Introducing iteration on vertices

src/Meshes.jl

@@ -559,6 +559,7 @@ export
   measurematrix,
   adjacencymatrix,
   atol,
+  eachvertex,
 
   # visualization
   viz,

src/domains/meshes.jl

@@ -23,7 +23,7 @@ function vertex end
 
 Return the vertices of the `mesh`.
 """
-vertices(m::Mesh) = [vertex(m, ind) for ind in 1:nvertices(m)]
+vertices(m::Mesh) = collect(eachvertex(m))
 
 """
     nvertices(mesh)
@@ -32,6 +32,13 @@ Return the number of vertices of the `mesh`.
 """
 nvertices(m::Mesh) = nvertices(topology(m))
 
+"""
+    eachvertex(mesh)
+
+Return an iterator for the vertices in the `mesh`.
+"""
+eachvertex(m::Mesh) = (vertex(m, ind) for ind in 1:nvertices(m))
+
 """
     faces(mesh, rank)
 

src/geometries/multigeom.jl

@@ -48,12 +48,14 @@ Base.isapprox(m₁::Multi, m₂::Multi; atol=atol(lentype(m₁)), kwargs...) =
 # POLYTOPE
 # ---------
 
-vertex(m::MultiPolytope, ind) = vertices(m)[ind]
+vertex(m::MultiPolytope, ind) = getindex(Base.iterate(Base.Iterators.drop(eachvertex(m), ind - 1)), 1) # nth(itr, n)
 
-vertices(m::MultiPolytope) = [vertex for geom in m.geoms for vertex in vertices(geom)]
+vertices(m::MultiPolytope) = collect(eachvertex(m))
 
 nvertices(m::MultiPolytope) = sum(nvertices, m.geoms)
 
+eachvertex(m::MultiPolytope) = (v for g in m.geoms for v in vertices(g))
+
 Base.unique(m::MultiPolytope) = unique!(deepcopy(m))
 
 function Base.unique!(m::MultiPolytope)

src/geometries/polytopes.jl

@@ -251,6 +251,13 @@ Return the number of vertices in the `polytope`.
 """
 nvertices(p::Polytope) = nvertices(typeof(p))
 
+"""
+    eachvertex(polytope)
+
+Return an iterator for the vertices in the `polytope`
+"""
+eachvertex(p::Polytope) = (v for v in vertices(p))
+
 """
     unique(polytope)
 

test/meshes.jl

@@ -789,6 +789,7 @@ end
   @test crs(mesh) <: Cartesian{NoDatum}
   @test Meshes.lentype(mesh) == ℳ
   @test vertices(mesh) == points
+  @test collect(eachvertex(mesh)) == points
   @test collect(faces(mesh, 2)) == triangles
   @test collect(elements(mesh)) == triangles
   @test nelements(mesh) == 4
@@ -873,13 +874,15 @@ end
   mesh₂ = SimpleMesh(cart.([(1, 0), (1, 1), (0, 1)]), connect.([(1, 2, 3)]))
   mesh = merge(mesh₁, mesh₂)
   @test vertices(mesh) == [vertices(mesh₁); vertices(mesh₂)]
+  @test collect(eachvertex(mesh)) == vertices(mesh)
   @test collect(elements(topology(mesh))) == connect.([(1, 2, 3), (4, 5, 6)])
 
   # merge operation with 3D geometries
   mesh₁ = SimpleMesh(cart.([(0, 0, 0), (1, 0, 0), (0, 1, 0), (0, 0, 1)]), connect.([(1, 2, 3, 4)], Tetrahedron))
   mesh₂ = SimpleMesh(cart.([(1, 0, 0), (1, 1, 0), (0, 1, 0), (1, 1, 1)]), connect.([(1, 2, 3, 4)], Tetrahedron))
   mesh = merge(mesh₁, mesh₂)
   @test vertices(mesh) == [vertices(mesh₁); vertices(mesh₂)]
+  @test collect(eachvertex(mesh)) == vertices(mesh)
   @test collect(elements(topology(mesh))) == connect.([(1, 2, 3, 4), (5, 6, 7, 8)], Tetrahedron)
 
   # convert any mesh to SimpleMesh

test/multigeoms.jl

@@ -12,6 +12,7 @@
   @test vertex(multi, 1) == vertex(poly, 1)
   @test vertices(multi) == [vertices(poly); vertices(poly)]
   @test nvertices(multi) == nvertices(poly) + nvertices(poly)
+  @test collect(eachvertex(multi)) == [vertices(poly); vertices(poly)]
   @test boundary(multi) == merge(boundary(poly), boundary(poly))
   @test rings(multi) == [rings(poly); rings(poly)]
 
@@ -20,6 +21,7 @@
   multi = Multi([poly1, poly2])
   @test vertices(multi) == [vertices(poly1); vertices(poly2)]
   @test nvertices(multi) == nvertices(poly1) + nvertices(poly2)
+  @test collect(eachvertex(multi)) == [vertices(poly1); vertices(poly2)]
   @test area(multi) == area(poly1) + area(poly2)
   @test perimeter(multi) == perimeter(poly1) + perimeter(poly2)
   @test centroid(multi) == cart(1, 1)

test/polytopes.jl

@@ -302,6 +302,10 @@ end
   @test vertices(Ngon{3}(pts...)) == verts
   @test vertices(Ngon{3}(tups...)) == verts
 
+  @test collect(eachvertex(Ngon(pts))) == verts
+  @test @allocated eachvertex(Ngon(pts)) == 0
+  @test @allocated Base.iterate(eachvertex(Ngon(pts))) == 0
+
   NGONS = [Triangle, Quadrangle, Pentagon, Hexagon, Heptagon, Octagon, Nonagon, Decagon]
   NVERT = 3:10
   for (i, NGON) in enumerate(NGONS)