def backtrack(csp):
"""Performs the backtracking search for the given csp.
If there is a solution, this method returns True; otherwise, it returns False.
"""
if len(csp.assignment) == len(csp.variables):
return True
variable = select_unassigned_variable(csp)
value = order_domain_values(csp, variable)
#print variable
#print value
flag = 0
for x in value:
csp.variables.begin_transaction()
if is_consistent(csp, variable, x):
#print "past is_consistent"
for var in csp.variables:
if var == variable:
var.assign(x)
var.is_assigned()
solution = backtrack(csp)
if solution != False:
return True
csp.variables.rollback()
return False
def backtrack(csp):
"""Performs the backtracking search for the given csp.
If there is a solution, this method returns True; otherwise, it returns False.
"""
if len(csp.assignment) == len(csp.variables):
return True
variable = select_unassigned_variable(csp)
value = order_domain_values(csp, variable)
#print variable
#print value
flag = 0
for x in value:
csp.variables.begin_transaction()
if is_consistent(csp, variable, x):
#print "past is_consistent"
for var in csp.variables:
if var == variable:
var.assign(x)
var.is_assigned()
solution = backtrack(csp)
if solution != False:
return True
csp.variables.rollback()
return False
def backtrack(csp):
"""Performs the backtracking search for the given csp.
If there is a solution, this method returns True; otherwise, it returns False.
"""
if is_complete(csp):
return True
# get the next unassigned variable
var = select_unassigned_variable(csp)
result = False
orderedDomain = order_domain_values(csp, var)
# for each value in var
for value in orderedDomain:
if is_consistent(csp, var, value):
csp.variables.begin_transaction()
var.assign(value)
if inference(csp, var):
result = backtrack(csp)
if result:
return result
csp.variables.rollback()
return None
def backtrack(csp):
"""Performs the backtracking search for the given csp.
If there is a solution, this method returns True; otherwise, it returns False.
"""
''' Initial completion check '''
complete = is_complete(csp)
if (complete):
return complete
#print len(csp.variables) + " length"
currentVariable = select_unassigned_variable(csp)
if not (currentVariable is None):
#print str(currentVariable.name)
for dv in order_domain_values(csp, currentVariable):
domainValue = dv
#print "domainValue: " + str(domainValue)
if (is_consistent(csp, currentVariable, domainValue)):
#print "assign"
csp.variables.begin_transaction()
''' assign variable '''
currentVariable.assign(domainValue)
result = backtrack(csp)
if not (result == False):
return True
csp.variables.rollback()
return False
def backtrack(csp):
"""Performs the backtracking search for the given csp.
If there is a solution, this method returns True; otherwise, it returns False.
"""
# TODO copy from p3
solution = is_complete(csp)
if solution:
return solution
nextVar = select_unassigned_variable(csp)
# solution = False here
for i in order_domain_values(csp, nextVar):
if is_consistent(csp, nextVar, i):
csp.variables.begin_transaction()
nextVar.assign(i)
if backtrack(csp):
return True
csp.variables.rollback()
return solution
def backtrack(csp):
"""Performs the backtracking search for the given csp.
If there is a solution, this method returns True; otherwise, it returns False.
"""
# TODO implement this
solution = is_complete(csp)
if solution:
return solution
nextVar = select_unassigned_variable(csp)
# solution = False here
for i in order_domain_values(csp, nextVar):
if is_consistent(csp, nextVar, i):
csp.variables.begin_transaction()
nextVar.assign(i)
if backtrack(csp):
return True
csp.variables.rollback()
return solution
def backtrack(csp):
"""Performs the backtracking search for the given csp.
If there is a solution, this method returns True; otherwise, it returns False.
"""
#print "Finding Match"
# TODO implement this
if is_complete(csp):
return True
else:
variable = select_unassigned_variable(csp)
#print variable
for value in order_domain_values(csp, variable):
#print value
if is_consistent(csp, variable, value):
#print "Found Valid"
csp.variables.begin_transaction()
variable.assign(value)
if backtrack(csp):
return True
csp.variables.rollback()
return False
def backtrack(csp): """Performs the backtracking search for the given csp. If there is a solution, this method returns True; otherwise, it returns False. """ # TODO implement this #pass ''' Initial completion check ''' complete = is_complete(csp) if (complete): return complete #print len(csp.variables) + " length" currentVariable = select_unassigned_variable(csp) if not(currentVariable is None): #print str(currentVariable.name) for dv in order_domain_values(csp, currentVariable): domainValue = dv #print "domainValue: " + str(domainValue) if (is_consistent(csp, currentVariable, domainValue)): #print "assign" csp.variables.begin_transaction() ''' assign variable ''' currentVariable.assign(domainValue) result = backtrack(csp) if not(result == False): return True csp.variables.rollback() return False