Quantum Monte Carlo simulations on ten thousand to a million cores
Lead Research Organisation:
UNIVERSITY COLLEGE LONDON
Department Name: Earth Sciences
Abstract
Abstracts are not currently available in GtR for all funded research. This is normally because the abstract was not required at the time of proposal submission, but may be because it included sensitive information such as personal details.
Organisations
People |
ORCID iD |
| Dario Alfe (Principal Investigator) |
Publications
Al-Hamdani Y
(2014)
Water on BN doped benzene: A hard test for exchange-correlation functionals and the impact of exact exchange on weak binding
in The Journal of Chemical Physics
Alfè D
(2013)
Communication: energy benchmarking with quantum Monte Carlo for water nano-droplets and bulk liquid water.
in The Journal of chemical physics
Chen J
(2016)
Evidence for stable square ice from quantum Monte Carlo
in Physical Review B
Cox S
(2014)
Benchmarking the performance of density functional theory and point charge force fields in their description of sI methane hydrate against diffusion Monte Carlo
in The Journal of Chemical Physics
Dario Alfe (Co-Author)
(2011)
Petascale computing opens new vistas for quantum Monte Carlo
Droghetti A
(2013)
Ground state of a spin-crossover molecule calculated by diffusion Monte Carlo
in Physical Review B
Droghetti A
(2012)
Assessment of density functional theory for iron(II) molecules across the spin-crossover transition.
in The Journal of chemical physics
Gillan MJ
(2015)
Energy benchmarks for methane-water systems from quantum Monte Carlo and second-order Møller-Plesset calculations.
in The Journal of chemical physics
Gillan MJ
(2016)
Perspective: How good is DFT for water?
in The Journal of chemical physics
| Description | We are living through a technological revolution, watching the world change as information technology (IT) permeates every area of our lives. Driven by the extraordinary increase in computer power over the past few decades, the IT revolution has advanced to the point that it has become almost impossible to imagine a world without computers. Science has been affected too, perhaps more than most other aspects of society, with computer simulation now playing a central role in almost all research fields. In materials science, in particular, computer simulations based on density functional theory (DFT) have had a huge impact. DFT is a relatively simple but fully quantum mechanical approach capable of providing an accurate description of the microscopic world in many cases, with no inputs other than the identities of the atoms. Applications of DFT to real-life problems span many disciplines, with recent successes including the prediction of novel catalysts, the design of improved batteries, and a better understanding of the temperature and composition of the Earth's core. However, in many room-temperature biological and chemical contexts, the approximations on which real DFT calculations are based are not good enough and the scientific community is calling for more accurate approaches. This project aims to accelerate the development of one such approach, the diffusion quantum Monte Carlo (DMC) method. Unlike DFT, DMC is normally capable of delivering the high accuracy required for most room-temperature biology, chemistry and materials science. Unlike most other accurate methods, DMC is also capable of simulating very large systems, although at a high computational cost. Our main objective is to improve the CASINO DMC code, developed primarily by Richard Needs and his group, to the point that it can be used by physicists, biologists, chemists, earth scientists, and others in much the same way as DFT is used today. CASINO is the world's most widely used DMC code, but like all existing DMC codes it lacks certain features required for real applications in materials science. For example, no DMC code can yet perform quantum molecular dynamics simulations for general systems. One of the aims of our project is to remedy this deficiency. For the past few decades, computers have become faster as processor clock speeds have increased. Today, however, clock speeds are approaching fundamental limits and computers are becoming more powerful only by the inclusion of additional processors. Personal computers often have four or six cores, and some of the supercomputers used for scientific simulations have hundreds of thousands. The bad news is that programming massively-parallel supercomputers is so difficult that the scientific community is being forced to re-think many of its approaches from scratch. The good news is that DMC is one of very few "naturally" parallel materials-simulation algorithms, and that CASINO already runs efficiently on machines with 10,000 processors. Once we have made the improvements described in this proposal, we are confident that CASINO will run efficiently on the million-core computers of tomorrow. We need to re-work CASINO to harness the power of the future. A few years from now, when petascale computers are becoming more common, the work carried out in this proposal is making it possible to use DMC to simulate phenomena that today can only be studied at the DFT level, providing the improved accuracy required to take significant steps forward in many areas of science and technology. |
| Exploitation Route | The development of a better QMC code will benefit the quantum Monte Carlo community, and more generally the material science computer simulation community. |
| Sectors | Chemicals Digital/Communication/Information Technologies (including Software) Education Electronics Energy Environment Other |
| Description | They have facilitated the use of specific QMC computer codes, and the improved efficiency has reduced the amount of computer power required per unit of science produced. |
| First Year Of Impact | 2014 |
| Sector | Other |
| Impact Types | Cultural |
| Title | PHON - A program to calculate phonons using the small displacement method |
| Description | I am not entirely sure if this is relevant, but here it is. The PHON code is a computer software that is used to compute vibrational frequencies of materials, and with them also compute their thermodynamic properties. The programme is freely available from my personal web-page, and also from Github and from the Computer Physics Communications website. |
| Type Of Material | Improvements to research infrastructure |
| Year Produced | 2009 |
| Provided To Others? | Yes |
| Impact | PHON is used by hundreds of groups worldwide, and the describing paper (Computer Physics Communication 180, 2622-2633 (2009)) has been already cited more than 400 times. I am associating this product with all my grants as I have been developing this code over the years, and so all my grants have contributed to sustain this development. |
| URL | http://www.homepages.ucl.ac.uk/~ucfbdxa/phon/ |
| Title | CASINO 2.12 |
| Description | New software release with better scaling to large number of processors |
| Type Of Technology | Software |
| Year Produced | 2013 |
| Impact | N/A |