Hello again! For my multiphysics problem, I think a DMComposite might make the most sense, since some variables are only defined in 1d (so any 2d information is just wasting memory and CPU), while others have a full 2d distribution. To tell PETSc how the two DMs should be coupled, it looks like I need DMCompositeSetCoupling, but there are no examples on how to use it, or even what the parameters of the provided function mean. Does anyone have a simple example to share? Doesn't have to be full code, a snippet would be just fine.
Thanks, Ellen Price