def _make_init(internal_init, win, aut):
"""Return initial conditions for implementation.
Depending on `aut.qinit`,
synthesize the initial condition `aut.env_init`
using the winning states `win`.
@param internal_init: initial condition for
internal variables.
"""
qinit = aut.qinit
# impl qinit = '\A \A' # we synthesize `env_init` below
env_init = aut.init['env']
new_sys_init = aut.init['sys'] & internal_init & win
# synthesize initial predicate
if qinit in ('\A \A', '\A \E', '\E \E'):
new_env_init = env_init & new_sys_init
elif qinit == '\E \A':
env_bound = aut.exist(aut.varlist['sys'], env_init)
u = env_init & new_sys_init
u |= ~ env_bound
sys_bound = aut.forall(aut.varlist['env'], u)
new_env_init = env_bound & sys_bound
else:
raise ValueError(
'unknown `qinit` value "{qinit}"'.format(
qinit=qinit))
assert new_env_init != aut.false
assert new_sys_init != aut.false
assert is_state_predicate(new_env_init)
assert is_state_predicate(new_sys_init)
aut.init['impl_env'] = new_env_init
aut.init['impl_sys'] = new_sys_init
def _make_init(internal_init, win, aut):
"""Return initial conditions for implementation.
Depending on `aut.qinit`,
synthesize the initial condition `aut.env_init`
using the winning states `win`.
@param internal_init: initial condition for
internal variables.
"""
qinit = aut.qinit
# impl qinit = '\A \A' # we synthesize `env_init` below
env_init = aut.init['env']
new_sys_init = aut.init['sys'] & internal_init & win
# synthesize initial predicate
if qinit in ('\A \A', '\A \E', '\E \E'):
new_env_init = env_init & new_sys_init
elif qinit == '\E \A':
env_bound = aut.exist(aut.varlist['sys'], env_init)
u = env_init & new_sys_init
u |= ~env_bound
sys_bound = aut.forall(aut.varlist['env'], u)
new_env_init = env_bound & sys_bound
else:
raise ValueError('unknown `qinit` value "{qinit}"'.format(qinit=qinit))
assert new_env_init != aut.false
assert new_sys_init != aut.false
assert is_state_predicate(new_env_init)
assert is_state_predicate(new_sys_init)
aut.init['impl_env'] = new_env_init
aut.init['impl_sys'] = new_sys_init
def solve_rabin_game(aut, rank=1):
"""Return winning set and iterants for Rabin(1) game.
@param aut: compiled game with <>[] & []<> winning
@type aut: `temporal.Automaton`
"""
assert rank == 1, 'only rank 1 supported for now'
assert aut.bdd.vars or not aut.vars, (
'first call `Automaton.build`')
# TODO: can these assertions be removed elegantly ?
assert len(aut.win['<>[]']) > 0
assert len(aut.win['[]<>']) > 0
aut.build()
z = aut.false
zold = None
zk = list()
yki = list()
xkijr = list()
while z != zold:
zold = z
xijr = list()
yi = list()
for hold in aut.win['<>[]']:
y, xjr = _cycle_inside(zold, hold, aut)
z |= y
xijr.append(xjr)
yi.append(y)
zk.append(z)
yki.append(yi)
xkijr.append(xijr)
assert is_state_predicate(z), z.support
return zk, yki, xkijr
def solve_rabin_game(aut, rank=1):
"""Return winning set and iterants for Rabin(1) game.
@param aut: compiled game with <>[] & []<> winning
@type aut: `temporal.Automaton`
"""
assert rank == 1, 'only rank 1 supported for now'
assert aut.bdd.vars or not aut.vars, (
'first call `Automaton.build`')
# TODO: can these assertions be removed elegantly ?
assert len(aut.win['<>[]']) > 0
assert len(aut.win['[]<>']) > 0
aut.build()
z = aut.false
zold = None
zk = list()
yki = list()
xkijr = list()
while z != zold:
zold = z
xijr = list()
yi = list()
for hold in aut.win['<>[]']:
y, xjr = _cycle_inside(zold, hold, aut)
z |= y
xijr.append(xjr)
yi.append(y)
zk.append(z)
yki.append(yi)
xkijr.append(xijr)
assert is_state_predicate(z), z.support
return zk, yki, xkijr
def _assert_is_win(d):
if isinstance(d, list):
for u in d:
assert prm.is_state_predicate(u), u
return
assert isinstance(d, dict), d
for _, v in d.items():
_assert_is_win(v)
def test_is_state_predicate():
fol = setup()
s = "x = -3 /\ ~ y"
u = fol.add_expr(s)
assert prm.is_state_predicate(u)
assert not prm.is_primed_state_predicate(u, fol)
assert not prm.is_proper_action(u)
s = "x' = -3 /\ ~ y'"
u = fol.add_expr(s)
assert not prm.is_state_predicate(u)
assert prm.is_primed_state_predicate(u, fol)
assert not prm.is_proper_action(u)
s = "x = -3 /\ ~ y'"
u = fol.add_expr(s)
assert not prm.is_state_predicate(u)
assert not prm.is_primed_state_predicate(u, fol)
assert prm.is_proper_action(u)
def _assert_is_win(d):
if isinstance(d, list):
for u in d:
assert prm.is_state_predicate(u), u
return
assert isinstance(d, dict), d
for _, v in d.items():
_assert_is_win(v)
def trap(env_action, sys_action, safe, aut, unless=None):
"""Return subset of `safe` with contolled exit.
