spot/src/tgbaalgos/simulation.cc
Alexandre Duret-Lutz bb2ce45b8a simulation: simplify using tgba_digraph more
* src/graph/graph.hh (new_states): New.
* src/tgba/tgbagraph.hh (graph_t): Make it public.
* src/tgbaalgos/simulation.cc: Get read of the acc_compl_automaton
class and replace it by a loop over all states of a tgba_digraph.
Remove some useless data structures.
2014-05-23 18:36:43 +02:00

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// -*- coding: utf-8 -*-
// Copyright (C) 2012, 2013, 2014 Laboratoire de Recherche et Développement
// de l'Epita (LRDE).
//
// This file is part of Spot, a model checking library.
//
// Spot is free software; you can redistribute it and/or modify it
// under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 3 of the License, or
// (at your option) any later version.
//
// Spot is distributed in the hope that it will be useful, but WITHOUT
// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
// or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
// License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
#include <queue>
#include <map>
#include <utility>
#include <cmath>
#include <limits>
#include "tgba/tgbaexplicit.hh"
#include "simulation.hh"
#include "priv/acccompl.hh"
#include "misc/minato.hh"
#include "tgba/bddprint.hh"
#include "tgbaalgos/reachiter.hh"
#include "tgbaalgos/sccfilter.hh"
#include "tgbaalgos/scc.hh"
#include "tgbaalgos/dupexp.hh"
#include "tgbaalgos/dotty.hh"
// The way we developed this algorithm is the following: We take an
// automaton, and reverse all these acceptance conditions. We reverse
// them to go make the meaning of the signature easier. We are using
// bdd, and we want to let it make all the simplification. Because of
// the format of the acceptance condition, it doesn't allow easy
// simplification. Instead of encoding them as: "a!b!c + !ab!c", we
// use them as: "ab". We complement them because we want a
// simplification if the condition of the transition A implies the
// transition of B, and if the acceptance condition of A is included
// in the acceptance condition of B. To let the bdd makes the job, we
// revert them.
// Then, to check if a transition i-dominates another, we'll use the bdd:
// "sig(transA) = cond(trans) & acc(trans) & implied(class(trans->state))"
// Idem for sig(transB). The 'implied'
// (represented by a hash table 'relation_' in the implementation) is
// a conjunction of all the class dominated by the class of the
// destination. This is how the relation is included in the
// signature. It makes the simplifications alone, and the work is
// done. The algorithm is cut into several step:
//
// 1. Run through the tgba and switch the acceptance condition to their
// negation, and initializing relation_ by the 'init_ -> init_' where
// init_ is the bdd which represents the class. This function is the
// constructor of Simulation.
// 2. Enter in the loop (run).
// - Rename the class.
// - run through the automaton and computing the signature of each
// state. This function is `update_sig'.
// - Enter in a double loop to adapt the partial order, and set
// 'relation_' accordingly. This function is `update_po'.
// 3. Rename the class (to actualize the name in the previous_class and
// in relation_).
// 4. Building an automaton with the result, with the condition:
// "a transition in the original automaton appears in the simulated one
// iff this transition is included in the set of i-maximal neighbour."
// This function is `build_output'.
// The automaton simulated is recomplemented to come back to its initial
// state when the object Simulation is destroyed.
//
// Obviously these functions are possibly cut into several little one.
// This is just the general development idea.
// How to use isop:
// I need all variable non_acceptance & non_class.
// bdd_support(sig(X)): All var
// bdd_support(sig(X)) - allacc - allclassvar
// TODO LIST: Play on the order of the selection in the
// dont_care_simulation. The good place to work is in add_to_map_imply.
namespace spot
{
namespace
{
// Some useful typedef:
// Used to get the signature of the state.
typedef std::unordered_map<const state*, bdd,
state_ptr_hash,
state_ptr_equal> map_state_bdd;
typedef std::vector<bdd> vector_state_bdd;
typedef std::map<const state*, const state*,
state_ptr_less_than> map_state_state;
typedef std::vector<const state*> vector_state_state;
// Get the list of state for each class.
typedef std::map<bdd, std::list<unsigned>,
bdd_less_than> map_bdd_lstate;
typedef std::map<bdd, const state*,
bdd_less_than> map_bdd_state;
// Our constraint: (state_src, state_dst) = to_add.
// We define the couple of state as the key of the constraint.
typedef std::pair<const state*, const state*> constraint_key;
// But we need a comparator for that key.
struct constraint_key_comparator
{
bool operator()(const constraint_key& l,
const constraint_key& r) const
{
if (l.first->compare(r.first) < 0)
return true;
else
if (l.first->compare(r.first) > 0)
return false;
if (l.second->compare(r.second) < 0)
return true;
else
if (l.second->compare(r.second) > 0)
return false;
return false;
}
};
// The full definition of the constraint.
typedef std::map<constraint_key, bdd,
constraint_key_comparator> map_constraint;
typedef std::tuple<const state*, const state*, bdd> constraint;
// Helper to create the map of constraints to give to the
// simulation.
