Add getadtype function

Author: penelopeysm

Project.toml

@@ -3,7 +3,7 @@ uuid = "80f14c24-f653-4e6a-9b94-39d6b0f70001"
 keywords = ["markov chain monte carlo", "probabilistic programming"]
 license = "MIT"
 desc = "A lightweight interface for common MCMC methods."
-version = "5.6.1"
+version = "5.7.0"
 
 [deps]
 BangBang = "198e06fe-97b7-11e9-32a5-e1d131e6ad66"

src/interface.jl

@@ -19,6 +19,16 @@ then `reduce(chainscat, c)` is called.
 chainsstack(c) = c
 chainsstack(c::AbstractVector{<:AbstractChains}) = reduce(chainscat, c)
 
+"""
+    getadtype(sampler::AbstractSampler)
+
+If the sampler specifies an automatic differentiation (AD) backend to use, this
+function should return the corresponding `ADTypes.AbstractADType`.
+
+By default, this returns `nothing`.
+"""
+getadtype(::AbstractSampler) = nothing
+
 """
     bundle_samples(samples, model, sampler, state, chain_type[; kwargs...])