add examples/GA3C

examples/GA3C/Config.py

+# --------------------------------------------------------
+# GA3C for Dragon
+# Copyright(c) 2017 SeetaTech
+# Written by Ting Pan
+# --------------------------------------------------------
+
+class Config(object):
+
+    #########################################################################
+    # Game configuration
+
+    # Name of the game, with version (e.g. PongDeterministic-v0)
+    ATARI_GAME = 'PongDeterministic-v0'
+
+    # Enable to see the trained agent in action
+    PLAY_MODE = False
+    # Enable to train
+    TRAIN_MODELS = True
+    # Load old models. Throws if the model doesn't exist
+    LOAD_CHECKPOINT = False
+    # If 0, the latest checkpoint is loaded
+    LOAD_EPISODE = 32000
+
+    #########################################################################
+    # Number of agents, predictors, trainers and other system settings
+    
+    # If the dynamic configuration is on, these are the initial values.
+    # Number of Agents
+    AGENTS = 32
+    # Number of Predictors
+    PREDICTORS = 2
+    # Number of Trainers
+    TRAINERS = 2
+
+    # Device
+    DEVICE = 'gpu:0'
+
+    # Enable the dynamic adjustment (+ waiting time to start it)
+    DYNAMIC_SETTINGS = True
+    DYNAMIC_SETTINGS_STEP_WAIT = 20
+    DYNAMIC_SETTINGS_INITIAL_WAIT = 10
+
+    #########################################################################
+    # Algorithm parameters
+
+    # Discount factor
+    DISCOUNT = 0.99
+    
+    # Tmax
+    TIME_MAX = 5
+    
+    # Reward Clipping
+    REWARD_MIN = -1
+    REWARD_MAX = 1
+
+    # Max size of the queue
+    MAX_QUEUE_SIZE = 100
+    PREDICTION_BATCH_SIZE = 128
+
+    # Input of the DNN
+    STACKED_FRAMES = 4
+    IMAGE_WIDTH = 84
+    IMAGE_HEIGHT = 84
+
+    # Total number of episodes and annealing frequency
+    EPISODES = 400000
+    ANNEALING_EPISODE_COUNT = 400000
+
+    # Entropy regualrization hyper-parameter
+    BETA_START = 0.01
+    BETA_END = 0.01
+
+    # Learning rate
+    LEARNING_RATE_START = 0.0003
+    LEARNING_RATE_END = 0.0003
+
+    # RMSProp parameters
+    RMSPROP_DECAY = 0.99
+    RMSPROP_MOMENTUM = 0.0
+    RMSPROP_EPSILON = 0.1
+
+    # Dual RMSProp - we found that using a single RMSProp for the two cost function works better and faster
+    DUAL_RMSPROP = False
+    
+    # Gradient clipping
+    USE_GRAD_CLIP = True
+    GRAD_CLIP_NORM = 40.0 
+    # Epsilon (regularize policy lag in GA3C)
+    LOG_EPSILON = 1e-6
+    # Training min batch size - increasing the batch size increases the stability of the algorithm, but make learning slower
+    TRAINING_MIN_BATCH_SIZE = 0
+    
+    #########################################################################
+    # Log and save
+
+    # Enable TensorBoard
+    TENSORBOARD = False
+    # Update TensorBoard every X training steps
+    TENSORBOARD_UPDATE_FREQUENCY = 1000
+
+    # Enable to save models every SAVE_FREQUENCY episodes
+    SAVE_MODELS = True
+    # Save every SAVE_FREQUENCY episodes
+    SAVE_FREQUENCY = 2000
+    
+    # Print stats every PRINT_STATS_FREQUENCY episodes
+    PRINT_STATS_FREQUENCY = 1
+    # The window to average stats
+    STAT_ROLLING_MEAN_WINDOW = 1000
+
+    # Results filename
+    RESULTS_FILENAME = 'results.txt'
+    # Network checkpoint name
+    NETWORK_NAME = 'network'
+
+    #########################################################################
+    # More experimental parameters here
+    
+    # Minimum policy
+    MIN_POLICY = 0.0
+    # Use log_softmax() instead of log(softmax())
+    USE_LOG_SOFTMAX = False