void add_to_map(const std::list<constraint>& list,
map_constraint& feed_me)
{
for (auto& p: list)
feed_me.insert(std::make_pair(std::make_pair(std::get<0>(p),
std::get<1>(p)),
std::get<2>(p)));
}
// This class helps to compare two automata in term of
// size.
struct automaton_size
{
automaton_size()
: transitions(0),
states(0)
{
}
inline bool operator!=(const automaton_size& r)
{
return transitions != r.transitions || states != r.states;
}
inline bool operator<(const automaton_size& r)
{
if (states < r.states)
return true;
if (states > r.states)
return false;
if (transitions < r.transitions)
return true;
if (transitions > r.transitions)
return false;
return false;
}
inline bool operator>(const automaton_size& r)
{
if (states < r.states)
return false;
if (states > r.states)
return true;
if (transitions < r.transitions)
return false;
if (transitions > r.transitions)
return true;
return false;
}
int transitions;
int states;
};
// The direct_simulation. If Cosimulation is true, we are doing a
// cosimulation.
template <bool Cosimulation, bool Sba>
class direct_simulation
{
protected:
// Shortcut used in update_po and go_to_next_it.
typedef std::map<bdd, bdd, bdd_less_than> map_bdd_bdd;
public:
direct_simulation(const tgba* t, const map_constraint* map_cst = 0)
: a_(0),
po_size_(0),
all_class_var_(bddtrue),
map_cst_(map_cst),
original_(t)
{
// We need to do a dupexp for being able to run scc_map later.
// new_original_ is the map that contains the relation between
// the names (addresses) of the states in the automaton
// returned by dupexp, and in automaton given in argument to
// the constructor.
a_ = tgba_dupexp_dfs(t, new_original_);
scc_map_ = new scc_map(a_);
scc_map_->build_map();
old_a_ = a_;
acc_compl ac(a_->all_acceptance_conditions(),
a_->neg_acceptance_conditions());
// Replace all the acceptance conditions by their complements.
// (In the case of Cosimulation, we also flip the transitions.)
{
if (Cosimulation)
{
bdd_dict* bd = a_->get_dict();
a_ = new tgba_digraph(bd);
bd->register_all_variables_of(old_a_, a_);
a_->copy_acceptance_conditions_of(old_a_);
}
tgba_digraph::graph_t& gout = a_->get_graph();
tgba_digraph::graph_t& gin = old_a_->get_graph();
unsigned ns = gin.num_states();
if (Cosimulation)
gout.new_states(ns);
for (unsigned s = 0; s < ns; ++s)
{
for (auto& t: gin.out(s))
{
bdd acc;
if (Sba && Cosimulation)
{
// If the acceptance is interpreted as
// state-based, to apply the reverse simulation
// on a SBA, we should pull the acceptance of
// the destination state on its incoming arcs
// (which now become outgoing arcs after
// transposition).
acc = bddfalse;
for (auto& td: gin.out(t.dst))
{
acc = ac.complement(td.acc);
break;
}
}
else
{
acc = ac.complement(t.acc);
}
if (Cosimulation)
gout.new_transition(t.dst, s, t.cond, acc);
else
t.acc = acc;
}
}
size_a_ = ns;
}
initial_state = a_->get_init_state();
// Now, we have to get the bdd which will represent the
// class. We register one bdd by state, because in the worst
// case, |Class| == |State|.
unsigned set_num = a_->get_dict()
->register_anonymous_variables(size_a_ + 1, this);
all_acceptance_conditions_ = a_->all_acceptance_conditions();
all_proms_ = bdd_support(all_acceptance_conditions_);
bdd_initial = bdd_ithvar(set_num++);
bdd init = bdd_ithvar(set_num++);
used_var_.push_back(init);
// Initialize all classes to init.
previous_class_.resize(size_a_);
for (unsigned s = 0; s < size_a_; ++s)
previous_class_[s] = init;
// Put all the anonymous variable in a queue, and record all
// of these in a variable all_class_var_ which will be used
// to understand the destination part in the signature when
// building the resulting automaton.
all_class_var_ = init;
for (unsigned i = set_num; i < set_num + size_a_ - 1; ++i)
{
free_var_.push(i);
all_class_var_ &= bdd_ithvar(i);
}
relation_[init] = init;
}
// Reverse all the acceptance condition at the destruction of
// this object, because it occurs after the return of the
// function simulation.
virtual ~direct_simulation()
{
a_->get_dict()->unregister_all_my_variables(this);
delete scc_map_;
delete old_a_;
// a_ is a new automaton only if we are doing a cosimulation.
if (Cosimulation)
delete a_;
}
// Update the name of the classes.
void update_previous_class()
{
std::list<bdd>::iterator it_bdd = used_var_.begin();
// We run through the map bdd/list<state>, and we update
// the previous_class_ with the new data.
for (auto& p: bdd_lstate_)
{
// If the signature of a state is bddfalse (no
// transitions) the class of this state is bddfalse
// instead of an anonymous variable. It allows
// simplifications in the signature by removing a
// transition which has as a destination a state with
// no outgoing transition.
