Custom data structure for repeatedly partial sorting constant-size array

General Usage Performance
1

I have an application where, as a subroutine, I need to (partial) sort a specific n-dimensional vector repeatedly (for n>10^7). Given initial data x^{(0)} and some perturbation \epsilon^{(i)} in step i, I want to obtain x^{(i)} = \texttt{sort}(x^{(i-1)} + \epsilon^{(i)}) and the permutation \pi such that (x^{(i-1)} + \epsilon^{(i)})_\pi = x^{(i)}.

So, I am repeatedly (partial) sorting a vector of the same dimension. Based on the discussion here, it was suggested to use a custom data structure. What I have done so far is to pre-allocate x = zeros(Float64, n), e = zeros(Float64, n), and p = zeros(Int64, n) and then call sortperm! (or partialsortperm!) on my data in step i. Is there a data structure that I could use in this case to speed up the sortperm!?

2

Not a direct reply, but you can find such specific datatypes for example in DataStructures.jl, see the Sorted Containers section.

However, my feeling is that these types can only help if the perturbation \epsilon^{(i)} is sparse, e.g. if you can somehow replace the addition with a few delete! and push! operations.