* src/tgbaalgos/ndfs_result.hh: New file factorizing the computation of

accepting runs for ndfs emptiness check algoritms.
* src/tgbaalgos/Makefile.am: Add it.
* src/tgbaalgos/magic.cc, src/tgbaalgos/se05.cc,
src/tgbaalgos/tau03.cc, src/tgbaalgos/tau03opt.cc: Remove the old
result classes and use the new one.
This commit is contained in:
Denis Poitrenaud 2004-12-13 08:43:05 +00:00
parent abbd0eee07
commit 964f856bb5
7 changed files with 506 additions and 468 deletions

View file

@ -20,8 +20,6 @@
// 02111-1307, USA.
/// FIXME:
/// * Add the necessary calls to pop_notify in the subclass result.
///
/// * Test some heuristics on the order of visit of the successors in the blue
/// dfs:
/// - favorize the arcs conducting to the blue stack (the states of color
@ -43,14 +41,13 @@
#endif
#include <cassert>
#include <list>
#include "misc/hash.hh"
#include "tgba/tgba.hh"
#include "emptiness.hh"
#include "emptiness_stats.hh"
#include "tau03opt.hh"
#include "weight.hh"
#include "bfssteps.hh"
#include "ndfs_result.hh"
namespace spot
{
@ -104,7 +101,7 @@ namespace spot
h.add_new_state(s0, CYAN, current_weight);
push(st_blue, s0, bddfalse, bddfalse);
if (dfs_blue())
return new result(*this);
return new ndfs_result<tau03_opt_search<heap>, heap>(*this);
return 0;
}
@ -116,25 +113,22 @@ namespace spot
return os;
}
const heap& get_heap() const
{
return h;
}
const stack_type& get_st_blue() const
{
return st_blue;
}
const stack_type& get_st_red() const
{
return st_red;
}
private:
struct stack_item
{
stack_item(const state* n, tgba_succ_iterator* i, bdd l, bdd a)
: s(n), it(i), label(l), acc(a) {};
/// The visited state.
const state* s;
/// Design the next successor of \a s which has to be visited.
tgba_succ_iterator* it;
/// The label of the transition traversed to reach \a s
/// (false for the first one).
bdd label;
/// The acceptance set of the transition traversed to reach \a s
/// (false for the first one).
bdd acc;
};
typedef std::list<stack_item> stack_type;
void push(stack_type& st, const state* s,
const bdd& label, const bdd& acc)
{
@ -332,287 +326,6 @@ namespace spot
return false;
}
class result: public emptiness_check_result
{
private:
typedef Sgi::hash_set<const state*,
state_ptr_hash, state_ptr_equal> state_set;
class shortest_path: public bfs_steps
{
public:
shortest_path(const tgba* a, const state* t,
const state_set& d, heap& h)
: bfs_steps(a), target(t), dead(d), h(h)
{
}
~shortest_path()
{
}
const state*
search(const state* start, tgba_run::steps& l)
{
const state* s = filter(start);
if (s)
return this->bfs_steps::search(s, l);
else
return 0;
}
const state*
filter(const state* s)
{
typename heap::color_ref c = h.get_color_ref(s);
if (c.is_white())
{
delete s;
return 0;
}
else if (dead.find(s) != dead.end())
return 0;
seen.insert(s);
return s;
}
const state_set&
get_seen() const
{
return seen;
}
bool
match(tgba_run::step&, const state* dest)
{
return target->compare(dest) == 0;
}
private:
state_set seen;
const state* target;
const state_set& dead;
heap& h;
};
stack_type st1;
tau03_opt_search& ms_;
void complete_cycle(tgba_run::steps& cycle, bdd& covered_acc,
const tgba_run::step& start, tgba_run::steps& path,
const state_set& dead)
{
tgba_run::steps new_cycle;
// find the minimal path between st1.back().s and st1.front().s
if (st1.back().s->compare(st1.front().s)!=0)
{
shortest_path s(ms_.a_, st1.front().s, dead, ms_.h);
const state* res = s.search(st1.back().s, new_cycle);
assert(res && res->compare(st1.front().s) == 0);
(void)res;
for (tgba_run::steps::const_iterator it = new_cycle.begin();
it != new_cycle.end(); ++it)
covered_acc |= it->acc;
}
// traverse the accepting transition
covered_acc |= start.acc;
tgba_run::step s = { st1.front().s->clone(), start.label, start.acc };
new_cycle.push_back(s);
// follow the minimal path returning to st1.back().s
for (tgba_run::steps::const_iterator it = path.begin();
it != path.end(); ++it)
covered_acc |= it->acc;
new_cycle.splice(new_cycle.end(), path);
// concat this new loop to the existing ones
cycle.splice(cycle.end(), new_cycle);
}
bool dfs_result(const state* target, tgba_run::steps& cycle,
bdd& covered_acc)
{
state_set seen, dead;
seen.insert(target);
while (!st1.empty())
{
stack_item& f = st1.front();
