The rapid acquisition of mutations conferring resistance to particular drugs remains a significan... more The rapid acquisition of mutations conferring resistance to particular drugs remains a significant cause of anti-HIV treatment failure. Informatics based techniques give resistance scores to individual mutations which can be combined additively to assess the resistance levels of complete sequences. It is likely however, that the full picture is more complicated, with non-linear epistatic effects between combinations of mutations playing
The UK MHD Consortium was formed in October 1996 and brings together the prominent MHD groups in ... more The UK MHD Consortium was formed in October 1996 and brings together the prominent MHD groups in the UK. The research topics are in Astrophysics with particular emphasis on the Solar Corona (St Andrews University), the Earth’s Geodynamo (Exeter, Glasgow and Newcastle Universities) and dynamo action in turbulent plasmas (Newcastle University).
The Community Earth System Model (CESM) is a coupled climate model for simulating the earth's... more The Community Earth System Model (CESM) is a coupled climate model for simulating the earth's climate system. Composed of four separate sub-models simultaneously simulating the earth's atmosphere, ocean, land surface ice and sea ice, and one central coupler component, CESM allows researchers to conduct fundamental research into the earth's past, present and future climate states [1]. This report describes the work undertaken under the embedded CSE programme of the ARCHER UK National Supercomputing Service [2], and was entitled "Porting and Enabling use of the Community Earth System Model on ARCHER", where the PIs were Dr Massimo Bollasina and Dr Mike Mineter, University of Edinburgh, with the technical work undertaken by the author, between the beginning of April and mid-November, 2014. [1]www.cesm.ucar.edu/modesl/cesm1.0<br> [2]www.archer.ac.uk
In this paper we compare the performance characteristics of two 3-dimensional hierarchical N-body... more In this paper we compare the performance characteristics of two 3-dimensional hierarchical N-body solvers: an O(N ) and an O(N log N ) solver. We present the execution times for numerous N-body force evaluations using the two methods, with various values of N and ffl, where ffl is the prescribed error. We find that the O(N log N ) method is more suited to problems which demand a high precision and large N . We then consider how parallelisation affects the algorithms' relative performance. 1 Introduction The N-body problem consists of a collection of N particles each exerting a force upon one another. The Nth particle is acted upon by the remaining (N \\Gamma 1) particles, hence the time to compute the force acting on each particle is O(N 2 ). There are a collection of N-body solvers which reduce the time to compute the N-body problem by introducing approximations. In this paper we compare the performance characteristics of two 3dimensional hierarchical N-body solvers; an O(N) a...
... This code was developed by Steve Purchase, University of Edinburgh, based on the original cod... more ... This code was developed by Steve Purchase, University of Edinburgh, based on the original code NBODY1 by Sverre Aarseth. ... This work was done in support of the MHD Consortium (led by Dr. Alan Hood) and was funded by the UK's High Performance Computing Initiative. ...
A process for vapor phase soldering of electronic components comprises applying to the surface of... more A process for vapor phase soldering of electronic components comprises applying to the surface of a substrate or to the surface of components on such substrate a solder cream comprising 85 to 90% of finely divided solder metal and 10 to 15% of a fluorinated tertiary alkylamine, preferably a perfluorotrihexyl amine, by weight of the sum of the two components, and positioning electronic components on the substrate, with contacts of such components on the solder cream-coated surface. The substrate is placed in a chamber in contact with the boiling vapors of a second liquid fluorinated tertiary alkylamine having a lower boiling point than the fluorinated tertiary alkylamine in the solder cream, preferably perfluorotriamyl amine, in the chamber, and melting the solder metal in the solder cream and fusing the solder joints of the electronic components to form solder joints substantially free of organic residue. The fluorinated tertiary alkylamine in the solder cream dissolves in the lower...
The PGPGrid project aims to apply Grid technologies to the production of computergenerated animat... more The PGPGrid project aims to apply Grid technologies to the production of computergenerated animation. This involves undertaking the compute-intensive processes of modelling and rendering by employing Grids in a Virtual Organisation setting. The project will attempt to implement a Wide-Area Rendering Environment (WARE) that will allow the exploitation of remote rendering farms. This involves the design and implementation of a Remote Rendering System (RRS) based on Java and Web Services. This paper presents the high level designs of the WARE and RRS and the experience gained from the implementation of a prototype based on these designs.
