Typeerror when computing the Hessian

[YichengDWu]

julia> using ComponentArrays, Zygote

julia> ps = (;bias = rand(4))
(bias = [0.028680052413891932, 0.028488060933192783, 0.14102421410834098, 0.5148641146388963],)

julia> Zygote.gradient(x -> sum(x.^3 .+ ps.bias), Zygote.seed(rand(4),Val(12)))[1]
4-element Vector{ForwardDiff.Dual{Nothing, Float64, 12}}:
 Dual{Nothing}(1.9044946542432517,4.78057902883312,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0)
 Dual{Nothing}(0.9007160656424562,0.0,3.2876424361097234,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0)
 Dual{Nothing}(1.443553597479418,0.0,0.0,4.162047953802673,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0)
 Dual{Nothing}(0.854126057634067,0.0,0.0,0.0,3.201486013027201,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0)

julia> ps = ComponentArray(;bias = rand(4))
ComponentVector{Float64}(bias = [0.8753842481152277, 0.816098534734367, 0.5547681434517868, 0.7963916275223])

julia> Zygote.gradient(x -> sum(x.^3 .+ ps), Zygote.seed(rand(4),Val(12)))[1]
4-element Vector{ForwardDiff.Dual{Nothing, Float64, 12}}:
 Dual{Nothing}(0.44589405810839866,2.313164217538561,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0)
 Dual{Nothing}(0.3204937948764665,0.0,1.9611031432634027,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0)
 Dual{Nothing}(1.2913481890316207,0.0,0.0,3.936518546683027,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0)
 Dual{Nothing}(0.43271702177241456,0.0,0.0,0.0,2.27872865020585,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0)

julia> gradient(x -> sum(x.^3 .+ getdata(ps)), Zygote.seed(rand(4),Val(12)))[1]
4-element Vector{ForwardDiff.Dual{Nothing, Float64, 12}}:
 Dual{Nothing}(2.9040980928805133,5.903319160825219,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0)
 Dual{Nothing}(0.12702647408947199,0.0,1.234632612996135,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0)
 Dual{Nothing}(1.7155041799425579,0.0,0.0,4.537185268347623,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0)
 Dual{Nothing}(0.5602367500231364,0.0,0.0,0.0,2.592844191284474,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0)

julia> Zygote.gradient(x -> sum(x.^3 .+ ps.bias), Zygote.seed(rand(4),Val(12)))[1]
ERROR: TypeError: in typeassert, expected Float64, got a value of type ForwardDiff.Dual{Nothing, Float64, 12}
Stacktrace:
  [1] setindex!(A::Vector{Float64}, x::ForwardDiff.Dual{Nothing, Float64, 12}, i1::Int64)
    @ Base .\array.jl:903
  [2] setindex!
    @ .\array.jl:917 [inlined]
  [3] macro expansion
    @ C:\Users\Luffy\.julia\packages\ComponentArrays\IQNQW\src\array_interface.jl:0 [inlined]
  [4] _setindex!(x::ComponentVector{Float64}, v::Vector{ForwardDiff.Dual{Nothing, Float64, 12}}, idx::Val{:bias})
    @ ComponentArrays C:\Users\Luffy\.julia\packages\ComponentArrays\IQNQW\src\array_interface.jl:129
  [5] setproperty!
    @ C:\Users\Luffy\.julia\packages\ComponentArrays\IQNQW\src\namedtuple_interface.jl:17 [inlined]
  [6] (::ComponentArrays.var"#getproperty_adjoint#88"{ComponentVector{Float64, Vector{Float64}, Tuple{Axis{(bias = 1:4,)}}}, Symbol})(Δ::Vector{ForwardDiff.Dual{Nothing, Float64, 12}})
    @ ComponentArrays C:\Users\Luffy\.julia\packages\ComponentArrays\IQNQW\src\compat\chainrulescore.jl:4
  [7] ZBack
    @ C:\Users\Luffy\.julia\packages\Zygote\IoW2g\src\compiler\chainrules.jl:205 [inlined]
  [8] Pullback
    @ .\REPL[271]:1 [inlined]
  [9] (::typeof(∂(#509)))(Δ::ForwardDiff.Dual{Nothing, Float64, 12})
    @ Zygote C:\Users\Luffy\.julia\packages\Zygote\IoW2g\src\compiler\interface2.jl:0
 [10] (::Zygote.var"#60#61"{typeof(∂(#509))})(Δ::ForwardDiff.Dual{Nothing, Float64, 12})
    @ Zygote C:\Users\Luffy\.julia\packages\Zygote\IoW2g\src\compiler\interface.jl:41
 [11] gradient(f::Function, args::Vector{ForwardDiff.Dual{Nothing, Float64, 12}})
    @ Zygote C:\Users\Luffy\.julia\packages\Zygote\IoW2g\src\compiler\interface.jl:76
 [12] top-level scope
    @ REPL[271]:1

[jonniedie]

Interesting, looks like we need to promote the eltype before the setproperty!

[YichengDWu]

It's fixed! Thanks!