if (p.first == bddfalse)
for (auto s: p.second)
previous_class_[s] = bddfalse;
else
for (auto s: p.second)
previous_class_[s] = *it_bdd;
++it_bdd;
}
}
void main_loop()
{
unsigned int nb_partition_before = 0;
unsigned int nb_po_before = po_size_ - 1;
while (nb_partition_before != bdd_lstate_.size()
|| nb_po_before != po_size_)
{
update_previous_class();
nb_partition_before = bdd_lstate_.size();
bdd_lstate_.clear();
nb_po_before = po_size_;
po_size_ = 0;
update_sig();
go_to_next_it();
}
update_previous_class();
}
// The core loop of the algorithm.
tgba* run()
{
main_loop();
return build_result();
}
// Take a state and compute its signature.
bdd compute_sig(unsigned src)
{
bdd res = bddfalse;
for (auto& t: a_->get_graph().out(src))
{
bdd acc = bddtrue;
map_constraint::const_iterator it;
// We are using
// new_original_[old_a_->state_from_number(...)] because
// we have the constraints in the original automaton which
// has been duplicated twice to get the current automaton.
if (map_cst_
&& ((it = map_cst_
->find(std::make_pair
(new_original_[old_a_->state_from_number(src)],
new_original_[old_a_->state_from_number(t.dst)])))
!= map_cst_->end()))
{
acc = it->second;
}
else
{
acc = t.acc;
}
// to_add is a conjunction of the acceptance condition,
// the label of the transition and the class of the
// destination and all the class it implies.
bdd to_add = acc & t.cond & relation_[previous_class_[t.dst]];
res |= to_add;
}
// When we Cosimulate, we add a special flag to differentiate
// the initial state from the other.
if (Cosimulation && src == 0)
res |= bdd_initial;
return res;
}
void update_sig()
{
for (unsigned s = 0; s < size_a_; ++s)
bdd_lstate_[compute_sig(s)].push_back(s);
}
// This method rename the color set, update the partial order.
void go_to_next_it()
{
int nb_new_color = bdd_lstate_.size() - used_var_.size();
// If we have created more partitions, we need to use more
// variables.
for (int i = 0; i < nb_new_color; ++i)
{
assert(!free_var_.empty());
used_var_.push_back(bdd_ithvar(free_var_.front()));
free_var_.pop();
}
// If we have reduced the number of partition, we 'free' them
// in the free_var_ list.
for (int i = 0; i > nb_new_color; --i)
{
assert(!used_var_.empty());
free_var_.push(bdd_var(used_var_.front()));
used_var_.pop_front();
}
assert((bdd_lstate_.size() == used_var_.size())
|| (bdd_lstate_.find(bddfalse) != bdd_lstate_.end()
&& bdd_lstate_.size() == used_var_.size() + 1));
// Now we make a temporary hash_table which links the tuple
// "C^(i-1), N^(i-1)" to the new class coloring. If we
// rename the class before updating the partial order, we
// loose the information, and if we make it after, I can't
// figure out how to apply this renaming on rel_.
// It adds a data structure but it solves our problem.
map_bdd_bdd now_to_next;
std::list<bdd>::iterator it_bdd = used_var_.begin();
for (auto& p: bdd_lstate_)
{
// If the signature of a state is bddfalse (no
// transitions) the class of this state is bddfalse
// instead of an anonymous variable. It allows
// simplifications in the signature by removing a
// transition which has as a destination a state with
// no outgoing transition.
now_to_next[p.first] =
(p.first == bddfalse) ? bddfalse : *it_bdd;
++it_bdd;
}
update_po(now_to_next, relation_);
}
// This function computes the new po with previous_class_ and
// the argument. `now_to_next' contains the relation between the
// signature and the future name of the class. We need a
// template parameter because we use this function with a
// map_bdd_bdd, but later, we need a list_bdd_bdd. So to
// factorize some code we use a template.
template <typename container_bdd_bdd>
void update_po(const container_bdd_bdd& now_to_next,
map_bdd_bdd& relation)
{
// This loop follows the pattern given by the paper.
// foreach class do
// | foreach class do
// | | update po if needed
// | od
// od
for (typename container_bdd_bdd::const_iterator it1
= now_to_next.begin();
it1 != now_to_next.end();
++it1)
{
bdd accu = it1->second;
for (typename container_bdd_bdd::const_iterator it2
= now_to_next.begin();
it2 != now_to_next.end();
++it2)
{
// Skip the case managed by the initialization of accu.
if (it1 == it2)
continue;
if (bdd_implies(it1->first, it2->first))
{
accu &= it2->second;
++po_size_;
}
}
relation[it1->second] = accu;
}
}
automaton_size get_stat() const
{
assert(stat.states != 0);
return stat;
}
bool result_is_deterministic() const
{
assert(stat.states != 0);
return res_is_deterministic;
}
// Build the minimal resulting automaton.
tgba* build_result()
{
// Now we need to create a state per partition. But the
// problem is that we don't know exactly the class. We know
// that it is a combination of the acceptance condition
// contained in all_class_var_. So we need to make a little
// workaround. We will create a map which will associate bdd
// and unsigned.
