Antisocial dance (naive/knn)

antisocial.jl

# using naive search
using GLMakie, LinearAlgebra
using StaticArrays
rot(θ) = @SMatrix [cos(θ) -sin(θ); sin(θ) cos(θ) ]
x = [Point2f(0,1), Point2f(1,0), Point2f(3, 0)]

xnew = copy(x)
δ = 0.001
xall = [copy(x)]
i = 1
for iter in 1:20000
    global x, xnew, xall
    for i in eachindex(x)
        n = argmin(i==j ? Inf : norm(x[j] .- x[i]) for j in eachindex(x) )
        Δ = x[i] - x[n]
        a = norm(Δ)
        if a < 1e-7
            xnew[i] = x[i] + δ*((Point2f(-Δ[2], Δ[1]))/a)
        else
            xnew[i] = x[n] + rot(δ/a)*Δ
        end
    end
    xnew, x = x, xnew
    iter % 100 == 0 && push!(xall, copy(x))
end
fig = scatterlines(getindex.(xall, 1), markersize=1.5, linewidth=0.1)
for i in 2:3; scatterlines!(getindex.(xall, i), markersize=1.5, linewidth=0.1); end
fig 

# animation settings
n_frames = 100
framerate = 30
iter = LinRange(1, length(xall), n_frames)
points = Observable(xall[1])
scene = scatter(points, markersize=15.0)
xlims!(scene.axis, (-5,5))
ylims!(scene.axis, (-5,5))

Makie.record(scene, "antisocial.mp4", iter; framerate = framerate) do i
    points[] = xall[round(Int,i)]
end

antisocial_knn.jl

# using NearestNeighbors.jl
using GLMakie, LinearAlgebra, Random, NearestNeighbors, ProgressMeter
using StaticArrays
rot(θ) = @SMatrix [cos(θ) -sin(θ); sin(θ) cos(θ) ]
#x = [Point2f(0,1), Point2f(1,0), Point2f(3, 0)]
x = rand(Point2f, 1000)
Random.seed!(1)
#append!(x, x .+ 0.01*rand(Point2f, 4))
xnew = copy(x)
δ = 0.001
xall = [copy(x)]
i = 1
# animation settings
n_frames = 100
framerate = 30
iter = LinRange(1, length(xall), n_frames)
points = Observable(x)
scene = scatter(points, markersize=15.0)
xlims!(scene.axis, (-5,5))
ylims!(scene.axis, (-5,5))
display(scene)
ProgressMeter.@showprogress for iter in 1:50000
    global x, xnew, xall
    kdtree = KDTree(x)
    for i in eachindex(x)
       
        n, a = nn(kdtree, x[i], x -> x == i)
        #n = argmin(i==j ? Inf : norm(x[j] .- x[i]) for j in eachindex(x) )
#        a = norm(Δ)
        Δ = x[i] - x[n]
        if a < 1e-7
            xnew[i] = x[i] + δ*((Point2f(-Δ[2], Δ[1]))/a)
        else
            xnew[i] = x[n] + rot(δ/a)*Δ
        end
    end
    xnew, x = x, xnew
    iter % 100 == 0 && push!(xall, copy(x))
    if iter % 1000 == 0 
     #   points[] = x
    end
end
fig = scatterlines(getindex.(xall, 1), markersize=1.5, linewidth=0.1)
for i in 2:3; scatterlines!(getindex.(xall, i), markersize=1.5, linewidth=0.1); end
fig 

# animation settings
n_frames = 200
framerate = 30
iter = LinRange(1, length(xall), n_frames)
points = Observable(xall[1])
scene = scatter(points, markersize=15.0)
xlims!(scene.axis, (-10,10))
ylims!(scene.axis, (-10,10))

Makie.record(scene, "antisocial.mp4", iter; framerate = framerate) do i
    points[] = xall[round(Int,i)]
end