bugfix in vectorfun arithmetic (#166)

* bugfix in vectorfun arithmetic

* version bump to v0.6.13

* check for approx instead of exact

* Add tests

Author: jishnub

Project.toml

@@ -1,6 +1,6 @@
 name = "ApproxFunBase"
 uuid = "fbd15aa5-315a-5a7d-a8a4-24992e37be05"
-version = "0.6.12"
+version = "0.6.13"
 
 [deps]
 AbstractFFTs = "621f4979-c628-5d54-868e-fcf4e3e8185c"

src/Multivariate/VectorFun.jl

@@ -124,8 +124,8 @@ for OP in (:*,:+,:-)
         $OP(f::ArrayFun,                A::AbstractArray{<:Fun}) = Fun($OP(Array(f),A))
         $OP(A::UniformScaling,          f::ArrayFun) = Fun($OP(A,Array(f)))
         $OP(f::ArrayFun,                A::UniformScaling) = Fun($OP(Array(f),A))
-        $OP(A::Number,                  f::ArrayFun) = Fun($OP(A,Array(f)))
-        $OP(f::ArrayFun,                A::Number) = Fun($OP(Array(f),A))
+        $OP(A::Number,                  f::ArrayFun) = Fun($OP(A*I,Array(f)))
+        $OP(f::ArrayFun,                A::Number) = Fun($OP(Array(f),A*I))
 
         $OP(f::ScalarFun,               A::AbstractArray) = Fun(broadcast($OP,f,A))
         $OP(A::AbstractArray,           f::ScalarFun) = Fun(broadcast($OP,A,f))

test/SpacesTest.jl

@@ -287,5 +287,15 @@ using ApproxFunOrthogonalPolynomials
             @test newvals(f2) ≈ values(f3)
             @test values(f2) ≈ values(f3)
         end
+
+        @testset "Multivariate" begin
+            @testset for S in Any[Chebyshev(), Legendre()]
+                f = Fun(x->ones(2,2), S)
+                @test (f+1) * f ≈ (1+f) * f ≈ f^2 + f
+                @test (f-1) * f ≈ f^2 - f
+                @test (1-f) * f ≈ f - f^2
+                @test f + f ≈ 2f ≈ f*2
+            end
+        end
     end
 end