def solve(F, converter=None, solver=None, n=1, target_variables=None, **kwds):
"""
Solve system of Boolean polynomials ``F`` by solving the
SAT-problem -- produced by ``converter`` -- using ``solver``.
INPUT:
- ``F`` - a sequence of Boolean polynomials
- ``n`` - number of solutions to return. If ``n`` is +infinity
then all solutions are returned. If ``n <infinity`` then ``n``
solutions are returned if ``F`` has at least ``n``
solutions. Otherwise, all solutions of ``F`` are
returned. (default: ``1``)
- ``converter`` - an ANF to CNF converter class or object. If
``converter`` is ``None`` then
:class:`sage.sat.converters.polybori.CNFEncoder` is used to
construct a new converter. (default: ``None``)
- ``solver`` - a SAT-solver class or object. If ``solver`` is
``None`` then :class:`sage.sat.solvers.cryptominisat.CryptoMiniSat`
is used to construct a new converter. (default: ``None``)
- ``target_variables`` - a list of variables. The elements of the list are
used to exclude a particular combination of variable assignments of a
solution from any further solution. Furthermore ``target_variables``
denotes which variable-value pairs appear in the solutions. If
``target_variables`` is ``None`` all variables appearing in the
polynomials of ``F`` are used to construct exclusion clauses.
(default: ``None``)
- ``**kwds`` - parameters can be passed to the converter and the
solver by prefixing them with ``c_`` and ``s_`` respectively. For
example, to increase CryptoMiniSat's verbosity level, pass
``s_verbosity=1``.
OUTPUT:
A list of dictionaries, each of which contains a variable
assignment solving ``F``.
EXAMPLES:
We construct a very small-scale AES system of equations::
sage: sr = mq.SR(1,1,1,4,gf2=True,polybori=True)
sage: F,s = sr.polynomial_system()
and pass it to a SAT solver::
sage: from sage.sat.boolean_polynomials import solve as solve_sat # optional - cryptominisat
sage: s = solve_sat(F) # optional - cryptominisat
sage: F.subs(s[0]) # optional - cryptominisat
Polynomial Sequence with 36 Polynomials in 0 Variables
This time we pass a few options through to the converter and the solver::
sage: s = solve_sat(F, s_verbosity=1, c_max_vars_sparse=4, c_cutting_number=8) # optional - cryptominisat
c ...
...
sage: F.subs(s[0]) # optional - cryptominisat
Polynomial Sequence with 36 Polynomials in 0 Variables
We construct a very simple system with three solutions and ask for a specific number of solutions::
sage: B.<a,b> = BooleanPolynomialRing() # optional - cryptominisat
sage: f = a*b # optional - cryptominisat
sage: l = solve_sat([f],n=1) # optional - cryptominisat
sage: len(l) == 1, f.subs(l[0]) # optional - cryptominisat
(True, 0)
sage: l = sorted(solve_sat([a*b],n=2)) # optional - cryptominisat
sage: len(l) == 2, f.subs(l[0]), f.subs(l[1]) # optional - cryptominisat
(True, 0, 0)
sage: sorted(solve_sat([a*b],n=3)) # optional - cryptominisat
[{b: 0, a: 0}, {b: 0, a: 1}, {b: 1, a: 0}]
sage: sorted(solve_sat([a*b],n=4)) # optional - cryptominisat
[{b: 0, a: 0}, {b: 0, a: 1}, {b: 1, a: 0}]
sage: sorted(solve_sat([a*b],n=infinity)) # optional - cryptominisat
[{b: 0, a: 0}, {b: 0, a: 1}, {b: 1, a: 0}]
In the next example we see how the ``target_variables`` parameter works::
sage: from sage.sat.boolean_polynomials import solve as solve_sat # optional - cryptominisat
sage: R.<a,b,c,d> = BooleanPolynomialRing() # optional - cryptominisat
sage: F = [a+b,a+c+d] # optional - cryptominisat
First the normal use case::
sage: sorted(solve_sat(F,n=infinity)) # optional - cryptominisat
[{d: 0, c: 0, b: 0, a: 0},
{d: 0, c: 1, b: 1, a: 1},
{d: 1, c: 0, b: 1, a: 1},
{d: 1, c: 1, b: 0, a: 0}]
Now we are only interested in the solutions of the variables a and b::
sage: solve_sat(F,n=infinity,target_variables=[a,b]) # optional - cryptominisat
[{b: 0, a: 0}, {b: 1, a: 1}]
.. NOTE::
Although supported, passing converter and solver objects
instead of classes is discouraged because these objects are
stateful.
"""
assert(n>0)
try:
len(F)
except AttributeError:
F = F.gens()
len(F)
P = next(iter(F)).parent()
K = P.base_ring()
if target_variables is None:
target_variables = PolynomialSequence(F).variables()
else:
target_variables = PolynomialSequence(target_variables).variables()
assert(set(target_variables).issubset(set(P.gens())))
# instantiate the SAT solver
if solver is None:
from sage.sat.solvers import CryptoMiniSat as solver
if not isinstance(solver, SatSolver):
solver_kwds = {}
for k, v in six.iteritems(kwds):
if k.startswith("s_"):
solver_kwds[k[2:]] = v
solver = solver(**solver_kwds)
# instantiate the ANF to CNF converter
if converter is None:
from sage.sat.converters.polybori import CNFEncoder as converter
if not isinstance(converter, ANF2CNFConverter):
converter_kwds = {}
for k, v in six.iteritems(kwds):
if k.startswith("c_"):
converter_kwds[k[2:]] = v
converter = converter(solver, P, **converter_kwds)
phi = converter(F)
rho = dict((phi[i], i) for i in range(len(phi)))
S = []
while True:
s = solver()
if s:
S.append(dict((x, K(s[rho[x]])) for x in target_variables))
if n is not None and len(S) == n:
break
exclude_solution = tuple(-rho[x] if s[rho[x]] else rho[x] for x in target_variables)
solver.add_clause(exclude_solution)
else:
try:
learnt = solver.learnt_clauses(unitary_only=True)
if learnt:
S.append(dict((phi[abs(i)-1], K(i<0)) for i in learnt))
else:
S.append(s)
break
except (AttributeError, NotImplementedError):
# solver does not support recovering learnt clauses
S.append(s)
break
if len(S) == 1:
if S[0] is False:
return False
if S[0] is None:
return None
elif S[-1] is False:
return S[0:-1]
return S
def learn(F, converter=None, solver=None, max_learnt_length=3, interreduction=False, **kwds):
"""
Learn new polynomials by running SAT-solver ``solver`` on
SAT-instance produced by ``converter`` from ``F``.
INPUT:
- ``F`` - a sequence of Boolean polynomials
- ``converter`` - an ANF to CNF converter class or object. If ``converter`` is ``None`` then
:class:`sage.sat.converters.polybori.CNFEncoder` is used to construct a new
converter. (default: ``None``)
- ``solver`` - a SAT-solver class or object. If ``solver`` is ``None`` then
:class:`sage.sat.solvers.cryptominisat.CryptoMiniSat` is used to construct a new converter.
(default: ``None``)
- ``max_learnt_length`` - only clauses of length <= ``max_length_learnt`` are considered and
converted to polynomials. (default: ``3``)
- ``interreduction`` - inter-reduce the resulting polynomials (default: ``False``)
.. NOTE::
More parameters can be passed to the converter and the solver by prefixing them with ``c_`` and
``s_`` respectively. For example, to increase CryptoMiniSat's verbosity level, pass
``s_verbosity=1``.
OUTPUT:
A sequence of Boolean polynomials.
