Background to the Science

Daresbury Laboratory supports a very wide range of research in science and engineering using state of the art experimental and computing equipment. Whatever the question, whether it be about superconducting materials, ceramics, biological tissue, pharmaceuticals, reacting fluids or micro-engineering, Daresbury usually has the technology to find an answer.

A ``Theory Group'' was formed at Daresbury under the leadership of Prof. A. Donnachie of Manchester University in July 1970. (Source: Quest, vol.3 no.3 July 1970). They worked on nuclear physics and carried on until the Nuclear Structure Facility was closed unexpectedly around 1991, after which most of the group moved to work on projects in other countries.

The introduction of the Cray-1 to the UK in 1979 brought other opportunities.

Mary Culligan, in her editorial to the Cray Channels magazine in 1979 [50] had this to say: While visiting Daresbury I was extremely impressed with the facilities and struck by the high level of interest and enthusiasm exhibited by the diverse staff.

There is a strong esprit de corps among the Daresbury physisicts and computer experts, engineers, technical craftsmen, and administrators. Central to this feeling is the knowledge that the work being done at the Lab will help provide scientific advances in many fields.

Scientists throughout the British Isles can access the Daresbury computer network, either directly at the Lab or through any of a number of universities and research institutes. Thus the Cray-1 at Daresbury is servicing a multitude of scientific disciplines, providing the computing capability necessary to support the links between the growing experimental programs and the theoretical studies.

We would like to think that, with more modern equipment, this remains true today.

The research background of the scientific staff at the laboratory is the guiding light in our use of technology. Which technology in particular has changed many times over the years from the original NINA electron synchrotron and Van der Graaf NSF (Nuclear Structure Facility) used for nuclear physics to the dedicated SRS (Synchrotron Radiation Source) electron synchrotron and RUSTI (Research Unit for Surfaces Transforms and Interfaces). These experimental facilities have been complemented by IBM, Perkin-Elmer, DEC, Cray, NAS (National Advanced Systems), Alliant, FPS (Floating Point Systems) and later Convex, Intel and Sun supercomputers and distributed systems for theoretical support and data analysis. The intensity with which we pursue research in collaboration with universities and industrial groups worldwide quickly brings about changes to using the latest technology at the lowest cost to our sponsors. Since the early 1980s Cray and IBM have been widely known as supercomputer providers and a plethora of vendors are now satisfying the commodity cluster market. The Distributed Computing Programme under the service level agreement with EPSRC provides help and advice about the current systems to universities all over the UK.

The Theory and Computational Science Division at Daresbury Laboratory was formed on 1/10/1977 by combining the existing Daresbury theory group with the computational atomic physics, quantum chemistry and crystallography group which moved to Daresbury from the Rutherford Laboratory. A report on the first year's work of the division was published in 1978 [12]. At that time, the theory group was supporting experimental work carried out on the Synchrotron Radiation Source (SRS) and Nuclear Structure Facility (NSF). The computational science group supported the large projects undertaken in partner universities, the origin of the CCPs described below.

The use of computational methods in research has been a major growth area in science over the last (four plus) decades. Many mathematically intractable theories have now given way to calculation from first principles, experiments are analysed with increasing sophistication and real systems of ever increasing complexity can be modelled computationally. With all this new science comes a continual need for more and more computer power and power deployed in a variety of ways - not just number crunching but also experimental control and data collection, visualisation, interactive working and integration with database systems. Until around 1990 it was standard for academic researchers to access powerful remote supercomputer centres, of which Daresbury was one. This has been very successful and will no doubt continue, but there is a new challenge to these centralised facilities.

The explosive growth of the cost/ performance ratio in the workstation to mini-supercomputer range and most recently the availability of cheap and very powerful parallel supercomputers, has enabled individual research groups to run high performance computing systems dedicated to their own projects. As will be clear from what follows, such developments are common to many countries, but we shall concentrate on activities at Daresbury Laboratory to highlight the benefits and potential pitfalls of the distributed computing approach from the point of view of the researcher and user, as well as its impact on the scientific community involved [24].

Computational science at Daresbury in 1994 was mostly associated with three activities: the Synchrotron Radiation Source (SRS), the Collaborative Computational Projects (CCPs) and ``externally'' funded contracts (including industrial and European Community projects). In 2006 this is different with a growing focus on the new Diamond Light Source in Oxfordshire requiring both simulation and analysis applications embedded in an e-Science infrastructure, and also the growing hope that similar services will be provided again at Daresbury at some future date.

