Merge pull request #444 from matbesancon/fix-typemin

add typemax typemin

Author: andreasnoack

src/dual.jl

@@ -86,7 +86,7 @@ end
     if S ≺ T
         d
     else
-        throw(DualMismatchError(T,S))        
+        throw(DualMismatchError(T,S))
     end
 end
 
@@ -612,3 +612,11 @@ function Base.show(io::IO, d::Dual{T,V,N}) where {T,V,N}
     end
     print(io, ")")
 end
+
+function Base.typemin(::Type{ForwardDiff.Dual{T,V,N}}) where {T,V,N}
+    ForwardDiff.Dual{T,V,N}(typemin(V))
+end
+
+function Base.typemax(::Type{ForwardDiff.Dual{T,V,N}}) where {T,V,N}
+    ForwardDiff.Dual{T,V,N}(typemax(V))
+end

test/DualTest.jl

@@ -476,4 +476,15 @@ end
     @test pow(x1, 0) === x1^0 === Dual{:t1}(1.0, 0.0)
 end
 
+@testset "Type min/max" begin
+    d1 = Dual(1.0)
+    dinf = typemax(typeof(d1))
+    dminf = typemin(typeof(d1))
+    @test dminf < d1 < dinf
+    @test typeof(dminf) === typeof(d1)
+    @test typeof(dinf) === typeof(d1)
+    @test !isfinite(dminf)
+    @test !isfinite(dinf)
+end
+
 end # module