Alpha wrapping: re-use and resume functionalities #7805

MaelRL · 2023-10-17T15:15:53Z

Summary of Changes

AW3: improve manifoldness enforcing heuristics #7629
Add benchmarking executables and scripts to generate reports on the state of AW3.
Add functionality + example to interrupt the wrapping process, and resume it.
Add functionality + example on re-using the 3D triangulation of a previous wrap with new alpha (and offset) values.
Introduce zombie mechanism to avoid having to clean the queues when facets are destroyed by a new Steiner point.
Use a consistent value in the sorted queue (circumradius of the surface Delaunay ball, and not of the facet).
Distinguish between inside/outside cells, and cells that are flagged "inside" to get a manifold result.
Add a function + named parameter to purge pockets of outside cells that are disconnected from the outside.
Introduce a new queue that is a simple LIFO instead of sorting by circumradius, which speeds things up:
Misc general improvements.

TODO:

Cached oracle queries: https://gist.github.com/MaelRL/ddb3db8a2ddd7ae5319e68655f255bdd. Useful for sorted queues (noticeable speed-up), but pointless (even costly) for FIFO queues.
check computation of values in the demo. cube-minus-cube alpha = 20 is too large?

Release Management

Affected package(s): Alpha_wrap_3
Issue(s) solved (if any): -
Feature/Small Feature (if any): -
License and copyright ownership: no change

This combinatorial choice seemed like a good idea, but it can have nasty cascading effects, adding very large tetrahedra. See this issue: CGAL#7625 In the end, the only thing we care about is small volumes being added. I keep the artificial vertex for now, but I am not fully convinced these should be actually kept too.

@albert-github

Thanks @albert-github!

In a normal run of the algorithm, we shall never ask the facet status of a facet that is already outside, but it's better to be complete and it costs nothing.

…ormal facets Artificial facets are *not* infinite facets.

…tion

Meaning, use the value that we compare against alpha, and not simply the radius of the smallest circumscribing ball. This strongly changes the order of the queue and thus thus results are very different, but still the same (same guarantees, same element quality, only a little bit more elements, etc.) Also a massive, ~35% speed-up, that needs to be investigated.

This doesn't bring any speed-up because it was a very fast exit in push_facet(): the neighbor was necessarily outside (since we come from it), and we are done.

…ness

If one day this becomes annoying because one wishes to call oracle.add_XXX() multiple times AND it's a significant runtime burden, we can just add a function add_XXXs() with a single call of accelerate_distance_queries()

lrineau · 2023-11-29T15:56:02Z

Mael asked me not to merge this PR. I tag it with Not yet approved The feature or pull-request has not yet been approved. .

Reasoning is: this is what users expect.

sloriot · 2023-12-07T08:49:38Z

Successfully tested in CGAL-6.0-Ic-122

MaelRL added 30 commits August 3, 2023 12:30

Add debug code

8076e20

Add some comments on AW3 manifoldness heuristics criteria

b4e207a

Fix spelling

330ff2e

Thanks @albert-github!

Enable changing the oracle in the AW3 builder

88bcd40

Rewrite the extraction of possibly non-manifold wraps

4512b0e

Consider all cases in facet_status

4d50ec4

In a normal run of the algorithm, we shall never ask the facet status of a facet that is already outside, but it's better to be complete and it costs nothing.

Simplify the gate comparer: we can also sort artificial facets like n…

bff07b2

…ormal facets Artificial facets are *not* infinite facets.

Enable restarting from a previous wrap

5304f73

Add an example of successive AW3 restarts

3601733

Improve debug code

19cb693

Merge remote-tracking branch 'cgal/master' into AW3-Resume_aw3-GF

d3b6603

Update some variable names to reflect the genericity of the triangula…

c82f2a9

…tion

Put the warnings outside of verbosity macros (too important)

62bb2a5

Fix typo

bc8351f

Add benchmarking scripts

00f167a

Rename a variable

53c8947

Expose useful typedefs from Alpha_wrapper_3

e3854f6

Complete the sort functor in AW3's main queue

cfae913

Minor debug code cleaning

be42e0f

Avoid one useless facet check

8ccce4c

This doesn't bring any speed-up because it was a very fast exit in push_facet(): the neighbor was necessarily outside (since we come from it), and we are done.

Minor error message tweak

c178413

Change nomenclature to clarify the different types of gate permissive…

9fa445f

…ness

Factorize code generating filenames out of examples

ad5ae27

Accelerate trees manually to avoid skewing timers in flood_fill()

660d620

If one day this becomes annoying because one wishes to call oracle.add_XXX() multiple times AND it's a significant runtime burden, we can just add a function add_XXXs() with a single call of accelerate_distance_queries()

Check for degenerate segments + add warnings

8846876

Add a new function to the AW3 visitor: go_further()

85c53f2

Fix return type of function returning smallest circumradius

3ff06d5

Add debug code

76add80

MaelRL added 2 commits November 29, 2023 16:53

Merge remote-tracking branch 'cgal/master' into AW3-Resume_aw3-GF

1dc0ba2

Fix bbox initialization

7b79189

lrineau removed the rm only: ready for master For the release team only: that indicates that a PR is about to be merged in 'master' label Nov 29, 2023

MaelRL force-pushed the AW3-Resume_aw3-GF branch from ea44f95 to 7b79189 Compare November 29, 2023 15:55

lrineau added the Not yet approved The feature or pull-request has not yet been approved. label Nov 29, 2023

github-actions bot removed the Tested label Nov 29, 2023

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MaelRL added Ready to be tested and removed Not yet approved The feature or pull-request has not yet been approved. labels Nov 29, 2023

sloriot added the Under Testing label Nov 29, 2023

MaelRL added the Work in progress label Nov 30, 2023

MaelRL added 3 commits November 30, 2023 11:37

Enable pocket purging by default

6ad37cd

Reasoning is: this is what users expect.

Add some comments

fae9bcd

Fix exit codes in benchmark scripts

07f2f29

MaelRL removed the Work in progress label Dec 6, 2023

sloriot added Tested and removed Ready to be tested Under Testing labels Dec 7, 2023

lrineau added the rm only: ready for master For the release team only: that indicates that a PR is about to be merged in 'master' label Dec 7, 2023

Fix typo in benchmarks

20b9952

github-actions bot removed the Tested label Dec 11, 2023

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MaelRL added the Tested label Dec 11, 2023

lrineau merged commit 222fafc into CGAL:master Dec 11, 2023
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lrineau removed the rm only: ready for master For the release team only: that indicates that a PR is about to be merged in 'master' label Dec 11, 2023

lrineau deleted the AW3-Resume_aw3-GF branch December 11, 2023 13:11

MaelRL mentioned this pull request Jan 10, 2024

Alpha Wrapping Strange Features #7625

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lrineau added the Merged_in_6.0 label Oct 1, 2024

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Alpha wrapping: re-use and resume functionalities #7805

Alpha wrapping: re-use and resume functionalities #7805

MaelRL commented Oct 17, 2023 •

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lrineau commented Nov 29, 2023 •

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sloriot commented Dec 7, 2023

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Alpha wrapping: re-use and resume functionalities #7805

Alpha wrapping: re-use and resume functionalities #7805

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MaelRL commented Oct 17, 2023 • edited Loading

Summary of Changes

Release Management

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lrineau commented Nov 29, 2023 • edited Loading

sloriot commented Dec 7, 2023

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MaelRL commented Oct 17, 2023 •

edited

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lrineau commented Nov 29, 2023 •

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