> Il giorno 24 feb 2020, alle ore 12:24, Matthew Knepley <[email protected]> ha > scritto: > > On Mon, Feb 24, 2020 at 5:30 AM Pierpaolo Minelli <[email protected] > <mailto:[email protected]>> wrote: > Hi, > I'm developing a 3D code in Fortran to study the space-time evolution of > charged particles within a Cartesian domain. > The domain decomposition has been made by me taking into account symmetry and > load balancing reasons related to my specific problem. > > That may be a problem. DMDA can only decompose itself along straight lines > through the domain. Is that how your decomposition looks?
My decomposition at the moment is paractically a 2D decomposition because i have: M = 251 (X) N = 341 (Y) P = 161 (Z) and if i use 24 MPI procs, i divided my domain in a 3D Cartesian Topology with: m = 4 n = 6 p = 1 > > In this first draft, it will remain constant throughout my simulation. > > Is there a way, using DMDAs, to solve Poisson's equation, using the domain > decomposition above, obtaining as a result the local solution including its > ghost cells values? > > How do you discretize the Poisson equation? I intend to use a 7 point stencil like that in this example: https://www.mcs.anl.gov/petsc/petsc-current/src/ksp/ksp/examples/tutorials/ex22f.F90.html <https://www.mcs.anl.gov/petsc/petsc-current/src/ksp/ksp/examples/tutorials/ex22f.F90.html> > > Thanks, > > Matt > > As input data at each time-step I know the electric charge density in each > local subdomain (RHS), including the ghost cells, even if I don't think they > are useful for the calculation of the equation. > Matrix coefficients (LHS) and boundary conditions are constant during my > simulation. > > As an output I would need to know the local electrical potential in each > local subdomain, including the values of the ghost cells in each > dimension(X,Y,Z). > > Is there an example that I can use in Fortran to solve this kind of problem? > > Thanks in advance > > Pierpaolo Minelli > > Thanks Pierpaolo > > -- > 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 > > https://www.cse.buffalo.edu/~knepley/ <http://www.cse.buffalo.edu/~knepley/>
