Add Enzyme tests

.github/workflows/CI.yml

@@ -27,6 +27,7 @@ jobs:
           - x64
         group:
           - Others
+          - Enzyme
           - ForwardDiff
           - Tracker
           - ReverseDiff
@@ -36,6 +37,10 @@ jobs:
             os: macOS-latest
             arch: x64
             group: Others
+          - version: '1'
+            os: macOS-latest
+            arch: x64
+            group: Enzyme
           - version: '1'
             os: macOS-latest
             arch: x64
@@ -53,23 +58,14 @@ jobs:
             arch: x64
             group: Zygote
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - uses: julia-actions/setup-julia@v1
         with:
           version: ${{ matrix.version }}
           arch: ${{ matrix.arch }}
-      - uses: actions/cache@v1
-        env:
-          cache-name: cache-artifacts
-        with:
-          path: ~/.julia/artifacts
-          key: ${{ runner.os }}-test-${{ env.cache-name }}-${{ hashFiles('**/Project.toml') }}
-          restore-keys: |
-            ${{ runner.os }}-test-${{ env.cache-name }}-
-            ${{ runner.os }}-test-
-            ${{ runner.os }}-
-      - uses: julia-actions/julia-buildpkg@latest
-      - uses: julia-actions/julia-runtest@latest
+      - uses: julia-actions/cache@v1
+      - uses: julia-actions/julia-buildpkg@v1
+      - uses: julia-actions/julia-runtest@v1
         with:
           coverage: false
         env:

test/Project.toml

@@ -3,6 +3,7 @@ ChainRulesCore = "d360d2e6-b24c-11e9-a2a3-2a2ae2dbcce4"
 ChainRulesTestUtils = "cdddcdb0-9152-4a09-a978-84456f9df70a"
 Combinatorics = "861a8166-3701-5b0c-9a16-15d98fcdc6aa"
 Distributions = "31c24e10-a181-5473-b8eb-7969acd0382f"
+Enzyme = "7da242da-08ed-463a-9acd-ee780be4f1d9"
 FiniteDifferences = "26cc04aa-876d-5657-8c51-4c34ba976000"
 ForwardDiff = "f6369f11-7733-5829-9624-2563aa707210"
 LazyArrays = "5078a376-72f3-5289-bfd5-ec5146d43c02"
@@ -21,6 +22,7 @@ ChainRulesCore = "1"
 ChainRulesTestUtils = "1.9.2"
 Combinatorics = "1.0.2"
 Distributions = "0.25.15"
+Enzyme = "0.12"
 FiniteDifferences = "0.11.3, 0.12"
 ForwardDiff = "0.10.12"
 LazyArrays = "1"

test/ad/distributions.jl

@@ -61,8 +61,9 @@
         DistSpec(Poisson, (0.5,), 1),
         DistSpec(Poisson, (0.5,), [1, 1]),
 
-        DistSpec(Skellam, (1.0, 2.0), -2),
-        DistSpec(Skellam, (1.0, 2.0), [-2, -2]),
+        # Enzyme: no forward rule for ccall 
+        DistSpec(Skellam, (1.0, 2.0), -2, broken=(:Enzyme,)),
+        DistSpec(Skellam, (1.0, 2.0), [-2, -2], broken=(:Enzyme,)),
 
