A Loop over a CellIterator returns an Object of type CellCache

[Firimo]

Hello,

The Minimal working example looks as follows

using Ferrite

grid = generate_grid(Quadrilateral, (5,5))

for cell in CellIterator(grid)
    @show typeof(cell)
    break
end

where cell is of the typeCellCache. However, I would expect cell to be of the type CellIterator and this used (v0.3.10) to be the standard behavior.

What I am trying to say is, that the real issue is, that v0.3.11 should have been called v0.4.11, since it introduced a breaking change.

Consequently there are two pathways, either the behavior of the CellIterator constructor is changed, or all Ferrite.jl versions dating back to v0.3.11 are renamed v0.4.xx.

Kind regards

P.S.: I believe this issue arises from a function called Base.iterate() found in the file iterators.jl

[fredrikekre]

Hi and thanks for the report!

I am sorry that you ran into this issue. This was an intentional change (#546) that I didn't imagine would be breaking. For example, as you can see in the PR, it didn't break any of the Ferrite documentation examples which is usually quite similar to "user code". Can you elaborate how it breaks your code? Perhaps you define methods like f(::CellIterator) or something? In that case, fortunately the fix is pretty easy.

Since this is not a very recent change I don't think we can or will revert the releases at this point. If you don't have time to upgrade right now I suggest you pin Ferrite to version 0.3.10 and use that.

[Firimo]

Hi @fredrikekre ,

indeed I have read #546 and indeed I use f(::CellIterator). Independent of my personal struggle with version maintenance, it does nonetheless seem rather counter-intuitive from a user perspective to construct a CellIterator and get a CellCache object.

Thanks for your (very) quick answer

[fredrikekre]

it does nonetheless seem rather counter-intuitive from a user perspective to construct a CellIterator and get a CellCache object.

I disagree. One of the reasons for #546 was actually that the previous behavior was counter-intuitive for many people. For example, if you loop over a vector, the iterates are not the vector itself, but the elements of the vector. Similarly, after #546, the elements of the CellIterator are the CellCaches.

(Also, since you are a Ferrite user I haven't seen before: Welcome! We are hosting a user and developer day on October 6 in Bochum, Germany, and everyone curious about Ferrite is welcome to join, see https://ferrite-fem.github.io/FerriteCon/ for more details.)

[Firimo]

Hi @fredrikekre ,

That is, I have to say, a logic I cannot argue against and thanks for the welcoming words, they are receipted gratefully.

Greetings