Tested with TF 2.3.1

Tested with TF 2.3.1

07_Pong-reinforcement-learning_DQN_CNN/Pong-v0_DQN_CNN_TF2.py

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+# Tutorial by www.pylessons.com
+# Tutorial written for - Tensorflow 2.3.1
+
+import os
+#os.environ['TF_CPP_MIN_LOG_LEVEL'] = '2'
+os.environ['CUDA_VISIBLE_DEVICES'] = '0'
+import random
+import gym
+import pylab
+import numpy as np
+from collections import deque
+from tensorflow.keras.models import Model, load_model
+from tensorflow.keras.layers import Input, Dense, Lambda, Add, Conv2D, Flatten
+from tensorflow.keras.optimizers import Adam, RMSprop
+from tensorflow.keras import backend as K
+from PER import *
+import cv2
+
+def OurModel(input_shape, action_space, dueling):
+    X_input = Input(input_shape)
+    X = X_input
+
+    #X = Conv2D(64, 5, strides=(3, 3),padding="valid", input_shape=input_shape, activation="relu", data_format="channels_first")(X)
+    X = Conv2D(32, 8, strides=(4, 4),padding="valid", input_shape=input_shape, activation="relu", data_format="channels_first")(X)
+    X = Conv2D(64, 4, strides=(2, 2),padding="valid", activation="relu", data_format="channels_first")(X)
+    X = Conv2D(64, 3, strides=(1, 1),padding="valid", activation="relu", data_format="channels_first")(X)
+    X = Flatten()(X)
+
+    # 'Dense' is the basic form of a neural network layer
+    X = Dense(512, activation="relu", kernel_initializer='he_uniform')(X)
+
+    X = Dense(256, activation="relu", kernel_initializer='he_uniform')(X)
+
+    X = Dense(64, activation="relu", kernel_initializer='he_uniform')(X)
+
+    if dueling:
+        state_value = Dense(1, kernel_initializer='he_uniform')(X)
+        state_value = Lambda(lambda s: K.expand_dims(s[:, 0], -1), output_shape=(action_space,))(state_value)
+
+        action_advantage = Dense(action_space, kernel_initializer='he_uniform')(X)
+        action_advantage = Lambda(lambda a: a[:, :] - K.mean(a[:, :], keepdims=True), output_shape=(action_space,))(action_advantage)
+
+        X = Add()([state_value, action_advantage])
+    else:
+        # Output Layer with # of actions: 2 nodes (left, right)
+        X = Dense(action_space, activation="linear", kernel_initializer='he_uniform')(X)
+
+    model = Model(inputs = X_input, outputs = X)
+    #model.compile(loss="mean_squared_error", optimizer=RMSprop(lr=0.00025, rho=0.95, epsilon=0.01), metrics=["accuracy"])
+    #model.compile(optimizer=Adam(lr=0.00025), loss='mean_squared_error')
+    model.compile(optimizer=Adam(lr=0.00005), loss='mean_squared_error')
+
+    model.summary()
+    return model
+
+class DQNAgent:
+    def __init__(self, env_name):
+        self.env_name = env_name       
+        self.env = gym.make(env_name)
+        #self.env.seed(0)  
+        self.action_size = self.env.action_space.n
+        self.EPISODES = 1000
+
+        # Instantiate memory
+        memory_size = 25000
+        self.MEMORY = Memory(memory_size)
+        self.memory = deque(maxlen=memory_size)
+
+        self.gamma = 0.99    # discount rate
+
+        # EXPLORATION HYPERPARAMETERS for epsilon and epsilon greedy strategy
+        self.epsilon = 1.0  # exploration probability at start
+        self.epsilon_min = 0.02  # minimum exploration probability 
+        self.epsilon_decay = 0.00002  # exponential decay rate for exploration prob
+
+        self.batch_size = 32
+
+        # defining model parameters
+        self.ddqn = True # use doudle deep q network
+        self.dueling = True # use dealing netowrk
+        self.epsilon_greedy = False # use epsilon greedy strategy
+        self.USE_PER = True # use priority experienced replay
+
+
+        self.Save_Path = 'Models'
+        if not os.path.exists(self.Save_Path): os.makedirs(self.Save_Path)
+        self.scores, self.episodes, self.average = [], [], []
+
+        self.Model_name = os.path.join(self.Save_Path, self.env_name+"_CNN.h5")
+
+        self.ROWS = 80
+        self.COLS = 80
+        self.REM_STEP = 4
+        self.update_model_steps = 1000
+
+        self.state_size = (self.REM_STEP, self.ROWS, self.COLS)
+        self.image_memory = np.zeros(self.state_size)
+
+        # create main model and target model
+        self.model = OurModel(input_shape=self.state_size, action_space = self.action_size, dueling = self.dueling)
+        self.target_model = OurModel(input_shape=self.state_size, action_space = self.action_size, dueling = self.dueling)  
+
+    # after some time interval update the target model to be same with model
+    def update_target_model(self, game_steps):
+        if game_steps % self.update_model_steps == 0:
+            self.target_model.set_weights(self.model.get_weights())
+            return
+
+    def remember(self, state, action, reward, next_state, done):
+        experience = state, action, reward, next_state, done
+        if self.USE_PER:
+            self.MEMORY.store(experience)
+        else:
+            self.memory.append((experience))
+
+    def act(self, state, decay_step):
+        # EPSILON GREEDY STRATEGY
+        if self.epsilon_greedy:
+        # Here we'll use an improved version of our epsilon greedy strategy for Q-learning
