csong@0: '''
csong@0: Author: Chunyang Song
csong@0: Institution: Centre for Digital Music, Queen Mary University of London
csong@1: '''
csong@0: 
csong@14: from basic_functions import concatenate, repeat, subdivide, ceiling, get_rhythm_category
csong@0: 
csong@14: terminalNodes = []		# Global variable, storing all the terminal nodes from recursive tree structure in time order
csong@0: 
csong@1: # Each terminnal node contains two properties: its node type (note or rest) and its metrical weight.
csong@1: class Node:
csong@14: 	def __init__(self,nodeType,metricalWeight):
csong@14: 		self.nodeType = nodeType
csong@14: 		self.metricalWeight = metricalWeight
csong@0: 
csong@1: # This function will recurse the tree for a binary sequence and return a sequence containing the terminal nodes in time order.
csong@14: def recursive_tree(binarySequence, subdivisionSequence, weightSequence, metricalWeight, level):
csong@14: 	# If matching to a Note type, add to terminal nodes
csong@14: 	if binarySequence == concatenate([1],repeat([0],len(binarySequence)-1)):	
csong@14: 		terminalNodes.append(Node('N',metricalWeight))
csong@0: 
csong@14: 	# If matching to a Rest type, add to terminal nodes
csong@14: 	elif binarySequence == repeat([0],len(binarySequence)):					
csong@14: 		terminalNodes.append(Node('R',metricalWeight))
csong@0: 
csong@14: 	# Keep subdividing by the subdivisor of the next level
csong@14: 	else:													
csong@14: 		subBinarySequences = subdivide(binarySequence, subdivisionSequence[level+1])	
csong@14: 		subWeightSequences = concatenate([metricalWeight],repeat([weightSequence[level+1]],subdivisionSequence[level+1]-1))
csong@14: 		for a in range(len(subBinarySequences)):
csong@14: 			recursive_tree(subBinarySequences[a], subdivisionSequence, weightSequence, subWeightSequences[a], level+1)
csong@0: 
csong@14: def get_syncopation(bar, weightSequence = None, LMax = None):
csong@14: 	'''
csong@14: 	The get_syncopation function calculates syncopation value . 
csong@14: 	'''
csong@14: #def get_syncopation(seq, subdivision_seq, weight_seq, prebar_seq, rhythm_category):
csong@1: 	syncopation = None
csong@14: 
csong@14: 	binarySequence = bar.get_binary_sequence()
csong@14: 	subdivisionSequence = bar.get_subdivision_sequence()
csong@14: 
csong@14: 	if get_rhythm_category(binarySequence, subdivisionSequence) == 'poly':
csong@14: 		print 'Warning: LHL model detects polyrhythms so returning None.'
csong@1: 	else:
csong@14: 		if weightSequence == None:
csong@14: 			if LMax == None:
csong@14: 				LMax  = 5
csong@14: 				weightSequence = range(0,-LMax,-1)
csong@14: 
csong@1: 		# If there is rhythm in previous bar, process its tree structure
csong@14: 		if bar.get_previous_bar() != None:
csong@14: 			prebarBinarySequence = bar.get_previous_bar().get_binary_sequence()
csong@14: 			recursive_tree(ceiling(prebarBinarySequence), subdivisionSequence, weightSequence, weightSequence[0],0)
csong@1: 			
csong@1: 			# Only keep the last note-type node
csong@14: 			while terminalNodes[-1].node_type != 'N':
csong@14: 				del terminalNodes[-1]
csong@14: 			del terminalNodes[0:-1]
csong@0: 
csong@1: 		# For the rhythm in the current bar, process its tree structure and store the terminal nodes 
csong@14: 		recursive_tree(ceiling(binarySequence), subdivisionSequence, weightSequence, weightSequence[0],0)
csong@1: 		
csong@14: 		# for t in terminalNodes:
csong@1: 		# 	print '<', t.node_type, t.metrical_weight, '>'
csong@0: 
csong@14: 		# Search for the NR pairs that contribute to syncopation, 
csong@14: 		# then add the weight-difference to the NRpairSyncopation list
csong@14: 		NRpairSyncopation = []
csong@14: 		for i in range(len(terminalNodes)-1,0,-1):
csong@14: 			if terminalNodes[i].node_type == 'R':
csong@1: 				for j in range(i-1, -1, -1):
csong@14: 					if (terminalNodes[j].node_type == 'N') & (terminalNodes[i].metricalWeight >= terminalNodes[j].metricalWeight):
csong@14: 						NRpairSyncopation.append(terminalNodes[i].metricalWeight - terminalNodes[j].metricalWeight)
csong@1: 						break
csong@14: 		#print NRpairSyncopation
csong@0: 
csong@14: 		# If there are syncopation, sum all the local syncopation values stored in NRpairSyncopation list	
csong@14: 		if len(NRpairSyncopation) != 0:
csong@14: 			syncopation = sum(NRpairSyncopation)
csong@14: 		# If no syncopation, the value is -1; 	
csong@14: 		elif len(terminalNodes) != 0:
csong@1: 			syncopation = -1
csong@0: 
csong@1: 	return syncopation
csong@14: 
csong@14: