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Merged
merged 2 commits into from
Sep 13, 2019
Merged

Dispatch more cases to BLAS.gemm! #33229

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67f98df
Dispatch more cases to BLAS.gemm!
tkf Sep 11, 2019
0df7694
Use α and β instead of alpha′ and beta′
tkf Sep 12, 2019
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16 changes: 12 additions & 4 deletions stdlib/LinearAlgebra/src/matmul.jl
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Original file line number Diff line number Diff line change
Expand Up @@ -152,15 +152,23 @@ function (*)(A::AbstractMatrix, B::AbstractMatrix)
TS = promote_op(matprod, eltype(A), eltype(B))
mul!(similar(B, TS, (size(A,1), size(B,2))), A, B)
end
@inline mul!(C::StridedMatrix{T}, A::StridedVecOrMat{T}, B::StridedVecOrMat{T},
alpha::Union{T, Bool}, beta::Union{T, Bool}) where {T<:BlasFloat} =
gemm_wrapper!(C, 'N', 'N', A, B, MulAddMul(alpha, beta))

@inline function mul!(C::StridedMatrix{T}, A::StridedVecOrMat{T}, B::StridedVecOrMat{T},
α::Number, β::Number) where {T<:BlasFloat}
alpha, beta = promote(α, β, zero(T))
if alpha isa T && beta isa T
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Why not use a separate method for this?

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Are you suggesting to write

@inline function mul!(C::StridedMatrix{T}, A::StridedVecOrMat{T}, B::StridedVecOrMat{T},
                      alpha::$TA, beta::$TB) where {T<:BlasFloat}
    ...

with some expressions $TA and $TB? Is it possible? We need to express "alpha and beta would be promoted to T" in the type domain. I don't know how to do it.

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I didn't see the accents. So no, it's not possible.

return gemm_wrapper!(C, 'N', 'N', A, B, MulAddMul(alpha, beta))
else
return generic_matmatmul!(C, 'N', 'N', A, B, MulAddMul(α, β))
end
end

# Complex Matrix times real matrix: We use that it is generally faster to reinterpret the
# first matrix as a real matrix and carry out real matrix matrix multiply
for elty in (Float32,Float64)
@eval begin
@inline function mul!(C::StridedMatrix{Complex{$elty}}, A::StridedVecOrMat{Complex{$elty}}, B::StridedVecOrMat{$elty},
alpha::Union{$elty, Bool}, beta::Union{$elty, Bool})
alpha::Real, beta::Real)
Afl = reinterpret($elty, A)
Cfl = reinterpret($elty, C)
mul!(Cfl, Afl, B, alpha, beta)
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2 changes: 1 addition & 1 deletion stdlib/LinearAlgebra/test/matmul.jl
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Expand Up @@ -586,7 +586,7 @@ end
A = rand(n, n)
B = rand(n, n)
C = zeros(n, n)
mul!(C, A, B, -1, 0)
mul!(C, A, B, -1 + 0im, 0)
D = -A * B
@test D ≈ C

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