From 92898c5c87bee170b858a24e2cfe88e9beb013fd Mon Sep 17 00:00:00 2001
From: "William S. Moses" <gh@wsmoses.com>
Date: Wed, 9 Oct 2024 19:52:31 -0400
Subject: [PATCH] Special case Enzyme usage

---
 Project.toml             | 3 +++
 src/internal/jacobian.jl | 8 +++++++-
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/Project.toml b/Project.toml
index 1651aab2a..dfc4201f7 100644
--- a/Project.toml
+++ b/Project.toml
@@ -6,9 +6,11 @@ version = "3.15.1"
 [deps]
 ADTypes = "47edcb42-4c32-4615-8424-f2b9edc5f35b"
 ArrayInterface = "4fba245c-0d91-5ea0-9b3e-6abc04ee57a9"
+BenchmarkTools = "6e4b80f9-dd63-53aa-95a3-0cdb28fa8baf"
 ConcreteStructs = "2569d6c7-a4a2-43d3-a901-331e8e4be471"
 DiffEqBase = "2b5f629d-d688-5b77-993f-72d75c75574e"
 DifferentiationInterface = "a0c0ee7d-e4b9-4e03-894e-1c5f64a51d63"
+Enzyme = "7da242da-08ed-463a-9acd-ee780be4f1d9"
 FastBroadcast = "7034ab61-46d4-4ed7-9d0f-46aef9175898"
 FastClosures = "9aa1b823-49e4-5ca5-8b0f-3971ec8bab6a"
 FiniteDiff = "6a86dc24-6348-571c-b903-95158fe2bd41"
@@ -32,6 +34,7 @@ SimpleNonlinearSolve = "727e6d20-b764-4bd8-a329-72de5adea6c7"
 SparseArrays = "2f01184e-e22b-5df5-ae63-d93ebab69eaf"
 SparseConnectivityTracer = "9f842d2f-2579-4b1d-911e-f412cf18a3f5"
 SparseMatrixColorings = "0a514795-09f3-496d-8182-132a7b665d35"
+StaticArrays = "90137ffa-7385-5640-81b9-e52037218182"
 StaticArraysCore = "1e83bf80-4336-4d27-bf5d-d5a4f845583c"
 SymbolicIndexingInterface = "2efcf032-c050-4f8e-a9bb-153293bab1f5"
 TimerOutputs = "a759f4b9-e2f1-59dc-863e-4aeb61b1ea8f"
diff --git a/src/internal/jacobian.jl b/src/internal/jacobian.jl
index b78eb7383..50c6dfc51 100644
--- a/src/internal/jacobian.jl
+++ b/src/internal/jacobian.jl
@@ -1,3 +1,5 @@
+using Enzyme
+
 """
     JacobianCache(prob, alg, f::F, fu, u, p; autodiff = nothing,
         vjp_autodiff = nothing, jvp_autodiff = nothing, linsolve = missing) where {F}
@@ -88,7 +90,11 @@ function JacobianCache(prob, alg, f::F, fu_, u, p; stats, autodiff = nothing,
                 if iip
                     DI.jacobian(f, fu, di_extras, autodiff, u, Constant(p))
                 else
-                    DI.jacobian(f, di_extras, autodiff, u, Constant(p))
+                    if autodiff <: AutoEnzyme()
+                        hcat(Enzyme.autodiff(Forward, f, BatchDuplicated(u, Enzyme.onehot(u)), Const(p))[1]...)
+                    else
+                        DI.jacobian(f, di_extras, autodiff, u, Constant(p))
+                    end
                 end
             end
         else