update projects

projects/codes/envs/stochastic_mdp.py

@@ -0,0 +1,53 @@
+#!/usr/bin/env python
+# coding=utf-8
+'''
+Author: John
+Email: johnjim0816@gmail.com
+Date: 2021-03-24 22:12:19
+LastEditor: John
+LastEditTime: 2021-03-26 17:12:43
+Discription: 
+Environment: 
+'''
+import numpy as np
+import random
+
+
+class StochasticMDP:
+    def __init__(self):
+        self.end = False
+        self.curr_state = 2
+        self.n_actions = 2
+        self.n_states = 6
+        self.p_right = 0.5
+
+    def reset(self):
+        self.end = False
+        self.curr_state = 2
+        state = np.zeros(self.n_states)
+        state[self.curr_state - 1] = 1.
+        return state
+
+    def step(self, action):
+        if self.curr_state != 1:
+            if action == 1:
+                if random.random() < self.p_right and self.curr_state < self.n_states:
+                    self.curr_state += 1
+                else:
+                    self.curr_state -= 1
+
+            if action == 0:
+                self.curr_state -= 1
+        if self.curr_state == self.n_states:
+            self.end = True
+
+        state = np.zeros(self.n_states)
+        state[self.curr_state - 1] = 1.
+
+        if self.curr_state == 1:
+            if self.end:
+                return state, 1.00, True, {}
+            else:
+                return state, 1.00/100.00, True, {}
+        else:
+            return state, 0.0, False, {}