getCritic

Get critic representation from reinforcement learning agent

Syntax

critic = getCritic(agent)

Description

critic = getCritic(agent) returns the critic representation object for the specified reinforcement learning agent.

Examples

Modify Critic Parameter Values

Assume that you have an existing trained reinforcement learning agent. For this example, load the trained agent from Train DDPG Agent to Control Double Integrator System.

load('DoubleIntegDDPG.mat','agent') 

Obtain the critic representation from the agent.

critic = getCritic(agent);

Obtain the learnable parameters from the critic.

params = getLearnableParameters(critic);

Modify the parameter values. For this example, simply multiply all of the parameters by 2.

modifiedParams = cellfun(@(x) x*2,params,'UniformOutput',false);

Set the parameter values of the critic to the new modified values.

critic = setLearnableParameters(critic,modifiedParams);

Set the critic in the agent to the new modified critic.

agent = setCritic(agent,critic);

Input Arguments

agent — Reinforcement learning agent

rlQAgent object | rlSARSAAgent object | rlDQNAgent object | rlDDPGAgent object | rlTD3Agent object | rlPGAgent object | rlACAgent object | rlPPOAgent object

Reinforcement learning agent that contains a critic representation, specified as one of the following:

• rlQAgent object

• rlSARSAAgent object

• rlDQNAgent object

• rlDDPGAgent object

• rlTD3Agent object

• rlACAgent object

• rlPPOAgent object

• rlPGAgent object that estimates a baseline value function using a critic

Output Arguments

critic — Critic representation

rlValueRepresentation object | rlQValueRepresentation object | two-element row vector of rlQValueRepresentation objects

Critic representation object, returned as one of the following:

• rlValueRepresentation object — Returned when agent is an rlACAgent, rlPGAgent, or rlPPOAgent object

• rlQValueRepresentation object — Returned when agent is an rlQAgent, rlSARSAAgent, rlDQNAgent, rlDDPGAgent, or rlTD3Agent object with a single critic

• Two-element row vector of rlQValueRepresentation objects — Returned when agent is an rlTD3Agent object with two critics