Remove Pkg, and increase compat of StaticArrays

Closes #65

Project.toml

@@ -6,7 +6,6 @@ version = "1.5.3"
 [deps]
 LaTeXStrings = "b964fa9f-0449-5b57-a5c2-d3ea65f4040f"
 LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
-Pkg = "44cfe95a-1eb2-52ea-b672-e2afdf69b78f"
 PrecompileTools = "aea7be01-6a6a-4083-8856-8a6e6704d82a"
 Random = "9a3f8284-a2c9-5f02-9a11-845980a1fd5c"
 Requires = "ae029012-a4dd-5104-9daa-d747884805df"
@@ -35,10 +34,9 @@ GenericLinearAlgebra = "0.3.11"
 LaTeXStrings = "1"
 Latexify = "0.15, 0.16"
 LinearAlgebra = "1"
-Pkg = "1.11.0"
 PrecompileTools = "1.1.1"
 Random = "1"
 Requires = "1"
-StaticArrays = "1"
+StaticArrays = "1.8.1"
 Symbolics = "0.1, 1, 2, 3, 4, 5, 6"
 julia = "1.6"

ext/QuaternionicChainRulesCoreExt.jl

@@ -1,47 +1,12 @@
 module QuaternionicChainRulesCoreExt
 
-using Pkg
 using Quaternionic
 import Quaternionic: _sincu, _cossu
 using StaticArrays
 isdefined(Base, :get_extension) ?
     (using ChainRulesCore; import ChainRulesCore: rrule, rrule_via_ad, RuleConfig, ProjectTo) :
     (using ..ChainRulesCore; import ...ChainRulesCore: rrule, rrule_via_ad, RuleConfig, ProjectTo)
 
-
-## StaticArrays
-# It's likely that StaticArrays will have its own ChainRulesCore extension someday, so we
-# need to check if there is already a ProjectTo defined for SArray.  If so, we'll use that.
-# If not, we'll define one here.
-staticarrays_info = Pkg.dependencies()[Base.UUID("90137ffa-7385-5640-81b9-e52037218182")]
-if staticarrays_info.version < v"1.8.1"
-    # These are ripped from https://github.com/JuliaArrays/StaticArrays.jl/pull/1068
-    function (project::ProjectTo{<:Tangent{<:Tuple}})(dx::SArray)
-        dy = reshape(dx, axes(project.elements))  # allows for dx::OffsetArray
-        dz = ntuple(i -> project.elements[i](dy[i]), length(project.elements))
-        return ChainRulesCore.project_type(project)(dz...)
-    end
-    function ProjectTo(x::SArray{S,T}) where {S, T}
-        return ProjectTo{SArray}(;
-            element=ChainRulesCore._eltype_projectto(T),
-            axes=axes(x), size=StaticArrays.Size(x)
-        )
-    end
-    @inline _sarray_from_array(::Size{T}, dx::AbstractArray) where {T} = SArray{Tuple{T...}}(dx)
-    (project::ProjectTo{SArray})(dx::AbstractArray) = _sarray_from_array(project.size, dx)
-    function rrule(::Type{T}, x::Tuple) where {T <: SArray}
-        project_x = ProjectTo(x)
-        ∇Array(∂y) = (NoTangent(), project_x(∂y))
-        return T(x), ∇Array
-    end
-    function rrule(::Type{T}, xs::Number...) where {T <: SVector}
-        project_x = ProjectTo(xs)
-        ∇Array(∂y) = (NoTangent(), project_x(∂y)...)
-        return T(xs...), ∇Array
-    end
-end
-
-
 function rrule(::Type{QT}, arg::AbstractVector) where {QT<:AbstractQuaternion}
     AbstractQuaternion_pullback(Δquat) = (NoTangent(), components(unthunk(Δquat)))
     return QT(arg), AbstractQuaternion_pullback