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Defining neutral_element for xor (⊻) and fixing it for and (&). #602

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Merged
maleadt merged 2 commits into from
Jul 14, 2025
Merged

Defining neutral_element for xor (⊻) and fixing it for and (&). #602

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5b7cad5
Defining zero(T) as the neutral element for xor.
Hamiltonian-Action Jul 1, 2025
e37cd24
Modify neutral_element for & to ~zero(T). Included logical operators …
Hamiltonian-Action Jul 1, 2025
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3 changes: 2 additions & 1 deletion src/host/mapreduce.jl
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Original file line number Diff line number Diff line change
Expand Up @@ -15,9 +15,10 @@ neutral_element(op, T) =
Please pass it as an explicit argument to `GPUArrays.mapreducedim!`,
or register it globally by defining `GPUArrays.neutral_element(::typeof($op), T)`.""")
neutral_element(::typeof(Base.:(|)), T) = zero(T)
neutral_element(::typeof(Base.:(⊻)), T) = zero(T)
neutral_element(::typeof(Base.:(&)), T) = ~zero(T)
neutral_element(::typeof(Base.:(+)), T) = zero(T)
neutral_element(::typeof(Base.add_sum), T) = zero(T)
neutral_element(::typeof(Base.:(&)), T) = one(T)
neutral_element(::typeof(Base.:(*)), T) = one(T)
neutral_element(::typeof(Base.mul_prod), T) = one(T)
neutral_element(::typeof(Base.min), T) = typemax(T)
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5 changes: 5 additions & 0 deletions test/testsuite/reductions.jl
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Expand Up @@ -66,6 +66,11 @@ end
(0,)=>[1]]
@test compare(A->reduce(+, A; dims=dims, init=zero(ET)), AT, rand(range, sz))
@test compare(A->reduce(*, A; dims=dims, init=one(ET)), AT, rand(range, sz))
if ET <: Integer
@test compare(A->reduce(&, A; dims=dims, init=~zero(ET)), AT, rand(range, sz))
@test compare(A->reduce(|, A; dims=dims, init=zero(ET)), AT, rand(range, sz))
@test compare(A->reduce(⊻, A; dims=dims, init=zero(ET)), AT, rand(range, sz))
end
end
end
end
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