christopher@45: '''
christopher@45: Author: Chunyang Song
christopher@45: Institution: Centre for Digital Music, Queen Mary University of London
christopher@45: 
christopher@45: '''
christopher@45: from basic_functions import repeat, get_note_indices
christopher@45: 
christopher@45: # To find the product of multiple numbers
christopher@45: def cumu_multiply(numbers):
christopher@45: 	product = 1
christopher@45: 	for n in numbers:
christopher@45: 		product = product*n
christopher@45: 	return product
christopher@45: 
christopher@45: def get_syncopation(bar, parameters = None):
christopher@45: 	syncopation = None
christopher@45: 	
christopher@45: 	noteSequence = bar.get_note_sequence()
christopher@45: 	barTicks = bar.get_bar_ticks()
christopher@45: 	subdivisionSequence = bar.get_subdivision_sequence()
christopher@45: 	strongBeatLevel = bar.get_beat_level()
christopher@45: 	
christopher@45: 	nextbarNoteSequence = None
christopher@45: 	if bar.get_next_bar() != None:
christopher@45: 		nextbarNoteSequence = bar.get_next_bar().get_note_sequence()
christopher@45: 
christopher@45: 	# calculate each strong beat ticks
christopher@45: 	numberOfBeats = cumu_multiply(subdivisionSequence[:strongBeatLevel+1])
christopher@45: 	beatIntervalTicks = barTicks/numberOfBeats
christopher@45: 	# beatsTicks represents the ticks for all the beats in the current bar and the first two beats in the next bar
christopher@45: 	beatsTicks = [i*beatIntervalTicks for i in range(numberOfBeats+2)] 
christopher@45: 	#print beatsTicks
christopher@45: 	totalSyncopation = 0
christopher@45: 	for note in noteSequence:
christopher@45: 	#	print note.to_string()
christopher@45: 		# find such beatIndex such that note.startTime is located between (including) beatsTicks[beatIndex] and (not including) beatsTicks[beatIndex+1]
christopher@45: 		beatIndex = 0
christopher@45: 		while note.startTime < beatsTicks[beatIndex] or note.startTime >= beatsTicks[beatIndex+1]:
christopher@45: 			beatIndex += 1
christopher@45: 
christopher@45: 	#	print beatIndex
christopher@45: 		# calculate the distance of this note to its nearest beat
christopher@45: 		distanceToBeatOnLeft = abs(note.startTime - beatsTicks[beatIndex])/float(beatIntervalTicks)
christopher@45: 		distanceToBeatOnRight = abs(note.startTime - beatsTicks[beatIndex+1])/float(beatIntervalTicks)
christopher@45: 		distanceToNearestBeat = min(distanceToBeatOnLeft,distanceToBeatOnRight)
christopher@45: 	#	print distanceToNearestBeat
christopher@45: 
christopher@45: 		# calculate the WNBD measure for this note, and add to total syncopation value for this bar
christopher@45: 		if distanceToNearestBeat == 0:	
christopher@45: 			totalSyncopation += 0
christopher@45: 		# or if this note is held on past the following beat, but ends on or before the later beat  
christopher@45: 		elif beatsTicks[beatIndex+1] < note.startTime+note.duration <= beatsTicks[beatIndex+2]:
christopher@45: 			totalSyncopation += float(2)/distanceToNearestBeat
christopher@45: 		else:
christopher@45: 			totalSyncopation += float(1)/distanceToNearestBeat
christopher@45: 	#	print totalSyncopation
christopher@45: 
christopher@45: 	return totalSyncopation
christopher@45: 
christopher@45: #def get_syncopation(seq, subdivision_seq, strong_beat_level, postbar_seq):
christopher@45: # def get_syncopation(bar, parameters = None):
christopher@45: # 	syncopation = None
christopher@45: 	
christopher@45: # 	binarySequence = bar.get_binary_sequence()
christopher@45: # 	sequenceLength = len(binarySequence)
christopher@45: # 	subdivisionSequence = bar.get_subdivision_sequence()
christopher@45: # 	strongBeatLevel = bar.get_beat_level()
christopher@45: # 	nextbarBinarySequence = None
christopher@45: 
christopher@45: # 	if bar.get_next_bar() != None:
christopher@45: # 		nextbarBinarySequence = bar.get_next_bar().get_binary_sequence()
christopher@45: 
christopher@45: # 	numberOfBeats = cumu_multiply(subdivisionSequence[0:strongBeatLevel+1])	# numberOfBeats is the number of strong beats
christopher@45: 	
christopher@45: # 	if sequenceLength % numberOfBeats != 0:
christopher@45: # 		print 'Error: the length of sequence is not subdivable by the subdivision factor in subdivision sequence.'
