Begin implementing LAID

lib/diamondtail/application.ex

@@ -2,6 +2,7 @@ defmodule Diamondtail.Application do
   # See https://hexdocs.pm/elixir/Application.html
   # for more information on OTP Applications
   @moduledoc false
+  alias Diamondtail.ExternalLatencyManager
   alias Diamondtail.Genometracker
   alias Diamondtail.Population
 
@@ -15,7 +16,7 @@ defmodule Diamondtail.Application do
       {Plug.Cowboy, scheme: :http, plug: Diamondtail.Router, options: [port: 4001]},
       {Task.Supervisor, name: Diamondtail.TaskSupervisor},
       {Population, 1..10 |> Enum.map(fn _ -> Population.Genome.random end) |> Enum.to_list},
-      Genometracker
+      Genometracker, ExternalLatencyManager
     ]
 
     # See https://hexdocs.pm/elixir/Supervisor.html

lib/diamondtail/brain.ex

@@ -1,4 +1,7 @@
 defmodule Diamondtail.Brain do
+  import Diamondtail.Operators.Implication
+  alias Diamondtail.InternalLatencyManager
+  alias Diamondtail.ExternalLatencyManager
   alias Diamondtail.Population.Genome
   require Logger
 
@@ -83,17 +86,13 @@ defmodule Diamondtail.Brain do
       end
     end
 
-    def valid_actions(%GameState{type: :q, snakes: snakes, self: self} = state) do
+    def valid_actions(%GameState{type: :q, snakes: snakes, self: self}) do
       non_self_snakes = Map.delete(snakes, self)
       for i <- 0..(4 ** map_size(non_self_snakes)) - 1 do
         Enum.with_index(non_self_snakes)
         |> Enum.map(fn {{id, _}, j} ->
           {id, Enum.at([:up, :down, :left, :right], rem(floor(i / (4 ** j)), 4))}
         end)
-        |> Enum.filter(fn {id, action} ->
-          result = apply_actions(state, %{id => action})
-          !snake_dies?(result, id)
-        end)
         |> Map.new()
       end
     end
@@ -140,7 +139,7 @@ defmodule Diamondtail.Brain do
         # We only win if this is a Q state AND we're still alive, this might still be a draw
         case state.type do
           :v -> Float.min_finite()
-          :q -> if snake_dies?(state, state.self), do: IO.inspect(Float.min_finite()), else: Float.max_finite()
+          :q -> if snake_dies?(state, state.self), do: Float.min_finite(), else: Float.max_finite()
         end
       else
         {score, _alpha, _beta} = valid_actions(state)
@@ -241,13 +240,19 @@ defmodule Diamondtail.Brain do
     end
   end
 
-  @spec determine_move(Genome.t(), map(), map()) :: %{move: :up | :down | :left | :right, shout: String.t()}
-  def determine_move(genome, board, self) do
+  @spec determine_move(Genome.t(), map(), map(), map()) :: %{move: :up | :down | :left | :right, shout: String.t()}
+  def determine_move(genome, board, self, game) do
     base_state = GameState.from(board, self)
+    external_latency = ExternalLatencyManager.get_external_latency()
+    max_latency = game["timeout"]
+    target_latency = max_latency - external_latency - genome.latency_headroom
+
+    depth = InternalLatencyManager.best_depth(map_size(base_state.snakes), target_latency)
+
     options = GameState.valid_actions(base_state) |>
       Task.async_stream(fn action ->
         qstate = GameState.apply_actions(base_state, action)
-        {action, GameState.evaluate_state(genome, qstate, ceil(genome.search_depth))}
+        {action, GameState.evaluate_state(genome, qstate, depth)}
       end, ordered: false)
 
     if Enum.empty?(options) do

lib/diamondtail/externallatencymanager.ex

@@ -0,0 +1,33 @@
+defmodule Diamondtail.ExternalLatencyManager do
+  use Agent
+
+  def start_link(_) do
+    Agent.start_link(fn -> {0, 0, %{}} end, name: __MODULE__)
+  end
+
+  def report_internal_latency(move, latency) do
+    Agent.update(__MODULE__, fn {tot_latency, tot_datapoints, dangling_moves} ->
+      {tot_latency, tot_datapoints, Map.put(dangling_moves, move, latency)}
+    end)
+  end
+
+  def report_total_latency(move, latency) do
+    Agent.update(__MODULE__, fn {tot_latency, tot_datapoints, dangling_moves} ->
+      case Map.pop(dangling_moves, move) do
+        {nil, dangling_moves} -> {tot_latency, tot_datapoints, dangling_moves}
+        {internal_latency, dangling_moves} -> {tot_latency + (latency - internal_latency), tot_datapoints + 1, dangling_moves}
+      end
+    end)
+  end
+
+  def get_external_latency() do
+    {tot, dp} = Agent.get(__MODULE__, fn {tot, dp, _} -> {tot, dp} end)
+    tot / dp
+  end
+
+  def clear_dangling_moves(predicate \\ fn -> true end) do
+    Agent.update(__MODULE__, fn {tot_latency, tot_datapoints, dangling_moves} ->
+      {tot_latency, tot_datapoints, Map.filter(dangling_moves, fn {k, _} -> !predicate.(k) end)}
+    end)
+  end
+end

