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: 
christopher@45: from basic_functions import get_H, ceiling, velocity_sequence_to_min_timespan, get_rhythm_category
christopher@45: from parameter_setter import are_parameters_valid
christopher@45: 
christopher@45: # The get_metricity function calculates the metricity for a binary sequence with given sequence of metrical weights in a certain metrical level.
christopher@45: def get_metricity(binarySequence, H):
christopher@45: 	metricity = 0
christopher@45: 	for m in range(len(binarySequence)):
christopher@45: 		metricity = metricity + binarySequence[m]*H[m]
christopher@45: 	return metricity
christopher@45: 
christopher@45: # The get_max_metricity function calculates the maximum metricity for the same number of notes in a binary sequence.
christopher@45: def get_max_metricity(binarySequence, H):
christopher@45: 	maxMetricity = 0
christopher@45: 	H.sort(reverse=True) # Sort the metrical weight sequence from large to small
christopher@45: 	for i in range(sum(binarySequence)):
christopher@45: 		maxMetricity = maxMetricity+H[i]
christopher@45: 	return maxMetricity
christopher@45: 
christopher@45: # find the metrical level L that contains the same number of metrical positions as the length of the binary sequence
christopher@45: # if the given Lmax is not big enough to analyse the given sequence, request a bigger Lmax
christopher@45: def find_L(rhythmSequence, Lmax, weightSequence, subdivisionSequence):
christopher@45: 	L = Lmax
christopher@45: 
christopher@45: 	# initially assuming the Lmax is not big enough
christopher@45: 	needBiggerLmax = True 
christopher@45: 	
christopher@45: 	# from the lowest metrical level (Lmax) to the highest, find the matching metrical level that 
christopher@45: 	# has the same length as the length of binary sequence  
christopher@45: 	while L >= 0:
christopher@45: 		if len(get_H(weightSequence,subdivisionSequence, L)) == len(rhythmSequence):
christopher@45: 			needBiggerLmax = False
christopher@45: 			break
christopher@45: 		else:
christopher@45: 			L = L - 1
christopher@45: 
christopher@45: 	# if need a bigger Lmax, print error message and return None; otherwise return the matching metrical level L
christopher@45: 	if needBiggerLmax:
christopher@45: 		print 'Error: needs a bigger L_max (i.e. the lowest metrical level) to match the given rhythm sequence.'
christopher@45: 		L = None
christopher@45: 	
christopher@45: 	return L
christopher@45: 
christopher@45: # The get_syncopation function calculates the syncopation value of the given sequence for TMC model. 
christopher@45: #def get_syncopation(seq, subdivision_seq, weight_seq, L_max, rhythm_category):
christopher@45: def get_syncopation(bar, parameters = None):
christopher@45: 	syncopation = None
christopher@45: 	binarySequence = bar.get_binary_sequence()
christopher@45: 	subdivisionSequence = bar.get_subdivision_sequence()
christopher@45: 
christopher@45: 	if get_rhythm_category(binarySequence, subdivisionSequence) == 'poly':
christopher@45: 		print 'Warning: TMC model detects polyrhythms so returning None.'
christopher@45: 	else:
christopher@45: 		
christopher@45: 		# set the defaults
christopher@45: 		Lmax  = 5
christopher@45: 		weightSequence = range(Lmax+1,0,-1) # i.e. [6,5,4,3,2,1]
christopher@45: 		
christopher@45: 		if parameters!= None:
christopher@45: 			if 'Lmax' in parameters:
christopher@45: 				Lmax = parameters['Lmax']				
christopher@45: 			if 'W' in parameters:
christopher@45: 				weightSequence = parameters['W']
christopher@45: 
christopher@45: 		if not are_parameters_valid(Lmax, weightSequence, subdivisionSequence):
christopher@45: 			print 'Error: the given parameters are not valid.'
christopher@45: 		else:
christopher@45: 			binarySequence = velocity_sequence_to_min_timespan(binarySequence)	# converting to the minimum time-span format
christopher@45: 			L = find_L(binarySequence, Lmax, weightSequence, subdivisionSequence) 
christopher@45: 			if L != None:
christopher@45: 				#? generate the metrical weights of the lowest level, 
christopher@45: 				#? using the last matching_level number of elements in the weightSequence, to make sure the last element is 1
christopher@45: 				H = get_H (weightSequence[-(L+1):], subdivisionSequence, L)
christopher@45: 				metricity = get_metricity(binarySequence, H)	# converting to binary sequence then calculate metricity
christopher@45: 				maxMetricity = get_max_metricity(binarySequence, H)
christopher@45: 
christopher@45: 				syncopation = maxMetricity - metricity
christopher@45: 				
christopher@45: 	return syncopation
christopher@45: