tests, many broken

Author: mcabbott

test/rulesets/Base/base.jl

@@ -192,13 +192,13 @@
         test_frule(Base.literal_pow, ^, 3.5, Val(3))
         test_rrule(Base.literal_pow, ^, 3.5, Val(3))
 
-        @testset "$x^$p" for x in [-1.5, 0.0, 3.5], p in [-3, -1, 0, 1, 3]
+        @testset "regular: $x^$p" for x in [-1.5, 0.0, 3.5], p in [-3, -1, 0, 1, 3]
             x == 0 && p < 0 && continue
-            test_frule(Base.literal_pow, ^, -1.5, Val(3))
-            test_rrule(Base.literal_pow, ^, -1.5, Val(3))
+            test_frule(Base.literal_pow, ^, x, Val(p))
+            test_rrule(Base.literal_pow, ^, x, Val(p))
         end
 
-        @testset "singularities" begin
+        @testset "singularities: 0^0, 0^-1, 0^-2" begin
             # Trivial one: 0^0 == 1 in Julia
             @test frule((1,1,1,1), Base.literal_pow, ^, 0.0, Val(0)) == ((0.0)^0, 0)
             @test rrule(Base.literal_pow, ^, 0.0, Val(0))[2](1.0)[3] == 0.0
@@ -220,6 +220,13 @@
             @test frule((1,1,1,1), Base.literal_pow, ^, -0.0, Val(-2)) == ((-0.0)^-2, +Inf)
             @test rrule(Base.literal_pow, ^, -0.0, Val(-2))[1] == (-0.0)^-2 == Inf
             @test rrule(Base.literal_pow, ^, -0.0, Val(-2))[2](1.0)[3] == +Inf
+
+            # Not singluar, but ^ messed these up: x^1 and x^2
+            @test frule((1,1,1,1), Base.literal_pow, ^, 0.0, Val(2)) == (0.0, 0)
+            @test rrule(Base.literal_pow, ^, 0.0, Val(2))[2](1.0)[3] == 0.0
+
+            @test frule((1,1,1,1), Base.literal_pow, ^, 0.0, Val(1)) == (0.0, 1)
+            @test rrule(Base.literal_pow, ^, 0.0, Val(1))[2](1.0)[3] == 1.0
         end
     end
 

test/rulesets/Base/fastmath_able.jl

@@ -166,11 +166,62 @@ const FASTABLE_AST = quote
             # then x must be positive to avoid a DomainError
             test_frule(^, rand(T) + 3, rand(T) + 3)
             test_rrule(^, rand(T) + 3, rand(T) + 3)
+       
+            T <: Real && S <: Real && continue
+            test_frule(^, randn(T), rand(T))
+            test_rrule(^, rand(T), rand(T))
         end
+
         # @testset "^(x::$T, $p::Int)" for T in (Float64, ComplexF64), p in -2:2
-        #     x = rand(T) .+ 3
+        #     test_frule(^, randn(T) + 3, p ⊢ NoTangent())  # this doesn't just skip p's tangent
+        #     test_rrule(^, randn(T) + 3, p ⊢ NoTangent())
         # end
 
+        @testset "^(x::Float64, p::$S) near x=0, p=1,0,-1,-2" for S in (Int, Float64)
+            p = S(+2)
+            @test frule((1,1,1), ^, 0.0, p)[1] == 0
+            @test_broken frule((1,1,1), ^, 0.0, p)[2] == 0
+            @test rrule(^, 0.0, p)[1] == 0
+            @test unthunk(rrule(^, 0.0, p)[2](1.0)[2]) == 0
+
+            # Identity function x^1, at zero
+            p = S(+1)
+            @test frule((1,1,1), ^, 0.0, p)[1] == 0
+            @test_broken frule((1,1,1), ^, 0.0, p)[2] == 1
+            @test rrule(^, 0.0, p)[1] == 0
+            @test unthunk(rrule(^, 0.0, p)[2](1.0)[2]) == 1
+
+            # Trivial singularity: 0^0 == 1 in Julia
+            p = S(0)
+            @test_skip frule((1,1,1), ^, 0.0, p)[1] == (0.0)^0
+            @test_broken frule((1,1,1), ^, 0.0, p)[2] == 0
+            @test_broken unthunk(rrule(^, 0.0, p)[2](1.0)[3]) == 0.0
+            
+            # Odd power, 1/x
+            p = S(-1)
+            @test_skip frule((1,1,1), ^, 0.0, p)[1] == (0.0)^-1
+            @test_broken frule((1,1,1), ^, 0.0, p)[2] == -Inf
+            @test_skip rrule(^, 0.0, p)[1] == (0.0)^-1 == Inf
+            @test unthunk(rrule(^, 0.0, p)[2](1.0)[2]) == -Inf
+
+            @test_skip frule((1,1,1), ^, -0.0, p)[1] == (-0.0)^-1
+            @test_broken frule((1,1,1), ^, -0.0, p)[2] == -Inf
+            @test_skip rrule(^, -0.0, p)[1] == (-0.0)^-1 == -Inf
+            @test unthunk(rrule(^, -0.0, p)[2](1.0)[2]) == -Inf
+
+            # Even power, 1/x^2
+            p = S(-2)
+            @test_skip frule((1,1,1), ^, 0.0, p)[1] == (0.0)^-2
+            @test_broken frule((1,1,1), ^, 0.0, p)[2] == -Inf
+            @test_skip rrule(^, 0.0, p)[1] == (0.0)^-2 == Inf
+            @test unthunk(rrule(^, 0.0, p)[2](1.0)[2]) == -Inf
+
+            @test_skip frule((1,1,1), ^, -0.0, p)[1] == (-0.0)^-2
+            @test_broken frule((1,1,1), ^, -0.0, p)[2] == +Inf
+            @test_skip rrule(^, -0.0, p)[1] == (-0.0)^-2 == Inf
+            @test unthunk(rrule(^, -0.0, p)[2](1.0)[2]) == +Inf
+        end
+
         #     T <: Real && @testset "discontinuity for ^(x::Real, n::Int) when x ≤ 0" begin
         #         # finite differences doesn't work for x < 0, so we check manually
         #         x = -rand(T) .- 3
@@ -189,15 +240,6 @@ const FASTABLE_AST = quote
         #         @test ∂y ≈ 0
         #     end
         # end
-
-        # @testset "edge cases with ^" begin
-        #     # FIXME
-        #     @test_skip test_frule(^, 0.0, rand() + 3 ⊢ NoTangent(); fdm=forward_fdm(5,1))
-        #     test_rrule(^, 0.0, rand() + 3; fdm=forward_fdm(5,1))
-
-        #     test_frule(^, 0.0, 1.0 ⊢ NoTangent(); fdm=forward_fdm(5,1))
-        #     test_rrule(^, 0.0, 1.0; fdm=forward_fdm(5,1))
-        # end
     end
 
     @testset "sign" begin