def getLogLikelihood(w1, w2, a1, a2, model):
belief, ran, duration = beliefUpdate(w1, w2, model)
LL = 0
for i in xrange(len(w1)):
assignedLetter = a1[i]
LL += belief[i][assignmentToNumber(assignedLetter)]
for i in xrange(len(w2)):
assignedLetter = a2[i]
LL += belief[i + len(w1)][assignmentToNumber(assignedLetter)]
return LL, duration
def marginalize(belief, separator, varsInBelief, typeOfFactor):
if typeOfFactor=='o':
return belief
else:
msg = {x:0 for x in xrange(10)}
n = int(log10(len(belief.keys())))
for i in belief.keys():
assignment = numberToAssignment(i,n)
assignmentToSep = assignment[varsInBelief.index(separator)]
msg[assignmentToNumber(assignmentToSep)] += exp(belief[i])
return {x:log(msg[x]) for x in msg.keys()}
def marginalize(belief, separator, varsInBelief, typeOfFactor):
if typeOfFactor=='o':
return belief
else:
tempMaxFinder = {x:[] for x in xrange(10)}
msg = {x:0 for x in xrange(10)}
n = int(log10(len(belief.keys())))
for i in belief.keys():
assignment = numberToAssignment(i,n)
assignmentToSep = assignment[varsInBelief.index(separator)]
tempMaxFinder[assignmentToNumber(assignmentToSep)].append(belief[i])
for i in tempMaxFinder.keys():
msg[i] = max(tempMaxFinder[i])
return msg
def updateBelief(oldBelief, msg, separator, varsInBelief, edgeBelief, typeOfFactor):
if typeOfFactor=='o':
newBelief = {}
for i in oldBelief.keys():
newBelief[i] = oldBelief[i] + msg[i] - edgeBelief[i]
return newBelief
else:
n = int(log10(len(oldBelief.keys())))
newBelief = {}
for i in oldBelief.keys():
assignment = numberToAssignment(i, n)
assignmentToSeparator = assignment[varsInBelief.index(separator)]
indexSeparator = assignmentToNumber(assignmentToSeparator)
newBelief[i] = oldBelief[i] + msg[indexSeparator] - edgeBelief[indexSeparator]
return newBelief
def beliefUpdate(w1, w2, model):
betheGraph, betheMapping = getBetheClusterGraph(w1, w2, model)
#TODO: Check if two clusters can be connected by more than one edge (and therefore separator). Example, trans edge and skip edge b/w letters.
edgesInBetheGraph = {}
numOfEdges = 0
for i in betheGraph.keys():
neighours = list(betheGraph[i])
for j in neighours:
edge = ({i,j[0]}, j[1])
if edge not in edgesInBetheGraph.values():
edgesInBetheGraph[numOfEdges] = edge
numOfEdges += 1
#print edgesInBetheGraph
#print betheMapping
##############################################################################################
#Cluster Graph Initialization
#print betheGraph
#print betheMapping
#print edgesInBetheGraph
#print '\n\n'
beliefAtEachNode = {x:{} for x in betheMapping.keys()}
beliefAtEachEdge = {x:{y:0 for y in xrange(10)} for x in edgesInBetheGraph.keys()}
for x in betheMapping.keys():
factor = betheMapping[x]
typeOfFactor = factor[0]
varsInFactor = factor[1]
if typeOfFactor == 'o':
if varsInFactor<len(w1):
letter = w1[varsInFactor]
else:
letter = w2[varsInFactor - len(w1)]
beliefAtEachNode[x] = ocrDat[letter].copy()
beliefAtEachNode[x] = {assignmentToNumber(t): beliefAtEachNode[x][t] for t in beliefAtEachNode[x].keys()}
elif typeOfFactor == 't':
for i in xrange(100):
assignment = numberToAssignment(i,2)
beliefAtEachNode[x][i] = transDat[assignment[0]][assignment[1]]
elif typeOfFactor == 's':
for i in xrange(100):
assignment = numberToAssignment(i,2)
beliefAtEachNode[x][i] = getSkipFactor(assignment[0], assignment[1])
else:
for i in xrange(100):
assignment = numberToAssignment(i,2)
beliefAtEachNode[x][i] = getPairSkipFactor(assignment[0], assignment[1])
##############################################################################################
#Initialization Complete. Now starting Belief Updates.
numOfIterations = 0
start = time.clock()
while(True):
maxError = -50000
oldBelief = beliefAtEachNode.copy()
for i in edgesInBetheGraph.keys():
node1,node2 = edgesInBetheGraph[i][0]
separator = edgesInBetheGraph[i][1]
typeOfFactor1 = betheMapping[node1][0]
typeOfFactor2 = betheMapping[node2][0]
varsInNode1 = betheMapping[node1][1]
varsInNode2 = betheMapping[node2][1]
msg1to2 = marginalize(beliefAtEachNode[node1], separator, varsInNode1, typeOfFactor1)
beliefAtEachNode[node2] = updateBelief(beliefAtEachNode[node2], msg1to2, separator, varsInNode2, beliefAtEachEdge[i], typeOfFactor2)
beliefAtEachEdge[i] = msg1to2
msg2to1 = marginalize(beliefAtEachNode[node2], separator, varsInNode2, typeOfFactor2)
beliefAtEachNode[node1] = updateBelief(beliefAtEachNode[node1], msg2to1, separator, varsInNode1, beliefAtEachEdge[i], typeOfFactor1)
beliefAtEachEdge[i] = msg2to1
error1 = max([fabs(beliefAtEachNode[node1][i] - oldBelief[node1][i]) for i in oldBelief[node1].keys()])
error2 = max([fabs(beliefAtEachNode[node2][i] - oldBelief[node2][i]) for i in oldBelief[node2].keys()])
error = max(error1, error2)
#print error
if maxError<error:
maxError = error
##############################################################################################
#Normalization
for i in beliefAtEachNode.keys():
z = 0
for x in beliefAtEachNode[i].keys():
z += exp(beliefAtEachNode[i][x])
z = log(z)
for x in beliefAtEachNode[i].keys():
beliefAtEachNode[i][x] -= z
for i in beliefAtEachEdge.keys():
z = 0
for x in beliefAtEachEdge[i].keys():
z += exp(beliefAtEachEdge[i][x])
z = log(z)
for x in beliefAtEachEdge[i].keys():
beliefAtEachEdge[i][x] -= z
numOfIterations += 1
#print 'numOfIterations',numOfIterations
#print 'maxError', maxError
if (maxError<0.0001) or (numOfIterations >= 50):
end = time.clock()
duration = end - start
return beliefAtEachNode, betheMapping, duration
break
