ActiveTDConnectionList.cpp

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/************************************************************************
* Verve                                                                 *
* Copyright (C) 2004-2006                                               *
* Tyler Streeter  tylerstreeter@gmail.com                               *
* All rights reserved.                                                  *
* Web: http://verve-agents.sourceforge.net                              *
*                                                                       *
* This library is free software; you can redistribute it and/or         *
* modify it under the terms of EITHER:                                  *
*   (1) The GNU Lesser General Public License as published by the Free  *
*       Software Foundation; either version 2.1 of the License, or (at  *
*       your option) any later version. The text of the GNU Lesser      *
*       General Public License is included with this library in the     *
*       file license-LGPL.txt.                                          *
*   (2) The BSD-style license that is included with this library in     *
*       the file license-BSD.txt.                                       *
*                                                                       *
* This library 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 files    *
* license-LGPL.txt and license-BSD.txt for more details.                *
************************************************************************/

#include "ActiveTDConnectionList.h"
#include "TDConnection.h"

namespace verve
{
        ActiveTDConnectionList::ActiveTDConnectionList()
        {
        }

        ActiveTDConnectionList::~ActiveTDConnectionList()
        {
                mConnections.clear();
        }

        void ActiveTDConnectionList::clearList()
        {
                while (!mConnections.empty())
                {
                        mConnections.back()->setIsInActiveList(false);
                        mConnections.pop_back();
                }
        }

        void ActiveTDConnectionList::addNewActiveConnection(TDConnection* c)
        {
                if (c->isInActiveList())
                {
                        return;
                }

                // Insert the new element at the end of the list (because new 
                // TDConnections will probably have high eligibility traces, so 
                // this should help with sorting later).  The function 
                // std::list::insert(iterator pos, const T& x) inserts x before 
                // pos in constant time.
                mConnections.insert(mConnections.end(), c);

                c->setIsInActiveList(true);
        }

        void ActiveTDConnectionList::increaseETraces()
        {
                std::list<TDConnection*>::iterator iter;
                for (iter = mConnections.begin(); iter != mConnections.end(); ++iter)
                {
                        (*iter)->increaseETrace();
                }
        }

        void ActiveTDConnectionList::decayETraces()
        {
                // After we decay each TDConnection's eligibility trace, we need 
                // to remove any TDConnection whose eligibility trace has fallen 
                // below the active level.  

                std::list<TDConnection*>::iterator iter;
                for (iter = mConnections.begin(); iter != mConnections.end(); )
                {
                        (*iter)->decayETrace();

                        // If the TDConnection is no longer active, remove it.
                        if ((*iter)->getETrace() < defaults::activeETraceThreshold)
                        {
                                // Let the TDConnection know that it is no longer in 
                                // the active list.
                                (*iter)->setIsInActiveList(false);

                                // Reset the inactive TDConnection's eligibility 
                                // trace since it is probably not exactly zero.
                                (*iter)->setETrace(0);

                                // This returns an iterator to the element after the 
                                // one erased.  This operates in constant time.
                                iter = mConnections.erase(iter);
                        }
                        else
                        {
                                // The TDConnection must still be active.
                                ++iter;
                        }
                }
        }

        void ActiveTDConnectionList::trainConnections(
                real learningFactorTimesTDError)
        {
                std::list<TDConnection*>::iterator iter;
                for (iter = mConnections.begin(); iter != mConnections.end(); ++iter)
                {
                        (*iter)->applyTDLearning(learningFactorTimesTDError);
                }
        }
}

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