epsilonGreedy.cpp

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#include "epsilonGreedy.h"

#include <iostream>

using namespace Mdp;

EpsilonGreedy::EpsilonGreedy(double e, double eDecaySpeed, long long unsigned int eTimeout)
    : epsilon(e)
    , epsilonDecaySpeed(eDecaySpeed)
    , epsilonTimeout(eTimeout)
{
}


std::vector<double> EpsilonGreedy::generatePolicy(const std::vector<double>& actionValues, action_t bestAction)
{
    static size_t nbActions = actionValues.size();
    static std::vector<double> policy(nbActions);
    static const size_t nbActionsMinusOne = nbActions - 1;
    const double bestActionProba = 1.0 - epsilon;
    const double otherActionProba = epsilon / (double) nbActionsMinusOne;
    for (action_t i = 0; i < nbActions; i++)
    {
        policy[i] = ((i == bestAction) ? bestActionProba : otherActionProba);
    }
    updateEpsilon();
    return policy;
}

void EpsilonGreedy::updateEpsilon()
{
    static long long unsigned int counter = 0;
    epsilon *= epsilonDecaySpeed;
    if (epsilonTimeout && (counter ++> epsilonTimeout))//if epsilonTimeOut is set to 0, there's no timeout
    {
        epsilon = 0.0;
        epsilonTimeout = 0; //this improves performance somewhat
    }
}