Method selectNewAction

native/agent/ModelReusableAgent.cpp:248–285

    ActionPtr ModelReusableAgent::selectNewAction() {
        ActionPtr action = nullptr;
        action = this->selectUnperformedActionNotInReuseModel();
        if (nullptr != action) {
            BLOG("%s", "select action not in reuse model");
            return action;
        }

        action = this->selectUnperformedActionInReuseModel();
        if (nullptr != action) {
            BLOG("%s", "select action in reuse model");
            return action;
        }

        action = this->_newState->randomPickUnvisitedAction();
        if (nullptr != action) {
            BLOG("%s", "select action in unvisited action");
            return action;
        }

        // if all the actions are explored, use those two methods to generate new action based on q value.
        // there are two methods to choose from.
        // based on q value and a uniform distribution, select an action with the highest value.
        action = this->selectActionByQValue();
        if (nullptr != action) {
            BLOG("%s", "select action by qvalue");
            return action;
        }

        // use the traditional epsilon greedy strategy to choose the next action.
        action = this->selectNewActionEpsilonGreedyRandomly();
        if (nullptr != action) {
            BLOG("%s", "select action by EpsilonGreedyRandom");
            return action;
        }
        BLOGE("null action happened , handle null action");
        return handleNullAction();
    }

    /// Randomly choose an action that is not been visited before, which belongs to the following type:
    ///        BACK,