EXAMPLES::
sage: from sage.sat.boolean_polynomials import learn as learn_sat # optional - cryptominisat
We construct a simple system and solve it::
sage: set_random_seed(2300) # optional - cryptominisat
sage: sr = mq.SR(1,2,2,4,gf2=True,polybori=True) # optional - cryptominisat
sage: F,s = sr.polynomial_system() # optional - cryptominisat
sage: H = learn_sat(F) # optional - cryptominisat
sage: H[-1] # optional - cryptominisat
k033 + 1
"""
try:
len(F)
except AttributeError:
F = F.gens()
len(F)
P = next(iter(F)).parent()
K = P.base_ring()
# instantiate the SAT solver
if solver is None:
from sage.sat.solvers.cryptominisat import CryptoMiniSat as solver
solver_kwds = {}
for k, v in six.iteritems(kwds):
if k.startswith("s_"):
solver_kwds[k[2:]] = v
solver = solver(**solver_kwds)
# instantiate the ANF to CNF converter
if converter is None:
from sage.sat.converters.polybori import CNFEncoder as converter
converter_kwds = {}
for k, v in six.iteritems(kwds):
if k.startswith("c_"):
converter_kwds[k[2:]] = v
converter = converter(solver, P, **converter_kwds)
phi = converter(F)
rho = dict((phi[i], i) for i in range(len(phi)))
s = solver()
if s:
learnt = [x + K(s[rho[x]]) for x in P.gens()]
else:
learnt = []
try:
lc = solver.learnt_clauses()
except (AttributeError, NotImplementedError):
# solver does not support recovering learnt clauses
lc = []
for c in lc:
if len(c) <= max_learnt_length:
try:
learnt.append(converter.to_polynomial(c))
except (ValueError, NotImplementedError, AttributeError):
# the solver might have learnt clauses that contain CNF
# variables which have no correspondence to variables in our
# polynomial ring (XOR chaining variables for example)
pass
learnt = PolynomialSequence(P, learnt)
if interreduction:
learnt = learnt.ideal().interreduced_basis()
return learnt
def solve(F, converter=None, solver=None, n=1, target_variables=None, **kwds):
"""
Solve system of Boolean polynomials ``F`` by solving the
SAT-problem -- produced by ``converter`` -- using ``solver``.
INPUT:
- ``F`` - a sequence of Boolean polynomials
- ``n`` - number of solutions to return. If ``n`` is +infinity
then all solutions are returned. If ``n <infinity`` then ``n``
solutions are returned if ``F`` has at least ``n``
solutions. Otherwise, all solutions of ``F`` are
returned. (default: ``1``)
- ``converter`` - an ANF to CNF converter class or object. If
``converter`` is ``None`` then
:class:`sage.sat.converters.polybori.CNFEncoder` is used to
construct a new converter. (default: ``None``)
- ``solver`` - a SAT-solver class or object. If ``solver`` is
``None`` then :class:`sage.sat.solvers.cryptominisat.CryptoMiniSat`
is used to construct a new converter. (default: ``None``)
- ``target_variables`` - a list of variables. The elements of the list are
used to exclude a particular combination of variable assignments of a
solution from any further solution. Furthermore ``target_variables``
denotes which variable-value pairs appear in the solutions. If
``target_variables`` is ``None`` all variables appearing in the
polynomials of ``F`` are used to construct exclusion clauses.
(default: ``None``)
- ``**kwds`` - parameters can be passed to the converter and the
solver by prefixing them with ``c_`` and ``s_`` respectively. For
example, to increase CryptoMiniSat's verbosity level, pass
``s_verbosity=1``.
OUTPUT:
A list of dictionaries, each of which contains a variable
assignment solving ``F``.
EXAMPLES:
We construct a very small-scale AES system of equations::
sage: sr = mq.SR(1,1,1,4,gf2=True,polybori=True)
sage: while True: # workaround (see :trac:`31891`)
....: try:
....: F, s = sr.polynomial_system()
....: break
....: except ZeroDivisionError:
....: pass
and pass it to a SAT solver::
sage: from sage.sat.boolean_polynomials import solve as solve_sat # optional - cryptominisat
sage: s = solve_sat(F) # optional - cryptominisat
sage: F.subs(s[0]) # optional - cryptominisat
Polynomial Sequence with 36 Polynomials in 0 Variables
This time we pass a few options through to the converter and the solver::
sage: s = solve_sat(F, s_verbosity=1, c_max_vars_sparse=4, c_cutting_number=8) # optional - cryptominisat
c ...