examples/GA3C/Environment.py

+# --------------------------------------------------------
+# GA3C for Dragon
+# Copyright(c) 2017 SeetaTech
+# Written by Ting Pan
+# --------------------------------------------------------
+
+import numpy as np
+import scipy.misc as misc
+
+from Config import Config
+from GameManager import GameManager
+
+class Queue(object):
+    def __init__(self, maxsize):
+        self._maxsize = maxsize
+        self.queue = []
+
+    def full(self):
+        return len(self.queue) >= self._maxsize
+
+    def get(self):
+        ret = self.queue[0]
+        self.queue = self.queue[1:]
+        return ret
+
+    def put(self, x):
+        self.queue.append(x)
+
+    def clear(self):
+        self.queue = []
+
+
+class Environment:
+    def __init__(self):
+        self.game = GameManager(Config.ATARI_GAME, display=Config.PLAY_MODE)
+        self.nb_frames = Config.STACKED_FRAMES
+        self.frame_q = Queue(maxsize=self.nb_frames)
+        self.previous_state = None
+        self.current_state = None
+        self.total_reward = 0
+
+        self.reset()
+
+    @staticmethod
+    def _rgb2gray(rgb):
+        return np.dot(rgb[..., :3], [0.299, 0.587, 0.114])
+
+    @staticmethod
+    def _preprocess(image):
+        image = Environment._rgb2gray(image)
+        image = misc.imresize(image, [Config.IMAGE_HEIGHT, Config.IMAGE_WIDTH], 'bilinear')
+        image = image.astype(np.float32) / 128.0 - 1.0
+        return image
+
+    def _get_current_state(self):
+        if not self.frame_q.full():
+            return None  # frame queue is not full yet.
+        x_ = np.array(self.frame_q.queue, dtype=np.float32)
+        return x_
+
+    def _update_frame_q(self, frame):
+        if self.frame_q.full():
+            self.frame_q.get()
+        image = Environment._preprocess(frame)
+        self.frame_q.put(image)
+
+    def get_num_actions(self):
+        return self.game.env.action_space.n
+
+    def reset(self):
+        self.total_reward = 0
+        self.frame_q.clear()
+        self._update_frame_q(self.game.reset())
+        self.previous_state = self.current_state = None
+
+    def step(self, action):
+        observation, reward, done, _ = self.game.step(action)
+
+        self.total_reward += reward
+        self._update_frame_q(observation)
+
+        self.previous_state = self.current_state
+        self.current_state = self._get_current_state()
+        return reward, done
\ No newline at end of file

examples/GA3C/GA3C.py

+# --------------------------------------------------------
+# GA3C for Dragon
+# Copyright(c) 2017 SeetaTech
+# Written by Ting Pan
+# --------------------------------------------------------
+
+from Config import Config
+from Server import Server
+
+# Adjust configs for Play mode
+if Config.PLAY_MODE:
+    Config.AGENTS = 1
+    Config.PREDICTORS = 1
+    Config.TRAINERS = 1
+    Config.DYNAMIC_SETTINGS = False
+
+    Config.LOAD_CHECKPOINT = True
+    Config.TRAIN_MODELS = False
+    Config.SAVE_MODELS = False
+
+if __name__ == "__main__":
+
+    import dragon.config
+    dragon.config.EnableCUDA()
+
+    Server().main()

examples/GA3C/GameManager.py

+# --------------------------------------------------------
+# GA3C for Dragon
+# Copyright(c) 2017 SeetaTech
+# Written by Ting Pan
+# --------------------------------------------------------
+
+import gym
+
+
+class GameManager:
+    def __init__(self, game_name, display):
+        self.game_name = game_name
+        self.display = display
+
+        self.env = gym.make(game_name)
+        self.reset()
+
+    def reset(self):
+        observation = self.env.reset()
+        return observation
+
+    def step(self, action):
+        self._update_display()
+        observation, reward, done, info = self.env.step(action)
+        return observation, reward, done, info
+
+    def _update_display(self):
+        if self.display:
+            self.env.render()

