Merge pull request #39550 from JuliaLang/ksh/subnormallog

Add tests for logs of subnormals
JuliaLang · Feb 7, 2021 · c99a552 · c99a552
2 parents 1e54419 + b51f4cc
commit c99a552
Showing 1 changed file with 11 additions and 0 deletions.
diff --git a/test/math.jl b/test/math.jl
@@ -678,6 +678,17 @@ end
         @test isnan_type(T, log1p(T(NaN)))
         @test_throws DomainError log1p(-2*one(T))
     end
+    @testset "log of subnormals" begin
+        # checked results with WolframAlpha
+        for (T, lr) in ((Float32, LinRange(2.f0^(-129), 2.f0^(-128), 1000)),
+                        (Float64, LinRange(2.0^(-1025), 2.0^(-1024), 1000)))
+            for x in lr
+                @test log(x)   ≈ T(log(widen(x))) rtol=2eps(T)
+                @test log2(x)  ≈ T(log2(widen(x))) rtol=2eps(T)
+                @test log10(x) ≈ T(log10(widen(x))) rtol=2eps(T)
+            end
+        end
+    end
 end
 
 @testset "vectorization of 2-arg functions" begin