+            explore_probability = self.epsilon_min + (self.epsilon - self.epsilon_min) * np.exp(-self.epsilon_decay * decay_step)
+        # OLD EPSILON STRATEGY
+        else:
+            if self.epsilon > self.epsilon_min:
+                self.epsilon *= (1-self.epsilon_decay)
+            explore_probability = self.epsilon
+
+        if explore_probability > np.random.rand():
+            # Make a random action (exploration)
+            return random.randrange(self.action_size), explore_probability
+        else:
+            # Get action from Q-network (exploitation)
+            # Estimate the Qs values state
+            # Take the biggest Q value (= the best action)
+            return np.argmax(self.model.predict(state)), explore_probability
+
+    def replay(self):
+        if self.USE_PER:
+            # Sample minibatch from the PER memory
+            tree_idx, minibatch  = self.MEMORY.sample(self.batch_size)
+        else:
+            if len(self.memory) > self.batch_size:
+            # Randomly sample minibatch from the deque memory
+                minibatch = random.sample(self.memory, self.batch_size)
+            else:
+                return
+
+        state = np.zeros((self.batch_size, *self.state_size), dtype=np.float32)
+        action = np.zeros(self.batch_size, dtype=np.int32)
+        reward = np.zeros(self.batch_size, dtype=np.float32)
+        next_state = np.zeros((self.batch_size, *self.state_size), dtype=np.float32)
+        done = np.zeros(self.batch_size, dtype=np.uint8)
+
+        # do this before prediction
+        # for speedup, this could be done on the tensor level
+        # but easier to understand using a loop       
+        for i in range(len(minibatch)):
+            state[i], action[i], reward[i], next_state[i], done[i] = minibatch[i]
+
+        # do batch prediction to save speed
+        # predict Q-values for starting state using the main network
+        target = self.model.predict(state)
+        target_old = np.array(target)
+        # predict best action in ending state using the main network
+        target_next = self.model.predict(next_state)
+        # predict Q-values for ending state using the target network
+        target_val = self.target_model.predict(next_state)
+
+
+        for i in range(len(minibatch)):
+            # correction on the Q value for the action used
+            if done[i]:
+                target[i][action[i]] = reward[i]
+            else:
+                # the key point of Double DQN
+                # selection of action is from model
+                # update is from target model
+                if self.ddqn: # Double - DQN
+                    # current Q Network selects the action
+                    # a'_max = argmax_a' Q(s', a')
+                    a = np.argmax(target_next[i])
+                    # target Q Network evaluates the action
+                    # Q_max = Q_target(s', a'_max)
+                    target[i][action[i]] = reward[i] + self.gamma * target_val[i][a]
+                else: # Standard - DQN
+                    # DQN chooses the max Q value among next actions
+                    # selection and evaluation of action is on the target Q Network
+                    # Q_max = max_a' Q_target(s', a')
+                    # when using target model in simple DQN rules, we get better performance
+                    target[i][action[i]] = reward[i] + self.gamma * np.amax(target_val[i])
+
+        if self.USE_PER:
+            indices = np.arange(self.batch_size, dtype=np.int32)
+            absolute_errors = np.abs(target_old[indices, action]-target[indices, action])
+
+            # Update priority
+            self.MEMORY.batch_update(tree_idx, absolute_errors)
+
+        # Train the Neural Network with batches
+        self.model.fit(state, target, batch_size=self.batch_size, verbose=0)
+
+    def load(self, name):
+        self.model = load_model(name)
+
+    def save(self, name):
+        self.model.save(name)
+
+    pylab.figure(figsize=(18, 9))
+    def PlotModel(self, score, episode):
+        self.scores.append(score)
+        self.episodes.append(episode)
+        self.average.append(sum(self.scores[-50:]) / len(self.scores[-50:]))
+        pylab.plot(self.episodes, self.average, 'r')
+        pylab.plot(self.episodes, self.scores, 'b')
+        pylab.ylabel('Score', fontsize=18)
+        pylab.xlabel('Games', fontsize=18)
+        dqn = '_DQN'
+        dueling = ''
+        greedy = ''
+        PER = ''
+        if self.ddqn: dqn = '_DDQN'
+        if self.dueling: dueling = '_Dueling'
+        if self.epsilon_greedy: greedy = '_Greedy'
+        if self.USE_PER: PER = '_PER'
+        try:
+            pylab.savefig(self.env_name+dqn+dueling+greedy+PER+"_CNN.png")
+        except OSError:
+            pass
+        # no need to worry about model, when doing a lot of experiments
+        self.Model_name = os.path.join(self.Save_Path, self.env_name+dqn+dueling+greedy+PER+"_CNN.h5")
+
+        return self.average[-1]
+
+    def imshow(self, image, rem_step=0):
+        cv2.imshow("cartpole"+str(rem_step), image[rem_step,...])