examples/GA3C/NetworkVP.py

+# --------------------------------------------------------
+# GA3C for Dragon
+# Copyright(c) 2017 SeetaTech
+# Written by Ting Pan
+# --------------------------------------------------------
+
+import threading
+from dragon.core.tensor import Tensor
+import dragon.vm.theano as theano
+import dragon.vm.theano.tensor as T
+import dragon.ops as ops
+import dragon.core.workspace as ws
+import dragon.updaters as updaters
+
+from Config import Config
+
+mutex = threading.Lock()
+
+class NetworkVP:
+    def __init__(self, model_name, num_actions):
+        self.model_name = model_name
+        self.num_actions = num_actions
+        self.network_params = []
+
+        self.img_width = Config.IMAGE_WIDTH
+        self.img_height = Config.IMAGE_HEIGHT
+        self.img_channels = Config.STACKED_FRAMES
+
+        self.learning_rate = Config.LEARNING_RATE_START
+        self.beta = Config.BETA_START
+        self.log_epsilon = Config.LOG_EPSILON
+        self._create_graph()
+        if Config.PLAY_MODE:
+            ws
+
+    def _create_graph(self):
+        self.x = Tensor(shape=[None, self.img_channels, self.img_height, self.img_width]).Variable()
+        self.y_r = Tensor(shape=[None], name='Yr').Variable()
+
+        # As implemented in A3C paper
+        self.n1 = ops.Relu(ops.Conv2D([self.x] + self.weight_bias(), kernel_size=8, stride=4, num_output=16))
+        self.n2 = ops.Relu(ops.Conv2D([self.n1] + self.weight_bias(), kernel_size=4, stride=2, num_output=32))
+
+        self.action_index = Tensor(shape=[None, self.num_actions]).Variable()
+
+        self.d1 = ops.Relu(ops.InnerProduct([self.n2] + self.weight_bias(), num_output=256))
+
+        self.logits_v = ops.InnerProduct([self.d1] + self.weight_bias(), num_output=1)
+        self.cost_v = ops.L2Loss([self.y_r, self.logits_v])
+
+        self.logits_p = ops.InnerProduct([self.d1] + self.weight_bias(), num_output=self.num_actions)
+
+        if Config.USE_LOG_SOFTMAX: raise NotImplementedError()
+        else:
+            self.softmax_p = ops.Softmax(self.logits_p)
+            self.selected_action_prob = ops.Sum(self.softmax_p * self.action_index, axis=1)
+            self.cost_p_1 = ops.Log(ops.Clip(self.selected_action_prob, self.log_epsilon, None)) * \
+                            (self.y_r - ops.StopGradient(self.logits_v))
+            self.cost_p_2 = ops.Sum(ops.Log(ops.Clip(self.softmax_p, self.log_epsilon, None)) *
+                                      self.softmax_p, axis=1) * (-self.beta)
+        self.cost_p_1_agg = ops.Sum(self.cost_p_1)
+        self.cost_p_2_agg = ops.Sum(self.cost_p_2)
+        self.cost_p = -(self.cost_p_1_agg + self.cost_p_2_agg)
+        self.cost_all = self.cost_p + self.cost_v
+        
+        if Config.DUAL_RMSPROP: raise NotImplementedError()
+        else:
+            if Config.USE_GRAD_CLIP:
+                self.opt = updaters.RMSPropUpdater(decay=Config.RMSPROP_DECAY,
+                                                   eps=Config.RMSPROP_EPSILON,
+                                                   clip_gradient=Config.GRAD_CLIP_NORM)
+            else:
+                self.opt = updaters.RMSPropUpdater(decay=Config.RMSPROP_DECAY,
+                                                   eps=Config.RMSPROP_EPSILON)
+
+        grads = T.grad(self.cost_all, self.network_params)
+        for p, g in zip(self.network_params, grads):
+            self.opt.append((p, g), lr_mult=1.0)
+
+    def weight_bias(self, weights_init=None, no_bias=False):
+        if weights_init is None:
+            weight = Tensor().Xavier()
+        else:
+            weight = weights_init
+        if no_bias:
+            self.network_params.extend([weight])
+            return [weight]
+        bias = Tensor().Constant(value=0)
+        self.network_params.extend([weight, bias])
+        return [weight, bias]
+
+    def predict_single(self, x):
+        return self.predict_p(x[None, :])[0]
+
+    def predict_v(self, x):
+        if not hasattr(self, '_predict_p'):
+            self._predict_v = theano.function(inputs=self.x, outputs=self.logits_v)
+        return self._predict_v(x)
+
+    def predict_p(self, x):
+        if not hasattr(self, '_predict_p'):
+            self._predict_p = theano.function(inputs=self.x, outputs=self.softmax_p)
+        return self._predict_p(x)
+
+    def predict_p_and_v(self, x):
+        if not hasattr(self, '_predict_p_and_v'):
+            self._predict_p_and_v = theano.function(inputs=self.x, outputs=[self.softmax_p, self.logits_v])
+        global mutex
+        mutex.acquire()
+        p, v = self._predict_p_and_v(x)
+        mutex.release()
+        return p, v
+
+    def train(self, x, y_r, a):
+        if not hasattr(self, '_train'):
+            self._compute = theano.function(inputs=[self.x, self.y_r, self.action_index],
+                                            outputs=self.cost_all)
+            self._train = theano.function(updater=self.opt)
+        global mutex
+        mutex.acquire()
+        loss =  self._compute(x, y_r, a)
+        mutex.release()
+        self._train()
+        return loss
+
+    def save(self, episode):
+        filename = 'checkpoints/%s_%08d' % (self.model_name, episode)
+        ws.Snapshot(self.network_params, filename)
+
+    def load(self):
+        filename = 'checkpoints/%s_%08d.bin' % (self.model_name, Config.LOAD_EPISODE)
+        ws.Restore(filename)
+        return Config.LOAD_EPISODE
\ No newline at end of file

