Fix fallback methods

Author: Jutho

src/LinearMaps.jl

@@ -39,22 +39,25 @@ end
 # the following for multiplying with transpose and adjoint map are optional:
 # subtypes can overwrite nonmutating methods, implement mutating methods or do nothing
 function Base.At_mul_B(A::LinearMap, x::AbstractVector)
-    if length(methods(Base.At_mul_B!,Tuple{AbstractVector, typeof(A), AbstractVector})) > 1
+    l = methods(Base.At_mul_B!,Tuple{AbstractVector, typeof(A), AbstractVector})
+    if length(l) > 0 && first(l.ms).sig.parameters[3] != LinearMap
         Base.At_mul_B!(similar(x, promote_type(eltype(A), eltype(x)), size(A,2)), A, x)
     else
         throw(MethodError(Base.At_mul_B, (A, x)))
     end
 end
 function Base.At_mul_B!(y::AbstractVector, A::LinearMap, x::AbstractVector)
     length(y) == size(A, 2) || throw(DimensionMismatch("At_mul_B!"))
-    if length(methods(Base.At_mul_B,Tuple{typeof(A), AbstractVector})) > 1
+    l = methods(Base.At_mul_B,Tuple{typeof(A), AbstractVector})
+    if length(l) > 0 && first(l.ms).sig.parameters[2] != LinearMap
         copy!(y, Base.At_mul_B(A, x))
     else
         throw(MethodError(Base.At_mul_B!, (y, A, x)))
     end
 end
 function Base.Ac_mul_B(A::LinearMap,x::AbstractVector)
-    if length(methods(Base.Ac_mul_B!,Tuple{AbstractVector, typeof(A), AbstractVector})) > 1
+    l = methods(Base.Ac_mul_B!,Tuple{AbstractVector, typeof(A), AbstractVector})
+    if length(l) > 0 && first(l.ms).sig.parameters[3] != LinearMap
         Base.Ac_mul_B!(similar(x, promote_type(eltype(A), eltype(x)), size(A,2)), A, x)
     else
         throw(MethodError(Base.Ac_mul_B, (A, x)))
@@ -63,7 +66,8 @@ end
 function
 Base.Ac_mul_B!(y::AbstractVector, A::LinearMap, x::AbstractVector)
     length(y)==size(A,2) || throw(DimensionMismatch("At_mul_B!"))
-    if length(methods(Base.Ac_mul_B,Tuple{typeof(A), AbstractVector})) > 1
+    l = methods(Base.Ac_mul_B,Tuple{typeof(A), AbstractVector})
+    if length(l) > 0 && first(l.ms).sig.parameters[2] != LinearMap
         copy!(y, Base.Ac_mul_B(A, x))
     else
         throw(MethodError(Base.Ac_mul_B!, (y, A, x)))

test/runtests.jl

@@ -1,5 +1,9 @@
+if VERSION < v"0.7.0-DEV.2005"
+    const Test = Base.Test
+end
+
+using Test
 using LinearMaps
-using Base.Test
 
 import Base: *
 
@@ -45,6 +49,11 @@ F = LinearMap(cumsum,10)
 @test F*v == cumsum(v)
 @test_throws ErrorException F'*v
 
+# Test fallback methods:
+L = LinearMap(x->x,x->x,10)
+v = randn(10);
+@test (2*L)'*v ≈ 2*v
+
 # test linear combinations
 A = 2*rand(Complex128,(10,10)).-1
 M = LinearMap(A)