csong@0: '''
csong@0: Author: Chunyang Song
csong@0: Institution: Centre for Digital Music, Queen Mary University of London
csong@0: 
csong@0: ** Longuet-Higgins and Lee's Model (LHL) **
csong@0: 
csong@0: Algorithm:
csong@0: 
csong@0: Only applicable to simple rhtyhms.
csong@0: 
csong@0: Generate tree structure:
csong@0: 1) Time_signature decides sequence of subdivisions: 4/4 - [2,2,2,...2], 3/4 - [3,2,2,...2], 6/8 - [2,3,2,2...2]; 
csong@0: 2) If after subdivision, a node has at least one branch that is full rest or one note, then it cannot be subdivided;
csong@0: 3) Weight of node, initialized as 0, decrease by 1 with increasing depth of the tree.
csong@0: 
csong@0: Assign each node in the tree three attributes - weight, pos, event;
csong@0: Search for Note-Rest pairs that Note's weight is no more than Rest's weight;
csong@0: Syncopation for such a pair is the difference in weights; 
csong@0: Total Syncopation value for non-syncopation rhythms is -1; for syncopated rhythms is the sum of syncopation of all notes.
csong@0: 
csong@0: In order to evaluate LHL models with the others, re-scale LHL's measures to non-negative.
csong@0: Apart from the immeasuable rhythms, add 1 to each syncopation value. 
csong@0: 
csong@0: '''
csong@0: from MeterStructure import MeterStructure
csong@0: 
csong@0: class Node:
csong@0: 	def __init__(self, pos, event):
csong@0: 		self.pos = pos
csong@0: 		self.event = event
csong@0: 
csong@0: 	def assignWeight(self, time_sig):
csong@0: 		ms = MeterStructure(time_sig)
csong@0: 		# Retrieve the LHL meter hierarchy in one bar;
csong@0: 		#(e.g. weight = [0, -4, -3, -4, -2, -4, -3, -4, -1, -4, -3, -4, -2, -4, -3, -4] in 4/4 meter)
csong@0: 		weights = ms.getLHLWeights(1)	
csong@0: 		
csong@0: 		# find the metrical weight of the note that locates at certain position(self.pos)
csong@0: 		# index is the corresponding position of "self.pos" in the "weights" list
csong@0: 		index = int(((abs(self.pos)%48)/48.0)*len(weights))		
csong@0: 		self.weight = weights[index]
csong@0: 
csong@0: class Tree:
csong@0: 	def __init__(self):
csong@0: 		self.nodes = []
csong@0: 
csong@0: 	def add(self, Node):
csong@0: 		self.nodes.append (Node)
csong@0: 
csong@0: 	def getWeight(self, time_sig):
csong@0: 		for n in self.nodes:
csong@0: 			n.assignWeight(time_sig)
csong@0: 
csong@0: 	def display(self):
csong@0: 		print 'Pos, Event, Weight'
csong@0: 		for n in self.nodes:
csong@0: 			print '%02d    %s      %02d' % (n.pos, n.event, n.weight)
csong@0: 
csong@0: 
csong@0: def subdivide(sequence, segments_num):
csong@0: 	subSeq = []
csong@0: 	if len(sequence) % segments_num != 0:
csong@0: 		print 'Error: rhythm segment cannot be equally subdivided.'
csong@0: 	else:
csong@0: 		n = len(sequence) / segments_num
csong@0: 		start , end = 0, n
csong@0: 		for i in range(segments_num):
csong@0: 			subSeq.append(sequence[start : end])
csong@0: 			start = end
csong@0: 			end = end + n
csong@0: 	
csong@0: 	return subSeq
csong@0: 
csong@0: 
csong@0: def eventType (sequence):
csong@0: 	if not(1 in sequence):	
csong@0: 		event = 'R'  # Full rest
csong@0: 	elif sequence[0] == 1 and not(1 in sequence[1:]): 
csong@0: 		event = 'N'  # Only one on-beat note
csong@0: 	else:
csong@0: 		event = 'D'  # Divisable
csong@0: 
csong@0: 	return event
csong@0: 
csong@0: def splitInto2 (sequence, tree, pos, isRecursive):
csong@0: 	
csong@0: 	subs = subdivide(sequence, 2)
csong@0: 	
csong@0: 	for s in subs:
csong@0: 		if eventType(s) == 'R' or eventType(s) == 'N':
csong@0: 			#print 'test', s, eventType(s), pos
csong@0: 			tree.add( Node(pos, eventType(s)) )
csong@0: 		else:
csong@0: 			if isRecursive:
csong@0: 				#print 'test', s, eventType(s), pos
csong@0: 				splitInto2 (s, tree, pos, True)
csong@0: 			else:
csong@0: 				splitInto3 (s, tree, pos)
csong@0: 
csong@0: 		pos = pos + len(sequence) / 2
csong@0: 	
csong@0: 	return tree
csong@0: 
