::Function argument in recursive function is expensive #18207
Closed
Description
Just having a function as an argument in a recursive function creates an allocation at each call. This is a minimized example from one of my packages:
function knn_kernel2!(index::Int)
index > 1_000_000 && return
knn_kernel2!(2*index)
knn_kernel2!(2*index+1)
return
end
function knn_kernel2!(index::Int,
skippoint::Function)
index > 1_000_000 && return
knn_kernel2!(2*index, skippoint)
knn_kernel2!(2*index+1, skippoint)
return
endjulia> @time knn_kernel2!(1)
0.003125 seconds (4 allocations: 160 bytes)
julia> @time knn_kernel2!(1, x->false)
0.181919 seconds (2.00 M allocations: 30.511 MB, 2.16% gc time)Is there anyway to workaround this?
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