[Feature] Weights New Package

[danston]

This PR proposes a new Feature called Weights that implements a set of analytic and barycentric weights.

The weights implemented are:

• Wachspress weight
• authalic weight
• discrete harmonic weight
• cotangent weight
• mean value weight
• tangent weight
• three-point family weight
• uniform weight
• Shepard weight
• inverse distance weight
• uniform region weight
• triangular region weight
• barycentric region weight
• Voronoi region weight
• mixed Voronoi region weight

This package is used in the new version (PR #5738) of the Barycentric_coordinates_2 package for computing weights. It will also be used later to update several CGAL packages with new weights: Polygon mesh Processing, several Surface Mesh related packages, and Heat Method to unify the weight usage among different CGAL packages.

Release Management

This PR depends on #5736.

• Affected package(s): Feature, New Package
• Issue(s) solved (if any): no issues
• Feature/Small Feature (if any): Feature
• Link to compiled documentation (obligatory for small feature): docs
• License and copyright ownership: GF

[maxGimeno]

warning: https://cgal.geometryfactory.com/CGAL/testsuite/CGAL-5.4-Ic-25/Weights_Examples/TestReport_lrineau_Ubuntu-GCC_master_CXX20-Release.gz

[danston]

@maxGimeno Isn't this warning related to the Surface_mesh? It does not seem to be caused by the Weights package. I simply use surface mesh to store a few faces and vertices in the corresponding example.

[maxGimeno]

@danston oh, you are right

[lrineau]

@maxGimeno Isn't this warning related to the Surface_mesh? It does not seem to be caused by the Weights package. I simply use surface mesh to store a few faces and vertices in the corresponding example.

That warning is actually here:

/mnt/testsuite/include/CGAL/Surface_mesh/Surface_mesh.h: In constructor 'CGAL::Surface_mesh<P>::Surface_mesh() [with P = CGAL::Point_3<CGAL::Simple_cartesian<double> >]':
/mnt/testsuite/include/CGAL/Surface_mesh/Surface_mesh.h:2201:54: note: '<anonymous>' declared here
 2201 |     vpoint_   = add_property_map<Vertex_index, Point>("v:point").first;
      |                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~

The compiler cannot know that add_property_map<Vertex_index, Point>("v:point") will not fail.

The code should be:

auto add_vpoint_pmap = add_property_map<Vertex_index, Point>("v:point");
CGAL_assume(add_vpoint_pmap.second == true);
vpoint_ = add_vpoint_pmap.first;

[danston]

@lrineau I suppose it should be a different PR to fix it, not this one, right?

[lrineau]

@lrineau I suppose it should be a different PR to fix it, not this one, right?

That is right. And it should be discussed with the authors of Surface_mesh.h, in particular @afabri and @sloriot.

[maxGimeno]

tested in https://cgal.geometryfactory.com/CGAL/testsuite/results-5.4-Ic-26.shtml

[sloriot]

@maxGimeno Isn't this warning related to the Surface_mesh? It does not seem to be caused by the Weights package. I simply use surface mesh to store a few faces and vertices in the corresponding example.

That warning is actually here:

/mnt/testsuite/include/CGAL/Surface_mesh/Surface_mesh.h: In constructor 'CGAL::Surface_mesh<P>::Surface_mesh() [with P = CGAL::Point_3<CGAL::Simple_cartesian<double> >]':
/mnt/testsuite/include/CGAL/Surface_mesh/Surface_mesh.h:2201:54: note: '<anonymous>' declared here
 2201 |     vpoint_   = add_property_map<Vertex_index, Point>("v:point").first;
      |                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~

The compiler cannot know that add_property_map<Vertex_index, Point>("v:point") will not fail.

The code should be:

auto add_vpoint_pmap = add_property_map<Vertex_index, Point>("v:point");
CGAL_assume(add_vpoint_pmap.second == true);
vpoint_ = add_vpoint_pmap.first;

Returning false does not mean failing, it means that the property already exist internally. I'd be surprised if the proposed code fixes the warning.

[danston]

Should I prepare a small news entry for this feature for cgal.org?

[sloriot]

Sure

[sloriot]

I pushed 89aec88 directly in master adding the missing entry in the package overview.

[danston]

@MaelRL I have prepared a news entry for cgal.org and sent you it in pm. Thanks.