...
sage: F.subs(s[0]) # optional - cryptominisat
Polynomial Sequence with 36 Polynomials in 0 Variables
We construct a very simple system with three solutions and ask for a specific number of solutions::
sage: B.<a,b> = BooleanPolynomialRing() # optional - cryptominisat
sage: f = a*b # optional - cryptominisat
sage: l = solve_sat([f],n=1) # optional - cryptominisat
sage: len(l) == 1, f.subs(l[0]) # optional - cryptominisat
(True, 0)
sage: l = solve_sat([a*b],n=2) # optional - cryptominisat
sage: len(l) == 2, f.subs(l[0]), f.subs(l[1]) # optional - cryptominisat
(True, 0, 0)
sage: sorted((d[a], d[b]) for d in solve_sat([a*b],n=3)) # optional - cryptominisat
[(0, 0), (0, 1), (1, 0)]
sage: sorted((d[a], d[b]) for d in solve_sat([a*b],n=4)) # optional - cryptominisat
[(0, 0), (0, 1), (1, 0)]
sage: sorted((d[a], d[b]) for d in solve_sat([a*b],n=infinity)) # optional - cryptominisat
[(0, 0), (0, 1), (1, 0)]
In the next example we see how the ``target_variables`` parameter works::
sage: from sage.sat.boolean_polynomials import solve as solve_sat # optional - cryptominisat
sage: R.<a,b,c,d> = BooleanPolynomialRing() # optional - cryptominisat
sage: F = [a+b,a+c+d] # optional - cryptominisat
First the normal use case::
sage: sorted((D[a], D[b], D[c], D[d]) for D in solve_sat(F,n=infinity)) # optional - cryptominisat
[(0, 0, 0, 0), (0, 0, 1, 1), (1, 1, 0, 1), (1, 1, 1, 0)]
Now we are only interested in the solutions of the variables a and b::
sage: solve_sat(F,n=infinity,target_variables=[a,b]) # optional - cryptominisat
[{b: 0, a: 0}, {b: 1, a: 1}]
Here, we generate and solve the cubic equations of the AES SBox (see :trac:`26676`)::
sage: from sage.rings.polynomial.multi_polynomial_sequence import PolynomialSequence # optional - cryptominisat, long time
sage: from sage.sat.boolean_polynomials import solve as solve_sat # optional - cryptominisat, long time
sage: sr = sage.crypto.mq.SR(1, 4, 4, 8, allow_zero_inversions = True) # optional - cryptominisat, long time
sage: sb = sr.sbox() # optional - cryptominisat, long time
sage: eqs = sb.polynomials(degree = 3) # optional - cryptominisat, long time
sage: eqs = PolynomialSequence(eqs) # optional - cryptominisat, long time
sage: variables = map(str, eqs.variables()) # optional - cryptominisat, long time
sage: variables = ",".join(variables) # optional - cryptominisat, long time
sage: R = BooleanPolynomialRing(16, variables) # optional - cryptominisat, long time
sage: eqs = [R(eq) for eq in eqs] # optional - cryptominisat, long time
sage: sls_aes = solve_sat(eqs, n = infinity) # optional - cryptominisat, long time
sage: len(sls_aes) # optional - cryptominisat, long time
256
TESTS:
Test that :trac:`26676` is fixed::
sage: varl = ['k{0}'.format(p) for p in range(29)]
sage: B = BooleanPolynomialRing(names = varl)
sage: B.inject_variables(verbose=False)
sage: keqs = [
....: k0 + k6 + 1,
....: k3 + k9 + 1,
....: k5*k18 + k6*k18 + k7*k16 + k7*k10,
....: k9*k17 + k8*k24 + k11*k17,
....: k1*k13 + k1*k15 + k2*k12 + k3*k15 + k4*k14,
....: k5*k18 + k6*k16 + k7*k18,
....: k3 + k26,
....: k0 + k19,
....: k9 + k28,
....: k11 + k20]
sage: from sage.sat.boolean_polynomials import solve as solve_sat
sage: solve_sat(keqs, n=1, solver=SAT('cryptominisat')) # optional - cryptominisat
[{k28: 0,
k26: 1,
k24: 0,
k20: 0,
k19: 0,
k18: 0,
k17: 0,
k16: 0,
k15: 0,
k14: 0,
k13: 0,
k12: 0,
k11: 0,
k10: 0,
k9: 0,
k8: 0,
k7: 0,
k6: 1,
k5: 0,
k4: 0,
k3: 1,
k2: 0,
k1: 0,
k0: 0}]
sage: solve_sat(keqs, n=1, solver=SAT('picosat')) # optional - pycosat
[{k28: 0,
k26: 1,
k24: 0,
k20: 0,
k19: 0,
k18: 0,
k17: 0,
k16: 0,
k15: 0,
k14: 0,
k13: 1,
k12: 1,
k11: 0,
k10: 0,
k9: 0,
k8: 0,
k7: 0,
k6: 1,
k5: 0,
k4: 1,
k3: 1,
k2: 1,
k1: 1,
k0: 0}]
.. NOTE::
Although supported, passing converter and solver objects
instead of classes is discouraged because these objects are
stateful.
