Use contiguous memory layout for neighbor lists

Author: efaulhaber

Project.toml

@@ -4,12 +4,14 @@ authors = ["Erik Faulhaber <[email protected]>"]
 version = "0.2.4-dev"
 
 [deps]
+ArraysOfArrays = "65a8f2f4-9b39-5baf-92e2-a9cc46fdf018"
 LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
 Polyester = "f517fe37-dbe3-4b94-8317-1923a5111588"
 Reexport = "189a3867-3050-52da-a836-e630ba90ab69"
 StaticArrays = "90137ffa-7385-5640-81b9-e52037218182"
 
 [compat]
+ArraysOfArrays = "0.6
 LinearAlgebra = "1"
 Polyester = "0.7.5"
 Reexport = "1"

src/PointNeighbors.jl

@@ -2,6 +2,7 @@ module PointNeighbors
 
 using Reexport: @reexport
 
+using ArraysOfArrays: VectorOfVectors
 using LinearAlgebra: dot
 using Polyester: @batch
 @reexport using StaticArrays: SVector

src/nhs_neighbor_lists.jl

@@ -5,17 +5,17 @@ struct NeighborListsNeighborhoodSearch{NDIMS, NHS, NL, PB}
 
     function NeighborListsNeighborhoodSearch{NDIMS}(search_radius, n_particles;
                                                     periodic_box_min_corner = nothing,
-                                                    periodic_box_max_corner = nothing) where {
-                                                                                              NDIMS
-                                                                                              }
+                                                    periodic_box_max_corner = nothing
+                                                    backend = VectorOfVectors{Int}) where {
+                                                                                           NDIMS
+                                                                                           }
         nhs = GridNeighborhoodSearch{NDIMS}(search_radius, n_particles,
                                             periodic_box_min_corner = periodic_box_min_corner,
                                             periodic_box_max_corner = periodic_box_max_corner)
 
-        neighbor_lists = Vector{Vector{Int}}()
+        neighbor_lists = backend()
 
-        new{NDIMS, typeof(nhs),
-            typeof(neighbor_lists),
+        new{NDIMS, typeof(nhs), typeof(neighbor_lists),
             typeof(nhs.periodic_box)}(nhs, neighbor_lists, nhs.periodic_box)
     end
 end
@@ -59,6 +59,17 @@ function initialize_neighbor_lists!(neighbor_lists, neighborhood_search, x, y)
     end
 end
 
+function initialize_neighbor_lists!(neighbor_lists::VectorOfVectors, neighborhood_search, x,
+                                    y)
+    neighbor_lists_ = Vector{Vector{Int}}()
+    initialize_neighbor_lists!(neighbor_lists_, neighborhood_search, x, y)
+
+    empty!(neighbor_lists)
+    for i in eachindex(neighbor_lists_)
+        push!(neighbor_lists, neighbor_lists_[i])
+    end
+end
+
 @inline function foreach_neighbor(f, system_coords, neighbor_system_coords,
                                   neighborhood_search::NeighborListsNeighborhoodSearch,
                                   particle, search_radius = nothing)