SkeletonTriangulations + MultiField on different triangulations

[zjwegert]

While working on #1136 I found that the following produces an error:

using Gridap,Gridap.Algebra,Gridap.Arrays,Gridap.Geometry,
  Gridap.CellData,Gridap.ReferenceFEs,Gridap.FESpaces,Gridap.MultiField

domain = (0,1,0,1)
partition = (5,5)
model = CartesianDiscreteModel(domain,partition)
Γ = BoundaryTriangulation(model)
Λ = SkeletonTriangulation(model)
dΛ = Measure(Λ,2)
V1 = FESpace(Γ,ReferenceFE(lagrangian,Float64,1))
V2 = FESpace(model,ReferenceFE(lagrangian,Float64,1))
X = MultiFieldFESpace([V1,V2])
a(xh,yh) = ∫(mean(xh[1])*mean(yh[1])+mean(xh[2])*mean(yh[2]))dΛ
assemble_matrix(a,X,X)

I think the issue here is that Γ isn't anywhere part of Λ and this might be creating erroneous cache somewhere.

Note that the workaround is to simply remove the field on Γ from a because it wouldn't contribute anything anyway.

Here is the full error:

ERROR: TypeError: in typeassert, expected Gridap.Fields.OperationField{Gridap.Fields.LinearCombinationField{Matrix{Float64}, Gridap.Polynomials.MonomialBasis{2, Float64}}, Tuple{Gridap.Fields.LinearCombinationField{Vector{VectorValue{2, Float64}}, Gridap.Fields.VoidBasis{Gridap.Fields.LinearCombinationField{Matrix{Float64}, Gridap.Polynomials.MonomialBasis{1, Float64}}, 1, Gridap.Fields.LinearCombinationFieldVector{Matrix{Float64}, Gridap.Polynomials.MonomialBasis{1, Float64}}}}}}, got a value of type Gridap.Fields.OperationField{Gridap.Fields.LinearCombinationField{Matrix{Float64}, Gridap.Polynomials.MonomialBasis{2, Float64}}, Tuple{Gridap.Fields.LinearCombinationField{Matrix{VectorValue{2, Float64}}, Gridap.Fields.VoidBasis{Gridap.Fields.LinearCombinationField{Matrix{Float64}, Gridap.Polynomials.MonomialBasis{1, Float64}}, 1, Gridap.Fields.LinearCombinationFieldVector{Matrix{Float64}, Gridap.Polynomials.MonomialBasis{1, Float64}}}}}}
Stacktrace:
  [1] testitem
    @ C:\Users\Zac\Desktop\Repos\Gridap\src\Arrays\Interface.jl:154 [inlined]
  [2] return_cache(f::Vector{Gridap.Fields.OperationField{…}}, x::Vector{VectorValue{…}})
    @ Gridap.Fields C:\Users\Zac\Desktop\Repos\Gridap\src\Fields\FieldArrays.jl:39
  [3] return_cache(f::VectorBlock{Vector{Gridap.Fields.OperationField{…}}}, x::Vector{VectorValue{1, Float64}})
    @ Gridap.Fields C:\Users\Zac\Desktop\Repos\Gridap\src\Fields\FieldArrayBlocks.jl:52
  [4] evaluate(f::VectorBlock{Vector{Gridap.Fields.OperationField{…}}}, x::Vector{VectorValue{1, Float64}})
    @ Gridap.Arrays C:\Users\Zac\Desktop\Repos\Gridap\src\Arrays\Maps.jl:86
  [5] evaluate!(::Nothing, ::Function, ::VectorBlock{Vector{…}}, ::Vector{VectorValue{…}})
    @ Gridap.Arrays C:\Users\Zac\Desktop\Repos\Gridap\src\Arrays\Maps.jl:93
  [6] evaluate
    @ C:\Users\Zac\Desktop\Repos\Gridap\src\Arrays\Maps.jl:87 [inlined]
  [7] return_value
    @ C:\Users\Zac\Desktop\Repos\Gridap\src\Arrays\Maps.jl:64 [inlined]
  [8] return_type
    @ C:\Users\Zac\Desktop\Repos\Gridap\src\Arrays\Maps.jl:62 [inlined]
  [9] lazy_map(::Function, ::FillArrays.Fill{…}, ::CompressedArray{…})
    @ Gridap.Arrays C:\Users\Zac\Desktop\Repos\Gridap\src\Arrays\LazyArrays.jl:57
 [10] evaluate!(cache::Nothing, f::Gridap.CellData.CellFieldAt{…}, x::CellPoint{…})