lib/diamondtail/internallatencymanager.ex

@@ -0,0 +1,21 @@
+defmodule Diamondtail.InternalLatencyManager do
+  use Agent
+
+  def start_link(_) do
+    Agent.start_link(fn -> %{} end, name: __MODULE__)
+  end
+
+  def best_depth(player_count, max_latency) do
+    Agent.get(__MODULE__, fn records ->
+      if Map.has_key?(records, player_count) do
+        # Find the highest depth value matching our max latency
+        # TODO
+        3
+      else
+        # We've never seen this player count before, we'll learn how fast we are on this player count after this is done
+        # For now we'll return 1 so we don't die
+        1
+      end
+    end)
+  end
+end

lib/diamondtail/population.ex

@@ -25,7 +25,7 @@ defmodule Diamondtail.Population do
       field :food_distance_weight, float()
       field :own_accessible_tiles_weight, float()
 
-      field :search_depth, float()
+      field :latency_headroom, float()
       field :value_discount, float()
     end
 
@@ -77,7 +77,7 @@ defmodule Diamondtail.Population do
 
         own_accessible_tiles_weight: random_between(0.7, 1),
 
-        search_depth: random_between(3.0, 5.0),
+        latency_headroom: random_between(20.0, 50.0),
         value_discount: random_between(1.0, 20.0) # as percentage
       }
     end

lib/diamondtail/router.ex

@@ -1,5 +1,6 @@
 defmodule Diamondtail.Router do
   require Logger
+  alias Diamondtail.ExternalLatencyManager
   alias Diamondtail.Population
   alias Diamondtail.Brain
   alias Diamondtail.Genometracker
@@ -38,11 +39,22 @@ defmodule Diamondtail.Router do
   post "/move" do
     game_id = conn.params["game"]["id"]
     player_id = conn.params["you"]["id"]
+    turn_number = conn.params["turn"]
+
+    player_latency = conn.params["you"]["latency"]
+    if player_latency < conn.params["game"]["latency"] do
+      ExternalLatencyManager.report_total_latency({game_id, player_id, turn_number - 1}, player_latency)
+    end
+
     genome = Genometracker.get_genome({game_id, player_id})
     board = conn.params["board"]
+    game = conn.params["game"]
     self = conn.params["you"]
-    Logger.debug("Processing move #{game_id} as #{player_id} turn #{conn.params["turn"]}")
-    move = Brain.determine_move(genome, board, self)
+    Logger.debug("Processing move #{game_id} as #{player_id} turn #{turn_number}")
+    t_start = Time.utc_now()
+    move = Brain.determine_move(genome, board, self, game)
+    internal_latency = Time.diff(t_start, Time.utc_now(), :millisecond)
+    ExternalLatencyManager.report_internal_latency({game_id, player_id, turn_number}, internal_latency)
     Logger.debug("Our move: #{inspect(move)}")
     put_resp_content_type(conn, "application/json")
       |> send_resp(200, JSON.encode!(move))
@@ -51,8 +63,17 @@ defmodule Diamondtail.Router do
   post "/end" do
     game_id = conn.params["game"]["id"]
     player_id = conn.params["you"]["id"]
+    turn_number = conn.params["turn"]
+
+    player_latency = conn.params["you"]["latency"]
+    if player_latency < conn.params["game"]["latency"] do
+      ExternalLatencyManager.report_total_latency({game_id, player_id, turn_number - 1}, player_latency)
+    end
+    # Don't leave any unresolved moves gathering dust in the latency manager
+    ExternalLatencyManager.clear_dangling_moves(fn {game, player, _} -> game == game_id && player == player_id end)
+
     victory? = conn.params["board"]["snakes"] |> Enum.any?(fn %{"id" => snake_id} -> snake_id == player_id end)
-    Logger.info("Ending game '#{game_id}' as '#{player_id}' after #{conn.params["turn"]} turns. #{if victory?, do: "We won!", else: "We lost."}")
+    Logger.info("Ending game '#{game_id}' as '#{player_id}' after #{turn_number} turns. #{if victory?, do: "We won!", else: "We lost."}")
     Genometracker.game_end({game_id, player_id}, victory?)
     Logger.info("#{Population.size} genomes remain in the population.")
     Logger.debug("#{inspect(Population.avg)}")

lib/operators.ex

@@ -0,0 +1,8 @@
+defmodule Diamondtail.Operators do
+  defmodule Implication do
+    @moduledoc """
+    Implements logical implication, A ~> B is true if B is true or A is false
+    """
+    def a ~> b, do: !a || b
+  end
+end