Remove Ferrite.nfields

This patch deprecates the internal function `nfields(dh)` in favor of
`length(getfieldnames(dh))`. The reason is twofold: `nfields` where
barely used, not even internally, and `nfields` was easy to confuse with
the existing `Base.nfields` function that would still work, but behave
quite differently.

Closes #444.

CHANGELOG.md

@@ -17,6 +17,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Internal changes
 - `Ferrite.ndim(dh, fieldname)` has been removed, use `Ferrite.getfielddim(dh,
   fieldname)` instead. ([#658][github-658])
+- `Ferrite.nfields(dh)` has been removed, use `length(Ferrite.getfieldnames(dh))` instead.
+  ([#444][github-444], [#653][github-653])
  - `getfielddims(::FieldHandler)` and `getfieldinterpolations(::FieldHandler)` removed ([#647][github-647]) (Note that `getfieldnames(::FieldHandler)` was re-introduced in [#659][github-659])
 
 ## [0.3.13] - 2023-03-23
@@ -297,6 +299,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 [github-428]: https://github.com/Ferrite-FEM/Ferrite.jl/pull/428
 [github-431]: https://github.com/Ferrite-FEM/Ferrite.jl/pull/431
 [github-436]: https://github.com/Ferrite-FEM/Ferrite.jl/pull/436
+[github-444]: https://github.com/Ferrite-FEM/Ferrite.jl/issues/444
 [github-453]: https://github.com/Ferrite-FEM/Ferrite.jl/issues/453
 [github-455]: https://github.com/Ferrite-FEM/Ferrite.jl/pull/455
 [github-456]: https://github.com/Ferrite-FEM/Ferrite.jl/pull/456
@@ -384,9 +387,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 [github-621]: https://github.com/Ferrite-FEM/Ferrite.jl/pull/621
 [github-633]: https://github.com/Ferrite-FEM/Ferrite.jl/pull/633
 [github-645]: https://github.com/Ferrite-FEM/Ferrite.jl/pull/645
+[github-647]: https://github.com/Ferrite-FEM/Ferrite.jl/pull/647
 [github-650]: https://github.com/Ferrite-FEM/Ferrite.jl/pull/650
+[github-653]: https://github.com/Ferrite-FEM/Ferrite.jl/pull/653
 [github-658]: https://github.com/Ferrite-FEM/Ferrite.jl/pull/658
-[github-647]: https://github.com/Ferrite-FEM/Ferrite.jl/pull/647
 [github-659]: https://github.com/Ferrite-FEM/Ferrite.jl/pull/659
 
 [Unreleased]: https://github.com/Ferrite-FEM/Ferrite.jl/compare/v0.3.13...HEAD

src/Dofs/DofHandler.jl

@@ -28,8 +28,8 @@ end
 function Base.show(io::IO, ::MIME"text/plain", dh::DofHandler)
     println(io, "DofHandler")
     println(io, "  Fields:")
-    for i in 1:nfields(dh)
-        println(io, "    ", repr(dh.field_names[i]), ", interpolation: ", dh.field_interpolations[i],", dim: ", dh.field_dims[i])
+    for (i, name) in pairs(getfieldnames(dh))
+        println(io, "    ", repr(name), ", interpolation: ", dh.field_interpolations[i],", dim: ", dh.field_dims[i])
     end
     if !isclosed(dh)
         print(io, "  Not closed!")
@@ -40,7 +40,6 @@ function Base.show(io::IO, ::MIME"text/plain", dh::DofHandler)
 end
 
 ndofs_per_cell(dh::AbstractDofHandler, cell::Int=1) = dh.cell_dofs_offset[cell+1] - dh.cell_dofs_offset[cell]
-nfields(dh::AbstractDofHandler) = length(dh.field_names)
 getfieldnames(dh::AbstractDofHandler) = dh.field_names
 
 function find_field(dh::DofHandler, field_name::Symbol)
@@ -124,23 +123,25 @@ end
 function __close!(dh::DofHandler{dim}) where {dim}
     @assert !isclosed(dh)
 
+    numfields = length(dh.field_names)
+
     # `vertexdict` keeps track of the visited vertices. The first dof added to vertex v is
     # stored in vertexdict[v]
     # TODO: No need to allocate this vector for fields that don't have vertex dofs
-    vertexdicts = [zeros(Int, getnnodes(dh.grid)) for _ in 1:nfields(dh)]
+    vertexdicts = [zeros(Int, getnnodes(dh.grid)) for _ in 1:numfields]
 