std::map<bdd, unsigned, bdd_less_than> bdd2state;
unsigned int current_max = 0;
// We have all the a_'s acceptances conditions
// complemented. So we need to complement it when adding a
// transition. We *must* keep the complemented because it
// is easy to know if an acceptance condition is maximal or
// not.
acc_compl reverser(all_acceptance_conditions_,
a_->neg_acceptance_conditions());
bdd_dict* d = a_->get_dict();
tgba_explicit_number* res = new tgba_explicit_number(d);
d->register_all_variables_of(a_, res);
res->set_acceptance_conditions(all_acceptance_conditions_);
bdd sup_all_acc = bdd_support(all_acceptance_conditions_);
// Non atomic propositions variables (= acc and class)
bdd nonapvars = sup_all_acc & bdd_support(all_class_var_);
// Create one state per partition.
for (auto& p: bdd_lstate_)
{
res->add_state(++current_max);
bdd part = previous_class_[p.second.front()];
// The difference between the two next lines is:
// the first says "if you see A", the second "if you
// see A and all the classes implied by it".
bdd2state[part] = current_max;
bdd2state[relation_[part]] = current_max;
}
// Acceptance of states. Only used if Sba && Cosimulation.
std::vector<bdd> accst;
if (Sba && Cosimulation)
accst.resize(current_max + 1, bddfalse);
stat.states = bdd_lstate_.size();
stat.transitions = 0;
unsigned nb_satoneset = 0;
unsigned nb_minato = 0;
// For each partition, we will create
// all the transitions between the states.
for (auto& p: bdd_lstate_)
{
// Get the signature.
bdd sig = compute_sig(p.second.front());
if (Cosimulation)
sig = bdd_compose(sig, bddfalse, bdd_var(bdd_initial));
// Get all the variable in the signature.
bdd sup_sig = bdd_support(sig);
// Get the variable in the signature which represents the
// conditions.
bdd sup_all_atomic_prop = bdd_exist(sup_sig, nonapvars);
// Get the part of the signature composed only with the atomic
// proposition.
bdd all_atomic_prop = bdd_exist(sig, nonapvars);
// First loop over all possible valuations atomic properties.
while (all_atomic_prop != bddfalse)
{
bdd one = bdd_satoneset(all_atomic_prop,
sup_all_atomic_prop,
bddtrue);
all_atomic_prop -= one;
// For each possible valuation, iterate over all possible
// destination classes. We use minato_isop here, because
// if the same valuation of atomic properties can go
// to two different classes C1 and C2, iterating on
// C1 + C2 with the above bdd_satoneset loop will see
// C1 then (!C1)C2, instead of C1 then C2.
// With minatop_isop, we ensure that the no negative
// class variable will be seen (likewise for promises).
minato_isop isop(sig & one);
++nb_satoneset;
bdd cond_acc_dest;
while ((cond_acc_dest = isop.next()) != bddfalse)
{
++stat.transitions;
++nb_minato;
// Take the transition, and keep only the variable which
// are used to represent the class.
bdd dest = bdd_existcomp(cond_acc_dest,
all_class_var_);
// Keep only ones who are acceptance condition.
bdd acc = bdd_existcomp(cond_acc_dest, sup_all_acc);
// Keep the other!
bdd cond = bdd_existcomp(cond_acc_dest,
sup_all_atomic_prop);
// Because we have complemented all the acceptance
// conditions on the input automaton, we must
// revert them to create a new transition.
acc = reverser.reverse_complement(acc);
// Take the id of the source and destination. To
// know the source, we must take a random state in
// the list which is in the class we currently
// work on.
int src = bdd2state[previous_class_[p.second.front()]];
int dst = bdd2state[dest];
if (Cosimulation)
std::swap(src, dst);
// src or dst == 0 means "dest" or "prev..." isn't
// in the map. so it is a bug.
assert(src != 0);
assert(dst != 0);
// Create the transition, add the condition and the
// acceptance condition.
tgba_explicit_number::transition* t
= res->create_transition(src, dst);
t->condition = cond;
if (Sba && Cosimulation)
accst[dst] = acc;
else
t->acceptance_conditions = acc;
}
}
}
res->set_init_state(bdd2state[previous_class_[0]]);
res->merge_transitions();
// Mark all accepting state in a second pass, when
// dealing with SBA in cosimulation.
if (Sba && Cosimulation)
for (unsigned snum = current_max; snum > 0; --snum)
{
const state* s = res->get_state(snum);
bdd acc = accst[snum];
for (auto it: res->succ(s))
{
tgba_explicit_number::transition* t =
res->get_transition(it);
t->acceptance_conditions = acc;
}
}
res_is_deterministic = nb_minato == nb_satoneset;
return res;
}
// Debug:
// In a first time, print the signature, and the print a list
// of each state in this partition.
