Pseudospectral method is an efficient and high accuracy numerical method for simulating seismic wave propaga- tion in heterogeneous earth medium. Since its derivative operator is global, this method is commonly consid...Pseudospectral method is an efficient and high accuracy numerical method for simulating seismic wave propaga- tion in heterogeneous earth medium. Since its derivative operator is global, this method is commonly considered not suitable for parallel computation. In this paper, we introduce the parallel overlap domain decomposition scheme and give a parallel pseudospectral method implemented on distributed memory PC cluster system for modeling seismic wave propagation in heterogeneous medium. In this parallel method, the medium is decomposed into several subdomains and the wave equations are solved in each subdomain simultaneously. The solutions in each subdomain are connected through the transferring at the overlapped region. Using 2D models, we compared the parallel and traditional pseudospectral method, analyzed the accuracy of the parallel method. The results show that the parallel method can efficiently reduce computation time for the same accuracy as the traditional method. This method could be applied to large scale modeling of seismic wave propagation in 3D heterogeneous medium.展开更多
针对碳纤维复合材料涂层厚度检测问题,进行了综合性实验设计。提出结合L1范数的谱投影梯度算法(spectral projection gradient based L1,SPGL1)的涂层厚度检测方法,结合涂层测厚实际,明确了基底检测更适合使用反射式太赫兹时域系统。分...针对碳纤维复合材料涂层厚度检测问题,进行了综合性实验设计。提出结合L1范数的谱投影梯度算法(spectral projection gradient based L1,SPGL1)的涂层厚度检测方法,结合涂层测厚实际,明确了基底检测更适合使用反射式太赫兹时域系统。分析求解了凸最优问题需要的条件,给出了信号稀疏分解结合飞行时间法的涂层厚度检测方案。实验数据表明,当涂层折射率相差较大时,加入噪声后的结果与理想情况一致,当涂层折射率相近时,SPGL1方法具有良好的抗干扰能力。该实验基于教师科研成果,通过完整的实验设计能够帮助学生理解时域光谱、稀疏分解、飞行时间法等基本理论和方法,锻炼了学生的实践动手能力和知识综合运用能力,培养了探索热情和创新意识。展开更多
间断有限元算法(Discontinuous Galerkin Finite Element Method,DGM)是一种高精度的数值求解算法,针对电磁工程应用中DGM并行计算效率低、计算量较大的问题,提出了基于SW26010平台的并行DGM算法。通过区域分解、数据结构重构、热点函...间断有限元算法(Discontinuous Galerkin Finite Element Method,DGM)是一种高精度的数值求解算法,针对电磁工程应用中DGM并行计算效率低、计算量较大的问题,提出了基于SW26010平台的并行DGM算法。通过区域分解、数据结构重构、热点函数从核并行计算、计算与通信重叠及从核缓冲优化技术完成了DGM算法的并行优化。实现结果表明,与基于MPI进程级的DGM并行算法相比,可以获得46.8的平均加速比。展开更多
基金National Natural Science Foundation of China (40474012 and 40521002)
文摘Pseudospectral method is an efficient and high accuracy numerical method for simulating seismic wave propaga- tion in heterogeneous earth medium. Since its derivative operator is global, this method is commonly considered not suitable for parallel computation. In this paper, we introduce the parallel overlap domain decomposition scheme and give a parallel pseudospectral method implemented on distributed memory PC cluster system for modeling seismic wave propagation in heterogeneous medium. In this parallel method, the medium is decomposed into several subdomains and the wave equations are solved in each subdomain simultaneously. The solutions in each subdomain are connected through the transferring at the overlapped region. Using 2D models, we compared the parallel and traditional pseudospectral method, analyzed the accuracy of the parallel method. The results show that the parallel method can efficiently reduce computation time for the same accuracy as the traditional method. This method could be applied to large scale modeling of seismic wave propagation in 3D heterogeneous medium.
文摘针对碳纤维复合材料涂层厚度检测问题,进行了综合性实验设计。提出结合L1范数的谱投影梯度算法(spectral projection gradient based L1,SPGL1)的涂层厚度检测方法,结合涂层测厚实际,明确了基底检测更适合使用反射式太赫兹时域系统。分析求解了凸最优问题需要的条件,给出了信号稀疏分解结合飞行时间法的涂层厚度检测方案。实验数据表明,当涂层折射率相差较大时,加入噪声后的结果与理想情况一致,当涂层折射率相近时,SPGL1方法具有良好的抗干扰能力。该实验基于教师科研成果,通过完整的实验设计能够帮助学生理解时域光谱、稀疏分解、飞行时间法等基本理论和方法,锻炼了学生的实践动手能力和知识综合运用能力,培养了探索热情和创新意识。
文摘间断有限元算法(Discontinuous Galerkin Finite Element Method,DGM)是一种高精度的数值求解算法,针对电磁工程应用中DGM并行计算效率低、计算量较大的问题,提出了基于SW26010平台的并行DGM算法。通过区域分解、数据结构重构、热点函数从核并行计算、计算与通信重叠及从核缓冲优化技术完成了DGM算法的并行优化。实现结果表明,与基于MPI进程级的DGM并行算法相比,可以获得46.8的平均加速比。
