public static GridWorld RandomState()
{
var w = new GridWorld();
w.WorldState = new int[GridSize, GridSize, GridDepth];
Location wall;
Location pit;
Location goal;
Location player;
var invalid = false;
// Keep trying to get 4 unique random positions...
do
{
wall = Util.RandLoc(0, GridWorld.GridSize);
pit = Util.RandLoc(0, GridWorld.GridSize);
goal = Util.RandLoc(0, GridWorld.GridSize);
player = Util.RandLoc(0, GridWorld.GridSize);
invalid = (wall == pit || wall == goal || wall == player ||
pit == goal || pit == player ||
goal == player);
} while (invalid);
w.WorldState[wall.X, wall.Y, WallLayer] = 1;
w.WorldState[pit.X, pit.Y, PitLayer] = 1;
w.WorldState[goal.X, goal.Y, GoalLayer] = 1;
w.PlayerLocation = player;
w.WorldState[player.X, player.Y, PlayerLayer] = 1;
return(w);
}
public static GridWorld StandardState()
{
var w = new GridWorld();
w.WorldState = new int[GridSize, GridSize, GridDepth];
w.PlayerLocation = new Location(0, 1);
w.WorldState[0, 1, PlayerLayer] = 1;
w.WorldState[2, 2, WallLayer] = 1;
w.WorldState[1, 1, PitLayer] = 1;
w.WorldState[3, 3, GoalLayer] = 1;
return(w);
}
public Brain(int numInputs, int numActions)
{
CreatedDate = DateTime.Now;
TrainingTime = new TimeSpan();
NumInputs = numInputs;
NumActions = numActions;
// network
var layer1N = (numInputs + numActions) / 2;
Net = new Net();
Net.AddLayer(new InputLayer(1, 1, numInputs));
Net.AddLayer(new FullyConnLayer(layer1N));
Net.AddLayer(new ReluLayer());
Net.AddLayer(new FullyConnLayer(numActions));
Net.AddLayer(new RegressionLayer());
World = GridWorld.StandardState();
}
public static GridWorld RandomPlayerState()
{
var w = new GridWorld();
w.WorldState = new int[GridSize, GridSize, GridDepth];
w.WorldState[2, 2, WallLayer] = 1;
w.WorldState[1, 1, PitLayer] = 1;
w.WorldState[3, 3, GoalLayer] = 1;
Location p;
bool invalid = false;
do
{
p = Util.RandLoc(0, GridWorld.GridSize);
invalid = (w.WorldState[p.X, p.Y, WallLayer] != 0 || w.WorldState[p.X, p.Y, PitLayer] != 0 || w.WorldState[p.X, p.Y, GoalLayer] != 0);
} while (invalid);
w.PlayerLocation = p;
w.WorldState[p.X, p.Y, PlayerLayer] = 1;
return(w);
}
public void TrainWithExperienceReplay(int numGames, int batchSize, float initialRandomChance, bool degradeRandomChance = true, string saveToFile = null)
{
var gamma = 0.975f;
var buffer = batchSize * 2;
var h = 0;
//# Stores tuples of (S, A, R, S')
var replay = new List <object[]>();
_trainer = new SgdTrainer(Net)
{
LearningRate = 0.01, Momentum = 0.0, BatchSize = batchSize, L2Decay = 0.001
};
var startTime = DateTime.Now;
var batches = 0;
for (var i = 0; i < numGames; i++)
{
World = GridWorld.RandomPlayerState();
var gameMoves = 0;
double updatedReward;
var gameRunning = true;
while (gameRunning)
{
//# We are in state S
//# Let's run our Q function on S to get Q values for all possible actions
var state = GetInputs();
var qVal = Net.Forward(state);
var action = 0;
if (Util.Rnd.NextDouble() < initialRandomChance)
{
//# Choose random action
action = Util.Rnd.Next(NumActions);
}
else
{
//# Choose best action from Q(s,a) values
action = MaxValueIndex(qVal);
}
//# Take action, observe new state S'
World.MovePlayer(action);
gameMoves++;
TotalTrainingMoves++;
var newState = GetInputs();
//# Observe reward, limit turns
var reward = World.GetReward();
gameRunning = !World.GameOver();
//# Experience replay storage
if (replay.Count < buffer)
{
replay.Add(new[] { state, (object)action, (object)reward, newState });
}
else
{
h = (h < buffer - 1) ? h + 1 : 0;
replay[h] = new[] { state, (object)action, (object)reward, newState };
batches++;
var batchInputValues = new Volume[batchSize];
var batchOutputValues = new List <double>();
//# Randomly sample our experience replay memory
for (var b = 0; b < batchSize; b++)
{
var memory = replay[Util.Rnd.Next(buffer)];
var oldState = (Volume)memory[0];
var oldAction = (int)memory[1];
var oldReward = (int)memory[2];
var oldNewState = (Volume)memory[3];
//# Get max_Q(S',a)
var newQ = Net.Forward(oldNewState);
var y = GetValues(newQ);
var maxQ = MaxValue(newQ);
if (oldReward == GridWorld.ProgressScore)
{
//# Non-terminal state
updatedReward = (oldReward + (gamma * maxQ));
}
else
{
//# Terminal state
updatedReward = oldReward;
}
//# Target output
y[action] = updatedReward;
//# Store batched states
batchInputValues[b] = oldState;
batchOutputValues.AddRange(y);
}
Console.Write(".");
//# Train in batches with multiple scores and actions
_trainer.Train(batchOutputValues.ToArray(), batchInputValues);
TotalLoss += _trainer.Loss;
}
}
Console.WriteLine($"{(World.GetReward() == GridWorld.WinScore ? " WON!" : string.Empty)}");
Console.Write($"Game: {i + 1}");
TotalTrainingGames++;
// Save every 10 games...
