109 lines
3.3 KiB
Python
109 lines
3.3 KiB
Python
import gym
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import tensorflow as tf
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from tensorflow.keras import models, layers
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import numpy as np
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env = gym.make("CartPole-v0")
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env._max_episode_steps=500
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nbr_action=2
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gamma=tf.constant(0.98)
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epoch=20000
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best_score=0
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epsilon=1.
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epsilon_min=0.10
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start_epsilon=1
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end_epsilon=epoch//2
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epsilon_decay_value=epsilon/(end_epsilon-start_epsilon)
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def model():
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entree=layers.Input(shape=(4), dtype='float32')
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result=layers.Dense(30, activation='relu')(entree)
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result=layers.Dense(30, activation='relu')(result)
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sortie=layers.Dense(nbr_action)(result)
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model=models.Model(inputs=entree, outputs=sortie)
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return model
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def my_loss(target_q, predicted_q):
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loss=tf.reduce_mean(tf.math.square(target_q-predicted_q))
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return loss
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@tf.function
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def train_step(reward, action, observation, next_observation, done):
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next_Q_values=model(next_observation)
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best_next_actions=tf.math.argmax(next_Q_values, axis=1)
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next_mask=tf.one_hot(best_next_actions, nbr_action)
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next_best_Q_values=tf.reduce_sum(next_Q_values*next_mask, axis=1)
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target_Q_values=reward+(1-done)*gamma*next_best_Q_values
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target_Q_values=tf.reshape(target_Q_values, (-1, 1))
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mask=tf.one_hot(action, nbr_action)
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with tf.GradientTape() as tape:
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all_Q_values=model(observation)
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Q_values=tf.reduce_sum(all_Q_values*mask, axis=1, keepdims=True)
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loss=my_loss(target_Q_values, Q_values)
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gradients=tape.gradient(loss, model.trainable_variables)
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optimizer.apply_gradients(zip(gradients, model.trainable_variables))
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train_loss(loss)
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def train(debug=False):
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global epsilon, best_score, tab_score
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for e in range(epoch):
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print("EPOCH:", e, "epsilon", epsilon)
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score=0
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tab_observations=[]
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tab_rewards=[]
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tab_actions=[]
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tab_next_observations=[]
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tab_done=[]
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observations=env.reset()
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while True:
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tab_observations.append(observations)
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if np.random.random()>epsilon:
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valeurs_q=model(np.expand_dims(observations, axis=0))
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action=int(tf.argmax(valeurs_q[0], axis=-1))
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else:
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action=np.random.randint(0, nbr_action)
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observations, reward, done, info=env.step(action)
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tab_actions.append(action)
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tab_next_observations.append(observations)
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tab_done.append(done)
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if done:
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tab_rewards.append(-10.)
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print("FIN, score:", score)
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tab_score.append(score)
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score=0
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break
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score+=1
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tab_rewards.append(reward)
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tab_rewards=np.array(tab_rewards, dtype=np.float32)
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tab_actions=np.array(tab_actions, dtype=np.int32)
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tab_observations=np.array(tab_observations, dtype=np.float32)
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tab_next_observations=np.array(tab_next_observations, dtype=np.float32)
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tab_done=np.array(tab_done, dtype=np.float32)
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train_step(tab_rewards, tab_actions, tab_observations, tab_next_observations, tab_done)
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train_loss.reset_states()
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epsilon-=epsilon_decay_value
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epsilon=max(epsilon, epsilon_min)
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if np.mean(tab_score[-20:])>best_score:
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print("Sauvegarde du modele")
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model.save("my_model")
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best_score=np.mean(tab_score[-20:])
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if best_score==env._max_episode_steps-1:
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return
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model=model()
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optimizer=tf.keras.optimizers.Adam(learning_rate=1E-4)
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train_loss=tf.keras.metrics.Mean()
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tab_s=[]
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tab_score=[]
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train()
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np.save("tab_score", tab_score)
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