// In a second time, print foreach state, who is where,
// where is the new class name.
void print_partition()
{
for (auto& p: bdd_lstate_)
{
std::cerr << "partition: "
<< bdd_format_isop(a_->get_dict(), p.first)
<< std::endl;
for (auto s: p.second)
std::cerr << " - "
<< a_->format_state(a_->state_from_number(s))
<< '\n';
}
std::cerr << "\nPrevious iteration\n" << std::endl;
unsigned ps = previous_class_.size();
for (unsigned p = 0; p < ps; ++p)
{
std::cerr << a_->format_state(a_->state_from_number(p))
<< " was in "
<< bdd_format_set(a_->get_dict(), previous_class_[p])
<< '\n';
}
}
protected:
// The automaton which is simulated.
tgba_digraph* a_;
tgba_digraph* old_a_;
// Relation is aimed to represent the same thing than
// rel_. The difference is in the way it does.
// If A => A /\ A => B, rel will be (!A U B), but relation_
// will have A /\ B at the key A. This trick is due to a problem
// with the computation of the resulting automaton with the signature.
// rel_ will pollute the meaning of the signature.
map_bdd_bdd relation_;
// Represent the class of each state at the previous iteration.
vector_state_bdd previous_class_;
// The list of state for each class at the current_iteration.
// Computed in `update_sig'.
map_bdd_lstate bdd_lstate_;
// The queue of free bdd. They will be used as the identifier
// for the class.
std::queue<int> free_var_;
// The list of used bdd. They are in used as identifier for class.
std::list<bdd> used_var_;
// Size of the automaton.
unsigned int size_a_;
// Used to know when there is no evolution in the po. Updated
// in the `update_po' method.
unsigned int po_size_;
// All the class variable:
bdd all_class_var_;
// The flag to say if the outgoing state is initial or not
bdd bdd_initial;
// Initial state of the automaton we are working on
state* initial_state;
bdd all_proms_;
automaton_size stat;
scc_map* scc_map_;
map_state_state new_original_;
// This table link a state in the current automaton with a state
// in the original one.
map_state_state old_old_name_;
const map_constraint* map_cst_;
const tgba* original_;
bdd all_acceptance_conditions_;
bool res_is_deterministic;
};
// For now, we don't try to handle cosimulation.
class direct_simulation_dont_care: public direct_simulation<false, false>
{
typedef std::vector<std::list<constraint> > constraints;
typedef std::map<bdd, // Source Class.
std::map<bdd, // Destination (implied) Class.
std::list<constraint>, // Constraints list.
bdd_less_than>,
bdd_less_than> constraint_list;
typedef std::list<std::pair<bdd, bdd> > list_bdd_bdd;
public:
direct_simulation_dont_care(const tgba* t)
: direct_simulation<false, false>(t)
{
// This variable is used in the new signature.
on_cycle_ =
bdd_ithvar(a_->get_dict()->register_anonymous_variables(1, this));
// This one is used for the iteration on all the
// possibilities. Avoid computing two times "no constraints".
empty_seen_ = false;
// If this variable is set to true, we have a number limit of
// simulation to run.
has_limit_ = false;
notap = (bdd_support(all_acceptance_conditions_)
& all_class_var_ & on_cycle_);
}
// This function computes the don't care signature of the state
// src. This signature is similar to the classic one, excepts
// that if the transition is on a SCC, we add a on_cycle_ on it,
// otherwise we add !on_cycle_. This allows us to split the
// signature later.
bdd dont_care_compute_sig(unsigned src)
{
bdd res = bddfalse;
unsigned scc = scc_map_->scc_of_state(old_a_->state_from_number(src));
bool sccacc = scc_map_->accepting(scc);
for (auto& t: a_->get_graph().out(src))
{
bdd cl = previous_class_[t.dst];
bdd acc;
if (scc != scc_map_->scc_of_state(old_a_->state_from_number(t.dst)))
acc = !on_cycle_;
else if (sccacc)
acc = on_cycle_ & t.acc;
else
acc = on_cycle_ & all_proms_;
bdd to_add = acc & t.cond & relation_[cl];
res |= to_add;
}
return res;
}
// We used to have
// sig(s1) = (f1 | g1)
// sig(s2) = (f2 | g2)
// and we say that s2 simulates s1 if sig(s1)=>sig(s2).
// This amount to testing whether (f1|g1)=>(f2|g2),
// which is equivalent to testing both
// f1=>(f2|g2) and g1=>(f2|g2)
// separately.
//
// Now we have a slightly improved version of this rule.
// g1 and g2 are not on cycle, so they can make as many
// promises as we wish, if that helps. Adding promises
// to g2 will not help, but adding promises to g1 can.
//
// So we test whether
// f1=>(f2|g2)
// g1=>noprom(f2|g2)
// Where noprom(f2|g2) removes all promises from f2|g2.
