def atmost(cls, lits, bound=1, top_id=None, vpool=None,
encoding=EncType.seqcounter):
"""
This method can be used for creating a CNF encoding of an AtMostK
constraint, i.e. of :math:`\sum_{i=1}^{n}{x_i}\leq k`. The method
shares the arguments and the return type with method
:meth:`CardEnc.atleast`. Please, see it for details.
"""
if encoding < 0 or encoding > 9:
raise(NoSuchEncodingError(encoding))
assert not top_id or not vpool, \
'Use either a top id or a pool of variables but not both.'
# we are going to return this formula
ret = CNFPlus()
# if the list of literals is empty, return empty formula
if not lits:
return ret
# obtaining the top id from the variable pool
if vpool:
top_id = vpool.top
# choosing the maximum id among the current top and the list of literals
top_id = max(map(lambda x: abs(x), lits + [top_id if top_id != None else 0]))
# MiniCard's native representation is handled separately
if encoding == 9:
ret.atmosts, ret.nv = [(lits, bound)], top_id
return ret
if MainThread.check() == True:
# saving default SIGINT handler
def_sigint_handler = signal.signal(signal.SIGINT, signal.SIG_DFL)
res = pycard.encode_atmost(lits, bound, top_id, encoding, 1)
# recovering default SIGINT handler
def_sigint_handler = signal.signal(signal.SIGINT, def_sigint_handler)
else:
res = pycard.encode_atmost(lits, bound, top_id, encoding, 0)
if res:
ret.clauses, ret.nv = res
# updating vpool if necessary
if vpool:
if vpool._occupied and vpool.top <= vpool._occupied[0][0] <= ret.nv:
cls._update_vids(ret, vpool)
else:
vpool.top = ret.nv - 1
vpool._next()
return ret
def atmost(cls, lits, bound=1, top_id=None, encoding=EncType.seqcounter):
"""
This method can be used for creating a CNF encoding of an AtMostK
constraint, i.e. of :math:`\sum_{i=1}^{n}{x_i}\leq k`. The method
shares the arguments and the return type with method
:meth:`CardEnc.atleast`. Please, see it for details.
"""
if encoding < 0 or encoding > 9:
raise (NoSuchEncodingError(encoding))
if not top_id:
top_id = max(map(lambda x: abs(x), lits))
# we are going to return this formula
ret = CNFPlus()
# MiniCard's native representation is handled separately
if encoding == 9:
ret.atmosts, ret.nv = [(lits, bound)], top_id
return ret
# saving default SIGINT handler
def_sigint_handler = signal.signal(signal.SIGINT, signal.SIG_DFL)
res = pycard.encode_atmost(lits, bound, top_id, encoding)
# recovering default SIGINT handler
def_sigint_handler = signal.signal(signal.SIGINT, def_sigint_handler)
if res:
ret.clauses, ret.nv = res
return ret
def atmost(cls, lits, bound=1, top_id=None, vpool=None,
encoding=EncType.seqcounter):
"""
This method can be used for creating a CNF encoding of an AtMostK
constraint, i.e. of :math:`\sum_{i=1}^{n}{x_i}\leq k`. The method
shares the arguments and the return type with method
:meth:`CardEnc.atleast`. Please, see it for details.
"""
if encoding < 0 or encoding > 9:
raise(NoSuchEncodingError(encoding))
# checking if the bound is meaningless for any encoding
if bound < 0:
raise ValueError('Wrong bound: {0}'.format(bound))
if encoding in (0, 4, 5) and 1 < bound < len(lits) - 1:
raise(UnsupportedBound(encoding, bound))
assert not top_id or not vpool, \
'Use either a top id or a pool of variables but not both.'
# we are going to return this formula
ret = CNFPlus()
# if the list of literals is empty, return empty formula
if not lits:
return ret
# obtaining the top id from the variable pool
if vpool:
top_id = vpool.top
# making sure we are dealing with a list of literals
lits = list(lits)
# choosing the maximum id among the current top and the list of literals
top_id = max(map(lambda x: abs(x), lits + [top_id if top_id != None else 0]))
# MiniCard's native representation is handled separately
if encoding == 9:
ret.atmosts, ret.nv = [(lits, bound)], top_id
return ret
res = pycard.encode_atmost(lits, bound, top_id, encoding,
int(MainThread.check()))
if res:
ret.clauses, ret.nv = res
# updating vpool if necessary
if vpool:
if vpool._occupied and vpool.top <= vpool._occupied[0][0] <= ret.nv:
cls._update_vids(ret, vpool)
else:
# here, ret.nv id is assumed to be larger than the top id
vpool.top = ret.nv - 1
vpool._next()
return ret