|
|
@@ -10,12 +10,11 @@ import motion_model
|
|
|
|
|
|
import numpy as np
|
|
|
|
|
|
-
|
|
|
class SARSA:
|
|
|
def __init__(self, x_start, x_goal):
|
|
|
self.xI, self.xG = x_start, x_goal
|
|
|
- self.M = 500 # iteration numbers
|
|
|
- self.gamma = 0.9 # discount factor
|
|
|
+ self.M = 500 # iteration numbers
|
|
|
+ self.gamma = 0.9 # discount factor
|
|
|
self.alpha = 0.5
|
|
|
self.epsilon = 0.1
|
|
|
|
|
|
@@ -23,18 +22,17 @@ class SARSA:
|
|
|
self.motion = motion_model.Motion_model(self.xI, self.xG)
|
|
|
self.plotting = plotting.Plotting(self.xI, self.xG)
|
|
|
|
|
|
- self.u_set = self.env.motions # feasible input set
|
|
|
- self.stateSpace = self.env.stateSpace # state space
|
|
|
- self.obs = self.env.obs_map() # position of obstacles
|
|
|
- self.lose = self.env.lose_map() # position of lose states
|
|
|
+ self.u_set = self.env.motions # feasible input set
|
|
|
+ self.stateSpace = self.env.stateSpace # state space
|
|
|
+ self.obs = self.env.obs_map() # position of obstacles
|
|
|
+ self.lose = self.env.lose_map() # position of lose states
|
|
|
|
|
|
- self.name1 = "SARSA, M=" + str(self.M)
|
|
|
+ self.name1 = "Q-learning, M=" + str(self.M)
|
|
|
|
|
|
[self.value, self.policy] = self.Monte_Carlo(self.xI, self.xG)
|
|
|
self.path = self.extract_path(self.xI, self.xG, self.policy)
|
|
|
self.plotting.animation(self.path, self.name1)
|
|
|
|
|
|
-
|
|
|
def Monte_Carlo(self, xI, xG):
|
|
|
"""
|
|
|
Monte_Carlo experiments
|
|
|
@@ -48,9 +46,9 @@ class SARSA:
|
|
|
for k in range(self.M): # iterations
|
|
|
x = self.state_init() # initial state
|
|
|
u = self.epsilon_greedy(int(np.argmax(Q_table[x])), self.epsilon)
|
|
|
- while x != xG: # stop condition
|
|
|
+ while x != xG: # stop condition
|
|
|
x_next = self.move_next(x, self.u_set[u]) # next state
|
|
|
- reward = self.env.get_reward(x_next) # reward observed
|
|
|
+ reward = self.env.get_reward(x_next) # reward observed
|
|
|
u_next = self.epsilon_greedy(int(np.argmax(Q_table[x_next])), self.epsilon)
|
|
|
Q_table[x][u] = (1 - self.alpha) * Q_table[x][u] + \
|
|
|
self.alpha * (reward + self.gamma * Q_table[x_next][u_next])
|
|
|
@@ -61,7 +59,6 @@ class SARSA:
|
|
|
|
|
|
return Q_table, policy
|
|
|
|
|
|
-
|
|
|
def table_init(self):
|
|
|
"""
|
|
|
Initialize Q_table: Q(s, a)
|
|
|
@@ -81,7 +78,6 @@ class SARSA:
|
|
|
Q_table[x] = u
|
|
|
return Q_table
|
|
|
|
|
|
-
|
|
|
def state_init(self):
|
|
|
"""
|
|
|
initialize a starting state
|
|
|
@@ -93,7 +89,6 @@ class SARSA:
|
|
|
if (i, j) not in self.obs:
|
|
|
return (i, j)
|
|
|
|
|
|
-
|
|
|
def epsilon_greedy(self, u, error):
|
|
|
"""
|
|
|
generate a policy using epsilon_greedy algorithm
|
|
|
@@ -114,7 +109,6 @@ class SARSA:
|
|
|
return u_e
|
|
|
return u
|
|
|
|
|
|
-
|
|
|
def move_next(self, x, u):
|
|
|
"""
|
|
|
get next state.
|
|
|
@@ -140,12 +134,12 @@ class SARSA:
|
|
|
"""
|
|
|
|
|
|
x, path = xI, [xI]
|
|
|
- while x not in xG:
|
|
|
+ while x != xG:
|
|
|
u = self.u_set[policy[x]]
|
|
|
x_next = (x[0] + u[0], x[1] + u[1])
|
|
|
if x_next in self.obs:
|
|
|
print("Collision! Please run again!")
|
|
|
- break
|
|
|
+ return path
|
|
|
else:
|
|
|
path.append(x_next)
|
|
|
x = x_next
|