// (g1 do not have promises, and neither do g2).
bool could_imply_aux(bdd f1, bdd g1, bdd left_class,
bdd right, bdd right_class)
{
(void) left_class;
(void) right_class;
bdd f2g2 = bdd_exist(right, on_cycle_);
bdd f2g2n = bdd_exist(f2g2, all_proms_);
bdd both = left_class & right_class;
int lc = bdd_var(left_class);
f1 = bdd_compose(f1, both, lc);
g1 = bdd_compose(g1, both, lc);
f2g2 = bdd_compose(f2g2, both, lc);
f2g2n = bdd_compose(f2g2n, both, lc);
return bdd_implies(f1, f2g2) && bdd_implies(g1, f2g2n);
}
bool could_imply(bdd left, bdd left_class,
bdd right, bdd right_class)
{
bdd f1 = bdd_relprod(left, on_cycle_, on_cycle_);
bdd g1 = bdd_relprod(left, !on_cycle_, on_cycle_);
//bdd f1 = bdd_restrict(left, on_cycle_);
//bdd g1 = bdd_restrict(left, !on_cycle_);
return could_imply_aux(f1, g1, left_class,
right, right_class);
}
void dont_care_update_po(const list_bdd_bdd& now_to_next,
map_bdd_bdd& relation)
{
// This loop follows the pattern given by the paper.
// foreach class do
// | foreach class do
// | | update po if needed
// | od
// od
for (list_bdd_bdd::const_iterator it1 = now_to_next.begin();
it1 != now_to_next.end();
++it1)
{
bdd accu = it1->second;
bdd f1 = bdd_relprod(it1->first, on_cycle_, on_cycle_);
bdd g1 = bdd_relprod(it1->first, !on_cycle_, on_cycle_);
// bdd f1 = bdd_restrict(it1->first_, on_cycle_);
// bdd g1 = bdd_restrict(it1->first_, !on_cycle_);
for (list_bdd_bdd::const_iterator it2 = now_to_next.begin();
it2 != now_to_next.end();
++it2)
{
// Skip the case managed by the initialization of accu.
if (it1 == it2)
continue;
if (could_imply_aux(f1, g1, it1->second,
it2->first, it2->second))
{
accu &= it2->second;
++po_size_;
}
}
relation[it1->second] = accu;
}
}
#define ISOP(bdd) #bdd" - " << bdd_format_isop(a_->get_dict(), bdd)
inline bool is_out_scc(bdd b)
{
return bddfalse != bdd_relprod(b, !on_cycle_, on_cycle_);
// return bddfalse != bdd_restrict(b, !on_cycle_);
}
// This method solves three kind of problems, where we have two
// conjunctions of variable (that corresponds to a particular
// transition), and where left could imply right.
// Three cases:
// - αP₁ ⇒ xβP₁ where x is unknown.
// - xβP₁ ⇒ αP₁ where x is unknown.
// - xαP₁ ⇒ yβP₁ where x, y are unknown.
void create_simple_constraint(bdd left, bdd right,
const state* src_left,
const state* src_right,
std::list<constraint>& constraint)
{
assert(src_left != src_right);
// Determine which is the current case.
bool out_scc_left = is_out_scc(left);
bool out_scc_right = is_out_scc(right);
bdd dest_class = bdd_existcomp(left, all_class_var_);
assert(revert_relation_.find(dest_class) != revert_relation_.end());
const state* dst_left = revert_relation_[dest_class];
dest_class = bdd_existcomp(right, all_class_var_);
const state* dst_right = revert_relation_[dest_class];
assert(src_left != dst_left || src_right != dst_right);
left = bdd_exist(left, all_class_var_ & on_cycle_);
right = bdd_exist(right, all_class_var_ & on_cycle_);
unsigned src_left_n = a_->state_number(src_left);
unsigned src_right_n = a_->state_number(src_right);
unsigned dst_left_n = a_->state_number(dst_left);
unsigned dst_right_n = a_->state_number(dst_right);
if (!out_scc_left && out_scc_right)
{
bdd b = bdd_exist(right, notap);
bdd add = bdd_exist(left & b, bdd_support(b));
if (add != bddfalse
&& bdd_exist(add, all_acceptance_conditions_) == bddtrue)
{
assert(src_right != dst_right);
constraint.emplace_back
(new_original_[old_a_->state_from_number(src_right_n)],
new_original_[old_a_->state_from_number(dst_right_n)],
add);
}
}
else if (out_scc_left && !out_scc_right)
{
bdd b = bdd_exist(left, notap);
bdd add = bdd_exist(right & b, bdd_support(b));
if (add != bddfalse
&& bdd_exist(add, all_acceptance_conditions_) == bddtrue)
{
assert(src_left != dst_left);
constraint.emplace_back
(new_original_[old_a_->state_from_number(src_left_n)],
new_original_[old_a_->state_from_number(dst_left_n)],
add);
}
}
else if (out_scc_left && out_scc_right)
{
bdd b = bdd_exist(left, notap);
bdd add = bdd_exist(right & b, bdd_support(b));
if (add != bddfalse
&& bdd_exist(add, all_acceptance_conditions_) == bddtrue)
{
assert(src_left != dst_left && src_right != dst_right);
// FIXME: cas pas compris.
constraint.emplace_back
(new_original_[old_a_->state_from_number(src_left_n)],
new_original_[old_a_->state_from_number(dst_left_n)],
add);
constraint.emplace_back
(new_original_[old_a_->state_from_number(src_right_n)],
new_original_[old_a_->state_from_number(dst_right_n)],
add);
}
}
else
assert(0);
}
// This function run over the signatures, and select the
// transitions that are out of a SCC and call the function
// create_simple_constraint to solve the problem.
