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: from basic_functions import concatenate, repeat, subdivide, ceiling, get_rhythm_category
christopher@45: from parameter_setter import are_parameters_valid
christopher@45: 
christopher@45: 
christopher@45: 
christopher@45: 
christopher@50: # Each terminal node contains two properties: its node type (note or rest) and its metrical weight.
christopher@45: class Node:
christopher@45: 	def __init__(self,nodeType,metricalWeight):
christopher@45: 		self.nodeType = nodeType
christopher@45: 		self.metricalWeight = metricalWeight
christopher@45: 
christopher@45: # This function will recurse the tree for a binary sequence and return a sequence containing the terminal nodes in time order.
christopher@50: def recursive_tree(binarySequence, subdivisionSequence, weightSequence, metricalWeight, level, Lmax):
christopher@45: 	# If matching to a Note type, add to terminal nodes
christopher@50: 	output = list()
christopher@45: 	if binarySequence == concatenate([1],repeat([0],len(binarySequence)-1)):	
christopher@50: 		output.append(Node('N',metricalWeight))
christopher@45: 
christopher@45: 	# If matching to a Rest type, add to terminal nodes
christopher@45: 	elif binarySequence == repeat([0],len(binarySequence)):					
christopher@50: 		output.append(Node('R',metricalWeight))
christopher@50: 
christopher@50: 	elif level+1 == Lmax:
christopher@50: 		print "WARNING: LHL tree recursion descended to Lmax, returning a note node but result will not be fully accurate.  Check the rhythm pattern under test and/or specify larger Lmax to rectify the problem."
christopher@50: 		output.append(Node('N',metricalWeight))
christopher@45: 
christopher@45: 	# Keep subdividing by the subdivisor of the next level
christopher@50: 	else:	
christopher@45: 		subBinarySequences = subdivide(binarySequence, subdivisionSequence[level+1])	
christopher@45: 		subWeightSequences = concatenate([metricalWeight],repeat([weightSequence[level+1]],subdivisionSequence[level+1]-1))
christopher@45: 		for a in range(len(subBinarySequences)):
christopher@50: 			output = output + recursive_tree(subBinarySequences[a], subdivisionSequence, weightSequence, subWeightSequences[a], level+1, Lmax)
christopher@50: 	
christopher@50: 	return output
christopher@45: 
christopher@45: def get_syncopation(bar, parameters = None):
christopher@45: 	syncopation = None
christopher@50: 	naughtyglobal = 0
christopher@45: 
christopher@45: 	binarySequence = bar.get_binary_sequence()
christopher@45: 	subdivisionSequence = bar.get_subdivision_sequence()
christopher@45: 
christopher@45: 	# LHL can only measure monorhythms
christopher@45: 	if get_rhythm_category(binarySequence, subdivisionSequence) == 'poly':
christopher@45: 		print 'Warning: LHL model detects polyrhythms so returning None.'
christopher@50: 	elif bar.is_empty():
christopher@50: 		print 'LHL model detects empty bar so returning -1.'
christopher@50: 		syncopation = -1
christopher@45: 	else:
christopher@45: 		# set defaults
christopher@50: 		Lmax = 10
christopher@45: 		weightSequence = range(0,-Lmax-1,-1)
christopher@45: 		# if parameters are specified by users, check their validities and update parameters if valid		
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@50: 			
christopher@50: 			# For the rhythm in the current bar, process its tree structure and store the terminal nodes 
christopher@50: 			terminalNodes = recursive_tree(ceiling(binarySequence), subdivisionSequence, weightSequence, weightSequence[0],0, Lmax)
christopher@50: 			
christopher@50: 			# save the terminal nodes on the current bar so that 
christopher@50: 			# the next bar can access them...
christopher@50: 			bar.LHLterminalNodes = terminalNodes
christopher@50: 
christopher@50: 			# If there is rhythm in the previous bar and we've already processed it 
christopher@45: 			prevbar =  bar.get_previous_bar()
christopher@50: 			if prevbar != None and prevbar.is_empty() != True:
christopher@50: 				# get its LHL tree if it has one
christopher@50: 				try:
christopher@50: 					prevbarNodes = prevbar.LHLterminalNodes
christopher@50: 				except AttributeError:
christopher@50: 					prevbarNodes = []
christopher@50: 
christopher@50: 				# find the final note node in the previous bar:
christopher@50: 				if len(prevbarNodes)>0:
christopher@50: 					i = len(prevbarNodes) - 1
christopher@45: 					# Only keep the last note-type node
christopher@50: 					while prevbarNodes[i].nodeType != 'N' and i>=0:
christopher@50: 						i = i-1
christopher@50: 					# prepend the note to the terminal node list for this bar
christopher@50: 					terminalNodes = [ prevbarNodes[i] ] + terminalNodes
christopher@50: 						
christopher@45: 			
christopher@50: 			# Search for the NR pairs that contribute to syncopation, then add the weight-difference to the NRpairSyncopation list
christopher@45: 			NRpairSyncopation = []
christopher@45: 			for i in range(len(terminalNodes)-1,0,-1):
christopher@45: 				if terminalNodes[i].nodeType == 'R':
christopher@45: 					for j in range(i-1, -1, -1):
christopher@45: 						if (terminalNodes[j].nodeType == 'N') & (terminalNodes[i].metricalWeight >= terminalNodes[j].metricalWeight):
christopher@45: 							NRpairSyncopation.append(terminalNodes[i].metricalWeight - terminalNodes[j].metricalWeight)
christopher@45: 							break
christopher@45: 
christopher@45: 			# If there are syncopation, sum all the local syncopation values stored in NRpairSyncopation list	
christopher@45: 			if len(NRpairSyncopation) != 0:
christopher@45: 				syncopation = sum(NRpairSyncopation)
christopher@45: 			# If no syncopation, the value is -1; 	
christopher@45: 			elif len(terminalNodes) != 0:
christopher@45: 				syncopation = -1
christopher@45: 
christopher@45: 	return syncopation
christopher@45: 
christopher@45: