Merge pull request #85 from chriselrod/nothreaddefault

RFC: Do we want to multithread by default?

Author: YingboMa

src/lu.jl

@@ -18,7 +18,7 @@ if VERSION >= v"1.7.0-DEV.1188"
     to_stdlib_pivot(::Val{false}) = LinearAlgebra.NoPivot()
 end
 
-function lu(A::AbstractMatrix, pivot = Val(true), thread = Val(true); kwargs...)
+function lu(A::AbstractMatrix, pivot = Val(true), thread = Val(false); kwargs...)
     return lu!(copy(A), normalize_pivot(pivot), thread; kwargs...)
 end
 
@@ -59,7 +59,7 @@ if CUSTOMIZABLE_PIVOT
     end
 end
 
-function lu!(A, pivot = Val(true), thread = Val(true); check = true, kwargs...)
+function lu!(A, pivot = Val(true), thread = Val(false); check = true, kwargs...)
     m, n = size(A)
     minmn = min(m, n)
     npivot = normalize_pivot(pivot)
@@ -87,7 +87,7 @@ recurse(_) = false
 _ptrarray(ipiv) = PtrArray(ipiv)
 _ptrarray(ipiv::NotIPIV) = ipiv
 function lu!(A::AbstractMatrix{T}, ipiv::AbstractVector{<:Integer},
-    pivot = Val(true), thread = Val(true);
+    pivot = Val(true), thread = Val(false);
     check::Bool = true,
     # the performance is not sensitive wrt blocksize, and 8 is a good default
     blocksize::Integer = length(A) ≥ 40_000 ? 8 : 16,

test/runtests.jl

@@ -49,17 +49,17 @@ testlu(A::Union{Transpose, Adjoint}, MF, BF, p) = testlu(parent(A), parent(MF),
                 MF = mylu(A, p)
                 BF = baselu(A, p)
                 testlu(A, MF, BF, _p)
-                testlu(A, mylu(A, p, Val(false)), BF, false)
+                testlu(A, mylu(A, p, Val(true)), BF, false)
                 A′ = permutedims(A)
                 MF′ = mylu(A′', p)
                 testlu(A′', MF′, BF, _p)
-                testlu(A′', mylu(A′', p, Val(false)), BF, false)
+                testlu(A′', mylu(A′', p, Val(true)), BF, false)
                 i = rand(1:s) # test `MF.info`
                 A[:, i] .= 0
                 MF = mylu(A, p, check = false)
                 BF = baselu(A, p, check = false)
                 testlu(A, MF, BF, _p)
-                testlu(A, mylu(A, p, Val(false), check = false), BF, false)
+                testlu(A, mylu(A, p, Val(true), check = false), BF, false)
             end
         end
     end