         DistSpec(PoissonBinomial, ([0.5, 0.5],), 0),
 
@@ -159,10 +160,10 @@
         DistSpec(LogNormal, (1.0, 2.0), 0.5),
 
         # Dispatch error caused by ccall
-        DistSpec(NoncentralBeta, (1.0, 2.0, 1.0), 0.5, broken=(:Tracker, :ForwardDiff, :Zygote, :ReverseDiff)),
-        DistSpec(NoncentralChisq, (1.0, 2.0), 0.5, broken=(:Tracker, :ForwardDiff, :Zygote, :ReverseDiff)),
-        DistSpec(NoncentralF, (1.0, 2.0, 1.0), 0.5, broken=(:Tracker, :ForwardDiff, :Zygote, :ReverseDiff)),
-        DistSpec(NoncentralT, (1.0, 2.0), 0.5, broken=(:Tracker, :ForwardDiff, :Zygote, :ReverseDiff)),
+        DistSpec(NoncentralBeta, (1.0, 2.0, 1.0), 0.5, broken=(:Enzyme, :Tracker, :ForwardDiff, :Zygote, :ReverseDiff, :Enzyme)),
+        DistSpec(NoncentralChisq, (1.0, 2.0), 0.5, broken=(:Enzyme, :Tracker, :ForwardDiff, :Zygote, :ReverseDiff, :Enzyme)),
+        DistSpec(NoncentralF, (1.0, 2.0, 1.0), 0.5, broken=(:Enzyme, :Tracker, :ForwardDiff, :Zygote, :ReverseDiff, :Enzyme)),
+        DistSpec(NoncentralT, (1.0, 2.0), 0.5, broken=(:Enzyme, :Tracker, :ForwardDiff, :Zygote, :ReverseDiff, :Enzyme)),
 
         DistSpec(Normal, (), 0.5),
         DistSpec(Normal, (1.0,), 0.5),

test/ad/others.jl

@@ -14,7 +14,7 @@
         A = to_posdef(rand(3, 3))
         B = to_posdef(rand(3, 3))
 
-        test_reverse_mode_ad(randn(3, 3), A, B) do A, B
+        test_reverse_mode_ad(randn(3, 3), A, B; broken = (:Enzyme,)) do A, B
             return DistributionsAD.zygote_ldiv(A, B)
         end
     end

test/ad/utils.jl

@@ -5,6 +5,11 @@ using FiniteDifferences
 const FDM = FiniteDifferences
 
 # Load AD backends
+if GROUP == "All" || GROUP == "Enzyme"
+    @eval begin
+        using Enzyme
+    end
+end
 if GROUP == "All" || GROUP == "ForwardDiff"
     @eval using ForwardDiff
 end
@@ -18,13 +23,63 @@ if GROUP == "All" || GROUP == "Tracker"
     @eval using Tracker
 end
 
-function test_reverse_mode_ad(f, ȳ, x...; rtol=1e-6, atol=1e-6)
+function test_reverse_mode_ad(f, ȳ, x...; rtol=1e-6, atol=1e-6, broken=())
     # Perform a regular forwards-pass.
     y = f(x...)
 
     # Use finite differencing to compute reverse-mode sensitivities.
     x̄s_fdm = FDM.j′vp(central_fdm(5, 1), f, ȳ, x...)
 
+    if GROUP == "All" || GROUP == "Enzyme"
+        enzyme_broken = :Enzyme in broken
+        io = enzyme_broken ? devnull : stdout
+        testset = redirect_stdout(io) do
+            # Use Enzyme to compute reverse-mode sensitivities.
+            @testset "Enzyme: Reverse-mode AD of $f" begin
+                x̄s_enzyme_init = map(x) do xi
+                    xi isa Real ? nothing : zero(xi)
+                end
+                enzyme_autodiff_args = map(x, x̄s_enzyme_init) do xi, x̄si
+                    return if x̄si === nothing
+                        @assert xi isa Real
+                        Active(xi)
+                    else
+                        @assert typeof(xi) === typeof(x̄si)
+                        Duplicated(xi, x̄si)
+                    end
+                end
+                dot_f_ȳ(args...) = dot(f(args...), ȳ)
+                x̄s_enzyme_autodiff, y_dot_ȳ_enzyme =
+                    Enzyme.autodiff(ReverseWithPrimal, Const(dot_f_ȳ), Active, enzyme_autodiff_args...)
+                x̄s_enzyme = map(x̄s_enzyme_init, x̄s_enzyme_autodiff) do x̄s_init_i, x̄s_autodiff_i
+                    return if x̄s_init_i === nothing
+                        @assert x̄s_autodiff_i isa Real
+                        x̄s_autodiff_i
+                    else
+                        @assert x̄s_autodiff_i === nothing
+                        x̄s_init_i
+                    end
+                end
+
+                # Check that Enzyme primal is correct.
+                @test dot(y, ȳ) ≈ y_dot_ȳ_enzyme atol=atol rtol=rtol
+
+                # Check that Enzyme reverse-mode sensitivities are correct.
+                @test all(zip(x̄s_enzyme, x̄s_fdm)) do (x̄_enzyme, x̄_fdm)
+                    return isapprox(x̄_enzyme, x̄_fdm; atol=atol, rtol=rtol)
+                end
+            end
+        end
+
+        # change errors and fails to broken results, and count number of errors and fails
+        efs = errors_to_broken!(testset)
+
+        # ensure that passing tests are not marked as broken
+        if iszero(efs) && enzyme_broken
+            error("Enzyme tests of $f passed unexpectedly, please mark not as broken")
+        end
+    end
+
     if GROUP == "All" || GROUP == "Zygote"
         # Use Zygote to compute reverse-mode sensitivities.
         y_zygote, back_zygote = Zygote.pullback(f, x...)
@@ -350,6 +405,19 @@ end
 function test_ad(f, x, broken = (); rtol = 1e-6, atol = 1e-6)
     finitediff = FDM.grad(central_fdm(5, 1), f, x)[1]
 
