use isone/iszero, allow zero-sized uniform scalings

JuliaLinearAlgebra · Sep 26, 2019 · 67c762d · 67c762d
1 parent dd84018
commit 67c762d
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Showing 3 changed files with 10 additions and 10 deletions.
diff --git a/src/LinearMaps.jl b/src/LinearMaps.jl
@@ -29,22 +29,22 @@ Base.length(A::LinearMap) = size(A)[1] * size(A)[2]
 Base.:(*)(A::LinearMap, x::AbstractVector) = mul!(similar(x, promote_type(eltype(A), eltype(x)), size(A, 1)), A, x)
 function LinearAlgebra.mul!(y::AbstractVector, A::LinearMap, x::AbstractVector, α::Number=true, β::Number=false)
     length(y) == size(A, 1) || throw(DimensionMismatch("mul!"))
-    if α == 1
-        β == 0 && (A_mul_B!(y, A, x); return y)
-        β == 1 && (y .+= A * x; return y)
+    if isone(α)
+        iszero(β) && (A_mul_B!(y, A, x); return y)
+        isone(β) && (y .+= A * x; return y)
         # β != 0, 1
         rmul!(y, β)
         y .+= A * x
         return y
-    elseif α == 0
-        β == 0 && (fill!(y, zero(eltype(y))); return y)
-        β == 1 && return y
+    elseif iszero(α)
+        iszero(β) && (fill!(y, zero(eltype(y))); return y)
+        isone(β) && return y
         # β != 0, 1
         rmul!(y, β)
         return y
     else # α != 0, 1
-        β == 0 && (A_mul_B!(y, A, x); rmul!(y, α); return y)
-        β == 1 && (y .+= rmul!(A * x, α); return y)
+        iszero(β) && (A_mul_B!(y, A, x); rmul!(y, α); return y)
+        isone(β) && (y .+= rmul!(A * x, α); return y)
         # β != 0, 1
         rmul!(y, β)
         y .+= rmul!(A * x, α)

diff --git a/src/uniformscalingmap.jl b/src/uniformscalingmap.jl
@@ -2,7 +2,7 @@ struct UniformScalingMap{T} <: LinearMap{T}
     λ::T
     M::Int
     function UniformScalingMap(λ::Number, M::Int)
-        M ≤ 0 && throw(ArgumentError("size of UniformScalingMap must be (strictly) positive, got $M"))
+        M < 0 && throw(ArgumentError("size of UniformScalingMap must be non-negative, got $M"))
         return new{typeof(λ)}(λ, M)
     end
 end

diff --git a/test/uniformscalingmap.jl b/test/uniformscalingmap.jl
@@ -1,7 +1,7 @@
 using Test, LinearMaps, LinearAlgebra, BenchmarkTools
 
 @testset "identity/scaling map" begin
-    @test_throws ArgumentError LinearMaps.UniformScalingMap(true, 0)
+    @test_throws ArgumentError LinearMaps.UniformScalingMap(true, -1)
     A = 2 * rand(ComplexF64, (10, 10)) .- 1
     B = rand(size(A)...)
     M = @inferred 1 * LinearMap(A)