The last ten years have witnessed fast spreading of massively parallel computing clusters, from leading supercomputing facilities down to the average university computing center. Many companies in the private sector have undergone a similar evolution. In this scenario, the seamless integration of software and middleware libraries is a key ingredient to ensure portability of scientific codes and guarantees them an extended lifetime. In this work, we describe the integration of the ChASE library, a modern parallel eigensolver, into an existing legacy code for the first-principles computation of optical properties of materials via solution of the Bethe-Salpeter equation for the optical polarization function. Our numerical tests show that, as a result of integrating ChASE and parallelizing the reading routine, the code experiences a remarkable speedup and greatly improved scaling behavior on both multi- and many-core architectures. We demonstrate that such a modernized BSE code will, by fully exploiting parallel computing architectures and file systems, enable domain scientists to accurately study complex material systems that were not accessible before.

中文翻译：

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在大规模并行架构上求解 Bethe-Salpeter 方程

过去十年见证了大规模并行计算集群的快速传播，从领先的超级计算设施到普通的大学计算中心。私营部门的许多公司都经历了类似的演变。在这种情况下，软件和中间件库的无缝集成是确保科学代码可移植性并延长其生命周期的关键因素。在这项工作中，我们描述了 ChASE 库（一种现代并行特征求解器）与现有遗留代码的集成，通过求解光学偏振函数的 Bethe-Salpeter 方程来计算材料的光学特性的第一性原理。我们的数值测试表明，作为集成 ChASE 和并行化读取程序的结果，该代码在多核和众核架构上都经历了显着的加速和大大改进的缩放行为。我们证明，这种现代化的 BSE 代码将通过充分利用并行计算架构和文件系统，使领域科学家能够准确地研究以前无法访问的复杂材料系统。