examples/GA3C/ProcessAgent.py

+# --------------------------------------------------------
+# GA3C for Dragon
+# Copyright(c) 2017 SeetaTech
+# Written by Ting Pan
+# --------------------------------------------------------
+
+from datetime import datetime
+from multiprocessing import Process, Queue, Value
+
+import numpy as np
+import time
+
+from Config import Config
+from Environment import Environment
+
+class Experience(object):
+    def __init__(self, state, action, prob, reward, done):
+        self.state = state
+        self.action = action
+        self.prob = prob
+        self.reward = reward
+        self.done = done
+
+class ProcessAgent(Process):
+    def __init__(self, id, prediction_q, training_q, episode_log_q):
+        super(ProcessAgent, self).__init__()
+
+        self.id = id
+        self.prediction_q = prediction_q
+        self.training_q = training_q
+        self.episode_log_q = episode_log_q
+
+        self.env = Environment()
+        self.num_actions = self.env.get_num_actions()
+        self.actions = np.arange(self.num_actions)
+
+        self.discount_factor = Config.DISCOUNT
+        # one frame at a time
+        self.wait_q = Queue(maxsize=1)
+        self.exit_flag = Value('i', 0)
+
+    @staticmethod
+    def _accumulate_rewards(experiences, discount_factor, terminal_reward):
+        reward_sum = terminal_reward
+        for t in reversed(range(0, len(experiences) - 1)):
+            r = np.clip(experiences[t].reward, Config.REWARD_MIN, Config.REWARD_MAX)
+            reward_sum = discount_factor * reward_sum + r
+            experiences[t].reward = reward_sum
+        return experiences[:-1]
+
+    def convert_data(self, experiences):
+        x_ = np.array([exp.state for exp in experiences])
+        a_ = np.eye(self.num_actions)[np.array([exp.action for exp in experiences])].astype(np.float32)
+        r_ = np.array([exp.reward for exp in experiences], dtype=np.float32) # R
+        r_ = r_.reshape((-1, 1))
+        return x_, r_, a_
+
+    def predict(self, state):
+        # put the state in the prediction q
+        self.prediction_q.put((self.id, state))
+        # wait for the prediction to come back
+        p, v = self.wait_q.get()
+        return p, v
+
+    def select_action(self, prediction):
+        if Config.PLAY_MODE:
+            action = np.argmax(prediction)
+        else:
+            action = np.random.choice(self.actions, p=prediction)
+        return action
+
+    def run_episode(self):
+        self.env.reset()
+        done = False
+        experiences = []
+
+        time_count = 0
+        reward_sum = 0.0
+
+        while not done:
+            # very first few frames
+            if self.env.current_state is None:
+                self.env.step(0)  # 0 == NOOP
+                continue
+
+            prediction, value = self.predict(self.env.current_state)
+            action = self.select_action(prediction)
+            reward, done = self.env.step(action)
+            reward_sum += reward
+            exp = Experience(self.env.previous_state, action, prediction, reward, done)
+            experiences.append(exp)
+
+            if done or time_count == Config.TIME_MAX:
+                terminal_reward = 0 if done else value
+
+                updated_exps = ProcessAgent._accumulate_rewards(experiences, self.discount_factor, terminal_reward)
+                x_, r_, a_ = self.convert_data(updated_exps)
+                yield x_, r_, a_, reward_sum
+
+                # reset the tmax count
+                time_count = 0
+                # keep the last experience for the next batch
+                experiences = [experiences[-1]]
+                reward_sum = 0.0
+
+            time_count += 1
+
+    def run(self):
+        # randomly sleep up to 1 second. helps agents boot smoothly.
+        time.sleep(np.random.rand())
+        np.random.seed(np.int32(time.time() % 1 * 1000 + self.id * 10))
+
+        while self.exit_flag.value == 0:
+            total_reward = 0
+            total_length = 0
+            for x_, r_, a_, reward_sum in self.run_episode():
+                total_reward += reward_sum
+                total_length += len(r_) + 1  # +1 for last frame that we drop
+                self.training_q.put((x_, r_, a_))
+
+            self.episode_log_q.put((datetime.now(), total_reward, total_length))