"""
assert (n > 0)
try:
len(F)
except AttributeError:
F = F.gens()
len(F)
P = next(iter(F)).parent()
K = P.base_ring()
if target_variables is None:
target_variables = PolynomialSequence(F).variables()
else:
target_variables = PolynomialSequence(target_variables).variables()
assert (set(target_variables).issubset(set(P.gens())))
# instantiate the SAT solver
if solver is None:
from sage.sat.solvers import CryptoMiniSat as solver
if not isinstance(solver, SatSolver):
solver_kwds = {}
for k, v in kwds.items():
if k.startswith("s_"):
solver_kwds[k[2:]] = v
solver = solver(**solver_kwds)
# instantiate the ANF to CNF converter
if converter is None:
from sage.sat.converters.polybori import CNFEncoder as converter
if not isinstance(converter, ANF2CNFConverter):
converter_kwds = {}
for k, v in kwds.items():
if k.startswith("c_"):
converter_kwds[k[2:]] = v
converter = converter(solver, P, **converter_kwds)
phi = converter(F)
rho = dict((phi[i], i) for i in range(len(phi)))
S = []
while True:
s = solver()
if s:
S.append(dict((x, K(s[rho[x]])) for x in target_variables))
if n is not None and len(S) == n:
break
exclude_solution = tuple(-rho[x] if s[rho[x]] else rho[x]
for x in target_variables)
solver.add_clause(exclude_solution)
else:
try:
learnt = solver.learnt_clauses(unitary_only=True)
if learnt:
S.append(dict((phi[abs(i) - 1], K(i < 0)) for i in learnt))
else:
S.append(s)
break
except (AttributeError, NotImplementedError):
# solver does not support recovering learnt clauses
S.append(s)
break
if len(S) == 1:
if S[0] is False:
return False
if S[0] is None:
return None
elif S[-1] is False:
return S[0:-1]
return S
def learn(F,
converter=None,
solver=None,
max_learnt_length=3,
interreduction=False,
**kwds):
"""
Learn new polynomials by running SAT-solver ``solver`` on
SAT-instance produced by ``converter`` from ``F``.
INPUT:
- ``F`` - a sequence of Boolean polynomials
- ``converter`` - an ANF to CNF converter class or object. If ``converter`` is ``None`` then
:class:`sage.sat.converters.polybori.CNFEncoder` is used to construct a new
converter. (default: ``None``)
- ``solver`` - a SAT-solver class or object. If ``solver`` is ``None`` then
:class:`sage.sat.solvers.cryptominisat.CryptoMiniSat` is used to construct a new converter.
(default: ``None``)
- ``max_learnt_length`` - only clauses of length <= ``max_length_learnt`` are considered and
converted to polynomials. (default: ``3``)
- ``interreduction`` - inter-reduce the resulting polynomials (default: ``False``)
.. NOTE::
More parameters can be passed to the converter and the solver by prefixing them with ``c_`` and
``s_`` respectively. For example, to increase CryptoMiniSat's verbosity level, pass
``s_verbosity=1``.
OUTPUT:
A sequence of Boolean polynomials.