trace << "DFS1 treats: " << a_->format_state(f.s) << std::endl;
if (!f.it->done())
{
const state *s_prime = f.it->current_state();
trace << " Visit the successor: "
<< a_->format_state(s_prime) << std::endl;
bdd label = f.it->current_condition();
bdd acc = f.it->current_acceptance_conditions();
f.it->next();
typename heap::color_ref c_prime =
ms_.h.get_color_ref(s_prime);
if (!c_prime.is_white())
{
if (dead.find(s_prime) != dead.end())
{
trace << " it is dead, pop it" << std::endl;
}
else if (seen.find(s_prime) == seen.end())
{
trace << " it is not seen, go down" << std::endl;
seen.insert(s_prime);
tgba_succ_iterator* i = a_->succ_iter(s_prime);
i->first();
st1.push_front(stack_item(s_prime, i, label, acc));
}
else if ((acc & covered_acc) != acc)
{
trace << " a propagation is needed, start a search"
<< std::endl;
tgba_run::step s = {s_prime, label, acc};
if (search(s, target, dead, cycle, covered_acc))
return true;
}
else
{
trace << " already seen, pop it" << std::endl;
}
}
else
delete s_prime;
}
else
{
trace << " all the successors have been visited"
<< std::endl;
stack_item f_dest(f);
delete st1.front().it;
st1.pop_front();
if (!st1.empty() && (f_dest.acc & covered_acc) != f_dest.acc)
{
trace << " a propagation is needed, start a search"
<< std::endl;
tgba_run::step s = {f_dest.s,
f_dest.label,
f_dest.acc};
if (search(s, target, dead, cycle, covered_acc))
return true;
}
else
{
trace << " no propagation needed, pop it" << std::endl;
}
}
}
return false;
}
bool search(const tgba_run::step& start, const state* target,
state_set& dead, tgba_run::steps& cycle, bdd& covered_acc)
{
tgba_run::steps path;
if (start.s->compare(target)==0)
{
trace << " complete the cycle" << std::endl;
complete_cycle(cycle, covered_acc, start, path, dead);
return covered_acc == ms_.all_acc;
}
shortest_path s(ms_.a_, target, dead, ms_.h);
const state* res = s.search(start.s, path);
if (res)
{
assert(res->compare(target) == 0);
trace << " complete the cycle" << std::endl;
complete_cycle(cycle, covered_acc, start, path, dead);
return covered_acc == ms_.all_acc;
}
state_set::const_iterator it;
for (it = s.get_seen().begin(); it != s.get_seen().end(); ++it)
dead.insert(*it);
return false;
}
public:
result(tau03_opt_search& ms)
: emptiness_check_result(ms.a_),
ms_(ms)
{
}
virtual ~result()
{
while (!st1.empty())
{
delete st1.front().it;
st1.pop_front();
}
}
virtual tgba_run* accepting_run()
{
assert(!ms_.st_blue.empty());
assert(!ms_.st_red.empty());
tgba_run* run = new tgba_run;
const state* target = ms_.st_red.front().s;
bdd covered_acc = bddfalse;
typename stack_type::const_reverse_iterator i, j, end;
i = j = ms_.st_blue.rbegin(); ++j;
for (; i->s->compare(target) != 0; ++i, ++j)
{
tgba_run::step s = { i->s->clone(), j->label, j->acc };
run->prefix.push_back(s);
}
end = ms_.st_blue.rend();
for (; j != end; ++i, ++j)
{
covered_acc |= j->acc;
tgba_run::step s = { i->s->clone(), j->label, j->acc };
run->cycle.push_back(s);
}
j = ms_.st_red.rbegin();
covered_acc |= j->acc;
tgba_run::step s = { i->s->clone(), j->label, j->acc };
run->cycle.push_back(s);
i = j; ++j;
end = ms_.st_red.rend();
for (; j != end; ++i, ++j)
{
covered_acc |= j->acc;
tgba_run::step s = { i->s->clone(), j->label, j->acc };
run->cycle.push_back(s);
}
if (ms_.all_acc != covered_acc)
{
// try to minimize the first loop in run->cycle ??
// what transitions have to be preserved (it depend on
// the detection (in the blue or red dfs) ??
tgba_succ_iterator* i = a_->succ_iter(target);
i->first();
st1.push_front(stack_item(target, i, bddfalse, bddfalse));
bool b = dfs_result(target, run->cycle, covered_acc);
assert(b);
(void)b;
while (!st1.empty())
{
delete st1.front().it;
st1.pop_front();
}
}
return run;
}
};
};
class explicit_tau03_opt_search_heap
@ -757,6 +470,31 @@ namespace spot
{
}
bool has_been_visited(const state*& s) const
{
hcyan_type::const_iterator ic = hc.find(s);
if (ic == hc.end())
{
hash_type::const_iterator it = h.find(s);
if (it == h.end())
// white state
return false;
if (s != it->first)
{
delete s;
s = it->first;
}
// blue or red state
return true;
}
else if (s != ic->first)
{
delete s;
s = ic->first;
}
return true;
}
private:
// associate to each blue and red state its color and its acceptance set