Numerical studies of turbulent ows have always been prone to crude approximations due to the limi... more Numerical studies of turbulent ows have always been prone to crude approximations due to the limitations in computing power. With the advent of supercomputers, new turbulence models and fast particle algorithms, more highly resolved models can now be computed. Vortex Methods are grid-free and so avoid a number of shortcomings of gridbased methods for solving turbulent uid ow equations; these include such problems as poor resolution and numerical di usion. In these methods, the continuum vorticity eld is discretised into a collection of Lagrangian elements, known as vortex elements, which are free to move in the ow eld they collectively induce. The vortex element interaction constitutes an N -body problem, which may be calculated by a direct pairwise summation method, in a time proportional to N2. This time complexity may be reduced by use of fast particle algorithms. The most common algorithms are known as the N -body Treecodes and have a hierarchical structure. An in-depth investig...
The MITgcm (MIT General Circulation Model, http://mitgcm.org/) is a numerical model designed for ... more The MITgcm (MIT General Circulation Model, http://mitgcm.org/) is a numerical model designed for study of the atmosphere, ocean, and climate (Marshall et al. 1997a,b). Its nonChydrostatic formulation enables it to simulate fluid phenomena over a wide range of scales; its adjoint capability enables it to be applied to sensitivity analysis and state estimation problems. By employing fluid isomorphisms, one hydrodynamical kernel can be used to simulate flow in both the atmosphere and ocean. This report describes the work undertaken under the embedded CSE programme of the ARCHER UK National Supercomputing Service (www.archer.ac.uk), and was entitled "Providing the ARCHER community with adjoint modelling tools for highCperformance oceanographic and cryospheric computation", where the main proposer was Dr Dan Jones (British Antarctic Survey, or BAS), with coCproposers Dr Dan Goldberg (University of Edinburgh, or UoE), Dr Paul Holland (BAS), and Dr David Ferreira (Reading Univers...
The PGPGrid project aims to apply Grid technologies to the production of computer-generated anima... more The PGPGrid project aims to apply Grid technologies to the production of computer-generated animation. This involves undertaking the compute-intensive processes of modelling and rendering by employing Grids in a Virtual Organisation setting. The project will attempt to implement a Wide-Area Rendering Environment (WARE) that will allow the exploitation of remote rendering farms. This involves the design and implementation of a Remote Rendering System (RRS) based on Java and Web Services. This paper presents the high level designs of the WARE and RRS and the experience gained from the implementation of a prototype based on these designs.
The rapid acquisition of mutations conferring resistance to particular drugs remains a significan... more The rapid acquisition of mutations conferring resistance to particular drugs remains a significant cause of anti-HIV treatment failure. Informatics based techniques give resistance scores to individual mutations which can be combined additively to assess the resistance levels of complete sequences. It is likely however, that the full picture is more complicated, with non-linear epistatic effects between combinations of mutations playing
The UK MHD Consortium was formed in October 1996 and brings together the prominent MHD groups in ... more The UK MHD Consortium was formed in October 1996 and brings together the prominent MHD groups in the UK. The research topics are in Astrophysics with particular emphasis on the Solar Corona (St Andrews University), the Earth’s Geodynamo (Exeter, Glasgow and Newcastle Universities) and dynamo action in turbulent plasmas (Newcastle University).
The Community Earth System Model (CESM) is a coupled climate model for simulating the earth's... more The Community Earth System Model (CESM) is a coupled climate model for simulating the earth's climate system. Composed of four separate sub-models simultaneously simulating the earth's atmosphere, ocean, land surface ice and sea ice, and one central coupler component, CESM allows researchers to conduct fundamental research into the earth's past, present and future climate states [1]. This report describes the work undertaken under the embedded CSE programme of the ARCHER UK National Supercomputing Service [2], and was entitled "Porting and Enabling use of the Community Earth System Model on ARCHER", where the PIs were Dr Massimo Bollasina and Dr Mike Mineter, University of Edinburgh, with the technical work undertaken by the author, between the beginning of April and mid-November, 2014. [1]www.cesm.ucar.edu/modesl/cesm1.0<br> [2]www.archer.ac.uk
In this paper we compare the performance characteristics of two 3-dimensional hierarchical N-body... more In this paper we compare the performance characteristics of two 3-dimensional hierarchical N-body solvers: an O(N ) and an O(N log N ) solver. We present the execution times for numerous N-body force evaluations using the two methods, with various values of N and ffl, where ffl is the prescribed error. We find that the O(N log N ) method is more suited to problems which demand a high precision and large N . We then consider how parallelisation affects the algorithms' relative performance. 1 Introduction The N-body problem consists of a collection of N particles each exerting a force upon one another. The Nth particle is acted upon by the remaining (N \\Gamma 1) particles, hence the time to compute the force acting on each particle is O(N 2 ). There are a collection of N-body solvers which reduce the time to compute the N-body problem by introducing approximations. In this paper we compare the performance characteristics of two 3dimensional hierarchical N-body solvers; an O(N) a...
