Bad Dof-Ordering when using FerriteMeshParser in Ferrite#master

[Joroks]

Currently when using FerriteMeshParser to parse the .inp file I get the following stiffnes matrix:

If I want to get a somewhat good looking matrix I have to first sort the cellsets in the Grid:

values(grid.cellsets) .|> sort!

I then get

My guess is that this is because we don't use OrderedCollections like Ferrite#master does, so this should probably be a pretty simple fix?

[Joroks]

It seems like this only happens when using SubDofHandlers. I'll quickly set up a minimal example

[Joroks]

Here is the file I'm using: mesh.txt

using Ferrite # on current master branch
using FerriteMeshParser
grid = get_ferrite_grid("mesh.txt", meshformat=FerriteMeshParser.AbaqusMeshFormat(), generate_facetsets=false)
ip = Lagrange{RefHexahedron, 1}()

dh1 = DofHandler(grid)
add!(dh1, :u, ip)
close!(dh1)

dh2 = DofHandler(grid)
sdh = SubDofHandler(dh2, getcellset(grid, "FE"))
add!(sdh, :u, ip)
close!(dh2)

display(allocate_matrix(dh1))
display(allocate_matrix(dh2))

[KnutAM]

Thanks for the report and investigation!

My guess is that this is because we don't use OrderedCollections like Ferrite#master does, so this should probably be a pretty simple fix?

Adding my quick notes on how to make the change here (I don't have time to do it and test it right now), so for future me or others who wants to do this, the fix should be to change

FerriteMeshParser.jl/src/FerriteMeshParser.jl

Line 92 in fd138ca

facetset = sizehint!(Set{FacetIndex}(), length(nodeset))

and

FerriteMeshParser.jl/src/gridcreator.jl

Lines 48 to 49 in fd138ca

	cellsets = Dict(key => Set(getnumbers(rawelements)) for (key, rawelements) in rawelementsdict)
	merge!(cellsets, Dict(key => Set(nums) for (key, nums) in rawelementsets))

to OrderedSet. The only challenge is to support backwards compatibility with Ferrite v0.3. This could be done by changing

FerriteMeshParser.jl/src/FerriteMeshParser.jl

Lines 29 to 41 in fd138ca

	@static if !isdefined(Ferrite, :SerendipityQuadraticHexahedron)
	const SerendipityQuadraticHexahedron = Ferrite.Cell{3,20,6}
	const SerendipityQuadraticQuadrilateral = Ferrite.Cell{2,8,4}
	else
	const SerendipityQuadraticHexahedron = Ferrite.SerendipityQuadraticHexahedron
	const SerendipityQuadraticQuadrilateral = Ferrite.SerendipityQuadraticQuadrilateral
	end
	const FacetsDefined = isdefined(Ferrite, :FacetIndex) # Ferrite after v1.0 (Ferrite#914)
	const FacetIndex = FacetsDefined ? Ferrite.FacetIndex : Ferrite.FaceIndex
	const facets = FacetsDefined ? Ferrite.facets : Ferrite.faces
	const addfacetset! = FacetsDefined ? Ferrite.addfacetset! : Ferrite.addfaceset!

to

const FerritePreV1 = !isdefined(Ferrite, :FacetIndex)

const SerendipityQuadraticHexahedron    = FerritePreV1 ? Ferrite.Cell{3,20,6} : Ferrite.SerendipityQuadraticHexahedron
const SerendipityQuadraticQuadrilateral = FerritePreV1 ? Ferrite.Cell{2,8,4}  : Ferrite.SerendipityQuadraticQuadrilateral

const FacetIndex   = FerritePreV1 ? Ferrite.FaceIndex   : Ferrite.FacetIndex
const facets       = FerritePreV1 ? Ferrite.faces       : Ferrite.facets
const addfacetset! = FerritePreV1 ? Ferrite.addfaceset! : Ferrite.addfacetset!

and use FerritePreV1 to convert to Set. For code-simplicity, I suggest we do the extra conversion on the return part even if that is slower. I suspect most people will uppgrade to Ferrite v1 anyways, and then it is just a matter of supporting older versions during the transition phase.