Implicit propagation of directly addressed grids in lattice Boltzmann methods
Implicit propagation of directly addressed grids in lattice Boltzmann methods
复制标题
格子玻尔兹曼方法中直接寻址网格的隐式传播
DOI：
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发表时间：
2023
期刊：
影响因子：
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通讯作者：
M. Krause
中科院分区：
文献类型：
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作者：
A. Kummerländer;M. Dorn;M. Frank;M. Krause
格子玻尔兹曼方法（LBM）非常适合于高度并行的计算流体动力学模拟，因为它们可以分离成完全平行的碰撞步骤和仅在局部邻域内通信的传播步骤。传播步骤的实现为最大可能的带宽受限性能、存储器布局和向量指令的使用提供了约束。本文回顾并扩展了由A-A及其移位交换流（SSS）公式开始的直接寻址网格上的隐式传播工作，将其重新考虑为底层空间填充曲线的变换。在这项工作中，提出了一种新的周期性移位（PS）模式，对碰撞算子的实现施加最小的限制，并利用虚拟内存映射提供一致的性能在一系列的目标。各种实现方法以及时间依赖性和性能各向异性进行了讨论。提供了在SIMD CPU（包括Intel Xeon Phi以及Nvidia GPU）上进行SSS和PS测试的基准测试结果。最后，总结了PS作为开源LBM框架OpenLB的传播模式的应用。
Lattice Boltzmann methods (LBM) are well suited to highly parallel computational fluid dynamics simulations due to their separability into a perfectly parallel collision step and a propagation step that only communicates within a local neighborhood. The implementation of the propagation step provides constraints for the maximum possible bandwidth‐limited performance, memory layout and usage of vector instructions. This article revisits and extends the work on implicit propagation on directly addressed grids started by A‐A and its shift‐swap‐streaming (SSS) formulation by reconsidering them as transformations of the underlying space filling curve. In this work, a new periodic shift (PS) pattern is proposed that imposes minimal restrictions on the implementation of collision operators and utilizes virtual memory mapping to provide consistent performance across a range of targets. Various implementation approaches as well as time dependency and performance anisotropy are discussed. Benchmark results for SSS and PS on SIMD CPUs including Intel Xeon Phi as well as Nvidia GPUs are provided. Finally, the application of PS as the propagation pattern of the open source LBM framework OpenLB is summarized.