EPCC joins the UK’s ExCALIBUR programme to address the challenges of Exascale

Author: Kevin Stratford
Posted: 8 May 2020 | 09:37

ExCALIBUR is a £45.7m programme to address the challenges and opportunities offered by computing at the exascale (high performance computing at 1018 floating point operations per second). The programme will address problems of strategic importance, and how to approach them in an efficient, effective, and productive fashion on the world’s largest computers.

The Strategic Priorities Fund is one of the UK Government’s largest programmes to work on multi-disciplinary and inter-disciplinary research and innovation, and has the ultimate aim of boosting the productivity and competitiveness of the economy. In the context of ExCALIBUR, this includes work on currently intractable problems of strategic importance such as drug and vaccine research, climate and weather prediction, and fusion power and green energy sources.

Specifically, the aim is the redesign and reimplementation of high priority codes and algorithms to maintain a leading position for the UK in high performance computing.

With the first Exascale machines perhaps becoming available between 2021–2023, the challenges are certainly formidable. A range of development is required from systems software and libraries, applications themselves, and utilities to prepare, analyse and visualise large amounts of data.

A very high degree of parallelism will be relevant throughout – perhaps O(109)-O(1010) simultaneous threads of execution will be employed at the Exascale. Applications must maximise efficient use of computational resources, minimise costly data transfers and synchronisations, and at the same time deal with significant algorithmic complexity.

All this must be done with an eye not just to flexible and efficient computation and robust numerical results, but to the productivity of those doing the development, and to energy efficiency at the time of execution.

As the first stage in ExCALIBUR, in October 2019 UKRI put out a call for high priority use cases around which to form design and development working groups. EPCC is now active, in collaboration with universities and industrial partners around the UK, in three of the resultant eight groups which have been funded: see below. 

The three groups will concentrate on different areas: mesh generation and manipulation for finite element problems, materials simulations, and lattice field theory. It will be the results of such programmes which will enable the benefits of efficient Exascale computing to be achieved.

Each of these strands will be discussed in more detail in future.  

ExCALIBUR is led by the Met Office and the Engineering and Physical Sciences Research Council, and is a UK Research and Innovation (UKRI) Strategic Priorities Fund programme

Excalibur project website

EPCC’s ExCALIBUR collaborations

The Materials and Molecular Modelling Exascale Design and Development Working Group

This project brings together Research Software Engineers and experts from mathematics and computer science with domain experts in Materials and Molecular Modelling (MMM) to ensure this key research area is ready to exploit future Exascale computing resources. This will cover all components required by the community as pre-exascale and exascale computational resources become available to researchers. The project will equip the UK MMM community with the tools and communities required to use exascale computational resources efficiently to address many EPSRC Grand Challenges.

The project is led by UCL with EPCC among the co-leaders.


ELEMENT addresses the high priority use case of meshing for the Exascale (ensuring that meshes are of sufficient quality to represent Exascale problems and can be partitioned efficiently to minimise load imbalance) as well as meshing at the Exascale (creating highly scalable solutions able to exploit extreme levels of parallelism). The project is led by EPCC.

Meshing and geometry management remain a significant bottleneck for complex applications on HPC platforms, posing a challenging obstacle that must be overcome to enable Exascale simulations. From a technical perspective, these issues include improved geometric handling, mesh adaptation and optimisation, intelligent meshing, automation and robustness, all within a large distributed environment that lies outside of our current capabilities.

ELEMENT project website

EXALAT: Lattice Field Theory at the Exascale Frontier 

EXALAT is a collaboration led by the University of Edinburgh, with total funding of £365k to build on the recognised expertise in the Lattice Field Theory (LFT) community to use high-end computing to inform and upskill the wider scientific ecosystem for Exascale computing. 

The project will develop a roadmap for LFT, as an example for other domains, to prepare for science on the first Exascale computers. It will also develop initial resources (best practice, training, and algorithmic/ software templates) to begin the journey. 

Exalat website 


Kevin Stratford, EPCC Image    

Photo by Ricardo Cruz on Unsplash






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