csong@0: def splitInto3 (sequence, tree, pos):
csong@0: 
csong@0: 	subs = subdivide(sequence, 3)
csong@0: 
csong@0: 	for s in subs:
csong@0: 		if eventType(s) == 'R' or eventType(s) == 'N':
csong@0: 			#print 'test', s, eventType(s), pos
csong@0: 			tree.add( Node(pos, eventType(s)) )
csong@0: 	
csong@0: 		else:
csong@0: 			splitInto2 (s, tree, pos, True)			
csong@0: 		
csong@0: 		pos = pos + len(sequence) / 3
csong@0: 
csong@0: 	return tree
csong@0: 
csong@0: 
csong@0: def createTree(rhythm, time_sig, bar):
csong@0: 	t = Tree()
csong@0: 	# The root is the rhtyhm in a entire bar, has weight 0, at position 0
csong@0: 	weight, pos, event = 0 , 0, eventType(rhythm)
csong@0: 	root = Node (pos, event)
csong@0: 	if '2/4' in time_sig:
csong@0: 		t.add ( Node(-24, 'N') )  # Treat the last metronome beat in the previous bar as a sounded note
csong@0: 	
csong@0: 		if event == 'D':
csong@0: 			t = splitInto2(rhythm, t, pos, True)
csong@0: 		else:
csong@0: 			t.add (root)
csong@0: 
csong@0: 	elif '4/4' in time_sig:
csong@0: 		t.add ( Node(-12, 'N') )  # Treat the last metronome beat in the previous bar as a sounded note
csong@0: 	
csong@0: 		if event == 'D':
csong@0: 			t = splitInto2(rhythm, t, pos, True)
csong@0: 		else:
csong@0: 			t.add (root)
csong@0: 
csong@0: 	elif '3/4' in time_sig:
csong@0: 		t.add ( Node(-8, 'N') )  # Treat the last metronome beat in the previous bar as a sounded note
csong@0: 
csong@0: 		segments = subdivide (rhythm, bar)
csong@0: 
csong@0: 		for s in segments:
csong@0: 			if eventType(s) == 'D':
csong@0: 				t = splitInto3(s, t, pos)
csong@0: 			pos = pos + len(rhythm)/bar
csong@0: 
csong@0: 
csong@0: 	elif '6/8' in time_sig:
csong@0: 		t.add ( Node(-8, 'N') )  # Treat the last metronome beat in the previous bar as a sounded note
csong@0: 		
csong@0: 		segments = subdivide (rhythm, bar)
csong@0: 
csong@0: 		for s in segments:
csong@0: 			if eventType(s) == 'D': 
csong@0: 				t = splitInto2(s, t, pos, False)
csong@0: 			pos = pos + len(rhythm)/bar
csong@0: 
csong@0: 	else:
csong@0: 		print 'This time signature is not defined. Choose between 4/4, 3/4 or 6/8'
csong@0: 
csong@0: 	return t
csong@0: 
csong@0: 
csong@0: def lhl(rhythm, time_sig, category, bar):
csong@0: 	measures = []
csong@0: 
csong@0: 	if 'poly' in category:
csong@0: 		return -1
csong@0: 	else:
csong@0: 		tree = createTree(rhythm, time_sig, bar)	
csong@0: 		tree.getWeight(time_sig)
csong@0: 		#tree.display()
csong@0: 
csong@0: 		# find NR-pair that N's weight <= R's weight, add difference in weight to measures[] 
csong@0: 		N_weight = tree.nodes[0].weight
csong@0: 		size = len(tree.nodes)
csong@0: 
csong@0: 		for i in range(1, size):
csong@0: 		
csong@0: 			if tree.nodes[i].event == 'N':
csong@0: 				N_weight = tree.nodes[i].weight
csong@0: 
csong@0: 			if tree.nodes[i].event == 'R' and tree.nodes[i].weight >= N_weight:
csong@0: 				measures.append(tree.nodes[i].weight - N_weight )
csong@0: 
csong@0: 		# Calculate syncopation
csong@0: 		if len(measures) == 0: # syncopation of non-syncopated rhythm is -1
csong@0: 			syncopation = -1
csong@0: 		else:
csong@0: 			syncopation = sum(measures)  # syncopation of syncopated rhythm is the sum of measures[]
csong@0: 		
csong@0: 		return syncopation + 1 # For evaluation purpose, scale up by 1 to make scores above 0 
csong@0: 
csong@0: 
csong@0: # Retrieve the stimuli
csong@0: #f = file('stimuli.txt')
csong@0: f = file('stimuli_34only.txt')
csong@0: 
csong@0: #Calculate syncopation for each rhythm pattern
csong@0: while True:
csong@0: 	line = f.readline().split(';')
csong@0: 	if len(line) == 1:
csong@0: 		 break
csong@0: 	else:
csong@0: 		sti_name = line[0]
csong@0: 		rhythmString = line[1].split()
csong@0: 		time_sig = line[2]
csong@0: 		category = line[3]
csong@0: 		bar = int(line[4])
csong@0: 		
csong@0: 		rhythm = map(int,rhythmString[0].split(','))
csong@0: 
csong@0: 		print sti_name, lhl(rhythm, time_sig, category, bar)