From d778423d65b939fa2c40257b67056ce3f4fd79db Mon Sep 17 00:00:00 2001
From: JordiManyer <jordi.manyer@monash.edu>
Date: Wed, 13 Nov 2024 12:44:36 +1100
Subject: [PATCH] Started prototyping updateable triangulations

---
 ...rdi_embedded.jl => jordi_embedded_diff.jl} |  0
 scripts/Embedded/MWEs/updateable_trians.jl    | 75 +++++++++++++++++++
 src/Embedded/DifferentiableTriangulations.jl  |  7 ++
 3 files changed, 82 insertions(+)
 rename scripts/Embedded/MWEs/{jordi_embedded.jl => jordi_embedded_diff.jl} (100%)
 create mode 100644 scripts/Embedded/MWEs/updateable_trians.jl

diff --git a/scripts/Embedded/MWEs/jordi_embedded.jl b/scripts/Embedded/MWEs/jordi_embedded_diff.jl
similarity index 100%
rename from scripts/Embedded/MWEs/jordi_embedded.jl
rename to scripts/Embedded/MWEs/jordi_embedded_diff.jl
diff --git a/scripts/Embedded/MWEs/updateable_trians.jl b/scripts/Embedded/MWEs/updateable_trians.jl
new file mode 100644
index 0000000..652f28d
--- /dev/null
+++ b/scripts/Embedded/MWEs/updateable_trians.jl
@@ -0,0 +1,75 @@
+using GridapTopOpt
+using Gridap
+
+using GridapEmbedded
+using GridapEmbedded.LevelSetCutters
+using Gridap.Geometry, Gridap.FESpaces, Gridap.CellData, Gridap.Adaptivity
+
+function generate_model(D,n)
+  domain = (D==2) ? (0,1,0,1) : (0,1,0,1,0,1)
+  cell_partition = (D==2) ? (n,n) : (n,n,n)
+  base_model = UnstructuredDiscreteModel((CartesianDiscreteModel(domain,cell_partition)))
+  ref_model = refine(base_model, refinement_method = "barycentric")
+  model = ref_model.model
+  return model
+end
+
+φ(r) = interpolate(x->sqrt((x[1]-0.5)^2+(x[2]-0.5)^2)-r,V_φ) # Circle
+
+struct EmbeddedTriangulationCollection
+  func::Function
+  trians::Dict{Symbol,Triangulation}
+  bgmodel::DiscreteModel
+  cutgeo::EmbeddedDiscretization
+end
+
+function EmbeddedTriangulationCollection(
+  func::Function,bgmodel::DiscreteModel,φ0
+)
+  geo = DiscreteGeometry(φ0,bgmodel)
+  cutgeo = cut(bgmodel,geo)
+  trians = Dict(pairs(func(cutgeo)))
+  return EmbeddedTriangulationCollection(func,trians,bgmodel,cutgeo)
+end
+
+function update!(c::EmbeddedTriangulationCollection,φh)
+  geo = DiscreteGeometry(φh,c.bgmodel)
+  cutgeo = cut(c.bgmodel,geo)
+  trians = func(cutgeo)
+  for (key,value) in pairs(trians)
+    c.trians[key] = value
+  end
+  return c
+end
+
+function Base.getindex(c::EmbeddedTriangulationCollection,key)
+  return c.trians[key]
+end
+
+order = 1
+model = generate_model(2,10)
+
+Ω = Triangulation(model)
+dΩ = Measure(Ω,2*order)
+
+reffe = ReferenceFE(lagrangian,Float64,order)
+V_φ = TestFESpace(model,reffe)
+
+φ0 = φ(0.2)
+Ωs = EmbeddedTriangulationCollection(model,φ0) do cutgeo
+  (; 
+    :Ωin  => Triangulation(cutgeo,PHYSICAL_IN),
+    :Ωout => Triangulation(cutgeo,PHYSICAL_OUT),
+    :Γ    => EmbeddedBoundary(cutgeo)
+  )
+end
+
+area(Ωs) = sum(∫(1.0)*Measure(Ωs[:Ωin],2))
+contour(Ωs) = sum(∫(1.0)*Measure(Ωs[:Γ],2))
+
+for r in 0.2:0.1:0.5
+  update!(Ωs,φ(r))
+  println(" >> Radius: $r")
+  println(" >> Area: $(area(Ωs)) (expected: $(π*r^2))")
+  println(" >> Contour: $(contour(Ωs)) (expected: $(2π*r))")
+end
diff --git a/src/Embedded/DifferentiableTriangulations.jl b/src/Embedded/DifferentiableTriangulations.jl
index 8780399..ed754d1 100644
--- a/src/Embedded/DifferentiableTriangulations.jl
+++ b/src/Embedded/DifferentiableTriangulations.jl
@@ -37,6 +37,11 @@ function update_trian!(trian::DifferentiableTriangulation,φh)
   return trian
 end
 
+function update_trian!(trian::DifferentiableTriangulation,::Nothing)
+  trian.cell_values = nothing
+  return trian
+end
+
 function FESpaces._change_argument(
   op,f,trian::DifferentiableTriangulation,uh::SingleFieldFEFunction
 )
@@ -45,6 +50,7 @@ function FESpaces._change_argument(
     cf = CellField(U,cell_u)
     update_trian!(trian,cf)
     cell_grad = f(cf)
+    update_trian!(trian,nothing) # TODO: experimental
     get_contribution(cell_grad,trian)
   end
   g
@@ -361,6 +367,7 @@ function FESpaces._change_argument(
     cf = CellField(U,cell_u)
     update_trian!(trian,cf)
     cell_grad = f(cf)
+    update_trian!(trian,nothing) # TODO: experimental
     get_contribution(cell_grad,trian)
   end
   g