The SRS was the world's first dedicated source of X-ray synchrotron radiation; it supplied intense collimated beams of polarised light, tunable from infrared to VUV and hard X-ray wavelengths. It was designed c.1975 and operated for 28 years from 1980-2008 [39]. It supported a wide range of experiments including molecular chemistry, surface science, X-ray spectroscopy, biological spectroscopy, protein crystallography, single crystal and powder diffraction and small angle scattering. Many of these experiments need a high level of theoretical analysis to extract the maximum information and understanding from the data, for example angle and spin resolved photoemission, X-ray absorption and atomic and molecular photoionisation. Such analysis is always founded on a quantum mechanical description of the electronic structure and excitation spectrum of the system. Calculation of these quantities is a task of increasing computational intensity as experiments and theory become more sophisticated. Computer simulation of bulk materials can also play a role in understanding structural experiments in complex systems such as superionic conductors and zeolites, where quantum mechanical calculations are inappropriate or still too difficult due to the large number of atoms involved.

The broad discipline of engineering, both structural using finite element analysis techniques and dynamical, e.g. aerodynamics and multi-phase fluid flow through chemical reactors using computational fluid dynamics techniques, now also have a high profile at the laboratory. An intense collaboration involves a number of research groups brought together by the UK engineering community through CCP12, the international ERCOFTAC organisation and a CEC supported project with ICI plc [8].

The origin of the CCPs lies with decisions made at a meeting of the SERC Science Board on 10/10/1973 [12]. Prof. Mason presented input from the Atlas Laboratory Review Panel suggesting that ``Meeting Houses'' should be selected in various areas of science. Dr. Howlett, Director of Atlas, then set up a steering panel chaired by Prof. McWeeny with Profs. Bransden, Murrell and Burke. This resulted in agreement to form the first three CCPs. By 1980 [13], the CCPs had extended to seven groups.

For some recollections of the early days of CCP4 from Dr. Talapady Bhat, see Appendix B.

Since these early days, the CCPs have played a key role in the way computational science is coordinated in the UK. Each project brings together the major academic (and industrial) groups in a particular field to pool ideas and resources on software developments too large in scale, or too long term, to be tackled successfully by any individual group. The CCP programme currently includes the following projects:

Table 1: The Collaborative Computational Projects
Collaborative Computational Projects
CCP1 The Electronic Structure of Molecules (originally entitled Electron Correlation in Molecular Wavefunctions) (1974-2011)
CCP2 Continuum states of Atoms and Molecules (1978-2011)
CCP3 Computational Studies of Surfaces (1979-2011)
CCP4 Protein Crystallography, now called Nano-molecular Crystallography (1979-)
CCP5 Computer Simulation of Condensed Phases (originally entitled Molecular Dynamics and Monte Carlo Simulations of Bulk Systems) (1980-)
CCP6 Heavy Particle Dynamics (1980-2011)
CCP7 Analysis of Astronomical Spectra (1980-no longer active)
CCP8 Nuclear Physics (no longer active)
CCP9 Computational Electronic Structure of Condensed matter. Formerly known as Electronic Structure of Solids
CCP10 Plasma Physics (no longer active)
CCP11 Biosequence and Structure analysis (no longer active)
CCP12 High Performance COmputing in Engineering. Formerly known as Parallel Computing in Fluid Dynamics and Numerical Modelling
CCP13 Fibre diffraction (no longer active)
CCP14 Powder and Single Crystal diffraction (-2011)
CCP-ASEArch Algorithms and Software for Emerging Architectures (2011-)
CCP-BioSim Biomolecular Simulation
CCP-EM Electron cro-Microscopy (2011-)
CCPI Tomographic Imaging (2011-)
CCPN NMR Spectroscopy
CCP-NC NMR Crystallography (2011-)
CCPP Computational Plasma Physics (-2011)
CCPQ Atomic Physics (2011-, formerly CCP2 and CCP6)

For more information about the current CCPs see the Web site

As with the SRS community, the theme of ab initio quantum mechanics for atoms, molecules and solids recurs as does simulation and modelling. The CCPs also maintain and distribute program libraries via the staff at Daresbury and issue newsletters, organise conferences and workshops and support visits by an ever increasing number of overseas scientists. It is widely accepted that the projects have been instrumental in keeping UK groups at the forefront of computational science in many fields.

Whilst the outcome of the work is clearly discovery and innovation, the focus of this report is the computing equipment which was used in the research process, both experimental (sometimes referred to as in vivo) and theoretical (now often referred to as in silico or in virtuo).

Rob Allan 2016-09-20