fespace update fails for h derefinement after p adaption

[tradeqvest]

fespace update fails for h derefinement after p adaption

[dylan-copeland]

Hello @tradeqvest, thanks for your interest in hp-(de)refinement. In the current state of the MFEM master branch, hp-refinement should work for H1 spaces in serial (the parallel extension is a work in progress, see PR 4038). As far as I know, derefinement is not supported with variable-order spaces, even in serial. I think it works for h-derefinement (constant order), but even that is not tested in any example, miniapp, or unit test.

The error you posted is a failed verification that the last mesh operation was an h-refinement. My guess is that the last operation was NONE, in the case of p-refinement. In other words, this error says that derefinement is not supported when the last mesh operation was not an h-refinement.

Supporting derefinement in variable-order spaces may require significant development effort in the MFEM library, so there is likely no workaround or easy solution. We should add this capability in MFEM in the future (no definite plans currently).