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solver.py
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solver.py
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import re, sys, copy, time, argparse, os.path
import itertools
from random import shuffle
from collections import Counter
from eval import eval
def is_valid_file(parser, arg):
if not os.path.exists(arg):
parser.error("The file %s does not exist!" % arg)
else:
return arg
def parse_args():
parser = argparse.ArgumentParser(description='SAT solver by Marko Prelevikj and Luka Zlatecan')
parser.add_argument('-i', '--input', required=True, default='empty',
help='[required] Input file', metavar="FILE",
type=lambda x: is_valid_file(parser, x))
parser.add_argument('-o', '--output', required=True, default='empty',
help='[required] Output file', metavar="FILE")
parser.add_argument('-m', '--method', required=False, default='all',
help='[optional] Method to solve the problem. Available options: (greedy|shuffle|max|bin|all)')
args = parser.parse_args()
return args
def parse_inst(input_file): # parse CNF files
with open(input_file) as f: s = f.read()
clauses = s.split('\n')
fs = 0
nvars = 0
parsed = []
vars = set()
for f in clauses:
if f.startswith('c'):
continue
elif f.startswith('p'):
prob = re.split('\s+', f)
nvars = int(prob[2])
fs = int(prob[3])
elif f.strip() == '':
continue
else:
cl = list(map(lambda x: int(x), f.strip().split(' ')))
cl.pop()
vars = vars.union(set([abs(x) for x in cl]))
parsed.append(cl)
return parsed, dict.fromkeys(vars, None)
## modified simplify
def simplify(formula, valuations, add=None):
if not (add is None):
formula.insert(0, add)
id = 0
# print(formula)
while id < len(formula): # identify all the unit clauses
if len(formula[id]) == 1:
val = formula[id][0]
valuations[abs(val)] = val > 0 # value needed to be true
iid = 0
while iid < len(formula): # remove all clauses where the unit literal appears
if val in formula[iid]:
formula.remove(formula[iid])
iid -= 1
elif -val in formula[iid]:
formula[iid].remove(-val)
if(len(formula[iid]) == 0):
return formula, valuations
iid += 1
id = 0
else:
id += 1
return formula, valuations
def SATsolver(formula, valuations, add=None):
formula, valuations = simplify(formula, valuations, add)
if formula == []: # if we managed to empty the list, the formula is satisfied
return valuations
if [] in formula: # if there is an empty clause in the formula, the formula is not satisfied
raise Exception('Contradiction!')
shuffled_list = [e for e, x in valuations.items() if x is None]
for literal in shuffled_list:
value = valuations[literal]
try:
return SATsolver(copy.deepcopy(formula), copy.deepcopy(valuations), [literal])
except Exception:
try:
return SATsolver(list(formula), dict(valuations), [-literal])
except Exception:
continue
raise Exception('No match!')
def SATsolverShuffle(formula, valuations, add=None):
formula, valuations = simplify(formula, valuations, add)
if formula == []: # if we managed to empty the list, the formula is satisfied
return valuations
if [] in formula: # if there is an empty clause in the formula, the formula is not satisfied
raise Exception('Contradiction!')
shuffled_list = [e for e, x in valuations.items() if x is None]
shuffle(shuffled_list)
for literal in shuffled_list:
value = valuations[literal]
try:
return SATsolver(copy.deepcopy(formula), copy.deepcopy(valuations), [literal])
except Exception:
try:
return SATsolver(list(formula), dict(valuations), [-literal])
except Exception:
continue
raise Exception('No match!')
def findMaxOccList(formula):
totals = Counter(i for i in map(abs, list(itertools.chain.from_iterable(formula))))
return sorted(totals, key=totals.get, reverse=True)
def SATsolverMax(formula, valuations, add=None):
formula, valuations = simplify(formula, valuations, add)
if formula == []: # if we managed to empty the list, the formula is satisfied
return valuations
if [] in formula: # if there is an empty clause in the formula, the formula is not satisfied
raise Exception('Contradiction!')
maxOcc_list = findMaxOccList(formula)
for literal in maxOcc_list:
value = valuations[literal]
try:
return SATsolverMax(copy.deepcopy(formula), copy.deepcopy(valuations), [literal])
except Exception:
try:
return SATsolverMax(list(formula), dict(valuations), [-literal])
except Exception:
continue
raise Exception('No match!')
def findMaxOcc(formula):
totals = Counter(i for i in map(abs, list(itertools.chain.from_iterable(formula))))
return sorted(totals, key=totals.get, reverse=True)[0]
def SATsolverMaxBin(formula, valuations, add=None):
formula, valuations = simplify(formula, valuations, add)
if formula == []: # if we managed to empty the list, the formula is satisfied
return valuations
if [] in formula: # if there is an empty clause in the formula, the formula is not satisfied
raise Exception('Contradiction!')
maxOcc_el = findMaxOcc(formula)
try:
return SATsolverMaxBin(copy.deepcopy(formula), copy.deepcopy(valuations), [maxOcc_el])
except Exception:
try:
return SATsolverMaxBin(list(formula), dict(valuations), [-maxOcc_el])
except Exception:
raise Exception('No match!')
def obtainSolution(formula, variables, solverType, solver, output_file):
print('[{}] Finding solution:'.format(solverType))
time_started = time.time()
solution = solver(copy.deepcopy(formula), copy.deepcopy(variables))
check = eval(formula, solution)
print("[{}] Solution check = {}".format(solverType, check))
solution = solution if check else None
time_ended = time.time()
print('[{}] Execution time: {}'.format(solverType, time_ended - time_started))
# writeTo = os.path.join(os.path.dirname(output_file), 'out_{}_'.format(solverType) + os.path.basename(output_file))
writeTo = output_file
with open(writeTo, 'w') as file:
if solution is None:
print('FAIL')
file.write('0');
else:
print('SUCCESS')
for x, y in solution.items():
file.write('{} '.format(x if y else -x))
return (check, solution)
def main():
args = parse_args()
formula, variables = parse_inst(args.input)
findMaxOcc(formula)
try: # greedy|shuffle|max|bin
if (args.method == 'greedy'):
check_greedy, solution_greedy = obtainSolution(formula, variables, 'greedy', SATsolver, args.output)
elif args.method == 'shuffle':
check_shuffle, solution_shuffle = obtainSolution(formula, variables, 'shuffler', SATsolverShuffle, args.output)
elif args.method == 'max':
check_max, solution_max = obtainSolution(formula, variables, 'max-occ', SATsolverMax, args.output)
elif args.method == 'bin':
check_bin, solution_bin = obtainSolution(formula, variables, 'bin-max-occ', SATsolverMaxBin, args.output)
elif args.method == 'all':
check_greedy, solution_greedy = obtainSolution(formula, variables, 'greedy', SATsolver, args.output)
check_shuffle, solution_shuffle = obtainSolution(formula, variables, 'shuffler', SATsolverShuffle, args.output)
check_max, solution_max = obtainSolution(formula, variables, 'max-occ', SATsolverMax, args.output)
check_bin, solution_bin = obtainSolution(formula, variables, 'bin-max-occ', SATsolverMaxBin, args.output)
else:
print('No such option!')
sys.exit(-1)
except Exception as error:
print('FAIL', error)
if __name__ == '__main__':
main()