examples/GA3C/ProcessStats.py

+# --------------------------------------------------------
+# GA3C for Dragon
+# Copyright(c) 2017 SeetaTech
+# Written by Ting Pan
+# --------------------------------------------------------
+
+import sys
+
+if sys.version_info >= (3, 0):
+    from queue import Queue as queueQueue
+else:
+    from Queue import Queue as queueQueue
+
+from datetime import datetime
+from multiprocessing import Process, Queue, Value
+
+import numpy as np
+import time
+
+from Config import Config
+
+
+class ProcessStats(Process):
+    def __init__(self):
+        super(ProcessStats, self).__init__()
+        self.episode_log_q = Queue(maxsize=100)
+        self.episode_count = Value('i', 0)
+        self.training_count = Value('i', 0)
+        self.should_save_model = Value('i', 0)
+        self.trainer_count = Value('i', 0)
+        self.predictor_count = Value('i', 0)
+        self.agent_count = Value('i', 0)
+        self.total_frame_count = 0
+
+    def FPS(self):
+        # average FPS from the beginning of the training (not current FPS)
+        return np.ceil(self.total_frame_count / (time.time() - self.start_time))
+
+    def TPS(self):
+        # average TPS from the beginning of the training (not current TPS)
+        return np.ceil(self.training_count.value / (time.time() - self.start_time))
+
+    def run(self):
+        with open(Config.RESULTS_FILENAME, 'a') as results_logger:
+            rolling_frame_count = 0
+            rolling_reward = 0
+            results_q = queueQueue(maxsize=Config.STAT_ROLLING_MEAN_WINDOW)
+
+            self.start_time = time.time()
+            first_time = datetime.now()
+            while True:
+                episode_time, reward, length = self.episode_log_q.get()
+                results_logger.write('%s, %d, %d\n' % (episode_time.strftime("%Y-%m-%d %H:%M:%S"), reward, length))
+                results_logger.flush()
+
+                self.total_frame_count += length
+                self.episode_count.value += 1
+
+                rolling_frame_count += length
+                rolling_reward += reward
+
+                if results_q.full():
+                    old_episode_time, old_reward, old_length = results_q.get()
+                    rolling_frame_count -= old_length
+                    rolling_reward -= old_reward
+                    first_time = old_episode_time
+
+                results_q.put((episode_time, reward, length))
+
+                if self.episode_count.value % Config.SAVE_FREQUENCY == 0:
+                    self.should_save_model.value = 1
+
+                if self.episode_count.value % Config.PRINT_STATS_FREQUENCY == 0:
+                    print(
+                        '[Time: %8d] '
+                        '[Episode: %8d Score: %10.4f] '
+                        '[RScore: %10.4f RPPS: %5d] '
+                        '[PPS: %5d TPS: %5d] '
+                        '[NT: %2d NP: %2d NA: %2d]'
+                        % (int(time.time() - self.start_time),
+                           self.episode_count.value, reward,
+                           rolling_reward / results_q.qsize(),
+                           rolling_frame_count / (datetime.now() - first_time).total_seconds(),
+                           self.FPS(), self.TPS(),
+                           self.trainer_count.value, self.predictor_count.value, self.agent_count.value))
+                    sys.stdout.flush()