@param unless: if `None`, then returned controlled invariant
subset of `safe`. Otherwise, this defines an allowed set.
@rtype: BDD node
"""
logger.info('++ cinv')
assert is_state_predicate(safe), aut.support(safe)
q = aut.true # if `unless is not None`,
# then `q = safe` is wrong
qold = None
while q != qold:
qold = q
pre = step(env_action, sys_action, q, aut)
q = safe & pre
if unless is not None:
q |= unless
assert is_state_predicate(q), aut.support(q)
logger.info('-- cinv')
return q
def attractor(env_action, sys_action, target, aut, inside=None):
"""Return attractor for `target`.
Keyword args as `step`.
@param inside: remain in this set
"""
logger.info('++ attractor')
assert is_state_predicate(target), aut.support(target)
# ancestors
q = target
qold = None
while q != qold:
qold = q
pred = step(env_action, sys_action, q, aut)
q |= pred
if inside is not None:
q &= inside
assert is_state_predicate(q), aut.support(q)
logger.info('-- attractor')
return q
def trap(env_action, sys_action, safe, aut,
unless=None):
"""Return subset of `safe` with contolled exit.
@param unless: if `None`, then returned controlled invariant
subset of `safe`. Otherwise, this defines an allowed set.
@rtype: BDD node
"""
logger.info('++ cinv')
assert is_state_predicate(safe), aut.support(safe)
q = aut.true # if `unless is not None`,
# then `q = safe` is wrong
qold = None
while q != qold:
qold = q
pre = step(env_action, sys_action, q, aut)
q = safe & pre
if unless is not None:
q |= unless
assert is_state_predicate(q), aut.support(q)
logger.info('-- cinv')
return q
def attractor(env_action, sys_action, target, aut,
inside=None):
"""Return attractor for `target`.
Keyword args as `step`.
@param inside: remain in this set
"""
logger.info('++ attractor')
assert is_state_predicate(target), aut.support(target)
# ancestors
q = target
qold = None
while q != qold:
qold = q
pred = step(env_action, sys_action, q, aut)
q |= pred
if inside is not None:
q &= inside
assert is_state_predicate(q), aut.support(q)
logger.info('-- attractor')
return q
def print_nodes(u, dvars, bdd, care_set=None, care_bits=None):
"""Enumerate first-order models of a set.
A set of nodes is defined over unprimed variables.
@param dvars: table of unprimed variables
@type bdd: `BDD`
"""
assert scope.is_state_predicate(u), u.support
if u == bdd.false:
print('empty set')
return
if care_bits is not None:
assert scope.support_issubset(u, care_bits, bdd), (support, care_bits)
_print_enumeration(u, bdd, dvars, care_set, care_bits)
def _assert_invariant(components, aut, moore=True):
"""Assert invariant about `aut.varlists` and predicates.
- varlists of `components` are disjoint
- `aut.init` and `aut.win` contain state predicates
If `moore=True`, then assert that `aut.action` are actions
of `components`.
"""
varlists = {k: v for k, v in aut.varlist.items() if k in components}
actions = {k: v for k, v in aut.actions.items() if k in components}
assert prm.pairwise_disjoint(varlists), varlists
for u in aut.init.values():
assert prm.is_state_predicate(u)
_assert_is_win(aut.win)
if not moore:
return
for component, action in actions.items():
assert prm.is_action_of_player(action, component, aut)
def do_it_yourself():
"""Compute states *from* where we can reach a goal."""
aut, goal, action = spec()
# Compute the least fixpoint,
# so the states from where we can reach the `goal`
# with one or more steps, or we are already there.
vrs = aut.varlist['sys']
primed_vrs = stx.prime_vars(vrs)
r = aut.false
rold = None
# for sure != r, thus at least one iteration
assert r != rold
while r != rold:
rold = r # memo
target = aut.replace_with_primed(vrs, r)
pre = aut.exist(primed_vrs, action & target)
r |= goal | pre
assert prm.is_state_predicate(r)
print_expr(r, aut)
def _assert_invariant(components, aut, moore=True):
"""Assert invariant about `aut.varlists` and predicates.
- varlists of `components` are disjoint
- `aut.init` and `aut.win` contain state predicates
If `moore=True`, then assert that `aut.action` are actions
of `components`.
