Re: Accessing data during simulation

[fernanor]

Hi Albert!rnrnFirst, thanks alot for the quick reply.rnYour answer gave me some good starting points there. The main point of the in-situ visualization is to avoid writing out data, at least to a file I/O system.rnThe goal is to sort of “”process”” the data, create a reduced representation of some form, and only write out this very small amount of data. The use case would be for a large scale simulation on a supercomputer, where you can easily rack up a couple of terabytes.rnSay, for example, you are only interested in vortex core lines in some fluid simulation. So what you do is make all the calculations on your computo nodes, and discard all additional information. Needles to say, writing out the data for a few 1D-Manifolds is much smaller than writing out all relevant data and performing the analysis as a post-process.rnIt will also be much faster, since you completely skip the file I/O for the post-process step (if you consider both simulation and post-process time). rnThere are many other advantages (and disadvantages) to consider, but that is the basic idea.rnrnSo I didn’t take a look at the code yet, but in the end I don’t really want the *raw* data, but basically the information right before it gets written to some medium. Q1 seems to answer exactly that.rnrnAnd when I said fluxes, I was thinking in terms of Navier-Stokes.rnMy knowledge concerning the inner workings of the discretization methods are rather limited. I was told however that, LB methods work on small neighborhoods (i.e. what you said in Q2), and essentially only face-neighbors, which is a nice trait for large scales. Maybe there are pitfalls I don’t know about yet, but that’s why I’m here :)rnI will try to learn more about how LB works, and specifically the OpenLB code, and maybe I can ask more specific questions then. I just don’t want to dig to much when there is an obvious reason I shouldn’t.rnrnSo thanks once more for the quick and accurate reply, I’ll post again after checking out some things.