Replace broadcasted lambda with explicit loop (#738)

* Replace broadcasted lambda with explicit loop

* version bump and NEWS

* NEWS xref

NEWS.md

@@ -1,3 +1,7 @@
+MixedModels v4.22.5 Release Notes
+==============================
+* Replace broadcasted lambda with explicit loop and use `one`. This may result in a small performance improvement. [#738]
+
 MixedModels v4.22.4 Release Notes
 ==============================
 * Switch to explicit imports from all included packages (i.e. replace `using Foo` by `using Foo: Foo, bar, baz`) [#748]
@@ -495,5 +499,6 @@ Package dependencies
 [#715]: https://github.com/JuliaStats/MixedModels.jl/issues/715
 [#717]: https://github.com/JuliaStats/MixedModels.jl/issues/717
 [#733]: https://github.com/JuliaStats/MixedModels.jl/issues/733
+[#738]: https://github.com/JuliaStats/MixedModels.jl/issues/738
 [#744]: https://github.com/JuliaStats/MixedModels.jl/issues/744
 [#748]: https://github.com/JuliaStats/MixedModels.jl/issues/748

Project.toml

@@ -1,7 +1,7 @@
 name = "MixedModels"
 uuid = "ff71e718-51f3-5ec2-a782-8ffcbfa3c316"
 author = ["Phillip Alday <[email protected]>", "Douglas Bates <[email protected]>", "Jose Bayoan Santiago Calderon <[email protected]>"]
-version = "4.22.4"
+version = "4.22.5"
 
 [deps]
 Arrow = "69666777-d1a9-59fb-9406-91d4454c9d45"

src/remat.jl

@@ -564,7 +564,10 @@ function copyscaleinflate! end
 
 function copyscaleinflate!(Ljj::Diagonal{T}, Ajj::Diagonal{T}, Λj::ReMat{T,1}) where {T}
     Ldiag, Adiag = Ljj.diag, Ajj.diag
-    broadcast!((x, λsqr) -> x * λsqr + one(T), Ldiag, Adiag, abs2(only(Λj.λ)))
+    lambsq = abs2(only(Λj.λ.data))
+    @inbounds for i in eachindex(Ldiag, Adiag)
+        Ldiag[i] = lambsq * Adiag[i] + one(T)
+    end
     return Ljj
 end
 
@@ -606,14 +609,14 @@ function copyscaleinflate!(
     iszero(r) || throw(DimensionMismatch("size(Ljj, 1) is not a multiple of S"))
     λ = Λj.λ
     offset = 0
-    @inbounds for k in 1:q
+    @inbounds for _ in 1:q
         inds = (offset + 1):(offset + S)
         tmp = view(Ljj, inds, inds)
         lmul!(adjoint(λ), rmul!(tmp, λ))
         offset += S
     end
     for k in diagind(Ljj)
-        Ljj[k] += 1
+        Ljj[k] += one(T)
     end
     return Ljj
 end