examples/GA3C/README.md

+# GA3C [TinyDragon Style]
+
+This is a Dragon implementation of GA3C comparing to [NVlabs](https://github.com/NVlabs/GA3C) based on TensorFlow.
+
+GA3C is a hybrid CPU/GPU version of the Asynchronous Advantage Actor-Critic (A3C) algorithm.
+
+Currently the state-of-the-art method in reinforcement learning for various gaming tasks.
+
+This CPU/GPU implementation, based on Dragon, achieves a significant speed up compared to a similar CPU implementation.
+
+**```Attention```**:  GA3C does not support **Windows**, the hybrid Thread/Process will trigger a deadlock if trainers or predictors >=2.
+
+
+## How do I get set up? ###
+
+* Install [Dragon](https://github.com/neopenx/Dragon)
+* Install [OpenAI Gym](https://github.com/openai/gym)
+
+## How to Train a model from scratch? ###
+
+Run GA3C.
+
+You can modify the training parameters directly in `Config.py`.
+
+The output should look like below:
+
+...
+
+[Time:       33] [Episode:       26 Score:   -19.0000] [RScore:   -20.5000 RPPS:   822] [PPS:   823 TPS:   183] [NT:  2 NP:  2 NA: 32]
+
+[Time:       33] [Episode:       27 Score:   -20.0000] [RScore:   -20.4815 RPPS:   855] [PPS:   856 TPS:   183] [NT:  2 NP:  2 NA: 32]
+
+[Time:       35] [Episode:       28 Score:   -20.0000] [RScore:   -20.4643 RPPS:   854] [PPS:   855 TPS:   185] [NT:  2 NP:  2 NA: 32]
+
+[Time:       35] [Episode:       29 Score:   -19.0000] [RScore:   -20.4138 RPPS:   877] [PPS:   878 TPS:   185] [NT:  2 NP:  2 NA: 32]
+
+[Time:       36] [Episode:       30 Score:   -20.0000] [RScore:   -20.4000 RPPS:   899] [PPS:   900 TPS:   186] [NT:  2 NP:  2 NA: 32]
+
+...
+
+**PPS** (predictions per second) demonstrates the speed of processing frames, while **Score** shows the achieved score.
+
+**RPPS** and **RScore** are the rolling average of the above values.
+
+To stop the training procedure, adjuts `EPISODES` in `Config.py` propoerly, or simply use ctrl + c.
+
+## How to continue training a model? ###
+
+If you want to continue training a model, set `LOAD_CHECKPOINTS=True` in `Config.py`.
+
+Set `LOAD_EPISODE` to the episode number you want to load.
+
+Be sure that the corresponding model has been saved in the checkpoints folder (the model name includes the number of the episode).
+
+## How to play a game with a trained agent? ###
+
+set `PLAY_MODE=True` and set `LOAD_EPISODE=xxxx` in `Config.py`
+
+Run GA3C.py
+
+## How to change the game, configurations, etc.? ###
+
+All the configurations are in `Config.py`
+
+## Sample learning curves
+Typical learning curves for Pong and Boxing are shown here. These are easily obtained from the results.txt file.
+![Convergence Curves](http://mb2.web.engr.illinois.edu/images/pong_boxing.png)
+
+### References ###
+
+If you use this code, please refer to [ICLR 2017 paper](https://openreview.net/forum?id=r1VGvBcxl):
+
+```
+@conference{babaeizadeh2017ga3c,
+  title={Reinforcement Learning thorugh Asynchronous Advantage Actor-Critic on a GPU},
+  author={Babaeizadeh, Mohammad and Frosio, Iuri and Tyree, Stephen and Clemons, Jason and Kautz, Jan},
+  booktitle={ICLR},
+  biurl={https://openreview.net/forum?id=r1VGvBcxl},
+  year={2017}
+}
+```
+This work was first presented in an oral talk at the [The 1st International Workshop on Efficient Methods for Deep Neural Networks](http://allenai.org/plato/emdnn/papers.html), NIPS Workshop, Barcelona (Spain), Dec. 9, 2016:
+
+```
+@article{babaeizadeh2016ga3c,
+  title={{GA3C:} {GPU}-based {A3C} for Deep Reinforcement Learning},
+  author={Babaeizadeh, Mohammad and Frosio, Iuri and Tyree, Stephen and Clemons, Jason and Kautz, Jan},
+  journal={NIPS Workshop},
+  biurl={arXiv preprint arXiv:1611.06256},
+  year={2016}
+}
+```

