csong@0: '''
csong@0: Author: Chunyang Song
csong@0: Institution: Centre for Digital Music, Queen Mary University of London
csong@0: 
csong@0: '''
csong@0: 
csong@23: from basic_functions import get_H, ceiling, velocity_sequence_to_min_timespan, get_rhythm_category
csong@28: from parameter_setter import are_parameters_valid
csong@0: 
csong@1: # The get_metricity function calculates the metricity for a binary sequence with given sequence of metrical weights in a certain metrical level.
csong@20: def get_metricity(binarySequence, H):
csong@1: 	metricity = 0
csong@20: 	for m in range(len(binarySequence)):
csong@20: 		metricity = metricity + binarySequence[m]*H[m]
csong@1: 	return metricity
csong@1: 
csong@1: # The get_max_metricity function calculates the maximum metricity for the same number of notes in a binary sequence.
csong@20: def get_max_metricity(binarySequence, H):
csong@20: 	maxMetricity = 0
csong@1: 	H.sort(reverse=True) # Sort the metrical weight sequence from large to small
csong@20: 	for i in range(sum(binarySequence)):
csong@20: 		maxMetricity = maxMetricity+H[i]
csong@20: 	return maxMetricity
csong@20: 
csong@20: # find the metrical level L that contains the same number of metrical positions as the length of the binary sequence
csong@20: # if the given Lmax is not big enough to analyse the given sequence, request a bigger Lmax
csong@20: def find_L(rhythmSequence, Lmax, weightSequence, subdivisionSequence):
csong@20: 	L = Lmax
csong@20: 
csong@20: 	# initially assuming the Lmax is not big enough
csong@20: 	needBiggerLmax = True 
csong@20: 	
csong@20: 	# from the lowest metrical level (Lmax) to the highest, find the matching metrical level that 
csong@20: 	# has the same length as the length of binary sequence  
csong@20: 	while L >= 0:
csong@20: 		if len(get_H(weightSequence,subdivisionSequence, L)) == len(rhythmSequence):
csong@20: 			needBiggerLmax = False
csong@20: 			break
csong@20: 		else:
csong@20: 			L = L - 1
csong@20: 
csong@20: 	# if need a bigger Lmax, print error message and return None; otherwise return the matching metrical level L
csong@20: 	if needBiggerLmax:
csong@20: 		print 'Error: needs a bigger L_max (i.e. the lowest metrical level) to match the given rhythm sequence.'
csong@20: 		L = None
csong@20: 	
csong@20: 	return L
csong@1: 
csong@1: # The get_syncopation function calculates the syncopation value of the given sequence for TMC model. 
csong@20: #def get_syncopation(seq, subdivision_seq, weight_seq, L_max, rhythm_category):
csong@20: def get_syncopation(bar, parameters = None):
csong@1: 	syncopation = None
csong@20: 	binarySequence = bar.get_binary_sequence()
csong@20: 	subdivisionSequence = bar.get_subdivision_sequence()
csong@20: 
csong@20: 	if get_rhythm_category(binarySequence, subdivisionSequence) == 'poly':
csong@20: 		print 'Warning: TMC model detects polyrhythms so returning None.'
csong@1: 	else:
csong@28: 		
csong@28: 		# set the defaults
csong@28: 		Lmax  = 5
csong@28: 		weightSequence = range(Lmax+1,0,-1) # i.e. [6,5,4,3,2,1]
csong@28: 		
csong@28: 		if parameters!= None:
csong@28: 			if 'Lmax' in parameters:
csong@28: 				Lmax = parameters['Lmax']				
csong@28: 			if 'W' in parameters:
csong@28: 				weightSequence = parameters['W']
csong@1: 
csong@28: 		if not are_parameters_valid(Lmax, weightSequence, subdivisionSequence):
csong@28: 			print 'Error: the given parameters are not valid.'
csong@20: 		else:
csong@28: 			binarySequence = velocity_sequence_to_min_timespan(binarySequence)	# converting to the minimum time-span format
csong@28: 			L = find_L(binarySequence, Lmax, weightSequence, subdivisionSequence) 
csong@28: 			if L != None:
csong@28: 				#? generate the metrical weights of the lowest level, 
csong@28: 				#? using the last matching_level number of elements in the weightSequence, to make sure the last element is 1
csong@28: 				H = get_H (weightSequence[-(L+1):], subdivisionSequence, L)
csong@28: 				metricity = get_metricity(binarySequence, H)	# converting to binary sequence then calculate metricity
csong@28: 				maxMetricity = get_max_metricity(binarySequence, H)
csong@1: 
csong@28: 				syncopation = maxMetricity - metricity
csong@33: 				
csong@1: 	return syncopation
csong@0: