DiRAC: Memory Intensive 2.5x

Physicists across the astronomy, nuclear and particle physics communities are focussed
on understanding how the Universe works at a very fundamental level. The distance scales
with which they work vary by 50 orders of magnitude from the smallest distances probed
by experiments at the Large Hadron Collider, deep within the atomic
nucleus, to the largest scale galaxy clusters discovered out in space. The Science challenges,
however, are linked through questions such as: How did the Universe begin and how is it evolving?
and What are the fundamental constituents and fabric of the Universe and how do they interact?

Progress requires new astronomical observations and experimental data but also
new theoretical insights. Theoretical understanding comes increasingly from large-scale
computations that allow us to confront the consequences of our theories very accurately
with the data or allow us to interrogate the data in detail to extract information that has
impact on our theories. These computations test the fastest computers that we have and
push the boundaries of technology in this sector. They also provide an excellent
environment for training students in state-of-the-art techniques for code optimisation and
data mining and visualisation.

The DiRAC2 HPC facility has been operating since 2012, providing
computing resources for theoretical research in all areas of particle
physics, astronomy, cosmology and nuclear physics supported by
STFC. It is a highly productive facility, generating more than 250
papers annually in international, peer-reviewed journals. However, the
DiRAC2 hardware is now at least 5 years old and is therefore at
significant risk of failure. The loss of any one of the DiRAC2
services would have a potentially disastrous impact on the research
communities which rely on it to deliver their scientific research. The
main purpose of the requested funding for the DiRAC2.5x project is to
replace the ageing DiRAC2 hardware at Durham, Edinburgh and Leicester
while taking advantage of recent hardware advances to provide some new
capabilities (e.g. i/o acceleration using flash storage) as prototypes
for the proposed DiRAC3 services.

The DiRAC-2.5x project builds on the success of the DiRAC-2.5 HPC facility and will provide the resources needed
to support cutting edge research starting from 1/4/2018 in all areas of science supported by STFC.

Specifically the funding sort by Durham will allow:

A factor 2 increase in the size of calculation that can be run at Durham, and a 50% increase in the
available computing power (assuming the current DiRAC-2.5 systems continue to operate at the current level).
The usage of the system will be decided by the DiRAC Resource Allocation Committee primarily,
but it is envisaged that the enhanced system will be used for very large calculations, for example, to:

(i) simulate the merger of pairs of black holes which generate gravitational waves such as those recently discovered by the
LIGO consortium;

(ii) perform the most realistic simulations to date of the formation and evolution of galaxies in the Universe

(iii) carry out detailed simulations of the interior of the sun and of planetary interiors.

The anticipated impact of the DiRAC2.5x HPC facility aligns closely
with the recently published UK Industrial Strategy. As such, many of
our key impacts will be driven by our engagements with industry. Each
service provider for DiRAC2.5x has a local industrial strategy to
deliver increased levels of industrial returns over the next three
years. The "Pathways to impact" document which is attached to the
lead Je-S form from Leicester, describes the overall industrial strategy for DiRAC2.5x,
including our strategic goals and key performance indicators.