EXAMPLES::
sage: from sage.sat.boolean_polynomials import learn as learn_sat # optional - cryptominisat
We construct a simple system and solve it::
sage: set_random_seed(2300) # optional - cryptominisat
sage: sr = mq.SR(1,2,2,4,gf2=True,polybori=True) # optional - cryptominisat
sage: F,s = sr.polynomial_system() # optional - cryptominisat
sage: H = learn_sat(F) # optional - cryptominisat
sage: H[-1] # optional - cryptominisat
k033 + 1
"""
try:
len(F)
except AttributeError:
F = F.gens()
len(F)
P = next(iter(F)).parent()
K = P.base_ring()
# instantiate the SAT solver
if solver is None:
from sage.sat.solvers.cryptominisat import CryptoMiniSat as solver
solver_kwds = {}
for k, v in kwds.items():
if k.startswith("s_"):
solver_kwds[k[2:]] = v
solver = solver(**solver_kwds)
# instantiate the ANF to CNF converter
if converter is None:
from sage.sat.converters.polybori import CNFEncoder as converter
converter_kwds = {}
for k, v in kwds.items():
if k.startswith("c_"):
converter_kwds[k[2:]] = v
converter = converter(solver, P, **converter_kwds)
phi = converter(F)
rho = dict((phi[i], i) for i in range(len(phi)))
s = solver()
if s:
learnt = [x + K(s[rho[x]]) for x in P.gens()]
else:
learnt = []
try:
lc = solver.learnt_clauses()
except (AttributeError, NotImplementedError):
# solver does not support recovering learnt clauses
lc = []
for c in lc:
if len(c) <= max_learnt_length:
try:
learnt.append(converter.to_polynomial(c))
except (ValueError, NotImplementedError, AttributeError):
# the solver might have learnt clauses that contain CNF
# variables which have no correspondence to variables in our
# polynomial ring (XOR chaining variables for example)
pass
learnt = PolynomialSequence(P, learnt)
if interreduction:
learnt = learnt.ideal().interreduced_basis()
return learnt
def solve(F, converter=None, solver=None, n=1, target_variables=None, **kwds):
"""
Solve system of Boolean polynomials ``F`` by solving the
SAT-problem -- produced by ``converter`` -- using ``solver``.
INPUT:
- ``F`` - a sequence of Boolean polynomials
- ``n`` - number of solutions to return. If ``n`` is +infinity
then all solutions are returned. If ``n <infinity`` then ``n``
solutions are returned if ``F`` has at least ``n``
solutions. Otherwise, all solutions of ``F`` are
returned. (default: ``1``)
- ``converter`` - an ANF to CNF converter class or object. If
``converter`` is ``None`` then
:class:`sage.sat.converters.polybori.CNFEncoder` is used to
construct a new converter. (default: ``None``)
- ``solver`` - a SAT-solver class or object. If ``solver`` is
``None`` then :class:`sage.sat.solvers.cryptominisat.CryptoMiniSat`
is used to construct a new converter. (default: ``None``)
- ``target_variables`` - a list of variables. The elements of the list are
used to exclude a particular combination of variable assignments of a
solution from any further solution. Furthermore ``target_variables``
denotes which variable-value pairs appear in the solutions. If
``target_variables`` is ``None`` all variables appearing in the
polynomials of ``F`` are used to construct exclusion clauses.
(default: ``None``)
- ``**kwds`` - parameters can be passed to the converter and the
solver by prefixing them with ``c_`` and ``s_`` respectively. For
example, to increase CryptoMiniSat's verbosity level, pass
``s_verbosity=1``.
OUTPUT:
A list of dictionaries, each of which contains a variable
assignment solving ``F``.
EXAMPLES:
We construct a very small-scale AES system of equations::
sage: sr = mq.SR(1,1,1,4,gf2=True,polybori=True)
sage: F,s = sr.polynomial_system()
and pass it to a SAT solver::
sage: from sage.sat.boolean_polynomials import solve as solve_sat # optional - cryptominisat
sage: s = solve_sat(F) # optional - cryptominisat
sage: F.subs(s[0]) # optional - cryptominisat
Polynomial Sequence with 36 Polynomials in 0 Variables
This time we pass a few options through to the converter and the solver::
sage: s = solve_sat(F, s_verbosity=1, c_max_vars_sparse=4, c_cutting_number=8) # optional - cryptominisat
c --> ...
