ddecluster.cpp

/********************************************************************************
 *  Neural Network Framework.                                                   *
 *  Copyright (C) 2005-2011 Gianluca Massera <emmegian@yahoo.it>                *
 *                                                                              *
 *  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.                                         *
 *                                                                              *
 *  This program is distributed in the hope that it will be useful,             *
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of              *
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the               *
 *  GNU General Public License for more details.                                *
 *                                                                              *
 *  You should have received a copy of the GNU General Public License           *
 *  along with this program; if not, write to the Free Software                 *
 *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA  *
 ********************************************************************************/

#include "ddecluster.h"

namespace farsa {

DDECluster::DDECluster( const DoubleVector& c, unsigned int numNeurons, QString name )
    : Cluster( numNeurons, name ), tmpdata(numNeurons), tmpdata2(numNeurons) {
    setCoeff( c );
}

DDECluster::DDECluster( ConfigurationParameters& params, QString prefix )
    : Cluster( params, prefix ), tmpdata(numNeurons()), tmpdata2(numNeurons()) {
    // coefficients is a vector, that is a list of space-separated values
    QString str = params.getValue(prefix + "coefficients");
    if (!str.isEmpty()) {
        QStringList list = str.split(QRegExp("\\s+"), QString::SkipEmptyParts);
        coeff.resize( list.size() );
        for( int i=0; i<list.size(); i++) {
            bool ok;
            coeff[i] = list[i].toDouble(&ok);
            if (!ok) {
                coeff[i] = 0.0;
            }
        }
    }
}

DDECluster::~DDECluster() {
    /* Nothing to do */
}

void DDECluster::setCoeff( const DoubleVector& c ) {
    coeff = c;
    ds.resize( (c.size()>3) ? c.size()-3 : 0 );
    for( int i=0; i<ds.size(); i++ ) {
        ds[i].resize( numNeurons() );
        ds[i].zeroing();
    }
}

void DDECluster::update() {
    unsigned int csize = coeff.size();
    if ( csize == 0 ) {
        // uscita un po' strana!
        outputs().zeroing();
        setNeedReset( true );
        return;
    }
    // --- tmp <- a0
    tmpdata.setAll( coeff[0] );
    if ( csize == 1 ) {
        breakUpdate();
        return;
    }
    // --- tmp <- a0 + a1*f(x)
    outFunction()->apply( inputs(), tmpdata2 );
    tmpdata2 *= coeff[1];
    tmpdata += tmpdata2;
    if ( csize == 2 ) {
        breakUpdate();
        return;
    }
    // --- tmp <- a0 + a1*f(x) + a2*x
    tmpdata2.copyValues( inputs() );
    tmpdata2 *= coeff[2];
    tmpdata += tmpdata2;
    if ( csize == 3 ) {
        breakUpdate();
        return;
    }
    // --- tmp <- a0 + a1*f(x) + a2*x + a3*y ... aN*y^(n-3)
    for( int i=0; i<ds.size(); i++ ) {
        tmpdata2.copyValues( ds[i] );
        tmpdata2 *= coeff[i+3];
        tmpdata += tmpdata2;
    }
    breakUpdate();
    return;
}

void DDECluster::breakUpdate() {
    outputs().copyValues( tmpdata );
    updateDs();
    setNeedReset( true );
}

void DDECluster::updateDs() {
    if ( ds.size() == 0 ) return;
    // --- Le derivate sono semplici differenze:
    // --- y'  = y(t) - y(t-1)
    // --- y'' = y'(t) - y'(t-1)
    // ---  ... and so on
    if ( ds.size() == 1 ) {
        ds[0].copyValues( outputs() );
    } else if ( ds.size() == 2 ) {
        subtract( ds[1], outputs(), ds[0] );
        ds[0].copyValues( outputs() );
    } else {
        // ----- Problemi di questo tipo di calcolo:
        // *** calcola, cmq, anche la derivata ds.size()+1... l'ultimo tmpdata calcolato prima di uscire.
        tmpdata.copyValues( outputs() );
        for( int i=0; i<ds.size(); i++ ) {
            if ( i%2 == 0 ) {
                // calcola la derivata i+1 per il ciclo successivo
                subtract( tmpdata2, tmpdata, ds[1] );
                // memorizza il valore della derivata i calcolata al ciclo precedente i-1
                ds[i].copyValues( tmpdata );
            } else {
                // calcola la derivata i+1 per il ciclo successivo
                subtract( tmpdata, tmpdata2, ds[i] );
                // memorizza il valore della derivata i calcolata al ciclo precedente i-1
                ds[i].copyValues( tmpdata2 );
            }
        }
    }
}

void DDECluster::save(ConfigurationParameters& params, QString prefix)
{
    Cluster::save( params, prefix );
    params.startObjectParameters(prefix, "DDECluster", this);
    // First creating a string list, then transforming to a single string
    QStringList list;
    for (unsigned int i = 0; i < coeff.size(); i++) {
        list.push_back(QString::number(coeff[i]));
    }
    params.createParameter(prefix, "coefficients", list.join(" "));
}

void DDECluster::describe( QString type ) {
    Cluster::describe( type );
    Descriptor d = addTypeDescription( type, "A Cluster where the outputs depends on previous value", "The outputs are calculated accordlying with follow equation:\n y(t) <- a0 + a1*f(x) + a2*x(t) + a3*y(t-1) + a4*y'(t-1) + a5*y''(t-1) + a6*y'''(t-1) + ... \n NOTE: a simply leaky-integrator is possible by settings coefficients in the following way:\n a0 <- 0.0 ; a1 <- delta ; a2 <- 0.0 ; a3 <- 1.0-delta\n getting:\n y(t) <- (delta)*f(x) + (1.0-delta)*y(t-1)" );
    d.describeReal( "coefficients" ).def( 0.0 ).props( IsMandatory | IsList ).help( "The coefficients of the equation" );
}

}