/**
* Get the probability of the given transition, but do not perform that transition.
*
* <p>This must be called before the given transition is actually performed with {@link
* #doTransition(MidiNote, int, List)}.
*
* @param note The {@link MidiNote} whose transition probability we want.
* @param transition The value of the transition whose probability we want to get, given the
* {@link MidiNote} we want to check. A negative value tells us to add the {@link MidiNote} to
* a new {@link Voice} at index (-transition - 1). Any non-negative value tells us to add the
* {@link MidiNote} into the existing {@link Voice} at that index in newVoices.
* @param newVoices A List of the {@link Voice}s available to have the given {@link MidiNote}
* added to them.
* @return The probability of the given transition.
*/
private double getTransitionProb(MidiNote note, int transition, List<Voice> newVoices) {
double logProb;
Voice prev, next;
// For new Voices, we need to add the Voice, and then update the transition value to
// point to that new Voice so the lower code works.
if (transition < 0) {
transition = -transition - 1;
logProb = Math.log(params.NEW_VOICE_PROBABILITY);
prev = transition == 0 ? null : newVoices.get(transition - 1);
next = transition == newVoices.size() ? null : newVoices.get(transition);
} else {
logProb = Math.log(newVoices.get(transition).getProbability(note, params));
prev = transition == 0 ? null : newVoices.get(transition - 1);
next = transition == newVoices.size() - 1 ? null : newVoices.get(transition + 1);
}
// Check if we are in the wrong order with the prev or next Voices (or both)
if (prev != null && note.getPitch() < prev.getMostRecentNote().getPitch()) {
logProb -= Math.log(2);
}
if (next != null && note.getPitch() > next.getMostRecentNote().getPitch()) {
logProb -= Math.log(2);
}
if (logProb == Double.NEGATIVE_INFINITY) {
logProb = -Double.MAX_VALUE;
}
return logProb;
}
