def sum_out(var, factors): new_factor_list = [] for f in factors: if var in f.variables: new_variables = list(f.variables) new_variables.remove(var) name = '' for v in new_variables: name += v.name new_f = Factor(name,new_variables) new_f.phi = np.zeros((0,)) # DIRECTIONS # Must check that the other x assignments match, then add together v_index = f.variables.index(var) # WE NEED A MORE CREATIVE WAY TO DO THIS # IS INDEX TO ASSIGNMENT ACTUALLY WORKING?? for i in range(0, len(f.phi)): assignment1 = list(f.index_to_assignment(i)) #print 'assignment 1: ' + str(assignment1) is_sum = False next_sum = f.phi[i] for j in range(i, len(f.phi)): assignment2 = list(f.index_to_assignment(j)) summable = True #print'assignment 2: ' + str(assignment2) for k in range(0, len(assignment2)): idx2 = assignment2[k] idx1 = assignment1[k] #print assignment1, assignment2 if k == v_index: #print k, idx1, idx2 if idx2 == idx1: #print 'not summable, a1[k] == a2[k]' summable = False break if k != v_index: #print 'NOT', k, idx1, idx2 if idx2 != idx1: #print 'not summable, a1[k] != a2[k]' summable = False break if summable == True: is_sum = True next_sum += f.phi[j] if is_sum == True: new_f.phi = np.append(new_f.phi, next_sum) new_factor_list.append(new_f) #can't sum this factor out on this variable else: new_factor_list.append(f) return new_factor_list
def instantiate(var, factors): new_factor_list = [] for f in factors: if var in f.variables: new_variables = list(f.variables) new_variables.remove(var) name = '' for v in new_variables: name += v.name new_f = Factor(name,new_variables) new_f.phi = np.zeros((0,)) v_index = f.variables.index(var) for i in range(0, len(f.phi)): assignment = f.index_to_assignment(i) if assignment[v_index] == var.value: # print f.phi[i] new_f.phi = np.append(new_f.phi, f.phi[i]) new_factor_list.append(new_f) else: new_factor_list.append(f) return new_factor_list
def factorProduct(f1, f2, mnCards):
"""
Multiply two factors by finding same variable assignments and multiplying their phi together.
"""
# Get the unique variables across both factors
uniqueVars = f2.variables[:]
for i in range(len(f1.variables)):
if f1.variables[i] not in uniqueVars:
uniqueVars.insert(0, f1.variables[i])
# Create the new product factor
factor = Factor(uniqueVars)
for i in range(len(factor.variables)):
factor.setCard(i, mnCards[factor.variables[i]])
factor.calculateStrides()
j, k = 0, 0
psi = []
assignment = [0 for i in range(len(factor.variables))]
factorSize = 1
# Size of new factor will be product of each variable's cardinality
for i in range(len(factor.card)):
factorSize *= factor.card[i]
for i in range(factorSize):
if debug: print "multiplying", j, k, f1.phi[j], f2.phi[k]
psi.append(f1.phi[j] * f2.phi[k])
# Loop from last to first since values are 000, 001, 010, 011 instead of 000, 100, 010, 110
for v in range(len(factor.variables)-1,-1,-1):
curVariable = factor.variables[v]
assignment[v] += 1
if assignment[v] == factor.card[v]:
assignment[v] = 0
if curVariable in f1.variables:
j = j - (factor.card[v] - 1) * f1.stride[f1.variables.index(curVariable)]
if curVariable in f2.variables:
k = k - (factor.card[v] - 1) * f2.stride[f2.variables.index(curVariable)]
else:
if curVariable in f1.variables:
j = j + f1.stride[f1.variables.index(curVariable)]
if curVariable in f2.variables:
k = k + f2.stride[f2.variables.index(curVariable)]
break
factor.phi = psi[:]
return factor
def readFunctionTables(mnCards, mnCliques):
"""
Reads function tables defined in the input file
"""
mnFactors = []
factorIndex, factorNum = 0, 0
fClass = Factor(mnCliques[factorIndex])
for i in range(len(fClass.variables)):
fClass.setCard(i, mnCards[fClass.variables[i]])
fClass.calculateStrides()
factor = []
done = False
while not done:
inputRow = inFile.readline().strip()
if inputRow == "":
continue
else:
if " " in inputRow:
splitRow = inputRow.split()
if factorNum == 0:
factorNum = int(splitRow[0])
for i in range(1, len(splitRow)):
factor.append(float(splitRow[i]))
else:
for i in range(len(splitRow)):
factor.append(float(splitRow[i]))
if factorNum == len(factor):
factorNum = 0
fClass.phi = factor
mnFactors.append(fClass)
factor = []
factorIndex += 1
if factorIndex < len(mnCliques):
fClass = Factor(mnCliques[factorIndex])
for i in range(len(fClass.variables)):
fClass.setCard(i, mnCards[fClass.variables[i]])
fClass.calculateStrides()
else:
factorNum = int(inputRow)
if len(mnFactors) >= len(mnCliques):
# We have read in all the cliques so break out of while loop
done = True
return mnFactors
def readFunctionTables():
"""
Reads function tables defined in the input file
"""
global mnFactors
mnFactors = []
factorIndex, factorNum = 0, 0
fClass = Factor(mnCliques[factorIndex], mnCards)
factor = []
done = False
while not done:
inputRow = inFile.readline().strip()
if inputRow == "":
continue
else:
if " " in inputRow:
splitRow = inputRow.split()
if factorNum == 0:
factorNum = int(splitRow[0])
for i in range(1, len(splitRow)):
factor.append(float(splitRow[i]))
else:
for i in range(len(splitRow)):
factor.append(float(splitRow[i]))
if factorNum == len(factor):
# Reset for next factor
factorNum = 0
fClass.phi = factor
mnFactors.append(fClass)
factor = []
factorIndex += 1
if factorIndex < len(mnCliques):
fClass = Factor(mnCliques[factorIndex], mnCards)
else:
factorNum = int(inputRow)
if len(mnFactors) >= len(mnCliques):
# All cliques have been read so break out of while loop
done = True
if debug:
for i in range(len(mnFactors)):
mnFactors[i].printF()
def sumOutVariable(factor, variable):
"""
Sum out a variable for variable elimination
"""
if debug: print "eliminating factor"
newVars = [x for x in factor.variables if x != variable]
if debug: print "new vars: ", newVars
newF = Factor(newVars, mnCards)
if len(newVars) > 0:
varIndex = factor.variables.index(variable)
if debug:
print "var index: ", varIndex
newF.printF()
usedVar = [False for x in range(factor.size)]
if debug:
print "used var: ", usedVar
print "stride: ", factor.stride[varIndex], ", card: ", factor.card[varIndex]
psi = []
for i in range(newF.size):
psi.append(0)
start = 0
for k in range(factor.size):
if usedVar[k] == False:
start = k
break
for j in range(factor.card[varIndex]):
if debug: print "start: ", start, " stride: ", factor.stride[varIndex], " j: ", j
psi[i] += factor.phi[start + factor.stride[varIndex] * j]
usedVar[start + factor.stride[varIndex] * j] = True
if debug: print "psi: ", i, " ", psi[i]
newF.phi = psi[:]
return newF
