Dear all, I take this opportunity to ask for your important suggestion.
I am solving an elastic-acoustic-gravity equation on the planet. I have displacement vector (ux,uy,uz) in solid region, displacement potential (\xi) and pressure (p) in fluid region, and gravitational potential (\phi) in all of space. All these variables are coupled. Currently, I am using MATMPIAIJ and form a single global matrix. Does using a MATMPIBIJ or MATNEST improve the convergence/efficiency in this case? For your information, total degrees of freedoms are about a billion. Any suggestion would be greatly appreciated. Thanks, Hom Nath On Fri, Jan 22, 2016 at 10:32 AM, Matthew Knepley <[email protected]> wrote: > On Fri, Jan 22, 2016 at 9:27 AM, Mark Adams <[email protected]> wrote: >>> >>> >>> >>> I said the Hypre setup cost is not scalable, >> >> >> I'd be a little careful here. Scaling for the matrix triple product is >> hard and hypre does put effort into scaling. I don't have any data however. >> Do you? > > > I used it for PyLith and saw this. I did not think any AMG had scalable > setup time. > > Matt > >>> >>> but it can be amortized over the iterations. You can quantify this >>> just by looking at the PCSetUp time as your increase the number of >>> processes. I don't think they have a good >>> model for the memory usage, and if they do, I do not know what it is. >>> However, generally Hypre takes more >>> memory than the agglomeration MG like ML or GAMG. >>> >> >> agglomerations methods tend to have lower "grid complexity", that is >> smaller coarse grids, than classic AMG like in hypre. THis is more of a >> constant complexity and not a scaling issue though. You can address this >> with parameters to some extent. But for elasticity, you want to at least >> try, if not start with, GAMG or ML. >> >>> >>> Thanks, >>> >>> Matt >>> >>>> >>>> >>>> Giang >>>> >>>> On Mon, Jan 18, 2016 at 5:25 PM, Jed Brown <[email protected]> wrote: >>>>> >>>>> Hoang Giang Bui <[email protected]> writes: >>>>> >>>>> > Why P2/P2 is not for co-located discretization? >>>>> >>>>> Matt typed "P2/P2" when me meant "P2/P1". >>>> >>>> >>> >>> >>> >>> -- >>> What most experimenters take for granted before they begin their >>> experiments is infinitely more interesting than any results to which their >>> experiments lead. >>> -- Norbert Wiener >> >> > > > > -- > What most experimenters take for granted before they begin their experiments > is infinitely more interesting than any results to which their experiments > lead. > -- Norbert Wiener
