XPS:EXPL:DSD: Language Abstraction, Annotation, Compiler Optimization Techniques for Efficient CFD Computation

该项目旨在建立一种新颖的编程工具，使科学家和工程师能够设计出新的科学和工程应用程序，从而最好地利用当今最强大的计算机。该工具将专门针对计算流体动力学（CFD）中的应用，该领域涵盖了广泛的潜在应用，如喷气发动机设计，改进和优化微制造和“微流体装置”（如喷墨打印机），燃烧和柴油发动机技术，农业污水和灌溉，喷墨打印，医疗诊断和DNA分析。该工具允许程序员传达其应用程序的独特特性，编译器可以利用这些特性来匹配要运行该程序的计算机系统的任何独特硬件特性。这种匹配可以使程序运行得更快，更有效地利用资源。该项目将通过向计算科学与工程（CSE）社区提供工具，帮助促进跨学科研究、教学、培训和学习。通过普渡大学国家科学基金会支持的设施，为这个项目构建的工具将作为开源软件提供给高性能计算社区。将与普渡大学罗森高级计算中心合作组织教程和研讨会，针对普渡大学和其他地方的CSE教师和学生。该项目研究了新的特定于cfd的语言抽象和注释技术，以实现广泛的程序转换，旨在纠正程序结构和硬件之间的不匹配，从而显著提高性能。将开发一个原型编译器来验证新概念并演示其性能优势。该项目将基于健壮的模型，这些模型捕获了最重要的硬件因素，如通信、缓存内存和SIMD操作。高级规范的设计使得程序员可以向编译器指定高级程序语义，而不会被子例程调用层所掩盖。这种规范在高层上将程序构造和数据结构绑定在一起，使编译器能够在考虑通信效率、数据局部性和矢量运算效率的情况下，对通信调度和数据布局做出最佳决策。该项目将使有效的程序转换和组合应用于一系列重要的CFD方法和应用，例如使用高阶紧致有限差分格式解决包括多种化学物质在内的可压缩Navier-Stokes方程的射流湍流模拟；不可压缩均匀湍流；基于物理空间时间推进FFT算法的可压缩均匀湍流、高阶有限差分格式和WENO激波捕获格式；一种基于相场的方法和算法，用于模拟涉及自由界面、表面张力、移动接触线和疏水/亲水壁的有壁两相液气流动；处理两相大密度比和大粘度比的算法；以及湍流、流致振动、湍流尾迹和固体结构的频谱元模拟。

This project seeks to build a novel programming tool that will allow scientists and engineers to design new scientific and engineering application programs that can best utilize today's most powerful computers. This tool will specifically target applications in computational fluid dynamics (CFD), an area that covers a wide range of potential applications such as jet engine design, improving and optimizing micro-manufacturing and "micro-fluidic devices" (such as ink-jet printers), combustion and diesel engine technology, agricultural sewage and irrigation, ink-jet printing, medical diagnostics and DNA analysis. The tool allows the programmers to communicate the distinct nature of their application that can be exploited by the compiler to match any unique hardware features of the computer system on which the program is to be run. This matching could make the program run faster and make more efficient use of resources. The project will help promote interdisciplinary research, teaching, training, and learning by offering the tool to the Computational Science and Engineering (CSE) community. Through facilities supported by National Science Foundation at Purdue University, the tool built for this project will be offered to the high performance computing community as open source software. Tutorials and workshops will be organized in collaboration with Purdue University's Rosen Center for Advanced Computing, targeting the CSE faculty and students both at Purdue and elsewhere.This project investigates novel CFD-specific language abstraction and annotation techniques to enable extensive program transformation aimed at correcting mismatches between program constructs and hardware, leading to significant performance enhancement. A prototyping compiler will be developed to validate the new concepts and to demonstrate the performance advantages.This project will be based on robust models that capture the most significant hardware factors such as communication, cache memory, and SIMD operations. High level specifications are designed such that the programmer can specify to the compiler the high level program semantics without being obscured by layers of subroutine calls. Such specification binds program constructs and data structures at a high level, allowing the compiler to make the best decision concerning communication scheduling and data layout, taking into account communication efficiency, data locality and vector operation efficiency. This project will enable effective program transformation and composition that are applied to a range of important CFD methods and applications, such as jet turbulence simulations that solve the compressible Navier-Stokes equations including multiple chemical species using a high-order compact finite difference scheme; incompressible homogeneous turbulence; compressible homogeneous turbulence based on the FFT algorithm with time advancement in physical space, high-order finite difference schemes, and WENO shock capturing schemes; a phase field-based approach and algorithms for simulating wall-bounded two-phase liquid-gas flows involving free interfaces, surface tension, moving contact lines, and hydro-phobic/-philic walls; algorithms to handle large density ratios and large viscosity ratios of the two fluid phases; and spectral-element simulations of turbulence, flow-induced vibrations, turbulent wakes, and solid structures.