...
sage: F.subs(s[0]) # optional - cryptominisat
Polynomial Sequence with 36 Polynomials in 0 Variables
We construct a very simple system with three solutions and ask for a specific number of solutions::
sage: B.<a,b> = BooleanPolynomialRing() # optional - cryptominisat
sage: f = a*b # optional - cryptominisat
sage: l = solve_sat([f],n=1) # optional - cryptominisat
sage: len(l) == 1, f.subs(l[0]) # optional - cryptominisat
(True, 0)
sage: l = sorted(solve_sat([a*b],n=2)) # optional - cryptominisat
sage: len(l) == 2, f.subs(l[0]), f.subs(l[1]) # optional - cryptominisat
(True, 0, 0)
sage: sorted(solve_sat([a*b],n=3)) # optional - cryptominisat
[{b: 0, a: 0}, {b: 0, a: 1}, {b: 1, a: 0}]
sage: sorted(solve_sat([a*b],n=4)) # optional - cryptominisat
[{b: 0, a: 0}, {b: 0, a: 1}, {b: 1, a: 0}]
sage: sorted(solve_sat([a*b],n=infinity)) # optional - cryptominisat
[{b: 0, a: 0}, {b: 0, a: 1}, {b: 1, a: 0}]
In the next example we see how the ``target_variables`` parameter works::
sage: from sage.sat.boolean_polynomials import solve as solve_sat # optional - cryptominisat
sage: R.<a,b,c,d> = BooleanPolynomialRing() # optional - cryptominisat
sage: F = [a+b,a+c+d] # optional - cryptominisat
First the normal use case::
sage: sorted(solve_sat(F,n=infinity)) # optional - cryptominisat
[{d: 0, c: 0, b: 0, a: 0},
{d: 0, c: 1, b: 1, a: 1},
{d: 1, c: 0, b: 1, a: 1},
{d: 1, c: 1, b: 0, a: 0}]
Now we are only interested in the solutions of the variables a and b::
sage: solve_sat(F,n=infinity,target_variables=[a,b]) # optional - cryptominisat
[{b: 0, a: 0}, {b: 1, a: 1}]
.. NOTE::
Although supported, passing converter and solver objects
instead of classes is discouraged because these objects are
stateful.
"""
assert(n>0)
try:
len(F)
except AttributeError:
F = F.gens()
len(F)
P = next(iter(F)).parent()
K = P.base_ring()
if target_variables is None:
target_variables = PolynomialSequence(F).variables()
else:
target_variables = PolynomialSequence(target_variables).variables()
assert(set(target_variables).issubset(set(P.gens())))
# instantiate the SAT solver
if solver is None:
from sage.sat.solvers import CryptoMiniSat as solver
if not isinstance(solver, SatSolver):
solver_kwds = {}
for k, v in six.iteritems(kwds):
if k.startswith("s_"):
solver_kwds[k[2:]] = v
solver = solver(**solver_kwds)
# instantiate the ANF to CNF converter
if converter is None:
from sage.sat.converters.polybori import CNFEncoder as converter
if not isinstance(converter, ANF2CNFConverter):
converter_kwds = {}
for k, v in six.iteritems(kwds):
if k.startswith("c_"):
converter_kwds[k[2:]] = v
converter = converter(solver, P, **converter_kwds)
phi = converter(F)
rho = dict((phi[i], i) for i in range(len(phi)))
S = []
while True:
s = solver()
if s:
S.append(dict((x, K(s[rho[x]])) for x in target_variables))
if n is not None and len(S) == n:
break
exclude_solution = tuple(-rho[x] if s[rho[x]] else rho[x] for x in target_variables)
solver.add_clause(exclude_solution)
else:
try:
learnt = solver.learnt_clauses(unitary_only=True)
if learnt:
S.append(dict((phi[abs(i)-1], K(i<0)) for i in learnt))
else:
S.append(s)
break
except (AttributeError, NotImplementedError):
# solver does not support recovering learnt clauses
S.append(s)
break
if len(S) == 1:
if S[0] is False:
return False
if S[0] is None:
return None
elif S[-1] is False:
return S[0:-1]
return S