Return geometry by value (alternative 4)

[SoilRos]

This is yet another version of how to return the geometry by value (see #885, #884, #891, and #334). Compared to the others, this should be the fastest one. The trick is made by not sharing the ownership of the corners, just a non-owning pointer. Additionally, since the geometryInFather needs to store its own data, I simply changed its type for Dune::AxisAlignedCubeGeometry which does the same job, but faster.

[SoilRos]

jenkins build this serial please

[SoilRos]

benchmark please

[ytelses]

Benchmark result overview:

Test	Configuration	Relative
opm-git	OPM Benchmark: drogon - Threads: 1	0.998
opm-git	OPM Benchmark: drogon - Threads: 8	1.015
opm-git	OPM Benchmark: punqs3 - Threads: 1	0.991
opm-git	OPM Benchmark: punqs3 - Threads: 8	0.998
opm-git	OPM Benchmark: smeaheia - Threads: 1	1.003
opm-git	OPM Benchmark: smeaheia - Threads: 8	0.987
opm-git	OPM Benchmark: spe10_model_1 - Threads: 1	1.008
opm-git	OPM Benchmark: spe10_model_1 - Threads: 8	0.994
opm-git	OPM Benchmark: flow_mpi_extra - Threads: 1	1.001
opm-git	OPM Benchmark: flow_mpi_extra - Threads: 8	0.992
opm-git	OPM Benchmark: flow_mpi_norne - Threads: 1	0.992
opm-git	OPM Benchmark: flow_mpi_norne - Threads: 8	1.003

• Speed-up = Total time master / Total time pull request. Above 1.0 is an improvement. *

View result details @ https://www.ytelses.com/opm/?page=result&id=3163

[SoilRos]

The table above seems wrong, the actual table reported in the website is:

Test	Configuration	Relative
opm-git	OPM Benchmark: drogon - Threads: 1	1.001
opm-git	OPM Benchmark: drogon - Threads: 8	1.212
opm-git	OPM Benchmark: punqs3 - Threads: 1	0.996
opm-git	OPM Benchmark: punqs3 - Threads: 8	1.012
opm-git	OPM Benchmark: smeaheia - Threads: 1	0.998
opm-git	OPM Benchmark: smeaheia - Threads: 8	1.075
opm-git	OPM Benchmark: spe10_model_1 - Threads: 1	1.009
opm-git	OPM Benchmark: spe10_model_1 - Threads: 8	0.995
opm-git	OPM Benchmark: flow_mpi_extra - Threads: 1	1.002
opm-git	OPM Benchmark: flow_mpi_extra - Threads: 8	1.13
opm-git	OPM Benchmark: flow_mpi_norne - Threads: 1	1.002
opm-git	OPM Benchmark: flow_mpi_norne - Threads: 8	1.078

• Speed-up = Total time master / Total time pull request. Above 1.0 is an improvement. *

[SoilRos]

Locally (Apple M3 Max), I get simular results:

To me, this suggests that the assembly is already copying the geometry somewhere and we have been paying the price of the shared pointer reference counting.

[atgeirr]

Just a question: how can Dune::AxisAlignedCubeGeometry be used, our grid cells are not axis aligned (except for artificial test cases)?

[SoilRos]

@atgeirr geometryInFather() transforms the reference element of the child element onto the reference element of the father element. Both are axial aligned cube geometries even if the original element of the father/child element is a strange geometry, even if several corners are collapsed into one.