Hi Matt,
I am using two PETSc DM, one for vertices (nodes), and one for cells (elements). I want to do the following operation: x is a global vector generated from DM vertices, with length Nn. y is a global vector generated from DM cells, with length Ne. I want to generate a sparse matrix A with size Ne x Nn, so that y = A*x. The entry of A is set to a constant value, e.g., 1/4, if the corresponding vertex belongs to the cell. Hope I make it clear, thanks! Regards, Kai Matthew Knepley <knep...@gmail.com> 于2023年5月16日周二 16:29写道: > On Tue, May 16, 2023 at 10:27 AM K. Wu <wuktsing...@gmail.com> wrote: > >> Hi all, >> >> Good day! >> >> I am currently working on interploating the nodal field vector I obtained >> to its corresponding elemental field vector. I am doing it in a simple way >> by using structured mesh, the element value is just the average of its >> corresponding nodal values. >> >> Is it possible to generate a connectivity matrix to implement this >> function? I also need this matrix later on to do a reverse transformation. >> >> I am wondering is there a way in PETSc to generate this connectivity >> matrix between nodal and elemental mesh. Or is there any better way to >> accomplish this? >> >> Thanks for your kind help! >> > > 1. Are you using a PETSc DM, or your own mesh? > > 2. In order to define what you mean, you have to attach function spaces > (or something equivalent) to the > two representations. Do you mean linear interpolation between vertices > and constants on cells? > > Thanks, > > Matt > > >> Best regards, >> Kai >> > > > -- > 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/> >