TChem: A performance portable parallel software toolkit for complex kinetic mechanisms

We present TChem, a performance portable software toolkit to enable the analysis of complex kinetic mechanisms. The software provides tools for gas-phase and surface chemistry, thermodynamic properties, and implements formulations for several canonical reactor models. Analytical derivatives necessary to construct Jacobian matrices corresponding to all implemented functionalities are available through automatic differentiation. TChem uses the Kokkos framework to achieve portability across multiple heterogeneous computing platforms with a single version of the code. We implement a hierarchical parallelism framework to enable efficient chemical source term and thermodynamic property evaluations over the number of samples assigned to the local computing device. We analyze parallel efficiency results extracted from test cases for thermodynamic properties, source terms, and Jacobians evaluations on Intel Xeon CPUs and NVIDIA Volta GPUs.本研究提出TChem——一款支持复杂反应动力学机理分析的性能可移植软件工具包。该工具包涵盖气相与表面化学计算、热力学性质分析功能，并针对多种典型反应器模型实现了对应的数学建模方法。构建所有已实现功能对应的雅可比矩阵（Jacobian Matrix）所需的解析导数，可通过自动微分技术获取。TChem采用Kokkos框架，仅需单版本代码即可实现跨多种异构计算平台的可移植性。本研究构建了分层并行框架，可针对分配至本地计算设备的样本集高效完成化学源项与热力学性质的计算评估。此外，本研究针对热力学性质、化学源项及雅可比矩阵评估三类测试用例，在英特尔至强（Intel Xeon）CPU与英伟达Volta架构GPU上分析了其并行效率结果。