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getLearnableParameters

Obtain learnable parameter values from actor or critic function object

Description

example

val = getLearnableParameters(fcn) returns the values of the learnable parameters from the reinforcement learning actor or critic function object fcn.

Examples

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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 function approximator from the agent.

critic = getCritic(agent);

Obtain the learnable parameters from the critic.

params = getLearnableParameters(critic)
params=2×1 cell array
    {[-5.0077 -1.5619 -0.3475 -0.0961 -0.0455 -0.0026]}
    {[                                              0]}

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.

setCritic(agent,critic);

Display the new parameter values.

getLearnableParameters(getCritic(agent))
ans=2×1 cell array
    {[-10.0154 -3.1238 -0.6950 -0.1922 -0.0911 -0.0052]}
    {[                                               0]}

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 actor function approximator from the agent.

actor = getActor(agent);

Obtain the learnable parameters from the actor.

params = getLearnableParameters(actor)
params=2×1 cell array
    {[-15.4689 -7.1635]}
    {[               0]}

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 actor to the new modified values.

actor = setLearnableParameters(actor,modifiedParams);

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

setActor(agent,actor);

Display the new parameter values.

getLearnableParameters(getActor(agent))
ans=2×1 cell array
    {[-30.9378 -14.3269]}
    {[                0]}

Input Arguments

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Actor or critic function object, specified as one of the following:

To create an actor or critic function object, use one of the following methods.

  • Create a function object directly.

  • Obtain the existing critic from an agent using getCritic.

  • Obtain the existing actor from an agent using getActor.

Output Arguments

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Learnable parameter values for the function object, returned as a cell array. You can modify these parameter values and set them in the original agent or a different agent using the setLearnableParameters function.

Version History

Introduced in R2019a

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Behavior changed in R2022a

Behavior changed in R2020a