// NOTE: Currently, this may not be the most accurate method,
// because we check for equality in the destination part of the
// signature. We may just check the destination that can be
// implied instead.
std::list<constraint> create_new_constraint(const state* left,
const state* right,
map_state_bdd& state2sig)
{
bdd pcl = previous_class_[a_->state_number(left)];
bdd pcr = previous_class_[a_->state_number(right)];
bdd sigl = state2sig[left];
bdd sigr = state2sig[right];
std::list<constraint> res;
bdd ex = all_class_var_ & on_cycle_;
bdd both = pcl & pcr;
int lc = bdd_var(pcl);
#define DEST(x) bdd_compose(bdd_existcomp(x, ex), both, lc)
// Key is destination class, value is the signature part that
// led to this destination class.
map_bdd_bdd sigl_map;
{
minato_isop isop(sigl & on_cycle_);
bdd cond_acc_dest;
while ((cond_acc_dest = isop.next()) != bddfalse)
sigl_map[DEST(cond_acc_dest)]
|= cond_acc_dest;
}
{
minato_isop isop(sigl & !on_cycle_);
bdd cond_acc_dest;
while ((cond_acc_dest = isop.next()) != bddfalse)
sigl_map[DEST(cond_acc_dest)]
|= cond_acc_dest;
}
map_bdd_bdd sigr_map;
{
minato_isop isop2(sigr & on_cycle_);
bdd cond_acc_dest2;
while ((cond_acc_dest2 = isop2.next()) != bddfalse)
sigr_map[DEST(cond_acc_dest2)]
|= cond_acc_dest2;
}
{
minato_isop isop2(sigr & !on_cycle_);
bdd cond_acc_dest2;
while ((cond_acc_dest2 = isop2.next()) != bddfalse)
sigr_map[DEST(cond_acc_dest2)]
|= cond_acc_dest2;
}
// Iterate over the transitions of both states.
for (auto lp: sigl_map)
for (auto rp: sigr_map)
// And create constraints if any of the transitions
// is out of the SCC and the left could imply the right.
if ((is_out_scc(lp.second) || is_out_scc(rp.second))
&& (bdd_exist(lp.first, on_cycle_) ==
bdd_exist(rp.first, on_cycle_)))
create_simple_constraint(lp.second, rp.second,
left, right, res);
return res;
}
inline automaton_size get_stat() const
{
return min_size_;
}
tgba* run()
{
// Iterate the simulation until the end. We just don't return
// an automaton. This allows us to get all the information
// about the states and their signature.
main_loop();
// Compute the don't care signatures,
map_bdd_lstate dont_care_bdd_lstate;
// Useful to keep track of who is who.
map_state_bdd dont_care_state2sig;
map_state_bdd state2sig;
list_bdd_bdd dont_care_now_to_now;
map_bdd_state class2state;
list_bdd_bdd now_to_now;
bdd_lstate_.clear();
// Compute the don't care signature for all the states.
for (unsigned s = 0; s < size_a_; ++s)
{
const state* src = a_->state_from_number(s);
bdd clas = previous_class_[s];
bdd sig = dont_care_compute_sig(s);
dont_care_bdd_lstate[sig].push_back(s);
dont_care_state2sig[src] = sig;
dont_care_now_to_now.emplace_back(sig, clas);
class2state[clas] = src;
sig = compute_sig(s);
bdd_lstate_[sig].push_back(s);
state2sig[src] = sig;
now_to_now.push_back(std::make_pair(sig, clas));
}
map_bdd_bdd dont_care_relation;
map_bdd_bdd relation;
update_po(now_to_now, relation);
dont_care_update_po(dont_care_now_to_now, dont_care_relation);
constraint_list cc;
for (auto p: relation)
revert_relation_[p.second] = class2state[p.first];
int number_constraints = 0;
relation_ = relation;
// make the diff between the two tables: imply and
// could_imply.
for (unsigned s = 0; s < size_a_; ++s)
{
bdd clas = previous_class_[s];
assert(relation.find(clas) != relation.end());
assert(dont_care_relation.find(clas) != dont_care_relation.end());
bdd care_rel = relation[clas];
bdd dont_care_rel = dont_care_relation[clas];
if (care_rel == dont_care_rel)
continue;
// If they are different we necessarily have
// dont_care_rel == care_rel & diff
bdd diff = bdd_exist(dont_care_rel, care_rel);
assert(dont_care_rel == (care_rel & diff));
assert(diff != bddtrue);
do
{
bdd cur_diff = bdd_ithvar(bdd_var(diff));
cc[clas][cur_diff]
= create_new_constraint(a_->state_from_number(s),
class2state[cur_diff],
dont_care_state2sig);
++number_constraints;
diff = bdd_high(diff);
}
while (diff != bddtrue);
}
#ifndef NDEBUG
for (map_bdd_state::const_iterator i = class2state.begin();
i != class2state.end(); ++i)
assert(previous_class_[a_->state_number(i->second)] == i->first);
#endif
tgba* min = 0;
map_constraint cstr;
if (has_limit_)
rec(cc, cstr, &min, limit_);
else
rec(cc, cstr, &min);
return min;
}
#define ERASE(inner_map, bigger_map, it) \
inner_map.erase(it); \
if (inner_map.empty()) \
bigger_map.erase(bigger_map.begin())
// Add and erase.
