csong@1: '''
csong@1: Author: Chunyang Song
csong@1: Institution: Centre for Digital Music, Queen Mary University of London
csong@1: 
csong@1: '''
csong@1: 
csong@20: from basic_functions import ceiling, find_divisor, is_prime, get_min_timeSpan
csong@1: 
csong@20: def get_syncopation(bar, parameter = None):
csong@20: 	binarySequence = bar.get_binary_sequence()
csong@20: 	sequenceLength = len(binarySequence)
csong@20: 
csong@1: 	syncopation = 0
csong@1: 
csong@20: 	# if the length of b_sequence is 1 or a prime number, syncopation is 0;
csong@20: 	# otherwise the syncopation is calculated by adding up the number of off-beat notes
csong@20: 	if not ( (sequenceLength == 1) or (is_prime(sequenceLength)) ):
csong@20: 		# find all the divisors other than 1 and the length of this sequence
csong@20: 		divisors = find_divisor(sequenceLength)		
csong@20: 		del divisors[0]
csong@20: 		del divisors[-1]
csong@20: 
csong@20: 		# the on-beat/off-beat positions are the ones that can/cannot be subdivided by the sequenceLength;
csong@20: 		# the on-beat positions are set to be 0, off-beat positions are set to be 1
csong@20: 		offbeatness = [1]*sequenceLength			
csong@20: 		for index in range(sequenceLength):
csong@20: 			for d in divisors:
csong@20: 				if index % d == 0:
csong@20: 					offbeatness[index] = 0
csong@20: 					break
csong@20: 			#print 'offbeatness', offbeatness
csong@20: 			# syncopation is the sum of the hadamard-product of the rhythm binary-sequence and the off-beatness 
csong@20: 			syncopation += binarySequence[index]*offbeatness[index]
csong@20: 	
csong@1: 	return syncopation