Merge pull request 'Define a benchmark to measure the VNS performance and prevent redundant hierarchy calculations' (#298) from benchmark into main

Reviewed-on: #298

app/services/tables/distribution.rb

@@ -14,17 +14,18 @@ module Tables
 
     attr_accessor :tables, :min_per_table, :max_per_table, :hierarchy
 
-    def initialize(min_per_table:, max_per_table:)
+    def initialize(min_per_table:, max_per_table:, hierarchy: AffinityGroupsHierarchy.new)
       @min_per_table = min_per_table
       @max_per_table = max_per_table
-      @hierarchy = AffinityGroupsHierarchy.new
+      @hierarchy = hierarchy
       @tables = []
     end
 
-    def random_distribution(people)
+    def random_distribution(people, random: Random.new)
       min_tables = (people.count * 1.0 / @max_per_table).ceil
       max_tables = (people.count * 1.0 / @min_per_table).ceil
-      @tables = people.in_groups(rand(min_tables..max_tables), false)
+      table_size = random.rand(min_tables..max_tables)
+      @tables = people.in_groups(table_size, false)
                       .map { |group| Table.new(group) }
                       .each { |table| table.min_per_table = @min_per_table }
                       .each { |table| table.max_per_table = @max_per_table }
@@ -41,7 +42,8 @@ module Tables
     end
 
     def deep_dup
-      self.class.new(min_per_table: @min_per_table, max_per_table: @max_per_table).tap do |new_distribution|
+      self.class.new(min_per_table: @min_per_table, max_per_table: @max_per_table,
+                     hierarchy: @hierarchy).tap do |new_distribution|
         new_distribution.tables = @tables.map(&:dup)
       end
     end

lib/tasks/vns.rake

@@ -0,0 +1,29 @@
+# frozen_string_literal: true
+
+namespace :vns do
+  desc 'Benchmarks the efficiency of the VNS implementation'
+  task benchmark: :environment do
+    ActsAsTenant.with_tenant(Wedding.first) do
+      Rails.logger.info "There are #{Guest.potential.count} potential guests"
+
+      engine = VNS::Engine.new
+
+      engine.add_perturbation(Tables::Swap)
+      engine.add_perturbation(Tables::Shift)
+
+      hierarchy = AffinityGroupsHierarchy.new
+      initial_solution = Tables::Distribution.new(min_per_table: 8, max_per_table: 10, hierarchy:)
+
+      random = Random.new(561_163)
+      initial_solution.random_distribution(Guest.potential.shuffle(random:), random:)
+
+      engine.initial_solution = initial_solution
+
+      engine.target_function(&:discomfort)
+
+      solution = Rails.benchmark('VNS Benchmarking') { engine.run }
+
+      Rails.logger.info "Best solution found with discomfort: #{solution.discomfort}"
+    end
+  end
+end