    @ Gridap.CellData C:\Users\Zac\Desktop\Repos\Gridap\src\CellData\CellFields.jl:253
 [11] evaluate
    @ C:\Users\Zac\Desktop\Repos\Gridap\src\Arrays\Maps.jl:87 [inlined]
 [12] CellField
    @ C:\Users\Zac\Desktop\Repos\Gridap\src\CellData\CellFields.jl:247 [inlined]
 [13] #7
    @ C:\Users\Zac\Desktop\Repos\Gridap\src\CellData\CellFields.jl:398 [inlined]
 [14] map(f::Gridap.CellData.var"#7#8"{…}, t::Tuple{…})
    @ Base .\tuple.jl:356
 [15] evaluate!(cache::Nothing, f::Gridap.CellData.OperationCellField{…}, x::CellPoint{…})
    @ Gridap.CellData C:\Users\Zac\Desktop\Repos\Gridap\src\CellData\CellFields.jl:398
 [16] evaluate
    @ C:\Users\Zac\Desktop\Repos\Gridap\src\Arrays\Maps.jl:87 [inlined]
 [17] CellField
    @ C:\Users\Zac\Desktop\Repos\Gridap\src\CellData\CellFields.jl:247 [inlined]
 [18] #7
    @ C:\Users\Zac\Desktop\Repos\Gridap\src\CellData\CellFields.jl:398 [inlined]
 [19] map(f::Gridap.CellData.var"#7#8"{…}, t::Tuple{…})
    @ Base .\tuple.jl:356
 [20] evaluate!(cache::Nothing, f::Gridap.CellData.OperationCellField{…}, x::CellPoint{…})
    @ Gridap.CellData C:\Users\Zac\Desktop\Repos\Gridap\src\CellData\CellFields.jl:398
 [21] evaluate
    @ C:\Users\Zac\Desktop\Repos\Gridap\src\Arrays\Maps.jl:87 [inlined]
 [22] CellField
    @ C:\Users\Zac\Desktop\Repos\Gridap\src\CellData\CellFields.jl:247 [inlined]
 [23] #7
    @ C:\Users\Zac\Desktop\Repos\Gridap\src\CellData\CellFields.jl:398 [inlined]
 [24] map(f::Gridap.CellData.var"#7#8"{…}, t::Tuple{…})
    @ Base .\tuple.jl:356
 [25] evaluate!(cache::Nothing, f::Gridap.CellData.OperationCellField{…}, x::CellPoint{…})
    @ Gridap.CellData C:\Users\Zac\Desktop\Repos\Gridap\src\CellData\CellFields.jl:398
 [26] evaluate
    @ C:\Users\Zac\Desktop\Repos\Gridap\src\Arrays\Maps.jl:87 [inlined]
 [27] (::Gridap.CellData.OperationCellField{…})(x::CellPoint{…})
    @ Gridap.CellData C:\Users\Zac\Desktop\Repos\Gridap\src\CellData\CellFields.jl:247
 [28] integrate(f::Gridap.CellData.OperationCellField{…}, quad::CellQuadrature{…})
    @ Gridap.CellData C:\Users\Zac\Desktop\Repos\Gridap\src\CellData\CellQuadratures.jl:151
 [29] integrate(f::Gridap.CellData.OperationCellField{ReferenceDomain, typeof(+)}, b::Gridap.CellData.GenericMeasure)
    @ Gridap.CellData C:\Users\Zac\Desktop\Repos\Gridap\src\CellData\DomainContributions.jl:164
 [30] *(a::Integrand, b::Gridap.CellData.GenericMeasure)
    @ Gridap.CellData C:\Users\Zac\Desktop\Repos\Gridap\src\CellData\DomainContributions.jl:148
 [31] a(xh::MultiFieldCellField{ReferenceDomain}, yh::MultiFieldCellField{ReferenceDomain})
    @ Main c:\Users\Zac\Desktop\Repos\Gridap\test.jl:12
 [32] assemble_matrix(f::typeof(a), a::GenericSparseMatrixAssembler, U::MultiFieldFESpace{…}, V::MultiFieldFESpace{…})
    @ Gridap.FESpaces C:\Users\Zac\Desktop\Repos\Gridap\src\FESpaces\Assemblers.jl:295
 [33] assemble_matrix(f::Function, U::MultiFieldFESpace{…}, V::MultiFieldFESpace{…})
    @ Gridap.FESpaces C:\Users\Zac\Desktop\Repos\Gridap\src\FESpaces\Assemblers.jl:364
 [34] top-level scope
    @ c:\Users\Zac\Desktop\Repos\Gridap\test.jl:13
Some type information was truncated. Use `show(err)` to see complete types.

[JordiManyer]

This is also with the current AD framework, right?

[zjwegert]

Yeah, same error in master