validation study of the distinct lattice spring model (DLSM) for wave propagation problems is performed. DLSM is a microstructure-based numerical model, which is meshless and has advantages in modelling dynamic problems where stress wave propagation is important. To verify the applicability of DLSM to modelling wave propagation through a discontinuous medium, the virtual wave source (VWS) method is used to obtain analytical solutions for wave propagation across a jointed rock mass. Numerical modelling results of the commercial code UDEC are selected as the reference. The effects of particle size and lattice rotation angle on wave propagation are first studied. Then, the results of wave transmission across a single joint with a different joint stiffness and across multiple parallel joints with different joint spacings are derived with DLSM, UDEC and VWS. These results are in good agreement with each other. Therefore, the capability of DLSM to model P-wave propagation across jointed rock mass is verified, which provides confidence for the further application of DLSM to modelling more complex problems. 相似文献
6.
为减少CO2地质储存数值模拟计算时间和增强计算规模,文章提出基于OpenMP和动态内存分配的方式,重构TOUGH2-ECO2N数值模拟器。通过耗时评估可知,模拟器的主要耗时部分为状态方程计算、组建矩阵方程和方程求解。基于此,在遵循OpenMP并行化原则下,采用动态内存分配、处理跳转语句和算法内部的相关性,以及函数内部参数优化等措施,完成了多相流模拟器的并行化。计算试验结果表明,并行化模拟器算法正确、执行效率高,且具有加速效果良好的特点。针对中小规模的模型对比试验,4核的加速比可以达到2.28倍。 相似文献
7.
基于MPI的机群并行计算系统平台构建 总被引：4，自引：1，他引：4
在高性能计算机领域,机群并行系统已成为一种重要的系统结构。这里介绍了机群并行系统的特点和发展现状;给出了将PC机或工作站通过高速以太网连接,使用TCP/IP作为标准的通信协议,利用MPI作为分布式的并行计算软件环境,在Windows平台和Unix平台上搭建用户自己的PC机群系统的两种方法;还给出了MPI安装中需要注意的关键步骤。实践表明,PC机群系统具有高性能、高可用性和极高的性价比。 相似文献
8.
随着计算机技术的发展,以消息传递接口(MPI)标准为代表的高性价比集群计算技术使并行计算在大量传统的专业领域也得到了广泛应用.数字流域模型因需要对大范围流域进行分布式的水文、泥沙过程模拟而提出了较大规模的计算需求.同时,基于分水岭的单元划分方式和专门的河网编码方法使数字流域模型的并行化计算具有先天优势.提出了一种典型的并行调度流程,用于完成产汇流计算的动态任务分配.在自主搭建的MPI计算集群上进行的应用实验表明,集群计算提高了数字流域模型的计算效率,能够作为模型的计算平台.最后指出了此应用计算平台的发展方向. 相似文献
9.
将Monte-Carlo随机方法与并行有限元方法结合,设计了基于PC机群的并行随机有限元算法,每一次随机模拟产生一个随机场,作为一个样本,代入有限元进行稳定性计算,发挥并行有限元计算量大、计算速度快的特点,克服了Monte-Carlo方法计算时间长的缺点。用C++语言结合MPI消息传递接口开发了相应的计算软件,计算了1 000个随机样本的边坡可靠度问题,验证了程序的可靠性及高效性。 相似文献
10.
11.
A full rate-dependent cohesive law is implemented in the distinct lattice spring method (DLSM) to investigate the dynamic fracturing behavior of brittle materials. Both the spring ultimate deformation and spring strength are dependent on the spring deformation rate. From the simulation results, it is found that the dynamic crack propagation velocity can be well predicted by the DLSM through the implemented full rate-dependent cohesive law. Furthermore, a numerical investigation on dynamic branching is also conducted by using the DLSM code. 相似文献
12.
G.‐F. Zhao 《国际地质力学数值与分析法杂志》2014,38(10):1078-1100
This study develops the distinct lattice spring model (DLSM) for geometrically nonlinear large deformation problems. The formulation of a spring bond deformation under a large deformation is derived under the Lagrange framework using polar decomposition. The results reveal that the DLSM's stiffness matrix under small deformations is the tangent stiffness matrix of the DLSM under large deformations. The formulation of the spring bond internal force under a given configuration is also presented and can be used to calculate the unbalanced force. Using these formulations, three nonlinear solving methods (the Euler method, modified Euler method, and Newton method) are developed for the DLSM with which to tackle large deformation problems. To investigate the performance of the developed model, three numerical examples involving large deformations are presented, the results of which are also in good agreement with the analytical and finite element method solutions. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
13.
Parallel computers are potentially very attractive for the implementation of large size geomechanical models. One of the main difficulties of parallelization, however, relies on the efficient solution of the frequently ill‐conditioned algebraic system arising from the linearization of the discretized equilibrium equations. While very efficient preconditioners have been developed for sequential computers, not much work has been devoted to parallel solution algorithms in geomechanics. The present study investigates the state‐of‐the‐art performance of the factorized sparse approximate inverse (FSAI) as a preconditioner for the iterative solution of ill‐conditioned geomechanical problems. Pre‐and post‐filtration strategies are experimented with to increase the FSAI efficiency. Numerical results show that FSAI exhibits a promising potential for parallel geomechanical models mainly because of its almost ideal scalability. With the present formulation, however, at least 4 or 8 processors are required in the selected test cases to outperform one of the most efficient sequential algorithms available for FE geomechanics, i.e. the multilevel incomplete factorization (MIF). Further research is needed to improve the FSAI efficiency with a more effective selection of the preconditioner non‐zero pattern. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
14.