+        if cv2.waitKey(25) & 0xFF == ord("q"):
+            cv2.destroyAllWindows()
+            return
+
+    def GetImage(self, frame):
+        self.env.render()
+
+        # croping frame to 80x80 size
+        frame_cropped = frame[35:195:2, ::2,:]
+        if frame_cropped.shape[0] != self.COLS or frame_cropped.shape[1] != self.ROWS:
+            # OpenCV resize function 
+            frame_cropped = cv2.resize(frame, (self.COLS, self.ROWS), interpolation=cv2.INTER_CUBIC)
+
+        # converting to RGB (numpy way)
+        frame_rgb = 0.299*frame_cropped[:,:,0] + 0.587*frame_cropped[:,:,1] + 0.114*frame_cropped[:,:,2]
+        # converting to RGB (OpenCV way)
+        #frame_rgb = cv2.cvtColor(frame_cropped, cv2.COLOR_RGB2GRAY)     
+
+        # dividing by 255 we expresses value to 0-1 representation
+        new_frame = np.array(frame_rgb).astype(np.float32) / 255.0
+
+        # push our data by 1 frame, similar as deq() function work
+        self.image_memory = np.roll(self.image_memory, 1, axis = 0)
+
+        # inserting new frame to free space
+        self.image_memory[0,:,:] = new_frame
+
+        # show image frame   
+        #self.imshow(self.image_memory,0)
+        #self.imshow(self.image_memory,1)
+        #self.imshow(self.image_memory,2)
+        #self.imshow(self.image_memory,3)
+
+        return np.expand_dims(self.image_memory, axis=0)
+
+    def reset(self):
+        frame = self.env.reset()
+        for i in range(self.REM_STEP):
+            state = self.GetImage(frame)
+        return state
+
+    def step(self,action):
+        next_state, reward, done, info = self.env.step(action)
+        next_state = self.GetImage(next_state)
+        return next_state, reward, done, info
+
+    def run(self):
+        decay_step = 0
+        max_average = -21.0
+        for e in range(self.EPISODES):
+            state = self.reset()
+            done = False
+            score = 0
+            SAVING = ''
+            while not done:
+                decay_step += 1
+                action, explore_probability = self.act(state, decay_step)
+                next_state, reward, done, _ = self.step(action)
+                self.remember(state, action, reward, next_state, done)
+                state = next_state
+                score += reward
+
+                if done:
+                    # every episode, plot the result
+                    average = self.PlotModel(score, e)
+
+                    # saving best models
+                    if average >= max_average:
+                        max_average = average
+                        self.save(self.Model_name)
+                        SAVING = "SAVING"
+                    else:
+                        SAVING = ""
+                    print("episode: {}/{}, score: {}, e: {:.2f}, average: {:.2f} {}".format(e, self.EPISODES, score, explore_probability, average, SAVING))
+
+                # update target model
+                self.update_target_model(decay_step)
+
+                # train model
+                self.replay()
+
+        # close environemnt when finish training
+        self.env.close()
+
+    def test(self, Model_name):
+        self.load(Model_name)
+        for e in range(self.EPISODES):
+            state = self.reset()
+            done = False
+            score = 0
+            while not done:
+                self.env.render()
+                action = np.argmax(self.model.predict(state))
+                state, reward, done, _ = self.step(action)
+                score += reward
+                if done:
+                    print("episode: {}/{}, score: {}".format(e, self.EPISODES, score))
+                    break
+        self.env.close()
+
+if __name__ == "__main__":
+    env_name = 'Pong-v0'
+    agent = DQNAgent(env_name)
+    agent.run()
+    #agent.test('Models/Pong-v0_DDQN_CNN.h5')