     # `edgedict` keeps track of the visited edges, this will only be used for a 3D problem
     # An edge is determined from two vertices, but we also need to store the direction
     # of the first edge we encounter and add dofs too. When we encounter the same edge
     # the next time we check if the direction is the same, otherwise we reuse the dofs
     # in the reverse order
-    edgedicts = [Dict{Tuple{Int,Int},Tuple{Int,Bool}}() for _ in 1:nfields(dh)]
+    edgedicts = [Dict{Tuple{Int,Int},Tuple{Int,Bool}}() for _ in 1:numfields]
 
     # `facedict` keeps track of the visited faces. We only need to store the first dof we
     # added to the face; if we encounter the same face again we *always* reverse the order
     # In 2D a face (i.e. a line) is uniquely determined by 2 vertices, and in 3D a
     # face (i.e. a surface) is uniquely determined by 3 vertices.
-    facedicts = [Dict{NTuple{dim,Int},Int}() for _ in 1:nfields(dh)]
+    facedicts = [Dict{NTuple{dim,Int},Int}() for _ in 1:numfields]
 
     # celldofs are never shared between different cells so there is no need
     # for a `celldict` to keep track of which cells we have added dofs too.
@@ -163,7 +164,7 @@ function __close!(dh::DofHandler{dim}) where {dim}
     # loop over all the cells, and distribute dofs for all the fields
     for (ci, cell) in enumerate(getcells(dh.grid))
         @debug println("cell #$ci")
-        for field_idx in 1:nfields(dh)
+        for field_idx in 1:numfields
             interpolation_info = interpolation_infos[field_idx]
             @debug println("  field: $(dh.field_names[field_idx])")
             for (vi, vertex) in enumerate(vertices(cell))

src/Dofs/DofRenumbering.jl

@@ -133,7 +133,8 @@ Dof order passed to [`renumber!`](@ref) to renumber global dofs field wise resul
 globally blocked system.
 
 The default behavior is to group dofs of each field into their own block, with the same
-order as in the DofHandler. This can be customized by passing a vector of length `nfields`
+order as in the DofHandler. This can be customized by passing a vector of the same length
+as the total number of fields in the DofHandler (see `getfieldnames(dh)`)
 that maps each field to a "target block": to renumber a DofHandler with three fields `:u`,
 `:v`, `:w` such that dofs for `:u` and `:w` end up in the first global block, and dofs for
 `:v` in the second global block use `DofOrder.FieldWise([1, 2, 1])`.

src/Dofs/MixedDofHandler.jl

@@ -161,13 +161,6 @@ function getfielddim(dh::MixedDofHandler, field_idxs::NTuple{2, Int})
 end
 getfielddim(dh::MixedDofHandler, name::Symbol) = getfielddim(dh, find_field(dh, name))
 
-"""
-    nfields(dh::MixedDofHandler)
-
-Returns the number of unique fields defined.
-"""
-nfields(dh::MixedDofHandler) = length(getfieldnames(dh))
-
 """
     add!(dh::MixedDofHandler, fh::FieldHandler)
 

src/Dofs/sparsity_pattern.jl

@@ -7,7 +7,8 @@ with stored values in the correct places.
 
 The keyword argument `coupling` can be used to specify how fields (or components) in the dof
 handler couple to each other. `coupling` should be a square matrix of booleans with
-`nfields` (or `ncomponents`) rows/columns with `true` if fields are coupled and `false` if
+number of rows/columns equal to the total number of fields, or total number of components,
+in the DofHandler with `true` if fields are coupled and `false` if
 not. By default full coupling is assumed.
 
 See the [Sparsity Pattern](@ref) section of the manual.

src/deprecations.jl

@@ -7,3 +7,4 @@ import Base: push!
 @deprecate vertices(ip::Interpolation) vertexdof_indices(ip) false
 @deprecate faces(ip::Interpolation) facedof_indices(ip) false
 @deprecate edges(ip::Interpolation) edgedof_indices(ip) false
+@deprecate nfields(dh::AbstractDofHandler) length(getfieldnames(dh)) false