+    if GROUP == "All" || GROUP == "Enzyme"
+        if (:Enzyme in broken) || (:EnzymeForward in broken)
+            @test_broken collect(Enzyme.gradient(Enzyme.Forward, Const(f), x)) ≈ finitediff rtol=rtol atol=atol
+        else
+            @test collect(Enzyme.gradient(Enzyme.Forward, Const(f), x)) ≈ finitediff rtol=rtol atol=atol
+        end
+        if (:Enzyme in broken) || (:EnzymeReverse in broken)
+            @test_broken Enzyme.gradient(Enzyme.Reverse, Const(f), x) ≈ finitediff rtol=rtol atol=atol
+        else
+            @test Enzyme.gradient(Enzyme.Reverse, Const(f), x) ≈ finitediff rtol=rtol atol=atol
+        end
+    end
+
     if GROUP == "All" || GROUP == "Tracker"
         if :Tracker in broken
             @test_broken Tracker.data(Tracker.gradient(f, x)[1]) ≈ finitediff rtol=rtol atol=atol
@@ -398,7 +466,7 @@ end
 
 function testset_zygote_broken(distspec, args...; kwargs...)
     # don't show test errors - tests are known to be broken :)
-    testset = suppress_stdout() do
+    testset = redirect_stdout(devnull) do
         testset_zygote(distspec, args...; kwargs...)
     end
 
@@ -417,17 +485,6 @@ function testset_zygote_broken(distspec, args...; kwargs...)
     return testset
 end
 
-# `redirect_stdout(f, devnull)` is only available in Julia >= 1.6
-function suppress_stdout(f)
-    @static if VERSION < v"1.6"
-        open((@static Sys.iswindows() ? "NUL" : "/dev/null"), "w") do devnull
-            redirect_stdout(f, devnull)
-        end
-    else
-        redirect_stdout(f, devnull)
-    end
-end
-
 # change test errors and failures to broken results
 function errors_to_broken!(ts::Test.DefaultTestSet)
     results = ts.results

test/runtests.jl

@@ -12,6 +12,11 @@ using DistributionsAD: TuringMvNormal, TuringMvLogNormal,
                        TuringPoissonBinomial, TuringDirichlet
 using StatsFuns: StatsFuns, logsumexp, logistic
 
+import Enzyme 
+Enzyme.API.typeWarning!(false)
+# Enable runtime activity (workaround)
+Enzyme.API.runtimeActivity!(true)
+
 @static if VERSION >= v"1.8"
   using Pkg; Pkg.status(outdated=true) # show reasons why packages are held back
 end
@@ -26,7 +31,7 @@ if GROUP == "All" || GROUP == "Others"
     include("others.jl")
 end
 
-if GROUP == "All" || GROUP in ("ForwardDiff", "Zygote", "ReverseDiff", "Tracker")
+if GROUP == "All" || GROUP in ("Enzyme", "ForwardDiff", "Zygote", "ReverseDiff", "Tracker")
     include("ad/utils.jl")
     include("ad/others.jl")
     include("ad/distributions.jl")