examples/GA3C/Server.py

+# --------------------------------------------------------
+# GA3C for Dragon
+# Copyright(c) 2017 SeetaTech
+# Written by Ting Pan
+# --------------------------------------------------------
+
+from multiprocessing import Queue
+import time
+
+from Config import Config
+from Environment import Environment
+from NetworkVP import NetworkVP
+from ProcessAgent import ProcessAgent
+from ProcessStats import ProcessStats
+from ThreadDynamicAdjustment import ThreadDynamicAdjustment
+from ThreadPredictor import ThreadPredictor
+from ThreadTrainer import ThreadTrainer
+
+
+class Server(object):
+    def __init__(self):
+        self.stats = ProcessStats()
+
+        self.training_q = Queue(maxsize=Config.MAX_QUEUE_SIZE)
+        self.prediction_q = Queue(maxsize=Config.MAX_QUEUE_SIZE)
+
+        self.model = NetworkVP(Config.NETWORK_NAME, Environment().get_num_actions())
+        if Config.LOAD_CHECKPOINT:
+            self.stats.episode_count.value = self.model.load()
+
+        self.training_step = 0
+        self.frame_counter = 0
+
+        self.agents = []
+        self.predictors = []
+        self.trainers = []
+        self.dynamic_adjustment = ThreadDynamicAdjustment(self)
+
+    def add_agent(self):
+        self.agents.append(
+            ProcessAgent(len(self.agents), self.prediction_q, self.training_q, self.stats.episode_log_q))
+        self.agents[-1].start()
+
+    def remove_agent(self):
+        self.agents[-1].exit_flag.value = True
+        self.agents[-1].join()
+        self.agents.pop()
+
+    def add_predictor(self):
+        self.predictors.append(ThreadPredictor(self, len(self.predictors)))
+        self.predictors[-1].start()
+
+    def remove_predictor(self):
+        self.predictors[-1].exit_flag = True
+        self.predictors[-1].join()
+        self.predictors.pop()
+
+    def add_trainer(self):
+        self.trainers.append(ThreadTrainer(self, len(self.trainers)))
+        self.trainers[-1].start()
+
+    def remove_trainer(self):
+        self.trainers[-1].exit_flag = True
+        self.trainers[-1].join()
+        self.trainers.pop()
+
+    def train_model(self, x_, r_, a_):
+        self.model.train(x_, r_, a_)
+        self.training_step += 1
+        self.frame_counter += x_.shape[0]
+
+        self.stats.training_count.value += 1
+        self.dynamic_adjustment.temporal_training_count += 1
+
+        if Config.TENSORBOARD and self.stats.training_count.value % Config.TENSORBOARD_UPDATE_FREQUENCY == 0:
+            self.model.log(x_, r_, a_)
+
+    def save_model(self):
+        self.model.save(self.stats.episode_count.value)
+
+    def main(self):
+        self.stats.start()
+        self.dynamic_adjustment.start()
+
+        if Config.PLAY_MODE:
+            for trainer in self.trainers:
+                trainer.enabled = False
+
+        learning_rate_multiplier = (Config.LEARNING_RATE_END - Config.LEARNING_RATE_START) / Config.ANNEALING_EPISODE_COUNT
+
+        while self.stats.episode_count.value < Config.EPISODES:
+            step = min(self.stats.episode_count.value, Config.ANNEALING_EPISODE_COUNT - 1)
+            self.model.opt.lr = Config.LEARNING_RATE_START + learning_rate_multiplier * step
+
+            # Saving is async - even if we start saving at a given episode, we may save the model at a later episode
+            if Config.SAVE_MODELS and self.stats.should_save_model.value > 0:
+                self.save_model()
+                self.stats.should_save_model.value = 0
+
+            time.sleep(0.01)
+
+        self.dynamic_adjustment.exit_flag = True
+        while self.agents:
+            self.remove_agent()
+        while self.predictors:
+            self.remove_predictor()
+        while self.trainers:
+            self.remove_trainer()
+

examples/GA3C/ThreadDynamicAdjustment.py

+# --------------------------------------------------------
+# GA3C for Dragon
+# Copyright(c) 2017 SeetaTech
+# Written by Ting Pan
+# --------------------------------------------------------
+
+from threading import Thread
+
+import numpy as np
+import time
+
+from Config import Config
+
+class ThreadDynamicAdjustment(Thread):
+    def __init__(self, server):
+        super(ThreadDynamicAdjustment, self).__init__()
+        self.setDaemon(True)
+
+        self.server = server
+        self.enabled = Config.DYNAMIC_SETTINGS
+
+        self.trainer_count = Config.TRAINERS
+        self.predictor_count = Config.PREDICTORS
+        self.agent_count = Config.AGENTS
+
+        self.temporal_training_count = 0
+        self.exit_flag = False
+
+    def enable_disable_components(self):
+        cur_len = len(self.server.trainers)
+        if cur_len < self.trainer_count:
+            for _ in np.arange(cur_len, self.trainer_count):
+                self.server.add_trainer()
+        elif cur_len > self.trainer_count:
+            for _ in np.arange(self.trainer_count, cur_len):
+                self.server.remove_trainer()
+
+        cur_len = len(self.server.predictors)
+        if cur_len < self.predictor_count:
+            for _ in np.arange(cur_len, self.predictor_count):
+                self.server.add_predictor()
+        elif cur_len > self.predictor_count:
+            for _ in np.arange(self.predictor_count, cur_len):
+                self.server.remove_predictor()
+
+        cur_len = len(self.server.agents)
+        if cur_len < self.agent_count:
+            for _ in np.arange(cur_len, self.agent_count):
+                self.server.add_agent()
+        elif cur_len > self.agent_count:
+            for _ in np.arange(self.agent_count, cur_len):
+                self.server.remove_agent()
+
+    def random_walk(self):
+        # 3 directions, 1 for Trainers, 1 for Predictors and 1 for Agents
+        # 3 outcome for each, -1: add one, 0: no change, 1: remove one
+        direction = np.random.randint(3, size=3) - 1
+        self.trainer_count = max(1, self.trainer_count - direction[0])
+        self.predictor_count = max(1, self.predictor_count - direction[1])
+        self.agent_count = max(1, self.agent_count - direction[2])
+
+    def update_stats(self):
+        self.server.stats.trainer_count.value = self.trainer_count
+        self.server.stats.predictor_count.value = self.predictor_count
+        self.server.stats.agent_count.value = self.agent_count
+
+    def run(self):
+        self.enable_disable_components()
+        self.update_stats()
+        if not self.enabled: return
+
+        # Wait for initialization
+        time.sleep(Config.DYNAMIC_SETTINGS_INITIAL_WAIT)
+
+        while not self.exit_flag:
+            old_trainer_count, old_predictor_count, old_agent_count = \
+                self.trainer_count, self.predictor_count, self.agent_count
+            self.random_walk()
+
+            # If no change, do nothing
+            if self.trainer_count == old_trainer_count \
+                    and self.predictor_count == old_predictor_count \
+                    and self.agent_count == old_agent_count:
+                continue
+
+            old_count = self.temporal_training_count
+            self.enable_disable_components()
+
+            self.temporal_training_count = 0
+            time.sleep(Config.DYNAMIC_SETTINGS_STEP_WAIT)
+
+            cur_count = self.temporal_training_count
+            # if it didn't work, revert the changes
+            if cur_count < old_count:
+                self.trainer_count, self.predictor_count, self.agent_count = \
+                    old_trainer_count, old_predictor_count, old_agent_count
+
+            self.update_stats()
\ No newline at end of file

