From a81813797d0dca3d8cbd1468dbcc8fd633c55839 Mon Sep 17 00:00:00 2001 From: Josh Borrow <joshua.borrow@durham.ac.uk> Date: Fri, 8 Sep 2017 11:24:45 +0200 Subject: [PATCH] added a bit more information... --- data/public.md | 44 ++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 40 insertions(+), 4 deletions(-) diff --git a/data/public.md b/data/public.md index 2d9f769..b0b4be1 100644 --- a/data/public.md +++ b/data/public.md @@ -2,16 +2,52 @@ ## What is SWIFT? +SWIFT is a Smoothed Particle Hydrodynamics code for Astrophysics. What does +that even mean? It is a computer program designed for running on supercomputers +that simulates forces upon particles due to two main things: gravity and +hydrodynamics (forces that arise from fluids rubbing against each other). +This turns out to be quite a complicated problem, partly because we can't build +computers large enough to simulate down to an atomic level, so we need to +re-think the equations that describe the particles and how they interact, +and partly because we must solve the equations that describe these problems +numerically. + +We use SWIFT to run simulations of Astrophysical objects, such as galaxies. +We do this to test theories about how the Universe came about and evolved from +the big bang up to the present day! + +< MOVIE > + + + SPH Code + Used for Astrophysics + Calculates gravity + forces due to fluid dynamics ## Why create SWIFT? -+ We want to simulate the Universe! -+ Eagle II? -+ Old codes were slow -+ They had a bad parellisation strategey +We created SWIFT for a number of reasons. The primary reason is that we want to +be able to simulate a whole Universe! This has been attempted before (see +[the EAGLE Project](http://icc.dur.ac.uk/Eagle) and [the Illustris project]( +http://www.illustris-project.org) for more details), but the codes used to do +this have always been rather slow and difficult to modify. SWIFT aims to remedy +those points by choosing to parallelise the problem in a different way and by +having a more modular structure than other codes. + +The way that supercomputers are constructed is not by having one huge chip that +everything runs on, but rather by having lots of different computers that are +connected together by high-speed networks. Therefore the way to speed up your +code might not necessarily be to make it 'run faster' on a single machine, but +rather enable those machines to talk to each other in a more efficient way. +This is how SWIFT is different from other codes that are used in Astrophysics +for a similar purpose. + +Traditionally, you have each 'node' (computer) in the 'cluster' (supercomputer) +running the exact same code at the exact same time, and at the end of each bit +of the problem they all talk to each other and exchange information. SWIFT does +this a little differently, with each node working on different tasks than +others as and when those tasks need to be completed. This (theoretically) +should cut down on the time when a node is sitting and waiting for work, which +is just wasted time and electricity! ## What is SPH? -- GitLab