if (!string.IsNullOrEmpty(saveToFile) && (i % 10 == 0))
{
Util.SaveBrainToFile(this, saveToFile);
}
//# Optinoally: slowly reduce the chance of choosing a random action
if (degradeRandomChance && initialRandomChance > 0.05f)
{
initialRandomChance -= (1f / numGames);
}
}
var duration = (DateTime.Now - startTime);
LastLoss = _trainer.Loss;
TrainingTime += duration;
if (!string.IsNullOrEmpty(saveToFile))
{
Util.SaveBrainToFile(this, saveToFile);
}
Console.WriteLine($"\nAvg loss: {TotalLoss / TotalTrainingMoves}. Last: {LastLoss}");
Console.WriteLine($"Training duration: {duration}. Total: {TrainingTime}");
}
public void Train(int numGames, float initialRandomChance)
{
var gamma = 0.9f;
_trainer = new SgdTrainer(Net)
{
LearningRate = 0.01, Momentum = 0.0, BatchSize = 1, L2Decay = 0.001
};
var startTime = DateTime.Now;
for (var i = 0; i < numGames; i++)
{
World = GridWorld.StandardState();
double updatedReward;
var gameRunning = true;
var gameMoves = 0;
while (gameRunning)
{
//# We are in state S
//# Let's run our Q function on S to get Q values for all possible actions
var state = GetInputs();
var qVal = Net.Forward(state);
var action = 0;
if (Util.Rnd.NextDouble() < initialRandomChance)
{
//# Choose random action
action = Util.Rnd.Next(NumActions);
}
else
{
//# Choose best action from Q(s,a) values
action = MaxValueIndex(qVal);
}
//# Take action, observe new state S'
World.MovePlayer(action);
gameMoves++;
TotalTrainingMoves++;
var newState = GetInputs();
//# Observe reward
var reward = World.GetReward();
gameRunning = !World.GameOver();
//# Get max_Q(S',a)
var newQ = Net.Forward(newState);
var y = GetValues(newQ);
var maxQ = MaxValue(newQ);
if (gameRunning)
{
//# Non-terminal state
updatedReward = (reward + (gamma * maxQ));
}
else
{
//# Terminal state
updatedReward = reward;
TotalTrainingGames++;
Console.WriteLine($"Game: {TotalTrainingGames}. Moves: {gameMoves}. {(reward == 10 ? "WIN!" : "")}");
}
//# Target output
y[action] = updatedReward;
//# Feedback what the score would be for this action
_trainer.Train(state, y);
TotalLoss += _trainer.Loss;
}
//# Slowly reduce the chance of choosing a random action
if (initialRandomChance > 0.05f)
{
initialRandomChance -= (1f / numGames);
}
}
var duration = (DateTime.Now - startTime);
LastLoss = _trainer.Loss;
TrainingTime += duration;
Console.WriteLine($"Avg loss: {TotalLoss / TotalTrainingMoves}. Last: {LastLoss}");
Console.WriteLine($"Training duration: {duration}. Total: {TrainingTime}");
}
static void Main(string[] args)
{
Console.WriteLine(" ----------------------- ");
Console.WriteLine("| G.R.I.D --- W.O.R.L.D |");
Console.WriteLine(" ----------------------- ");
Console.WriteLine("Tutorial: http://outlace.com/Reinforcement-Learning-Part-3/\n");
Brain brain;
if (File.Exists(BrainFile))
{
brain = Util.ReadBrainFromFile(BrainFile);
Console.WriteLine("Brain loaded...");
Console.WriteLine($"Created: {brain.CreatedDate}. Training Time: {brain.TrainingTime} ({brain.TotalTrainingGames} games)");
Console.WriteLine($"Avg loss: {brain.TotalLoss / brain.TotalTrainingMoves}. Last: {brain.LastLoss}");
}
else
{
var numInputs = GridWorld.GridSize * GridWorld.GridSize * GridWorld.GridDepth;
var numActions = 4;
brain = new Brain(numInputs, numActions);
}
// Initial output:
var initialOutput = brain.DisplayOutput(brain.GetInputs());
//Console.WriteLine("Training...");
//brain.Train(1000, 1f);
Console.WriteLine("Batch Training...");
brain.TrainWithExperienceReplay(3000, 32, 1f, true, BrainFile);
// Sample output:
brain.World = GridWorld.RandomPlayerState();
var trainedOutput = brain.DisplayOutput(brain.GetInputs());
// Show results:
Console.WriteLine(brain.World.DisplayGrid());
Console.WriteLine($"Actions: ({_actionNames[0]} {_actionNames[1]} {_actionNames[2]} {_actionNames[3]})");
Console.WriteLine($"Initial output: {initialOutput}");
Console.WriteLine($"Sample output: {trainedOutput}");
Console.WriteLine("\nBrain saved...\nPress enter to play some games...");
Console.ReadLine();
// Play some games:
do
{
Console.Clear();
brain.World = GridWorld.RandomPlayerState();
Console.WriteLine("Initial state:");
Console.WriteLine(brain.World.DisplayGrid());
var moves = 0;
while (!brain.World.GameOver())
{
var action = brain.GetNextAction();
Console.WriteLine($"\nMove: {++moves}. Taking action: {_actionNames[action]}");
brain.World.MovePlayer(action);
Console.WriteLine(brain.World.DisplayGrid());
}
if (moves >= 10)
{
Console.WriteLine($"Game Over. Too many moves!");
}
else
{
Console.WriteLine($"Game {(brain.World.GetReward() == GridWorld.WinScore ? "WON!" : "LOST! :(")}");
}
Console.WriteLine("\nPress enter to play another game...");
Console.ReadLine();
} while (true);
}