Merge 9e6e9a8 into 71c5ac0

src/derivatives/linalg/arithmetic.jl

@@ -33,6 +33,9 @@ for A in ARRAY_TYPES
     @eval @inline Base.:+(x::$(A), y::TrackedArray{V,D}) where {V,D} = record_plus(x, y, D)
 end
 
+@inline Base.:+(x::TrackedArray{V,D}, y::StaticArray) where {V,D} = record_plus(x, Array(y), D)
+@inline Base.:+(x::StaticArray, y::TrackedArray{V,D}) where {V,D} = record_plus(Array(x), y, D)
+
 function record_plus(x, y, ::Type{D}) where D
     tp = tape(x, y)
     out = track(value(x) + value(y), D, tp)
@@ -108,6 +111,9 @@ for A in ARRAY_TYPES
     @eval Base.:-(x::$(A), y::TrackedArray{V,D}) where {V,D} = record_minus(x, y, D)
 end
 
+@inline Base.:-(x::TrackedArray{V,D}, y::StaticArray) where {V,D} = record_minus(x, Array(y), D)
+@inline Base.:-(x::StaticArray, y::TrackedArray{V,D}) where {V,D} = record_minus(Array(x), y, D)
+
 function Base.:-(x::TrackedArray{V,D}) where {V,D}
     tp = tape(x)
     out = track(-(value(x)), D, tp)

src/tracked.jl

@@ -172,6 +172,8 @@ function deriv!(t::NTuple{N,Any}, v::NTuple{N,Any}) where N
     return nothing
 end
 
+deriv!(t::StaticArray, v::AbstractArray) = deriv!(Tuple(t), Tuple(v))
+
 # pulling values from origin #
 #----------------------------#
 
@@ -223,6 +225,8 @@ unseed!(x::AbstractArray, i) = unseed!(x[i])
 capture(t::TrackedReal) = ifelse(hastape(t), t, value(t))
 capture(t::TrackedArray) = t
 capture(t::AbstractArray) = istracked(t) ?  map!(capture, similar(t), t) : copy(t)
+# `StaticArray`s don't support mutation unless the eltype is a bits type (`isbitstype`).
+capture(t::SA) where SA <: StaticArray = istracked(t) ? SA(map(capture, t)) : copy(t)
 
 ########################
 # Conversion/Promotion #