ann_policy.cpp

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// -*- Mode: c++ -*-
// copyright (c) 2004 by Christos Dimitrakakis <dimitrak@idiap.ch>
// $Id$
 
 
/***************************************************************************
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 ***************************************************************************/
 
#include <learning/ann_policy.h>
 
ANN_Policy::ANN_Policy (int n_states, int n_actions, int n_hidden, real alpha, real gamma, real lambda, bool eligibility, bool softmax, real randomness, real init_eval, bool separate_actions) : DiscretePolicy (n_states, n_actions, alpha, gamma, lambda, softmax, randomness, init_eval)
{
    this->separate_actions = separate_actions;
    this->eligibility = eligibility;
    if (eligibility) {
        message ("Using eligibility traces");
    }   
    if (separate_actions) {
        message ("Separate actions");
        J = NULL;
        Ja = new ANN* [n_actions];
        JQs = new real [n_actions];
        for (int i=0; i<n_actions; i++) {
            Ja[i] = NewANN (n_states, 1);
            if (n_hidden > 0) {
                ANN_AddHiddenLayer (Ja[i], n_hidden);
            }
            ANN_Init (Ja[i]);
            ANN_SetOutputsToLinear(Ja[i]);
            ANN_SetBatchMode(Ja[i], false);
            Ja[i]->eligibility_traces = eligibility;
            ANN_SetLambda(Ja[i],lambda*gamma);
            ANN_SetLearningRate (Ja[i], alpha);
        }
    } else {
        JQs = NULL;
        Ja = NULL;
        J = NewANN (n_states, n_actions);
        if (n_hidden > 0) {
            ANN_AddHiddenLayer (J, n_hidden);
        }
        ANN_Init (J);
        ANN_SetOutputsToLinear(J);
        ANN_SetBatchMode(J, false);
        J->eligibility_traces = eligibility;
        ANN_SetLambda(J,lambda*gamma);
        ANN_SetLearningRate (J, alpha);
    }
    ps = new real [n_states];
    delta_vector = new real [n_actions];
    J_ps_pa = 0.0;
}
 
ANN_Policy::~ANN_Policy()
{
    delete [] ps;
    delete [] delta_vector;
    if (separate_actions) {
        for (int i=0; i<n_actions; i++) {
            DeleteANN(Ja[i]);
        }
        delete [] Ja;
    } else {
        //ANN_ShowWeights(J);
        DeleteANN (J);
    }
}
 
int ANN_Policy::SelectAction (int s, real r, int forced_a)
{
    return DiscretePolicy::SelectAction(s, r, forced_a);
}
 
int ANN_Policy::SelectAction (real* s, real r, int forced_a)
{
    int a; // selected action
    int amax; //maximum evaluated action
    real* Q_s; // pointer to evaluations for state s
    if (confidence) {
        if (separate_actions) {
            for (int i=0; i<n_actions; i++) {
                ANN_StochasticInput (Ja[i], s);
                JQs[i] = ANN_GetOutput(Ja[i])[0];
            }
            Q_s = JQs;
        } else {
            ANN_StochasticInput (J, s);
            Q_s = ANN_GetOutput (J);
        }
    } else {
        if (separate_actions) {
            for (int i=0; i<n_actions; i++) {
                ANN_Input (Ja[i], s);
                JQs[i] = ANN_GetOutput(Ja[i])[0];
            }
            Q_s = JQs;
        } else {
            ANN_Input (J, s);
            Q_s = ANN_GetOutput (J);
        }
    }
    int argmax = argMax (Q_s);
 
    if (forced_learning) {
        a = forced_a;
    } else if (confidence) {
        a = argmax;
    } else if (smax) {
        a = softMax (Q_s);
        //printf ("Q[%d][%d]=%f\n", s, a, Q[s][a]);
    } else {
        a = eGreedy (Q_s);
    }
 
    if (a<0 || a>=n_actions) {
        fprintf (stderr, "Action %d out of bounds\n", a);
    }
 
    switch (learning_method) {
        
    case Sarsa: 
        amax = a;
        break;
    case QLearning:
        amax = argmax;
        break;
    default:
        amax = a;
        fprintf (stderr, "Unknown learning method\n");
    }
    if (pa>=0) { // do not update at start of episode
        real delta = r + gamma*Q_s[amax] - J_ps_pa;
        tdError = delta;
        for (int j=0; j<n_actions; j++) {
            delta_vector[j] = 0.0;
        }
        if (separate_actions) {
            if (eligibility) {
                delta_vector[0] = 1.0;
                ANN_Delta_Train (Ja[pa], delta_vector, delta);
                // Reset other actions' traces.
                for (int i=0; i<n_actions; i++) {
                    if (i!=pa) {
                        ANN_Reset(Ja[i]);
                    }
                }
            } else {
                delta_vector[0] = delta;
                ANN_Delta_Train (Ja[pa], delta_vector, 0.0);
            }
        } else {
            if (J->eligibility_traces) {
                delta_vector[pa] = 1.0;
                ANN_Delta_Train (J, delta_vector, delta);
            } else {
                delta_vector[pa] = delta;
                ANN_Delta_Train (J, delta_vector, 0.0);
            }
        }
 
 
    }
 
    //printf ("%d %d #STATE\n", min_el_state, max_el_state);
    //  printf ("Q[%d,%d]=%f r=%f e=%f ad=%f gl=%f #QV\n",
    //          ps, pa, Q[ps][pa], r, e[ps][pa], ad, gl);
 
    J_ps_pa = Q_s[a];
    pa = a;
 
    return a;
}
 
void ANN_Policy::Reset()
{
    if (separate_actions) {
        for (int i=0; i<n_actions; i++) {
            ANN_Reset (Ja[i]);
        }
    } else {
        ANN_Reset(J);
    }
}
 
bool ANN_Policy::useConfidenceEstimates (bool confidence, real zeta, bool confidence_eligibility) {
    this->confidence_eligibility = confidence_eligibility;
    return useConfidenceEstimates(confidence, zeta);
}

bool ANN_Policy::useConfidenceEstimates (bool confidence, real zeta) {
    this->confidence = confidence;
    this->zeta = zeta;
    if (separate_actions) {
        for (int i=0; i<n_actions; i++) {
            ANN_SetZeta(Ja[i], zeta);
        }
    } else {
        ANN_SetZeta(J, zeta);
    }
    if (confidence) {
        logmsg ("#+[CONDIFENCE]\n");
    } else {
        logmsg ("#-[CONDIFENCE]\n");
    }
 
    return confidence;
}