fix: ReLU is not invertible

JuliaReach · Feb 28, 2024 · d81475b · d81475b
1 parent e467be1
commit d81475b
Show file tree

Hide file tree

Showing 2 changed files with 3 additions and 3 deletions.
diff --git a/src/BackwardAlgorithms/backward_default.jl b/src/BackwardAlgorithms/backward_default.jl
@@ -95,7 +95,7 @@ function backward(y::AbstractVector, act::ActivationFunction, ::BackwardAlgorith
 end
 
 _inverse(x::AbstractVector, act::ActivationFunction) = [_inverse(xi, act) for xi in x]
-_inverse(x::Number, ::ReLU) = x >= zero(x) ? x : zero(x)
+_inverse(x::Number, ::ReLU) = x > zero(x) ? x : throw(ArgumentError("ReLU cannot be inverted"))
 _inverse(x::Number, ::Sigmoid) = @. -log(1 / x - 1)
 _inverse(x::Number, act::LeakyReLU) = x >= zero(x) ? x : x / act.slope
 

diff --git a/test/BackwardAlgorithms/backward.jl b/test/BackwardAlgorithms/backward.jl
@@ -210,8 +210,8 @@ end
         ## union is too complex -> only perform partial tests
         @test X ⊆ Y && low(X) == [-Inf, 1.0] && high(X) == [Inf, Inf]
         # union
-        Y = UnionSetArray([LineSegment([1.0, 1.0], [2.0, 2.0]), Singleton([0.0, 0.0])])
-        @test backward(Y, ReLU(), algo) == UnionSetArray([Y[1], Pneg])
+        Y = UnionSetArray([LineSegment([1.0, 1.0], [2.0, 2.0]), Singleton([1.0, 1.0])])
+        @test backward(Y, ReLU(), algo) == UnionSetArray([Y[1], Singleton([1.0, 1.0])])
 
         # 3D
         # positive point