examples/GA3C/ThreadPredictor.py

+# --------------------------------------------------------
+# GA3C for Dragon
+# Copyright(c) 2017 SeetaTech
+# Written by Ting Pan
+# --------------------------------------------------------
+
+from threading import Thread
+import numpy as np
+
+from Config import Config
+
+
+class ThreadPredictor(Thread):
+    def __init__(self, server, id):
+        super(ThreadPredictor, self).__init__()
+        self.setDaemon(True)
+
+        self.id = id
+        self.server = server
+        self.exit_flag = False
+
+    def run(self):
+        ids = np.zeros(Config.PREDICTION_BATCH_SIZE, dtype=np.uint16)
+        states = np.zeros(
+            (Config.PREDICTION_BATCH_SIZE, Config.STACKED_FRAMES, Config.IMAGE_HEIGHT, Config.IMAGE_WIDTH, ),
+            dtype=np.float32)
+
+        while not self.exit_flag:
+            ids[0], states[0] = self.server.prediction_q.get()
+
+            size = 1
+            while size < Config.PREDICTION_BATCH_SIZE and not self.server.prediction_q.empty():
+                ids[size], states[size] = self.server.prediction_q.get()
+                size += 1
+
+            batch = states[:size]
+            p, v = self.server.model.predict_p_and_v(batch)
+
+            for i in range(size):
+                if ids[i] < len(self.server.agents):
+                    self.server.agents[ids[i]].wait_q.put((p[i], v[i]))

examples/GA3C/ThreadTrainer.py

+# --------------------------------------------------------
+# GA3C for Dragon
+# Copyright(c) 2017 SeetaTech
+# Written by Ting Pan
+# --------------------------------------------------------
+
+from threading import Thread
+import numpy as np
+
+from Config import Config
+
+
+class ThreadTrainer(Thread):
+    def __init__(self, server, id):
+        super(ThreadTrainer, self).__init__()
+        self.setDaemon(True)
+
+        self.id = id
+        self.server = server
+        self.exit_flag = False
+
+    def run(self):
+        while not self.exit_flag:
+            batch_size = 0
+            while batch_size <= Config.TRAINING_MIN_BATCH_SIZE:
+                x_, r_, a_ = self.server.training_q.get()
+                if batch_size == 0:
+                    x__ = x_
+                    r__ = r_
+                    a__ = a_
+                else:
+                    x__ = np.concatenate((x__, x_))
+                    r__ = np.concatenate((r__, r_))
+                    a__ = np.concatenate((a__, a_))
+                batch_size += x_.shape[0]
+
+            if Config.TRAIN_MODELS:
+                self.server.train_model(x__, r__, a__)
\ No newline at end of file

examples/README.md

@@ -8,4 +8,6 @@ which was described in our arXiv paper: [Dragon: A Computation Graph Virtual Mac
 
 
 ## <a name="list-of-examples"></a>List of examples
 ## <a name="list-of-examples"></a>List of examples
 
 
-* [cifar10](https://github.com/neopenx/Dragon/tree/master/examples/cifar10) - How to train/infer a basic classification network [**Caffe1** Style]
+* [cifar10](https://github.com/neopenx/Dragon/tree/master/examples/cifar10) - How to train/infer a basic classification network [*Caffe1 Style*]
+
+* [GA3C](https://github.com/neopenx/Dragon/tree/master/examples/GA3C) -  A hybrid CPU/GPU version of the A3C algorithm [*TinyDragon Style*]