... This code was developed by Steve Purchase, University of Edinburgh, based on the original cod... more ... This code was developed by Steve Purchase, University of Edinburgh, based on the original code NBODY1 by Sverre Aarseth. ... This work was done in support of the MHD Consortium (led by Dr. Alan Hood) and was funded by the UK's High Performance Computing Initiative. ...
A process for vapor phase soldering of electronic components comprises applying to the surface of... more A process for vapor phase soldering of electronic components comprises applying to the surface of a substrate or to the surface of components on such substrate a solder cream comprising 85 to 90% of finely divided solder metal and 10 to 15% of a fluorinated tertiary alkylamine, preferably a perfluorotrihexyl amine, by weight of the sum of the two components, and positioning electronic components on the substrate, with contacts of such components on the solder cream-coated surface. The substrate is placed in a chamber in contact with the boiling vapors of a second liquid fluorinated tertiary alkylamine having a lower boiling point than the fluorinated tertiary alkylamine in the solder cream, preferably perfluorotriamyl amine, in the chamber, and melting the solder metal in the solder cream and fusing the solder joints of the electronic components to form solder joints substantially free of organic residue. The fluorinated tertiary alkylamine in the solder cream dissolves in the lower...
The PGPGrid project aims to apply Grid technologies to the production of computergenerated animat... more The PGPGrid project aims to apply Grid technologies to the production of computergenerated animation. This involves undertaking the compute-intensive processes of modelling and rendering by employing Grids in a Virtual Organisation setting. The project will attempt to implement a Wide-Area Rendering Environment (WARE) that will allow the exploitation of remote rendering farms. This involves the design and implementation of a Remote Rendering System (RRS) based on Java and Web Services. This paper presents the high level designs of the WARE and RRS and the experience gained from the implementation of a prototype based on these designs.
Numerical studies of turbulent ows have always been prone to crude approximations due to the limi... more Numerical studies of turbulent ows have always been prone to crude approximations due to the limitations in computing power. With the advent of supercomputers, new turbulence models and fast particle algorithms, more highly resolved models can now be computed. Vortex Methods are grid-free and so avoid a number of shortcomings of gridbased methods for solving turbulent uid ow equations; these include such problems as poor resolution and numerical di usion. In these methods, the continuum vorticity eld is discretised into a collection of Lagrangian elements, known as vortex elements, which are free to move in the ow eld they collectively induce. The vortex element interaction constitutes an N -body problem, which may be calculated by a direct pairwise summation method, in a time proportional to N2. This time complexity may be reduced by use of fast particle algorithms. The most common algorithms are known as the N -body Treecodes and have a hierarchical structure. An in-depth investig...
The MITgcm (MIT General Circulation Model, http://mitgcm.org/) is a numerical model designed for ... more The MITgcm (MIT General Circulation Model, http://mitgcm.org/) is a numerical model designed for study of the atmosphere, ocean, and climate (Marshall et al. 1997a,b). Its nonChydrostatic formulation enables it to simulate fluid phenomena over a wide range of scales; its adjoint capability enables it to be applied to sensitivity analysis and state estimation problems. By employing fluid isomorphisms, one hydrodynamical kernel can be used to simulate flow in both the atmosphere and ocean. This report describes the work undertaken under the embedded CSE programme of the ARCHER UK National Supercomputing Service (www.archer.ac.uk), and was entitled "Providing the ARCHER community with adjoint modelling tools for highCperformance oceanographic and cryospheric computation", where the main proposer was Dr Dan Jones (British Antarctic Survey, or BAS), with coCproposers Dr Dan Goldberg (University of Edinburgh, or UoE), Dr Paul Holland (BAS), and Dr David Ferreira (Reading Univers...
The PGPGrid project aims to apply Grid technologies to the production of computer-generated anima... more The PGPGrid project aims to apply Grid technologies to the production of computer-generated animation. This involves undertaking the compute-intensive processes of modelling and rendering by employing Grids in a Virtual Organisation setting. The project will attempt to implement a Wide-Area Rendering Environment (WARE) that will allow the exploitation of remote rendering farms. This involves the design and implementation of a Remote Rendering System (RRS) based on Java and Web Services. This paper presents the high level designs of the WARE and RRS and the experience gained from the implementation of a prototype based on these designs.
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Papers by Gavin J Pringle