Add TaylorDiff

Author: tansongchen

src/ADTypes.jl

@@ -47,6 +47,7 @@ export AutoChainRules,
        AutoReverseDiff,
        AutoSymbolics,
        AutoTapir,
+       AutoTaylorDiff,
        AutoTracker,
        AutoZygote
 @public AbstractMode

src/dense.jl

@@ -197,6 +197,36 @@ function Base.show(io::IO, backend::AutoForwardDiff{chunksize}) where {chunksize
     print(io, ")")
 end
 
+"""
+    AutoTaylorDiff{order}
+
+Struct used to select the [TaylorDiff.jl](https://github.com/JuliaDiff/TaylorDiff.jl) backend for automatic differentiation.
+
+Defined by [ADTypes.jl](https://github.com/SciML/ADTypes.jl).
+
+# Constructors
+
+    AutoTaylorDiff(; order = 1)
+    AutoTaylorDiff{order}()
+
+# Type parameters
+
+  - `order`: the order of the Taylor-mode automatic differentiation
+"""
+struct AutoTaylorDiff{order} <: AbstractADType end
+
+function AutoTaylorDiff(; order = 1)
+    return AutoTaylorDiff{order}()
+end
+
+mode(::AutoTaylorDiff) = ForwardMode()
+
+function Base.show(io::IO, ::AutoTaylorDiff{order}) where {order}
+    print(io, AutoTaylorDiff, "(")
+    print(io, "tag=", repr(order; context = io))
+    print(io, ")")
+end
+
 """
     AutoGTPSA{D}
 

test/dense.jl

@@ -182,6 +182,18 @@ end
     @test !ad.safe_mode
 end
 
+@testset "AutoTaylorDiff" begin
+    ad = AutoTaylorDiff{2}()
+    @test ad isa AbstractADType
+    @test ad isa AutoTaylorDiff{2}
+    @test mode(ad) isa ForwardMode
+
+    ad = AutoTaylorDiff()
+    @test ad isa AbstractADType
+    @test ad isa AutoTaylorDiff{1}
+    @test mode(ad) isa ForwardMode
+end
+
 @testset "AutoTracker" begin
     ad = AutoTracker()
     @test ad isa AbstractADType