void add_to_map_imply(constraint_list& constraints,
map_constraint& cstr)
{
constraint_list::iterator it = constraints.begin();
std::map<bdd,
std::list<constraint>,
bdd_less_than>::iterator it2 = it->second.begin();
add_to_map(it2->second, cstr);
bdd implied_list = relation_[it2->first]; // it2->first:
// destination class.
ERASE(it->second, constraints, it2);
if (constraints.empty())
return;
it = constraints.begin();
// At worst, implied_list is equal to it2->first.
while (implied_list != bddtrue)
{
bdd cur_implied = bdd_ithvar(bdd_var(implied_list));
std::map<bdd,
std::list<constraint>,
bdd_less_than>::iterator tmp
= it->second.find(cur_implied);
if (tmp != it->second.end())
{
add_to_map(tmp->second, cstr);
ERASE(it->second, constraints, tmp);
if (constraints.empty())
return;
}
implied_list = bdd_high(implied_list);
}
}
// Compute recursively all the combinations.
void rec(constraint_list constraints,
map_constraint cstr,
tgba** min,
int max_depth = std::numeric_limits<int>::max())
{
assert(max_depth > 0);
while (!constraints.empty())
{
if (!--max_depth)
break;
add_to_map_imply(constraints, cstr);
rec(constraints, cstr, min, max_depth);
}
if (empty_seen_ && cstr.empty())
return;
else if (cstr.empty())
empty_seen_ = true;
direct_simulation<false, false> dir_sim(original_, &cstr);
tgba* tmp = dir_sim.run();
automaton_size cur_size = dir_sim.get_stat();
if (*min == 0 || min_size_ > cur_size)
{
delete *min;
*min = tmp;
min_size_ = cur_size;
res_is_deterministic = dir_sim.result_is_deterministic();
}
else
{
delete tmp;
}
}
void set_limit(int n)
{
has_limit_ = true;
limit_ = n;
}
private:
// This bdd is used to differentiate parts of the signature that
// are in a SCC and those that are not.
bdd on_cycle_;
map_bdd_bdd dont_care_relation_;
map_bdd_state revert_relation_;
automaton_size min_size_;
bool empty_seen_;
bool has_limit_;
int limit_;
bdd notap;
};
} // End namespace anonymous.
tgba*
simulation(const tgba* t)
{
direct_simulation<false, false> simul(t);
return simul.run();
}
tgba*
simulation_sba(const tgba* t)
{
direct_simulation<false, true> simul(t);
return simul.run();
}
tgba*
cosimulation(const tgba* t)
{
direct_simulation<true, false> simul(t);
return simul.run();
}
tgba*
cosimulation_sba(const tgba* t)
{
direct_simulation<true, true> simul(t);
return simul.run();
}
template<bool Sba>
tgba*
iterated_simulations_(const tgba* t)
{
tgba* res = const_cast<tgba*> (t);
automaton_size prev;
automaton_size next;
do
{
prev = next;
direct_simulation<false, Sba> simul(res);
tgba* after_simulation = simul.run();
if (res != t)
delete res;
if (simul.result_is_deterministic())
{
res = after_simulation;
break;
}
direct_simulation<true, Sba> cosimul(after_simulation);
tgba* after_cosimulation = cosimul.run();
next = cosimul.get_stat();
delete after_simulation;
if (Sba)
res = scc_filter_states(after_cosimulation);
else
res = scc_filter(after_cosimulation, false);
delete after_cosimulation;
}
while (prev != next);
return res;
}
tgba*
iterated_simulations(const tgba* t)
{
return iterated_simulations_<false>(t);
}
tgba*
iterated_simulations_sba(const tgba* t)
{
return iterated_simulations_<true>(t);
}
tgba*
dont_care_simulation(const tgba* t, int limit)
{
direct_simulation<false, false> sim(t);
tgba* tmp = sim.run();
direct_simulation_dont_care s(tmp);
if (limit > 0)
s.set_limit(limit);
tgba* res = s.run();
delete tmp;
return res;
}
tgba*
dont_care_iterated_simulations(const tgba* t, int limit)
{
tgba* res = const_cast<tgba*> (t);
automaton_size prev;
automaton_size next;
do
{
prev = next;
tgba* after_simulation = dont_care_simulation(res, limit);
if (res != t)
delete res;
direct_simulation<true, false> cosimul(after_simulation);
tgba* after_cosimulation = cosimul.run();
delete after_simulation;
next = cosimul.get_stat();
res = scc_filter(after_cosimulation, true);
delete after_cosimulation;
}
while (prev != next);
return res;
}
} // End namespace spot.