Oleg, The first thing to do if you want to speed up you code is to profile your code. How do you know which part of the code is slow? Right now, it sounds that you are assuming that it is in the solver which may be true but it may not be. If you want to speed up your solver, you can 1) get a better preconditioner (maybe using algebraic multigrid) 2) make you code parallel. deal.II is multithreaded by default but not every operation is. On top of that multithreading does not work if the processors need to communicate through the network (which might be the case on the cluster you are testing). In that case, you will need to use MPI. Take a look at step-40 <https://dealii.org/current/doxygen/deal.II/step_40.html#LaplaceProblemsolve> It solves the Laplace equation with 52 millions DoFs in less than 10 seconds on 4000 processors.
Best Bruno On Thursday, December 5, 2019 at 9:10:19 AM UTC-5, Oleg Kmechak wrote: > > Dear All, > > I am working on RiverSIM program(https://github.com/okmechak/RiverSim/) > > This program solves laplace equation on river network geometry, > then makes some computaion(integration over these dence points on picture > and other processing) which result in river network evolution step by step. > > [image: test.jpg] > > > Program is quite big, but all Deal.II dependencies are encapsulated into > Solver class( > https://github.com/okmechak/RiverSim/blob/master/source/river/solver.hpp) > > which is adaptation of step-6 from tutorials( > https://www.dealii.org/current/doxygen/deal.II/step_6.html) > > > It works very well, but I need as much perfomance as it is possible :) > > > Mesh, as you can see, is very irregular and very dence at some points(see > picture above). > > On my laptop i5 from wsl(windows subsystem for linux) it takes ~8-10 > seconds on DoF with 250,000 degrees(65,000 active cells) > > And on cluster with 40 processors even longer - 10-13 seconds > > > Also is the solver already(by default) multithread or I should somehow > configure the Deal.II? > > Regards, > Oleg Kmecahk > > > -- The deal.II project is located at http://www.dealii.org/ For mailing list/forum options, see https://groups.google.com/d/forum/dealii?hl=en --- You received this message because you are subscribed to the Google Groups "deal.II User Group" group. To unsubscribe from this group and stop receiving emails from it, send an email to dealii+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/dealii/d1595f6a-206f-4350-9c65-7b39feeafc25%40googlegroups.com.
