Sample pairs of values from vectors x and y without replacement

SamplePairs.jl

import StatsBase
"""
    xs,ys = samplePairs(x,y,nSamples=length(x)*length(y))
Samples a pair of values, one from x and one from y, without repetition
"""
function samplePairs(x::AbstractVector{T}, y::AbstractVector{T}; nSamples=length(x)*length(y)) where {T}
    xout = Vector{T}(undef,nSamples)
    yout = Vector{T}(undef,nSamples)
    p = length(x)*length(y)
    s = zeros(Int,nSamples)
    StatsBase.knuths_sample!(1:p,s)
    @inbounds idx = CartesianIndices((length(x),length(y)))[s];
    @inbounds for i = 1:nSamples
        xout[i] = x[ idx[i][1] ]
        yout[i] = y[ idx[i][2] ]
    end
    return xout, yout
end