Fix scaling bug in default_blasmul!, AbstractTridiagonalLayout <: AbstractBandedLayout (#22)

Author: dlfivefifty

Project.toml

@@ -1,7 +1,7 @@
 name = "ArrayLayouts"
 uuid = "4c555306-a7a7-4459-81d9-ec55ddd5c99a"
 authors = ["Sheehan Olver <[email protected]>"]
-version = "0.3.2"
+version = "0.3.3"
 
 [deps]
 FillArrays = "1a297f60-69ca-5386-bcde-b61e274b549b"

src/memorylayout.jl

@@ -497,7 +497,7 @@ triangulardata(A::SubArray{<:Any,2,<:Any,<:Tuple{<:Union{Slice,Base.OneTo},<:Uni
 
 
 abstract type AbstractBandedLayout <: MemoryLayout end
-abstract type AbstractTridiagonalLayout <: MemoryLayout end
+abstract type AbstractTridiagonalLayout <: AbstractBandedLayout end
 
 struct DiagonalLayout{ML} <: AbstractBandedLayout end
 struct SymTridiagonalLayout{ML} <: AbstractTridiagonalLayout end

src/muladd.jl

@@ -178,16 +178,18 @@ function default_blasmul!(α, A::AbstractMatrix, B::AbstractMatrix, β, C::Abstr
     nA == mB || throw(DimensionMismatch("Dimensions must match"))
     size(C) == (mA, nB) || throw(DimensionMismatch("Dimensions must match"))
 
+    lmul!(β, C)
+
     (iszero(mA) || iszero(nB)) && return C
-    iszero(nA) && return lmul!(β, C)
+    iszero(nA) && return C
 
     @inbounds for k in colsupport(A), j in rowsupport(B,rowsupport(A,k))
         z2 = zero(A[k, 1]*B[1, j] + A[k, 1]*B[1, j])
         Ctmp = convert(promote_type(eltype(C), typeof(z2)), z2)
         @simd for ν = rowsupport(A,k) ∩ colsupport(B,j)
             Ctmp = muladd(A[k, ν],B[ν, j],Ctmp)
         end
-        C[k,j] = muladd(α,Ctmp, β*C[k,j])
+        C[k,j] = muladd(α,Ctmp, C[k,j])
     end
     C
 end