Andreas Klöckner

This leads (for example) to us doing unnecessary matvecs (`resample_by_mat`) instead of indirect memory access (`resample_by_picking`) in nodal DG. Solution started in #105 cc @nchristensen

Way out there, I know, but @thomasgibson, @lukeolson and I were thinking about it today. Currently, the DG face mass matrix code in grudge assumes that for each volume element,...

Some problems that currently crop up: - [x] Recreating meshes is awkward. @alexfikl proposes `Discretization.copy(mesh=...)` (or `.replace(mesh=...)`). (which?) That seems easy and useful, but it requires remembering the group factory...

Accelerate resample_by_picking through better ordering

5

`resample_by_picking` routinely shows up at the top of our GPU profiles. Here's an example from a run (mirgecom wave-eager, `nel_1d = 24`, 3D, order 3): ``` GPU activities: 15.95% 1.72898s...

- boundary groups may only contain boundary tags (all negative `neighbors`) - non-boundary groups may not contain boundary tags (all positive `neighbors`)

Sample run exhibiting the problem: https://github.com/inducer/meshmode/pull/25/checks?check_run_id=951397070 I ran into this as part of #25, but I decided to punt for now. cc @lukeolson @majosm

https://github.com/nschloe/meshio

Support gmsh file format version 4

1

Until then, you can convert your mesh with ``` gmsh your_msh4.msh -save -format msh2 -o your_msh2..msh ``` (via https://github.com/flow123d/flow123d/issues/1220) It's fairly different from the currently supported v2: https://gmsh.info/doc/texinfo/gmsh.html#MSH-file-format