Implement zero for affine quantities.

PainterQubits · Nov 1, 2018 · 5909934 · 5909934
1 parent 705ff3a
commit 5909934
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Showing 2 changed files with 4 additions and 6 deletions.
diff --git a/src/quantities.jl b/src/quantities.jl
@@ -286,11 +286,9 @@ for f in (:floor, :ceil, :trunc, :round)
 end
 
 zero(x::Quantity) = Quantity(zero(x.val), unit(x))
-zero(x::AffineQuantity) =
-    throw(AffineError("no additive identity element of type $(typeof(x))."))
+zero(x::AffineQuantity) = Quantity(zero(x.val), absoluteunit(x))
 zero(x::Type{Quantity{T,D,U}}) where {T,D,U<:ScalarUnits} = zero(T)*U()
-zero(x::Type{Quantity{T,D,U}}) where {T,D,U<:AffineUnits} =
-    throw(AffineError("no additive identity element of type $(typeof(x))."))
+zero(x::Type{Quantity{T,D,U}}) where {T,D,U<:AffineUnits} = zero(T)*absoluteunit(U())
 
 one(x::Quantity) = one(x.val)
 one(x::AffineQuantity) =

diff --git a/test/runtests.jl b/test/runtests.jl
@@ -191,8 +191,8 @@ end
         @test_throws AffineError (32°F) / 2
         @test_throws AffineError 2 / (32°F)
 
-        @test_throws AffineError zero(100°C)
-        @test_throws AffineError zero(typeof(100°C))
+        @test zero(100°C) === 0K
+        @test zero(typeof(100°C)) === 0K
         @test_throws AffineError one(100°C)
         @test_throws AffineError one(typeof(100°C))
         @test_throws AffineError oneunit(100°C)