An OpenMP approach was proposed to parallelize the sequential molecular dynamics(MD) code on shared memory machines. When a code is converted from the sequential form to the parallel form, data dependence is a main pr...An OpenMP approach was proposed to parallelize the sequential molecular dynamics(MD) code on shared memory machines. When a code is converted from the sequential form to the parallel form, data dependence is a main problem. A traditional sequential molecular dynamics code is anatomized to find the data dependence segments in it, and the two different methods, i.e., recover method and backward mapping method were used to eliminate those data dependencies in order to realize the parallelization of this sequential MD code. The performance of the parallelized MD code was analyzed by using some performance analysis tools. The results of the test show that the computing size of this code increases sharply form 1 million atoms before parallelization to 20 million atoms after parallelization, and the wall clock during computing is reduced largely. Some hot-spots in this code are found and optimized by improved algorithm. The efficiency of parallel computing is 30% higher than that of before, and the calculation time is saved and larger scale calculation problems are solved.展开更多
Installing the splitter plates is a passive aerodynamic solution for eliminating vortex-induced vibration (VIV). However, the influences of splitter plates on the VIV and aerostatic performances are more complicated d...Installing the splitter plates is a passive aerodynamic solution for eliminating vortex-induced vibration (VIV). However, the influences of splitter plates on the VIV and aerostatic performances are more complicated due to aerodynamic interference between highway and railway decks. To study the effects of splitter plates, wind tunnel experiments for measuring VIV and aerostatic forces of twin decks under two opposite flow directions were conducted, while the surrounding flow and wind pressure of static twin decks with and without splitter plates are numerically simulated. The results showed that the incoming flow direction affects the VIV response and aerostatic coefficients. The highway deck has poor vertical and torsional VIV, and the VIV region and amplitude are different under different directions. While the railway deck only has vertical VIV when located upstream. The splitter plates can impede the process of vortex generation, shedding and impinging at the gap between twin deck, and significantly reducing the surface fluctuating pressure coefficient, thus effectively suppressing the VIV of twin decks. While, the splitter plates hurt the upstream deck regarding static wind stability and have little effect on the downstream deck. The splitter plates of appropriate width are recommended to improve VIV performances in twin parallel bridges.展开更多
Peta-scale high-perfomlance computing systems are increasingly built with heterogeneous CPU and GPU nodes to achieve higher power efficiency and computation throughput. While providing unprecedented capabilities to co...Peta-scale high-perfomlance computing systems are increasingly built with heterogeneous CPU and GPU nodes to achieve higher power efficiency and computation throughput. While providing unprecedented capabilities to conduct computational experiments of historic significance, these systems are presently difficult to program. The users, who are domain experts rather than computer experts, prefer to use programming models closer to their domains （e.g., physics and biology） rather than MPI and OpenME This has led the development of domain-specific programming that provides domain-specific programming interfaces but abstracts away some performance-critical architecture details. Based on experience in designing large-scale computing systems, a hybrid programming framework for scientific computing on heterogeneous architectures is proposed in this work. Its design philosophy is to provide a collaborative mechanism for domain experts and computer experts so that both domain-specific knowledge and performance-critical architecture details can be adequately exploited. Two real-world scientific applications have been evaluated on TH-IA, a peta-scale CPU-GPU heterogeneous system that is currently the 5th fastest supercomputer in the world. The experimental results show that the proposed framework is well suited for developing large-scale scientific computing applications on peta-scale heterogeneous CPU/GPU systems.展开更多
基金Project (50371026) supported by the National Natural Science Foundation of China
文摘An OpenMP approach was proposed to parallelize the sequential molecular dynamics(MD) code on shared memory machines. When a code is converted from the sequential form to the parallel form, data dependence is a main problem. A traditional sequential molecular dynamics code is anatomized to find the data dependence segments in it, and the two different methods, i.e., recover method and backward mapping method were used to eliminate those data dependencies in order to realize the parallelization of this sequential MD code. The performance of the parallelized MD code was analyzed by using some performance analysis tools. The results of the test show that the computing size of this code increases sharply form 1 million atoms before parallelization to 20 million atoms after parallelization, and the wall clock during computing is reduced largely. Some hot-spots in this code are found and optimized by improved algorithm. The efficiency of parallel computing is 30% higher than that of before, and the calculation time is saved and larger scale calculation problems are solved.
基金Projects(51925808,52078504,51822803) supported by the National Natural Science Foundation of ChinaProject(2022JJ10082) supported by the Natural Science Foundation of Hunan Province,China+1 种基金Project(N2022Z004) supported by the Research on Technology Development Trend and Key Common Problems in Railway,ChinaProject(Xplorer Prize 2021) supported by the Tencent Foundation,China。
文摘Installing the splitter plates is a passive aerodynamic solution for eliminating vortex-induced vibration (VIV). However, the influences of splitter plates on the VIV and aerostatic performances are more complicated due to aerodynamic interference between highway and railway decks. To study the effects of splitter plates, wind tunnel experiments for measuring VIV and aerostatic forces of twin decks under two opposite flow directions were conducted, while the surrounding flow and wind pressure of static twin decks with and without splitter plates are numerically simulated. The results showed that the incoming flow direction affects the VIV response and aerostatic coefficients. The highway deck has poor vertical and torsional VIV, and the VIV region and amplitude are different under different directions. While the railway deck only has vertical VIV when located upstream. The splitter plates can impede the process of vortex generation, shedding and impinging at the gap between twin deck, and significantly reducing the surface fluctuating pressure coefficient, thus effectively suppressing the VIV of twin decks. While, the splitter plates hurt the upstream deck regarding static wind stability and have little effect on the downstream deck. The splitter plates of appropriate width are recommended to improve VIV performances in twin parallel bridges.
基金Project(61170049) supported by the National Natural Science Foundation of ChinaProject(2012AA010903) supported by the National High Technology Research and Development Program of China
文摘Peta-scale high-perfomlance computing systems are increasingly built with heterogeneous CPU and GPU nodes to achieve higher power efficiency and computation throughput. While providing unprecedented capabilities to conduct computational experiments of historic significance, these systems are presently difficult to program. The users, who are domain experts rather than computer experts, prefer to use programming models closer to their domains （e.g., physics and biology） rather than MPI and OpenME This has led the development of domain-specific programming that provides domain-specific programming interfaces but abstracts away some performance-critical architecture details. Based on experience in designing large-scale computing systems, a hybrid programming framework for scientific computing on heterogeneous architectures is proposed in this work. Its design philosophy is to provide a collaborative mechanism for domain experts and computer experts so that both domain-specific knowledge and performance-critical architecture details can be adequately exploited. Two real-world scientific applications have been evaluated on TH-IA, a peta-scale CPU-GPU heterogeneous system that is currently the 5th fastest supercomputer in the world. The experimental results show that the proposed framework is well suited for developing large-scale scientific computing applications on peta-scale heterogeneous CPU/GPU systems.
