CODEWITHSUNDEEP
mpiphysicsdistributed-computing
Ray
Ray

Reputation: 339

Distributed physics simulation help/advice

I'm working in a distributed memory environment. My task is to simulate using particles tied by springs big 3D objects by dividing them into smaller pieces and each piece get simulated by another computer. I'm using a 3rd party physics engine to a achieve simulation. The problem I am facing is how to transmit the particle information in the extremities where the object is divided. This information is needed to compute interacting particle forces. The line in the image shows where the cut has been made. Because the number o particles is big the communication overhead will be big as well. Is there a good way to transmit such information or is there a way to transmit another value which helps me determine the information I need? Any help is much appreciated. Thank-you example

PS: by particle information i mean the new positions from which to compute a resulting force to be applied on the particles simulated in the local machine

Upvotes: 1

Views: 590

Answers (1)

Jonathan Dursi
Jonathan Dursi

Reputation: 50937

"Big" means lots of things. Here the number of points with data being communicated may be "big" in that it's much more than one, but if you have say a million particles in a lattice, and are dividing it between 4 processors (say) by cutting it into squares, you're only communicating 500 particles across each boundary; big compared to one but very small compared to 1,000,000.

A library very commonly used for these sorts of distributed-memory computations (which is somwehat different than distributed computing, which suggests nodes scattered all over the internet; this sort of computation, involving tightly-coupled elements, is usually best done with a series of nearby computers in a lab or in a cluster) is MPI. This pattern of communication is very common, and is called "halo exchange" or "guardcell exchange" or "ghostzone exchange" or some combination; you should be able to find lots of examples of such things by searching for those terms. (There are a few questions on this site on the topic, but they're typically focussed on very specific implementation questions).

Upvotes: 1

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