Getting the boundary triangulation from the physical triangulation

[janmodderman]

Hey all,

When trying to extract a boundary triangulation from the physical triangulation of a cut geometry that intersects the boundary I get an error. I think the error is that the physical triangulation does not have the information about the boundary of the background triangulation. Getting the boundary triangulation of an active triangulation works. Any idea on how to fix this?

@ericneiva @fverdugo

below the error I get:

Stacktrace:
 [1] compute_active_model(t::AppendedTriangulation{2, 2, GridapEmbedded.Interfaces.SubCellTriangulation{2, 2, Float64, CartesianDiscreteModel{2, Float64, typeof(identity)}}, BodyFittedTriangulation{2, 2, CartesianDiscreteModel{2, Float64, typeof(identity)}, GridPortion{2, 2, CartesianGrid{2, Float64, typeof(identity)}}, Vector{Int32}}})
   @ Gridap.Geometry ~/.julia/packages/Gridap/OTENN/src/Geometry/Triangulations.jl:106
 [2] get_active_model(t::AppendedTriangulation{2, 2, GridapEmbedded.Interfaces.SubCellTriangulation{2, 2, Float64, CartesianDiscreteModel{2, Float64, typeof(identity)}}, BodyFittedTriangulation{2, 2, CartesianDiscreteModel{2, Float64, typeof(identity)}, GridPortion{2, 2, CartesianGrid{2, Float64, typeof(identity)}}, Vector{Int32}}})
   @ Gridap.Geometry ~/.julia/packages/Gridap/OTENN/src/Geometry/Triangulations.jl:100
 [3] BoundaryTriangulation(::AppendedTriangulation{2, 2, GridapEmbedded.Interfaces.SubCellTriangulation{2, 2, Float64, CartesianDiscreteModel{2, Float64, typeof(identity)}}, BodyFittedTriangulation{2, 2, CartesianDiscreteModel{2, Float64, typeof(identity)}, GridPortion{2, 2, CartesianGrid{2, Float64, typeof(identity)}}, Vector{Int32}}}; kwargs::Base.Pairs{Symbol, Vector{String}, Tuple{Symbol}, NamedTuple{(:tags,), Tuple{Vector{String}}}})
   @ Gridap.Geometry ~/.julia/packages/Gridap/OTENN/src/Geometry/BoundaryTriangulations.jl:178
 [4] top-level scope
   @ ~/Documents/GridapPF.jl/GridapPF.jl/src/coupling/error_repro_cut.jl:28

Error reproduction code:

using Gridap
using GridapEmbedded
R = 0.5
pmin = Point(1.0, 0.0)
pmax = Point(0.0, -1.0)
partition = (10, 10)
model = CartesianDiscreteModel(pmax, pmin, partition)
pmid = 0.5*(pmax + pmin) + VectorValue(0.0, 0.5)
geo = disk(R, x0=pmid)
cutgeo = cut(model, !(geo))
Ω = Interior(model) 
Ω⁻ = Interior(cutgeo, PHYSICAL_IN)
Ω⁻act = Interior(cutgeo, ACTIVE_IN)

Γf_act = BoundaryTriangulation(Ω⁻act, tags=["boundary"])     # active region cut works
Γf_phy = BoundaryTriangulation(Ω⁻, tags=["boundary"])        # physical region cut does not work

[ericneiva]

Hi, @JanModderman,

Are lines 35-37 here https://github.com/gridap/GridapEmbedded.jl/blob/master/test/InterfacesTests/EmbeddedFacetDiscretizationsTests.jl#L35 what you are looking after?

Γu = EmbeddedBoundary(cutgeo)
Γf = BoundaryTriangulation(cutgeo_facets,PHYSICAL)
Γ = lazy_append(Γu,Γf)

[janmodderman]

Yes! Thanks you very much, cutgeo_facets is exactly what I needed!

[ericneiva]

Good, reopen the issue if needed :)