126 lines
4 KiB
C#
126 lines
4 KiB
C#
//Copyright (C) 2005 Richard J. Northedge
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//
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// This library is free software; you can redistribute it and/or
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// modify it under the terms of the GNU Lesser General Public
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// License as published by the Free Software Foundation; either
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// version 2.1 of the License, or (at your option) any later version.
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//
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public
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// License along with this program; if not, write to the Free Software
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// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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//This file is based on the BasicEventStream.java source file found in the
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//original java implementation of MaxEnt. That source file contains the following header:
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// Copyright (C) 2001 Jason Baldridge
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//
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// This library is free software; you can redistribute it and/or
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// modify it under the terms of the GNU Lesser General Public
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// License as published by the Free Software Foundation; either
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// version 2.1 of the License, or (at your option) any later version.
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//
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public
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// License along with this program; if not, write to the Free Software
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// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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using System;
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namespace BotSharp.MachineLearning
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{
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/// <summary>
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/// An object which can deliver a stream of training events assuming
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/// that each event is represented as a space separated list containing
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/// all the contextual predicates, with the last item being the
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/// outcome, e.g.:
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///
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/// <p> cp_1 cp_2 ... cp_n outcome</p>
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/// </summary>
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public class BasicEventReader : ITrainingEventReader
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{
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private IContextGenerator<string> mContext;
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private ITrainingDataReader<string> mDataReader;
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private TrainingEvent mNextEvent;
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/// <summary>
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/// Constructor sets up the training event reader based on a stream of training data.
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/// </summary>
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/// <param name="dataReader">
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/// Stream of training data.
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/// </param>
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public BasicEventReader(ITrainingDataReader<string> dataReader)
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{
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mContext = new BasicContextGenerator();
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mDataReader = dataReader;
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if (mDataReader.HasNext())
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{
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mNextEvent = CreateEvent(mDataReader.NextToken());
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}
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}
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/// <summary>
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/// Returns the next Event object held in this EventReader. Each call to ReadNextEvent advances the EventReader.
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/// </summary>
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/// <returns>
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/// the Event object which is next in this EventReader
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/// </returns>
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public virtual TrainingEvent ReadNextEvent()
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{
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while (mNextEvent == null && mDataReader.HasNext())
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{
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mNextEvent = CreateEvent(mDataReader.NextToken());
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}
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TrainingEvent currentEvent = mNextEvent;
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if (mDataReader.HasNext())
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{
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mNextEvent = CreateEvent(mDataReader.NextToken());
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}
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else
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{
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mNextEvent = null;
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}
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return currentEvent;
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}
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/// <summary>
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/// Test whether there are any Events remaining in this EventReader.
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/// </summary>
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/// <returns>
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/// true if this EventReader has more Events
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/// </returns>
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public virtual bool HasNext()
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{
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while (mNextEvent == null && mDataReader.HasNext())
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{
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mNextEvent = CreateEvent(mDataReader.NextToken());
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}
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return mNextEvent != null;
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}
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private TrainingEvent CreateEvent(string observation)
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{
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int lastSpace = observation.LastIndexOf((char)' ');
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if (lastSpace == -1)
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{
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return null;
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}
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else
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{
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return new TrainingEvent(observation.Substring(lastSpace + 1), mContext.GetContext(observation.Substring(0, (lastSpace) - (0))));
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}
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}
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}
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}
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