Chris@181: /* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
Chris@181: 
Chris@181: /*
Chris@181:   Silvet
Chris@181: 
Chris@181:   A Vamp plugin for note transcription.
Chris@181:   Centre for Digital Music, Queen Mary University of London.
Chris@181:   This file Copyright 2012 Chris Cannam.
Chris@181:     
Chris@181:   This program is free software; you can redistribute it and/or
Chris@181:   modify it under the terms of the GNU General Public License as
Chris@181:   published by the Free Software Foundation; either version 2 of the
Chris@181:   License, or (at your option) any later version.  See the file
Chris@181:   COPYING included with this distribution for more information.
Chris@181: */
Chris@181: 
Chris@181: #ifndef AGENT_HYPOTHESIS_H
Chris@181: #define AGENT_HYPOTHESIS_H
Chris@181: 
Chris@181: #include "vamp-sdk/RealTime.h"
Chris@181: 
Chris@181: #include <set>
Chris@181: #include <map>
Chris@181: 
Chris@181: /**
Chris@181:  * An agent used to test an incoming series of timed observations or
Chris@181:  * estimates to see whether they fit a consistent single-object
Chris@181:  * relationship.
Chris@181:  *
Chris@181:  * A freshly constructed hypothesis object should be in New state and
Chris@181:  * should accept any observation.
Chris@181:  */
Chris@181: 
Chris@181: class AgentHypothesis
Chris@181: {
Chris@181: public:
Chris@181:     virtual ~AgentHypothesis() { }
Chris@181: 
Chris@181:     enum State {
Chris@181: 
Chris@181: 	/// Just constructed, will provisionally accept any observation
Chris@181: 	New,
Chris@181: 
Chris@181: 	/// Accepted at least one observation, but not enough evidence to satisfy
Chris@181: 	Provisional,
Chris@181: 
Chris@181: 	/// Could not find enough consistency in offered observations
Chris@181: 	Rejected,
Chris@181: 
Chris@181: 	/// Have accepted enough consistent observations to satisfy hypothesis
Chris@181: 	Satisfied,
Chris@181: 
Chris@181: 	/// Have been satisfied, but evidence has now changed: we're done
Chris@181: 	Expired
Chris@181:     };
Chris@181: 
Chris@181:     struct Observation {
Chris@181: 
Chris@181:         Observation() : value(0), time(), confidence(1) { }
Chris@181: 
Chris@181:         Observation(double _f, Vamp::RealTime _t, double _c) :
Chris@181:             value(_f), time(_t), confidence(_c) { }
Chris@181: 
Chris@181:         bool operator==(const Observation &o) const {
Chris@181:             return o.value == value && o.time == time && o.confidence == confidence;
Chris@181:         }
Chris@181:         bool operator<(const Observation &o) const {
Chris@181:             return
Chris@181:                 (time < o.time || 
Chris@181:                  (time == o.time && value < o.value) ||
Chris@181:                  (time == o.time && value == o.value && confidence < o.confidence));
Chris@181:         }
Chris@181: 
Chris@181: 	double value;
Chris@181:         Vamp::RealTime time;
Chris@181: 	double confidence;
Chris@181:     };
Chris@181:     typedef std::set<Observation> Observations;
Chris@181: 
Chris@181:     /**
Chris@181:      * Test the given observation to see whether it is consistent with
Chris@181:      * this hypothesis, and adjust the hypothesis' internal state
Chris@181:      * accordingly. If the observation is not inconsistent with the
Chris@181:      * hypothesis, return true.
Chris@181:      *!!! should be called e.g. test?
Chris@181:      */
Chris@181:     virtual bool accept(Observation) = 0;
Chris@181: 
Chris@181:     /**
Chris@181:      * Return the current state of this hypothesis.
Chris@181:      */
Chris@181:     virtual State getState() const = 0;
Chris@181: 
Chris@181:     /**
Chris@181:      * If the hypothesis has been satisfied (i.e. is in Satisfied or
Chris@181:      * Expired state), return the set of observations that it
Chris@181:      * accepted. Otherwise return an empty set
Chris@181:      */
Chris@181:     virtual Observations getAcceptedObservations() const = 0;
Chris@181: 
Chris@181:     /**
Chris@181:      * Convert the given set of accepted hypotheses (of type
Chris@181:      * subclassed from AgentHypothesis) into a flattened set of their
Chris@181:      * accepted observations.
Chris@181:      * 
Chris@181:      * That is, only one is included for at any given moment, so in
Chris@181:      * the case of overlapping hypotheses, the observations for the
Chris@181:      * earlier are taken until the next hypothesis begins and then the
Chris@181:      * latter's observations begin instead.
Chris@181:      *
Chris@181:      * (If there are gaps between hypotheses, the gaps remain in the
Chris@181:      * output.)
Chris@181:      */
Chris@181:     template <typename HypothesisType>
Chris@181:     static Observations flatten(const std::set<HypothesisType> &agents) {
Chris@181: 
Chris@181:         typedef typename std::set<HypothesisType>::const_iterator Itr;
Chris@181:         Observations flattened;
Chris@181: 
Chris@181:         if (agents.empty()) return flattened;
Chris@181:         Observations obs = agents.begin()->getAcceptedObservations();
Chris@181: 
Chris@181:         for (Itr i = agents.begin(); i != agents.end(); ++i) {
Chris@181: 
Chris@181:             Itr j = i;
Chris@181:             ++j;
Chris@181: 
Chris@181:             Observations nextObs;
Chris@181:             if (j != agents.end()) nextObs = j->getAcceptedObservations();
Chris@181: 
Chris@181:             for (Observations::const_iterator i = obs.begin();
Chris@181:                  i != obs.end(); ++i) {
Chris@181:                 if (!nextObs.empty() && i->time >= nextObs.begin()->time) {
Chris@181:                     break;
Chris@181:                 }
Chris@181:                 flattened.insert(*i);
Chris@181:             }
Chris@181: 
Chris@181:             obs = nextObs;
Chris@181:         }
Chris@181: 
Chris@181:         return flattened;
Chris@181:     }
Chris@181: };
Chris@181: 
Chris@181: #endif