Lazy evaluation in mirgecom

[matthiasdiener]

• [x] Get a lazy version of wave running (#220)
• [x] Implement reductions for vortex-mpi etc.
• [ ] Merge the pytato_array_context branches to master
  • [ ] Meshmode (https://github.com/inducer/meshmode/pull/116)
  • [ ] Pytato (https://github.com/kaushikcfd/pytato/tree/pytato_array_context)
  • [ ] Grudge (https://github.com/inducer/grudge/pull/45, https://github.com/inducer/grudge/pull/48)
  • [ ] Loopy (https://github.com/inducer/loopy/pull/222)
• [ ] Get profiling running for PytatoArrayContext
• [ ] Implement communication
• [ ] Make kernels run in parallel (enable here: https://github.com/kaushikcfd/meshmode/blob/pytato_array_context/meshmode/array_context.py#L930)

cc @inducer @kaushikcfd

[inducer]

As @matthiasdiener and I discussed earlier: I agree with that set of steps as a path towards lazy eval in mirgecom.