Just a quick note here... I've successfully used SerialMesh on over 10,000 processors... and ParallelMesh on over 100,000
That "128 processors" quote from the paper is quaint ;-) Derek On Mon, Jul 14, 2014 at 1:30 PM, John Peterson <[email protected]> wrote: > On Mon, Jul 14, 2014 at 11:32 AM, Hodge, Neil E. <[email protected]> wrote: > > I recently sat down and read > > > > Kirk, "libMesh: a C++ library for adaptive mesh refinement/coarsening > > simulations", Engineering with Computers, 2006. > > > > In that paper, I found the following: > > > > "On distributed memory machines, such as PC clusters, a complete copy of > > the mesh is maintained independently on each processor. This design > > decision limits practical 3D applications to on the order of 128 > > processors because of the overhead associated with storing the global > > mesh." > > Wow, I had forgotten the paper said this! > > It's definitely not true any more, and the sentence leaves out > something important, which is that the amount serial mesh "limits" you > of course depends on the size of the Mesh. > > In practice I use SerialMesh for nearly all of my applications, and > reserve ParallelMesh only for meshes which can't even be opened on a > single node because they don't fit in the available system memory. In > such cases, you have to use the Nemesis format and "split" your mesh > in a preprocessing step before running your application. > > One of the nastier things that we've discovered within the last year > or two is that std::map (which ParallelMesh uses to store its nodes > and elements) imposes an incredible memory overhead relative to > std::vectors, so that for small enough problems, running with > ParallelMesh actually requires *more* memory than running with > SerialMesh, even with the saving you get from parallelizing it > factored in. > > > > Is it possible to separate these two functionalities, i.e., to use the > mesh manipulation functionality, but not perform the element operations? > > Absolutely. > > -- > John > > > ------------------------------------------------------------------------------ > Want fast and easy access to all the code in your enterprise? Index and > search up to 200,000 lines of code with a free copy of Black Duck® > Code Sight™ - the same software that powers the world's largest code > search on Ohloh, the Black Duck Open Hub! Try it now. > http://p.sf.net/sfu/bds > _______________________________________________ > Libmesh-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/libmesh-users > ------------------------------------------------------------------------------ Want fast and easy access to all the code in your enterprise? Index and search up to 200,000 lines of code with a free copy of Black Duck Code Sight - the same software that powers the world's largest code search on Ohloh, the Black Duck Open Hub! Try it now. http://p.sf.net/sfu/bds _______________________________________________ Libmesh-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/libmesh-users
