I have the following issue: import ForwardDiff, DiffRules, IrrationalConstants, SpecialFunctions ∂logerfcx(x) = 2 * (x - inv(SpecialFunctions.erfcx(x)) / IrrationalConstants.sqrtπ) DiffRules.@define_diffrule SpecialFunctions.logerfcx(x) = :(∂logerfcx($x)) ForwardDiff.derivative(SpecialFunctions.log…

Ah thanks @kristoffer.carlsson that works! For future reference, ∂logerfcx(x) = 2 * (x - inv(SpecialFunctions.erfcx(x)) / IrrationalConstants.sqrtπ) DiffRules.@define_diffrule SpecialFunctions.logerfcx(x) = :(∂logerfcx($x)) eval(ForwardDiff.unary_dual_definition(:SpecialFunctions, :logerfcx)) And…

The rules for ForwardDiff are generated at using time. You need to add the rules to DiffRules.jl directly.

You mean in a pull request to the DiffRules.jl package?

Ok done https://github.com/JuliaDiff/DiffRules.jl/pull/74 . Hope it gets merged quick.

[image] e3c6: Like defining a method for ::Dual args? Yes, see https://github.com/JuliaDiff/ForwardDiff.jl/blob/ab0e239452cfa059e3c0d7467d6bb489e57ea1ab/src/dual.jl#L402 .

Issue with ForwardDiff custom AD rule

Specific Domains

e3c6 December 10, 2021, 12:19pm 6

Is there a hacky way to do it? Like defining a method for ::Dual args?

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Issue with ForwardDiff custom AD rule

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