Let's discuss now how to optimize a policy. In policy methods, our main objective is that a given policy 
with parameter vector 
finds the best values of the parameter vector. In order to measure which is the best, we measure 
the quality of the policy 
for different values of the parameter vector 
.
Before discussing the optimization methods, let's first figure out the different ways to measure the quality of a policy 
:
- If it's an episodic environment,
can be the value function of the start state 
that is if it starts from any state 
, then the value function of it would be the expected sum of reward from that state onwards. Therefore,
- If it's a continuing environment,
can be the average value function of the states. So, if the environment goes on and...
