|
| 1 | +import random |
| 2 | +import numpy as np |
| 3 | +from collections import deque |
| 4 | + |
| 5 | + |
| 6 | +class DQNAgent: |
| 7 | + def __init__(self, state_size, action_size,hiddenLayers,act): |
| 8 | + |
| 9 | + self.load_model = True |
| 10 | + |
| 11 | + # get size of state and action |
| 12 | + self.state_size = state_size |
| 13 | + self.action_size = action_size |
| 14 | + |
| 15 | + # These are hyper parameters for the DQN |
| 16 | + self.hiddenLayers = hiddenLayers |
| 17 | + self.activationType = act |
| 18 | + self.discount_factor = 0.99 |
| 19 | + self.learning_rate = 0.001 |
| 20 | + self.epsilon = 1.0 |
| 21 | + self.epsilon_decay = 0.9992 |
| 22 | + self.epsilon_min = 0.01 |
| 23 | + self.batch_size = 32 |
| 24 | + self.train_start = 1000 |
| 25 | + # create replay memory using deque |
| 26 | + self.memory = deque(maxlen=2000) |
| 27 | + |
| 28 | + # create main model and target model |
| 29 | + self.model = self.build_model() |
| 30 | + self.target_model = self.build_model() |
| 31 | + |
| 32 | + # initialize target model |
| 33 | + self.update_target_model() |
| 34 | + |
| 35 | + if self.load_model: |
| 36 | + self.model.load_weights("./save_model/ep"+str(file_count)+".h5") |
| 37 | + |
| 38 | + # approximate Q function using Neural Network |
| 39 | + # state is input and Q Value of each action is output of network |
| 40 | +l |
| 41 | + |
| 42 | + def build_model(self, hiddenLayers, activationType): |
| 43 | + model = Sequential() |
| 44 | + if len(hiddenLayers) == 0: |
| 45 | + model.add(Dense(self.action_size, input_dim=self.state_size) ) # model.add(Dense(self.output_size, input_shape=(self.state_size,)) ) # |
| 46 | + model.add(Activation("linear")) |
| 47 | + else : |
| 48 | + model.add(Dense(hiddenLayers[0], input_dim = self.state_size) ) |
| 49 | + |
| 50 | + for index in range(1, len(hiddenLayers)): |
| 51 | + |
| 52 | + layerSize = hiddenLayers[index] |
| 53 | + model.add(Dense(layerSize)) |
| 54 | + model.add(Activation(self.activationType)) |
| 55 | + |
| 56 | + model.add(Dense(self.action_size)) |
| 57 | + model.add(Activation("linear")) |
| 58 | + |
| 59 | + # optimizer = optimizers.RMSprop(lr=self.learningRate, rho=0.9, epsilon=1e-06) |
| 60 | + optimizer = optimizers.SGD(lr=self.learning_rate, clipnorm=1.) |
| 61 | + # optimizer = optimizers.Adam(lr=self.learning_rate) |
| 62 | + |
| 63 | + model.summary() |
| 64 | + |
| 65 | + model.compile(loss="mse", optimizer=optimizer) |
| 66 | + |
| 67 | + |
| 68 | + # after some time interval update the target model to be same with model |
| 69 | + def update_target_model(self): |
| 70 | + self.target_model.set_weights(self.model.get_weights()) |
| 71 | + |
| 72 | + # get action from model using epsilon-greedy policy |
| 73 | + def get_action(self, state): |
| 74 | + if np.random.rand() <= self.epsilon: |
| 75 | + return random.randrange(self.action_size) |
| 76 | + else: |
| 77 | + q_value = self.model.predict(state) |
| 78 | + return np.argmax(q_value[0]) |
| 79 | + |
| 80 | + # save sample <s,a,r,s'> to the replay memory |
| 81 | + def append_sample(self, state, action, reward, next_state, done): |
| 82 | + self.memory.append((state, action, reward, next_state, done)) |
| 83 | + if self.epsilon > self.epsilon_min: |
| 84 | + self.epsilon *= self.epsilon_decay |
| 85 | + |
| 86 | + # pick samples randomly from replay memory (with batch_size) |
| 87 | + def train_model(self): |
| 88 | + if len(self.memory) < self.train_start: |
| 89 | + return |
| 90 | + batch_size = min(self.batch_size, len(self.memory)) |
| 91 | + mini_batch = random.sample(self.memory, batch_size) |
| 92 | + |
| 93 | + update_input = np.zeros((batch_size, self.state_size)) |
| 94 | + update_target = np.zeros((batch_size, self.state_size)) |
| 95 | + action, reward, done = [], [], [] |
| 96 | + |
| 97 | + for i in range(self.batch_size): |
| 98 | + update_input[i] = mini_batch[i][0] |
| 99 | + action.append(mini_batch[i][1]) |
| 100 | + reward.append(mini_batch[i][2]) |
| 101 | + update_target[i] = mini_batch[i][3] |
| 102 | + done.append(mini_batch[i][4]) |
| 103 | + |
| 104 | + target = self.model.predict(update_input) |
| 105 | + target_val = self.target_model.predict(update_target) |
| 106 | + |
| 107 | + for i in range(self.batch_size): |
| 108 | + # Q Learning: get maximum Q value at s' from target model |
| 109 | + if done[i]: |
| 110 | + target[i][action[i]] = reward[i] |
| 111 | + else: |
| 112 | + target[i][action[i]] = reward[i] + self.discount_factor * ( |
| 113 | + np.amax(target_val[i])) |
| 114 | + |
| 115 | + # and do the model fit! |
| 116 | + self.model.fit(update_input, target, batch_size=self.batch_size, |
| 117 | + epochs=1, verbose=0) |
| 118 | + |
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