spot/src/tgbaalgos/isweakscc.cc
Alexandre Duret-Lutz 2fb436a174 Replace most uses of scc_map by scc_info.
This involves reimplementing some algorithms using tgba_digraph, and
implementing an explicit product that takes two tgba_digraphs and
produces a tgba_digraph.

* src/tgbaalgos/product.cc, src/tgbaalgos/product.hh: New files.
* src/tgbaalgos/Makefile.am: Adjust.
* src/bin/ltlcross.cc, src/tgba/tgba.cc, src/tgba/tgba.hh,
src/tgba/tgbasafracomplement.cc, src/tgba/tgbasafracomplement.hh,
src/tgbaalgos/cycles.cc, src/tgbaalgos/cycles.hh,
src/tgbaalgos/degen.cc, src/tgbaalgos/degen.hh,
src/tgbaalgos/isweakscc.cc, src/tgbaalgos/isweakscc.hh,
src/tgbaalgos/minimize.cc, src/tgbaalgos/minimize.hh,
src/tgbaalgos/powerset.cc, src/tgbaalgos/powerset.hh,
src/tgbaalgos/safety.cc, src/tgbaalgos/safety.hh,
src/tgbaalgos/sccinfo.cc, src/tgbaalgos/sccinfo.hh,
src/tgbatest/complementation.cc, src/tgbatest/emptchk.cc,
src/tgbatest/ltl2ta.test, src/tgbatest/ltl2tgba.cc,
src/tgbatest/randtgba.cc: Update to use scc_info and/or tgba_digraph.
2014-10-08 17:33:14 +02:00

120 lines
3 KiB
C++

// -*- coding: utf-8 -*-
// Copyright (C) 2012, 2013, 2014 Laboratoire de Recherche et
// Developpement 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 "cycles.hh"
#include "ltlast/formula.hh"
#include "isweakscc.hh"
namespace spot
{
namespace
{
// Look for a non-accepting cycle.
class weak_checker: public enumerate_cycles
{
public:
bool result;
weak_checker(const scc_info& map)
: enumerate_cycles(map), result(true)
{
}
virtual bool
cycle_found(const state* start)
{
dfs_stack::const_reverse_iterator i = dfs_.rbegin();
acc_cond::mark_t acc = 0U;
for (;;)
{
acc |= i->succ->current_acceptance_conditions();
if (i->ts->first == start)
break;
++i;
// The const cast is here to please old g++ versions.
// At least version 4.0 needs it.
assert(i != const_cast<const dfs_stack&>(dfs_).rend());
}
if (!aut_->acc().accepting(acc))
{
// We have found an non-accepting cycle, so the SCC is not
// weak.
result = false;
return false;
}
return true;
}
};
}
bool
is_inherently_weak_scc(scc_info& map, unsigned scc)
{
// If no cycle is accepting, the SCC is weak.
if (!map.is_accepting_scc(scc))
return true;
// If the SCC is accepting, but one cycle is not, the SCC is not
// weak.
weak_checker w(map);
w.run(scc);
return w.result;
}
bool
is_weak_scc(scc_info& map, unsigned scc)
{
// If no cycle is accepting, the SCC is weak.
if (!map.is_accepting_scc(scc))
return true;
// If all transitions use the same acceptance set, the SCC is weak.
return map.used_acc_of(scc).size() == 1;
}
bool
is_complete_scc(scc_info& map, unsigned scc)
{
auto a = map.get_aut();
for (auto s: map.states_of(scc))
{
bool has_succ = false;
bdd sumall = bddfalse;
for (auto& t: a->out(s))
{
has_succ = true;
if (map.scc_of(t.dst) == scc)
sumall |= t.cond;
if (sumall == bddtrue)
break;
}
if (!has_succ || sumall != bddtrue)
return false;
}
return true;
}
bool
is_terminal_scc(scc_info& map, unsigned scc)
{
// If all transitions use all acceptance conditions, the SCC is weak.
return (map.is_accepting_scc(scc)
&& map.used_acc_of(scc).size() == 1
&& is_complete_scc(map, scc));
}
}