Software Environment for Actionable & VVUQ-evaluated Exascale Applications (SEAVEA)

不确定性量化、验证和确认对于建立所有形式的基于计算机的模拟的可靠性和再现性至关重要。我们建议建立一个开源和开放开发的VVUQ工具包，优化在当前的前和新兴的艾级，这将提出新的挑战和新的机遇，在不同领域的模拟融合和气候modeling.Computer模拟结果进行验证与实验相比，在几个方面，从定性到定量的措施，适用于验证度量。同样，验证涉及确认数学模型和相应的算法已被正确编码。不确定性量化（UQ）涉及理解计算机模拟所伴随的误差的来源和评估误差的大小，无论是认识性的还是任意性的。VVUQ对于任何在事件发生前做出预测的模拟都是必要的，也就是说，它的输出在任何形式的决策过程中都很有用，从政府对流行病的干预到材料的选择，再到飞机机翼生产的联合收割机。此外，由于VVUQ基于集成的执行模式，其本质上是计算密集型的，因此它也需要Exascale资源以及高级资源管理策略来有效管理所需的大量并发运行。我们建议建立一个开源和开放开发的VVUQ工具包，以在当前的前和新兴的exascale上进行高效执行。这将包括替代建模的先进方法，以最大限度地减少执行计算密集型计算所需的费用和时间，并将展示其在多个科学应用中的各种VVUQ工作流程以及在建筑和地理上多样化的新兴艾级环境中的效率提升。在这个项目中开发、实施和基准测试的软件将成为英国ExCALIBUR社区的开放和宝贵资产，而且随着高性能计算进入艾级时代，在英国和国际上也将得到更广泛的应用。拟议的艾级工具包将建立在广泛使用的工具和服务的组合之上，这些工具和服务将不断发展，以处理日益复杂的系统。其中包括来自VECMA项目的组件（EasyVVUQ，FabSim 3，QCG-PJ和EasySurrogate），以及UCL-Alan Turing Institute多输出高斯过程仿真器（MOGP）。我们将把这些能力应用到几个应用中，包括：（i）英国原子能机构的托卡马克聚变建模用例，将为该用例生成一个工作软件环境;（ii）气象局的天气和气候预报;（iii）环境科学的湍流模拟;（iv）航空航天应用中石墨烯聚合物基纳米复合材料的先进材料性能预测;（v）用于医学研究的高保真病人专用虚拟人体血流系统;（vi）药物发现;以及（vii）人类迁移。

Uncertainty quantification, verification and validation are crucial to establish the reliability and reproducibility of all forms of computer-based simulation. We propose to establish an open source and open development VVUQ toolkit optimised for efficient execution at current pre- and emerging exascale, which will raise new challenges and new opportunities for simulations in fields as diverse as fusion and climate modelling.Computer simulation results are validated compared with experiment in several ways, ranging from qualitative to quantitative measures which apply a validation metric. Likewise, verification is concerned with confirmation that the mathematical model and corresponding algorithm have been coded correctly. Uncertainty quantification (UQ) is concerned with understanding the origins of and assessing the magnitudes of the errors which accompany computer simulations, whether epistemic or aleatoric. VVUQ is necessary for any simulation that makes predictions in advance of an event to become actionable - that is, for its output to be useful in any form of decision-making process, from government interventions in pandemics to the choice of materials to combine for aircraft wing production. Here, exascale computing offers more opportunities to make actionable predictions.Moreover, because VVUQ is intrinsically compute intensive due to its ensemble-based execution pattern, it too requires exascale resources, as well as advanced resource management strategies to efficiently manage the large numbers of concurrent runs necessary. We propose to establish an open source and open development VVUQ toolkit optimised for efficient execution at current pre- and emerging exascale. This will include advanced approaches for surrogate modelling in order to minimise the expense and time needed to perform the most compute-intensive calculations and will demonstrate its efficiency gains for a diverse array of VVUQ workflows within multiple scientific applications, and on architecturally and geographically diverse emerging exascale environments. The software developed, implemented and benchmarked in this project will become an open and invaluable asset to the UK ExCALIBUR community but also much more widely within UK and internationally as high-performance computing enters the exascale era.The proposed exascale toolkit will be built on a combination of widely used tools and services which will be evolved to handle systems of increasing levels of complexity. These include components from the VECMA project (EasyVVUQ, FabSim3, QCG-PJ and EasySurrogate), as well as the UCL-Alan Turing Institute Multi-Output Gaussian Process Emulator (MOGP). We will apply these capabilities to several applications, including: (i) the UKAEA's tokamak fusion modelling use case for which a working software environment will be produced; (ii) weather and climate forecasting for the Met Office; (iii) turbulent flow simulation for environmental science; (iv) prediction of advanced materials properties of graphene-polymer based nanocomposites for aerospace applications; (v) high-fidelity patient-specific virtual human blood flow system for medical research; (vi) drug discovery; and (vii) human migration.