"""
varlists = {k: v for k, v in aut.varlist.items()
if k in components}
actions = {k: v for k, v in aut.actions.items()
if k in components}
assert prm.pairwise_disjoint(varlists), varlists
for u in aut.init.values():
assert prm.is_state_predicate(u)
_assert_is_win(aut.win)
if not moore:
return
for component, action in actions.items():
assert prm.is_action_of_player(action, component, aut)
def solve_streett_game(aut, rank=1):
r"""Return winning set and iterants for Streett(1) game.
The returned value takes into account actions and
liveness, not initial conditions (i.e., it is the
fixpoint before reasoning about initial conditions).
Expects "env" and "sys" players. Writes:
- `aut.varlist["env'"]`
- `aut.varlist["sys'"]`
@param aut: compiled game with <>[] \/ []<> winning
@type aut: `temporal.Automaton`
"""
assert rank == 1, 'only rank 1 supported for now'
assert aut.bdd.vars or not aut.vars, (
'first call `Automaton.build`')
assert len(aut.win['<>[]']) > 0
assert len(aut.win['[]<>']) > 0
env_action = aut.action['env']
sys_action = aut.action['sys']
aut.build()
z = aut.true
zold = None
while z != zold:
zold = z
cox_z = fx.step(env_action, sys_action, z, aut)
xijk = list()
yij = list()
for goal in aut.win['[]<>']:
goal &= cox_z
y, yj, xjk = _attractor_under_assumptions(goal, aut)
z &= y
xijk.append(xjk)
yij.append(yj)
assert is_state_predicate(z), z.support
return z, yij, xijk
def solve_streett_game(aut, rank=1):
r"""Return winning set and iterants for Streett(1) game.
The returned value takes into account actions and
liveness, not initial conditions (i.e., it is the
fixpoint before reasoning about initial conditions).
Expects "env" and "sys" players. Writes:
- `aut.varlist["env'"]`
- `aut.varlist["sys'"]`
@param aut: compiled game with <>[] \/ []<> winning
@type aut: `temporal.Automaton`
"""
assert rank == 1, 'only rank 1 supported for now'
assert aut.bdd.vars or not aut.vars, (
'first call `Automaton.build`')
assert len(aut.win['<>[]']) > 0
assert len(aut.win['[]<>']) > 0
env_action = aut.action['env']
sys_action = aut.action['sys']
aut.build()
z = aut.true
zold = None
while z != zold:
zold = z
cox_z = fx.step(env_action, sys_action, z, aut)
xijk = list()
yij = list()
for goal in aut.win['[]<>']:
goal &= cox_z
y, yj, xjk = _attractor_under_assumptions(goal, aut)
z &= y
xijk.append(xjk)
yij.append(yj)
assert is_state_predicate(z), z.support
return z, yij, xijk
def _make_init(internal_init, win, aut):
"""Return initial conditions for implementation.
Depending on `aut.qinit`,
synthesize the initial condition `aut.init['impl']`
using the winning states `win`.
The cases are:
- `\A \A`: `InternalInit`
- `\E \E`: `InternalInit /\ Win /\ SysInit`
- `\A \E`:
- `plus_one is True`:
```
/\ SysInit /\ (EnvInit => Win)
/\ InternalInit
```
- `plus_one is False`:
```
/\ EnvInit => (SysInit /\ Win)
/\ InternalInit
```
- `\E \A`:
- `plus_one is True`:
```
/\ \A EnvVars: SysInit /\ (EnvInit => Win)
/\ InternalInit
```
- `plus_one is False`:
```
/\ \A EnvVars: EnvInit => (SysInit /\ Win)
/\ InternalInit
```
where `InternalInit` is the initial condition for internal variables.
@param internal_init: initial condition for
internal variables.
"""
sys_init = aut.init['sys']
env_init = aut.init['env']
env_vars = aut.varlist['env']
qinit = aut.qinit
plus_one = aut.plus_one
# In `omega.games.enumeration` both of these reduce
# to `sys_init & win` over those states that are
# enumerated as initial, because only states that
# satisfy `env_init` are enumerated--assuming
# `env_init` is independent of sys vars.
if plus_one:
form = sys_init & (win | ~ env_init)
else:
form = (sys_init & win) | ~ env_init
assert is_state_predicate(form)
if qinit == '\A \A':
# shared-state, env picks initial state
init = aut.true
elif qinit == '\E \E':
# shared-state, sys picks initial state
init = win & sys_init
elif qinit == '\A \E':
# disjoint-state
init = form
elif qinit == '\E \A':
# disjoint-state
init = aut.forall(env_vars, form)
else:
raise ValueError(
'unknown `qinit` value "{q}"'.format(q=qinit))
assert init != aut.false
assert is_state_predicate(init)
aut.init['impl'] = init & internal_init
