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Specialize lmul!/rmul! for strided triangular matrices #1228

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Merged
merged 1 commit into from
Feb 27, 2025
Merged

Specialize lmul!/rmul! for strided triangular matrices #1228

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47 changes: 41 additions & 6 deletions src/diagonal.jl
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Original file line number Diff line number Diff line change
Expand Up @@ -379,6 +379,26 @@ function rmul!(T::Tridiagonal, D::Diagonal)
end
return T
end
for T in [:UpperTriangular, :UnitUpperTriangular,
:LowerTriangular, :UnitLowerTriangular]
@eval rmul!(A::$T{<:Any, <:StridedMatrix}, D::Diagonal) = _rmul!(A, D)
@eval lmul!(D::Diagonal, A::$T{<:Any, <:StridedMatrix}) = _lmul!(D, A)
end
function _rmul!(A::UpperOrLowerTriangular, D::Diagonal)
P = parent(A)
isunit = A isa UnitUpperOrUnitLowerTriangular
isupper = A isa UpperOrUnitUpperTriangular
for col in axes(A,2)
rowstart = isupper ? firstindex(A,1) : col+isunit
rowstop = isupper ? col-isunit : lastindex(A,1)
for row in rowstart:rowstop
P[row, col] *= D.diag[col]
end
end
isunit && _setdiag!(P, identity, D.diag)
TriWrapper = isupper ? UpperTriangular : LowerTriangular
return TriWrapper(P)
end

function lmul!(D::Diagonal, B::AbstractVecOrMat)
matmul_size_check(size(D), size(B))
Expand All @@ -388,6 +408,13 @@ function lmul!(D::Diagonal, B::AbstractVecOrMat)
end
return B
end
# A' = D * A' => A = A * D'
# This uses the fact that D' is a Diagonal
function lmul!(D::Diagonal, A::AdjOrTransAbsMat)
f = wrapperop(A)
rmul!(f(A), f(D))
A
end

# in-place multiplication with a diagonal
# T .= D * T
Expand All @@ -402,12 +429,20 @@ function lmul!(D::Diagonal, T::Tridiagonal)
end
return T
end
# A' = D * A' => A = A * D'
# This uses the fact that D' is a Diagonal
function lmul!(D::Diagonal, A::AdjOrTransAbsMat)
f = wrapperop(A)
rmul!(f(A), f(D))
A
function _lmul!(D::Diagonal, A::UpperOrLowerTriangular)
P = parent(A)
isunit = A isa UnitUpperOrUnitLowerTriangular
isupper = A isa UpperOrUnitUpperTriangular
for col in axes(A,2)
rowstart = isupper ? firstindex(A,1) : col+isunit
rowstop = isupper ? col-isunit : lastindex(A,1)
for row in rowstart:rowstop
P[row, col] = D.diag[row] * P[row, col]
end
end
isunit && _setdiag!(P, identity, D.diag)
TriWrapper = isupper ? UpperTriangular : LowerTriangular
return TriWrapper(P)
end

@inline function __muldiag_nonzeroalpha!(out, D::Diagonal, B, alpha::Number, beta::Number)
Expand Down
4 changes: 2 additions & 2 deletions test/diagonal.jl
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Original file line number Diff line number Diff line change
Expand Up @@ -1197,11 +1197,11 @@ end
outTri = similar(TriA)
out = similar(A)
# 2 args
for fun in (*, rmul!, rdiv!, /)
@testset for fun in (*, rmul!, rdiv!, /)
@test fun(copy(TriA), D)::Tri == fun(Matrix(TriA), D)
@test fun(copy(UTriA), D)::Tri == fun(Matrix(UTriA), D)
end
for fun in (*, lmul!, ldiv!, \)
@testset for fun in (*, lmul!, ldiv!, \)
@test fun(D, copy(TriA))::Tri == fun(D, Matrix(TriA))
@test fun(D, copy(UTriA))::Tri == fun(D, Matrix(UTriA))
end
Expand Down