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@1: from basic_functions import get_H, ceiling, get_min_timeSpan
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@1: def get_metricity(seq, H):
csong@1: 	metricity = 0
csong@1: 	for m in range(len(seq)):
csong@1: 		metricity = metricity + seq[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@1: def get_max_metricity(seq, H):
csong@1: 	max_metricity = 0
csong@1: 	H.sort(reverse=True) # Sort the metrical weight sequence from large to small
csong@1: 	for i in range(sum(seq)):
csong@1: 		max_metricity = max_metricity+H[i]
csong@1: 	return max_metricity
csong@1: 
csong@1: # The get_syncopation function calculates the syncopation value of the given sequence for TMC model. 
csong@1: def get_syncopation(seq, subdivision_seq, weight_seq, L_max, rhythm_category):
csong@1: 	syncopation = None
csong@1: 	if rhythm_category == 'poly':
csong@1: 		print 'Error: TMC model cannot deal with polyrhythms.'
csong@1: 	else:
csong@1: 		seq = get_min_timeSpan(seq)	# converting to the minimum time-span format
csong@1: 
csong@1: 		# checking whether the given L_max is enough to analyse the given sequence, if not, request a bigger L_max
csong@1: 		new_L_max = True
csong@1: 		matching_level = L_max
csong@1: 		while matching_level >= 0:
csong@1: 			if len(get_H(weight_seq,subdivision_seq, matching_level)) == len(seq):
csong@1: 				new_L_max = False
csong@1: 				break
csong@1: 			else:
csong@1: 				matching_level = matching_level - 1
csong@1: 
csong@1: 		if new_L_max == True:
csong@1: 			print 'Error: needs a bigger L_max (i.e. the lowest metrical level) to match the given rhythm sequence.'
csong@0: 		
csong@0: 		else:
csong@1: 			# generate the metrical weights of the lowest level, 
csong@1: 			# using the last matching_level number of elements in the weight_seq list, to make sure the last element is 1
csong@1: 			H = get_H (weight_seq[-(matching_level+1):], subdivision_seq, matching_level)
csong@0: 			
csong@1: 			metricity = get_metricity(ceiling(seq), H)	# converting to binary sequence then calculate metricity
csong@1: 			max_metricity = get_max_metricity(ceiling(seq), H)
csong@0: 
csong@1: 			syncopation = max_metricity - metricity
csong@1: 	return syncopation
csong@0: