add some codes

codes/ddpg/env.py

@@ -0,0 +1,31 @@
+#!/usr/bin/env python
+# coding=utf-8
+'''
+@Author: John
+@Email: johnjim0816@gmail.com
+@Date: 2020-06-10 15:28:30
+@LastEditor: John
+@LastEditTime: 2020-06-12 22:49:18
+@Discription: 
+@Environment: python 3.7.7
+'''
+import gym
+import numpy as np
+
+class NormalizedActions(gym.ActionWrapper):
+
+    def action(self, action):
+        
+        low_bound   = self.action_space.low
+        upper_bound = self.action_space.high
+        action = low_bound + (action + 1.0) * 0.5 * (upper_bound - low_bound)
+        action = np.clip(action, low_bound, upper_bound)
+        
+        return action
+
+    def reverse_action(self, action):
+        low_bound   = self.action_space.low
+        upper_bound = self.action_space.high
+        action = 2 * (action - low_bound) / (upper_bound - low_bound) - 1
+        action = np.clip(action, low_bound, upper_bound)
+        return action