diff --git a/data/public.md b/data/public.md index b0b4be101c945c91fdfee34a40bc1e2fa6215964..ee752c2aa01e23c4f8c33c182ddd81940825b5e5 100644 --- a/data/public.md +++ b/data/public.md @@ -6,11 +6,11 @@ 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. +This turns out to be quite a complicated problem as we can't build +computers large enough to simulate down to an atomic level. This means +we need to re-think the equations that describe the particles and how they +interact. It turns out that we must solve the equations that describe these problems +numerically, which requires a lot of computing power and fast computer code. 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 @@ -18,23 +18,19 @@ 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 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 +We created SWIFT for a number of reasons. The primary reason beings 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. +that by choosing to parallelise the problem in a different way and by +having a more modular structure than other codes making it easier for users to +pick and choose what physics they want to include in their simulation. -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 +The way that supercomputers are constructed is not by having one huge superfast +'computer', 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. @@ -51,7 +47,13 @@ is just wasted time and electricity! ## What is SPH? -+ Smoothed Particle Hydrodynamics -+ Can't treat each particle in a fluid individually -+ Must find a way to still do fluid dynamics! +Smoothed Particle Hydrodynamics (SPH) is a method of calculating the forces +between fluid elements. Let's say that we want to simulate some water and a wave +within it. Even a liter of water has 100000000000000000000000000 particles in it. +To store that much data we would require a computer that as 100 trillion times as +much storage space as *all of the data on the internet*. It's clear that we need +a more efficient way of simulating this water if we are to have any hope! +It turns out that we can represent the water by many fewer particles (let's say +about 1000) if we can smooth over the gaps between them efficiently. Smoothed +Particle Hydrodynamics is the technique that we use to do that.