christopher@45: # 	else:
christopher@45: # 		# Find the indices of all the strong-beats
christopher@45: # 		beatIndices = []
christopher@45: # 		beatInterval = sequenceLength / numberOfBeats
christopher@45: # 		for i in range(numberOfBeats+1):
christopher@45: # 			beatIndices.append(i*beatInterval)
christopher@45: # 		if nextbarBinarySequence != None:		# if there is a postbar_seq, add another two beats index for later calculation
christopher@45: # 			beatIndices += [sequenceLength+beatInterval, sequenceLength+ 2* beatInterval]
christopher@45: 
christopher@45: # 		noteIndices = get_note_indices(binarySequence)	# all the notes
christopher@45: 
christopher@45: # 		# Calculate the WNBD measure for each note
christopher@45: # 		def measure_pernote(noteIndices, nextNoteIndex):
christopher@45: # 			# Find the nearest beats where this note locates - in [beat_indices[j], beat_indices[j+1]) 
christopher@45: # 			j = 0
christopher@45: # 			while noteIndices < beatIndices[j] or noteIndices >= beatIndices[j+1]:
christopher@45: # 				j = j + 1
christopher@45: 			
christopher@45: # 			# The distance of note to nearest beat normalised by the beat interval
christopher@45: # 			distanceToNearestBeat = min(abs(noteIndices - beatIndices[j]), abs(noteIndices - beatIndices[j+1]))/float(beatInterval)
christopher@45: 
christopher@45: # 			# if this note is on-beat
christopher@45: # 			if distanceToNearestBeat == 0:	
christopher@45: # 				measure = 0
christopher@45: # 			# or if this note is held on past the following beat, but ends on or before the later beat  
christopher@45: # 			elif beatIndices[j+1] < nextNoteIndex <= beatIndices[j+2]:
christopher@45: # 				measure = float(2)/distanceToNearestBeat
christopher@45: # 			else:
christopher@45: # 				measure = float(1)/distanceToNearestBeat
christopher@45: # 			return measure
christopher@45: 
christopher@45: # 		total = 0
christopher@45: # 		for i in range(len(noteIndices)):
christopher@45: # 			# if this is the last note, end_time is the index of the following note in the next bar
christopher@45: # 			if i == len(noteIndices)-1:
christopher@45: # 				# if the next bar is not none or a bar of full rest, 
christopher@45: # 				# the nextNoteIndex is the sum of sequence length in the current bar and the noteIndex in the next bar
christopher@45: # 				if nextbarBinarySequence != None and nextbarBinarySequence != repeat([0],len(nextbarBinarySequence)):
christopher@45: # 					nextNoteIndex = get_note_indices(nextbarBinarySequence)[0]+sequenceLength
christopher@45: # 				# else when the next bar is none or full rest, end_time is the end of this sequence.
christopher@45: # 				else:
christopher@45: # 					nextNoteIndex = sequenceLength
christopher@45: # 			# else this is not the last note, the nextNoteIndex is the following element in the noteIndices list
christopher@45: # 			else:
christopher@45: # 				nextNoteIndex = noteIndices[i+1]
christopher@45: # 			# sum up the syncopation value for individual note at noteIndices[i]
christopher@45: # 			total += measure_pernote(noteIndices[i],nextNoteIndex)
christopher@45: 
christopher@45: # 		#syncopation = float(total) / len(note_indices)
christopher@45: 
christopher@45: # 	# return the total value, leave the normalisation done in the end
christopher@45: # 	return total