Inflated geometric factors storage for affine elements #314

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1. majosm commented on Aug 10, 2023

   

   majosm

   on Aug 10, 2023

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   I'm told that we don't use a separate array context for init anymore in Y3, so it looks like this isn't affecting us at the moment.
2. inducer commented on Aug 10, 2023

   

   inducer

   on Aug 10, 2023

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   @kaushikcfd Could you elaborate on the circumstance under which you've observed this? Do you happen to know why this happens?
3. kaushikcfd commented on Aug 11, 2023

   

   kaushikcfd

   on Aug 11, 2023

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   I did not observe this in any production-related drivers. But I was writing some tests for #310 and noticed this behavior and thought sharing would be essential so that others do not repeat the same mistake.

   I have attached a minimal reproducer script for posterity.

   import grudge
   import pyopencl as cl
   from meshmode.discretization.connection import FACE_RESTR_INTERIOR
   
   from grudge.array_context import get_reasonable_array_context_class
   from meshmode.mesh.generation import generate_regular_rect_mesh
   
   ctx = cl.create_some_context()
   cq = cl.CommandQueue(ctx)
   
   ref_actx = get_reasonable_array_context_class(lazy=False, distributed=False)(cq)
   actx = get_reasonable_array_context_class(lazy=True, distributed=False)(cq)
   
   mesh = generate_regular_rect_mesh(a=(-0.5, -0.5),
                                     b=(0.5, 0.5),
                                     nelements_per_axis=(16, 16))
   
   dcoll = grudge.make_discretization_collection(ref_actx, mesh, order=4)
   nx, ny = actx.thaw(dcoll.normal(FACE_RESTR_INTERIOR))
   
   assert nx[0].shape[-1] == 1  # fails

   👍React with 👍1Reacted by Matt Smith
4. inducer commented on Aug 11, 2023

   

   inducer

   on Aug 11, 2023

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   Thanks for providing the reproducer. AFAICT, this affects only the normals. The main issue is that here:

   grudge/grudge/discretization.py

   Line 770 in 0d501c0

   return self._setup_actx.freeze(normal(self._setup_actx, self, dd))

   the setup actx is unconditionally used to populate the normal cache, making this an interface bug more than a "bug bug". Perhaps the most reasonable response is to deprecate DiscretizationCollection.normal. grudge.geometry.normal takes an actx and does not have this issue (and it's more convenient to use because there's no freeze/thaw cycle needed).
5. inducer

   added a commit that references this issue on Aug 11, 2023

   Deprecate DiscretizationCollection.normal (closes gh-314)

   This issue will close once commit 2bb1230 is merged into the 'main' branch.

   2bb1230
6. inducer commented on Aug 11, 2023

   

   inducer

   on Aug 11, 2023

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   #315
7. inducer

   closed this as completedin 294a4ccon Aug 12, 2023
8. alexfikl

   added a commit that references this issue on Mar 6, 2024

   Deprecate DiscretizationCollection.normal (closes inducergh-314)

   This issue will close once commit 294a4cc is merged into the 'master' branch.

   294a4cc