62 lines
2.5 KiB
Python
62 lines
2.5 KiB
Python
import tensorflow as tf
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def ppo_clip(policy, clip_param):
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"""
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the clip loss in ppo paper
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:param sampled_action: placeholder of sampled actions during interaction with the environment
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:param advantage: placeholder of estimated advantage values.
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:param clip param: float or Tensor of type float.
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:param policy: current `policy` to be optimized
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:param pi_old: old `policy` for computing the ppo loss as in Eqn. (7) in the paper
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"""
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action_ph = tf.placeholder(policy.act_dtype, shape=(None,) + policy.action_shape, name='ppo_clip_loss/action_placeholder')
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advantage_ph = tf.placeholder(tf.float32, shape=(None,), name='ppo_clip_loss/advantage_placeholder')
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policy.managed_placeholders['action'] = action_ph
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policy.managed_placeholders['processed_reward'] = advantage_ph
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log_pi_act = policy.log_prob(action_ph)
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log_pi_old_act = policy.log_prob_old(action_ph)
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ratio = tf.exp(log_pi_act - log_pi_old_act)
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clipped_ratio = tf.clip_by_value(ratio, 1. - clip_param, 1. + clip_param)
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ppo_clip_loss = -tf.reduce_mean(tf.minimum(ratio * advantage_ph, clipped_ratio * advantage_ph))
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return ppo_clip_loss
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def vanilla_policy_gradient(sampled_action, reward, pi, baseline="None"):
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"""
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vanilla policy gradient
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:param sampled_action: placeholder of sampled actions during interaction with the environment
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:param reward: placeholder of reward the 'sampled_action' get
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:param pi: current `policy` to be optimized
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:param baseline: the baseline method used to reduce the variance, default is 'None'
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:return:
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"""
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log_pi_act = pi.log_prob(sampled_action)
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vanilla_policy_gradient_loss = tf.reduce_mean(reward * log_pi_act)
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# TODO: Different baseline methods like REINFORCE, etc.
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return vanilla_policy_gradient_loss
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def dqn_loss(sampled_action, sampled_target, policy):
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"""
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deep q-network
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:param sampled_action: placeholder of sampled actions during the interaction with the environment
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:param sampled_target: estimated Q(s,a)
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:param policy: current `policy` to be optimized
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:return:
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"""
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sampled_q = policy.q_net.value_tensor
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return tf.reduce_mean(tf.square(sampled_target - sampled_q))
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def deterministic_policy_gradient(sampled_state, critic):
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"""
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deterministic policy gradient:
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:param sampled_action: placeholder of sampled actions during the interaction with the environment
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:param critic: current `value` function
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:return:
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"""
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return tf.reduce_mean(critic.get_value(sampled_state)) |