My primary question is: I want to write a custom adjoint for something that has a similar structure to the following, but I keep getting errors with my attempts. I think I am getting the types wrong.
using DynamicPolynomials
using Zygote
@polyvar x y
function compute_many_diffs(f::AbstractPolynomialLike, g::AbstractPolynomialLike)
return [differentiate(f,x,i) * differentiate(g,y,i) for i = 1:100]
end
In my application the output is accumulated to a scalar downstream.
In trying to sort this out I tried writing an artificial accumulation function:
g = (x + 2*y)^2
f0 = (x + y)^2;
function fake_accumulation_function(f)
sum(coefficients(f * g))
end
gradient(fake_accumulation_function, f0)
But this gives the error
ERROR: MethodError: no method matching termtype(::Tangent{Any, NamedTuple{(:a, :x), Tuple{FillArrays.Fill{Int64, 1, Tuple{Base.OneTo{Int64}}}, ZeroTangent}}})
Closest candidates are:
termtype(::Union{AbstractVector{PT}, Type{var"#s9"} where var"#s9"<:AbstractVector{PT}}) where PT<:(AbstractPolynomialLike) at /Users/mitchell/.julia/packages/MultivariatePolynomials/zlPtT/src/term.jl:53
termtype(::Union{AbstractVector{PT}, Type{var"#s9"} where var"#s9"<:AbstractVector{PT}}, ::Type{T}) where {PT<:(AbstractPolynomialLike), T} at /Users/mitchell/.julia/packages/MultivariatePolynomials/zlPtT/src/term.jl:54
termtype(::Union{Polynomial{C, T}, Term{C, T}, Type{var"#s23"} where var"#s23"<:Union{Polynomial{C, T}, Term{C, T}}}) where {C, T} at /Users/mitchell/.julia/packages/DynamicPolynomials/32Ech/src/DynamicPolynomials.jl:33
…
Stacktrace:
[1] adjoint_mult_right(p::Polynomial{true, Int64}, Δ::Tangent{Any, NamedTuple{(:a, :x), Tuple{FillArrays.Fill{Int64, 1, Tuple{Base.OneTo{Int64}}}, ZeroTangent}}})
@ MultivariatePolynomials ~/.julia/packages/MultivariatePolynomials/zlPtT/src/chain_rules.jl:46
[2] (::MultivariatePolynomials.var"#times_pullback2#116"{Polynomial{true, Int64}, Polynomial{true, Int64}})(ΔΩ̇::Tangent{Any, NamedTuple{(:a, :x), Tuple{FillArrays.Fill{Int64, 1, Tuple{Base.OneTo{Int64}}}, ZeroTangent}}})
@ MultivariatePolynomials ~/.julia/packages/MultivariatePolynomials/zlPtT/src/chain_rules.jl:54
[3] (::Zygote.ZBack{MultivariatePolynomials.var"#times_pullback2#116"{Polynomial{true, Int64}, Polynomial{true, Int64}}})(dy::NamedTuple{(:a, :x), Tuple{FillArrays.Fill{Int64, 1, Tuple{Base.OneTo{Int64}}}, Nothing}})
@ Zygote ~/.julia/packages/Zygote/dABKa/src/compiler/chainrules.jl:206
[4] Pullback
@ ./REPL[57]:2 [inlined]
[5] (::typeof(∂(fake_accumulation_function)))(Δ::Int64)
@ Zygote ~/.julia/packages/Zygote/dABKa/src/compiler/interface2.jl:0
[6] (::Zygote.var"#58#59"{typeof(∂(fake_accumulation_function))})(Δ::Int64)
@ Zygote ~/.julia/packages/Zygote/dABKa/src/compiler/interface.jl:45
[7] gradient(f::Function, args::Polynomial{true, Int64})
@ Zygote ~/.julia/packages/Zygote/dABKa/src/compiler/interface.jl:97
[8] top-level scope
@ REPL[58]:1
Any help at understanding this error, or more advice towards the original goal would be appreciated!