Investigation of highly efficient algorithms for solving linear equations in the discontinuous deformation analysis method 下载免费PDF全文
下载免费PDF全文 Large‐scale engineering computing using the discontinuous deformation analysis (DDA) method is time‐consuming, which hinders the application of the DDA method. The simulation result of a typical numerical example indicates that the linear equation solver is a key factor that affects the efficiency of the DDA method. In this paper, highly efficient algorithms for solving linear equations are investigated, and two modifications of the DDA programme are presented. The first modification is a linear equation solver with high efficiency. The block Jacobi (BJ) iterative method and the block conjugate gradient with Jacobi pre‐processing (Jacobi‐PCG) iterative method are introduced, and the key operations are detailed, including the matrix‐vector product and the diagonal matrix inversion. Another modification consists of a parallel linear equation solver, which is separately constructed based on the multi‐thread and CPU‐GPU heterogeneous platforms with OpenMP and CUDA, respectively. The simulation results from several numerical examples using the modified DDA programme demonstrate that the Jacobi‐PCG is a better iterative method for large‐scale engineering computing and that adoptive parallel strategies can greatly enhance computational efficiency. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
15.
A 3D distinct lattice spring model (DLSM) is proposed where matter is discretized into individual particles linked by springs. The presented model is different from the conventional lattice spring models where a shear spring is introduced to model the multibody force by evaluating the spring deformation from the local strain rather than the particle displacement. By doing this, the proposed model can represent the diversity of Poisson's ratio without violating the rotational invariance. The local strain of the spring is calculated through a least square method which makes the model possessing meshless properties. Because of this and explicitly representing the microstructure, DLSM is able to model dynamic fracturing problems and can be used to study the microstructure influences. The material parameters inputted in the model is the conventional material parameters, e.g. the elastic modules and the Poisson's ratio. Relationships between microscopic spring parameters and macroscopic material constants are derived based on the Cauchy–Born rules and the hyperelastic theory. Numerical examples are presented to show the abilities and properties of DLSM in modeling elastic and dynamic failure problems. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
16.
Inverse Analysis of Deep Excavation Using Differential Evolution Algorithm 总被引：1，自引：0，他引：1 下载免费PDF全文
下载免费PDF全文 This paper presents the applications of the differential evolution (DE) algorithm in back analysis of soil parameters for deep excavation problems. A computer code, named Python‐based DE, is developed and incorporated into the commercial finite element software ABAQUS, with a parallel computing technique to run an FE analysis for all trail vectors of one generation in DE in multiple cores of a cluster, which dramatically reduces the computational time. A synthetic case and a well‐instrumented real case, that is, the Taipei National Enterprise Center (TNEC) project, are used to demonstrate the capability of the proposed back‐analysis procedure. Results show that multiple soil parameters are well identified by back analysis using a DE optimization algorithm for highly nonlinear problems. For the synthetic excavation case, the back‐analyzed parameters are basically identical to the input parameters that are used to generate synthetic response of wall deflection. For the TNEC case with a total of nine parameters to be back analyzed, the relative errors of wall deflection for the last three stages are 2.2, 1.1, and 1.0%, respectively. Robustness of the back‐estimated parameters is further illustrated by a forward prediction. The wall deflection in the subsequent stages can be satisfactorily predicted using the back‐analyzed soil parameters at early stages. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
17.
多重网格区域分裂分布式计算 总被引：2，自引：0，他引：2
对分布式多重网格计算进行了研究.其顺序算法描述的是非递归形式, 算法并行化是基于区域分裂实现的.网状拓扑结构组织在多处理机上, 并行算法映射到多进程上, 在一定程度上显著提高并行化速度和并行化效率 相似文献
18.
This paper presents the computational procedures and solution strategy employed in ParCYCLIC, a parallel non‐linear finite element program developed based on an existing serial code CYCLIC for the analysis of cyclic seismically‐induced liquefaction problems. In ParCYCLIC, finite elements are employed within an incremental plasticity, coupled solid–fluid formulation. A constitutive model developed for simulating liquefaction‐induced deformations is a main component of this analysis framework. The elements of the computational strategy, designed for distributed‐memory message‐passing parallel computer systems, include: (a) an automatic domain decomposer to partition the finite element mesh; (b) nodal ordering strategies to minimize storage space for the matrix coefficients; (c) an efficient scheme for the allocation of sparse matrix coefficients among the processors; and (d) a parallel sparse direct solver. Application of ParCYCLIC to simulate 3‐D geotechnical experimental models is demonstrated. The computational results show excellent parallel performance and scalability of ParCYCLIC on parallel computers with a large number of processors. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
19.
积分方程法三维模拟井地电法并行算法研究 总被引：1，自引：1，他引：1
在积分方程法模拟三维电磁响应原理的基础上,对井地电法三维正演模拟并行算法做了研究。同时,还利用Fortran 6.5和消息传递接口(MPI)开发了井地电法三维正演模拟并行计算程序。在求解大型线性方程组时,采用的是稳定的双共轭梯度(BICGSTAB)算法,单机正演程序与并行正演程序的计算结果有着很好的一致性,这说明了并行算法的正确性,为进一步开发井地电法三维反演并行程序奠定了基础,也为井地电法三维正、反演程序实用化提供了技术支持。 相似文献
20.
机群并行系统与网络并行计算环境 总被引：8，自引：1，他引：8
网络并行计算环境是近年来国际上发展并行环境的一个重要方向。由网络并行环境支持的机群并行系统具有投资少、可扩展性好的优势及无可比拟的灵活性，特别适合应用于我国许多科研和教育部门。作者在本文中主要讨论了机群并行系统和网络并行计算环境的一些技术问题，并给出了一个建立PC机群并行系统的实例。 相似文献