spot/lbtt/src/BuchiProduct.cc
Alexandre Duret-Lutz cfdd81a919 Initial revision
2004-07-07 16:40:50 +00:00

98 lines
3.4 KiB
C++

/*
* Copyright (C) 1999, 2000, 2001, 2002, 2003, 2004
* Heikki Tauriainen <Heikki.Tauriainen@hut.fi>
*
* This program 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 2
* of the License, or (at your option) any later version.
*
* This program 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, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#include "BuchiProduct.h"
namespace Graph
{
/******************************************************************************
*
* Static member definitions for class BuchiProduct.
*
*****************************************************************************/
map< ::Ltl::LtlFormula*, BuchiProduct::SatisfiabilityMapping,
less< ::Ltl::LtlFormula*>, ALLOC(BuchiProduct::SatisfiabilityMapping) >
BuchiProduct::sat_cache;
/******************************************************************************
*
* Function definitions for class BuchiProduct.
*
*****************************************************************************/
/* ========================================================================= */
bool BuchiProduct::synchronizable
(const Graph<GraphEdgeContainer>::Edge& transition_1,
const Graph<GraphEdgeContainer>::Edge& transition_2)
/* ----------------------------------------------------------------------------
*
* Description: Tests whether two transitions of two Büchi automata are
* synchronizable by checking whether the conjunction of their
* guard formulas is satisfiable.
*
* Arguments: transition_1, -- Constant references to the transitions.
* transition_2
*
* Returns: true iff the transitions are synchronizable. The result is
* also stored into `this->sat_cache' for later reference.
*
* ------------------------------------------------------------------------- */
{
using ::Ltl::LtlFormula;
using ::Ltl::And;
LtlFormula* guard_1 = &static_cast<const BuchiAutomaton::BuchiTransition&>
(transition_1).guard();
LtlFormula* guard_2 = &static_cast<const BuchiAutomaton::BuchiTransition&>
(transition_2).guard();
if (guard_2 > guard_1)
{
LtlFormula* swap_guard = guard_2;
guard_2 = guard_1;
guard_1 = swap_guard;
}
map<LtlFormula*, SatisfiabilityMapping, less<LtlFormula*>,
ALLOC(SatisfiabilityMapping) >::iterator
sat_cache_element = sat_cache.find(guard_1);
if (sat_cache_element == sat_cache.end())
sat_cache_element = sat_cache.insert
(make_pair(guard_1, SatisfiabilityMapping())).first;
else
{
SatisfiabilityMapping::const_iterator sat_result
= sat_cache_element->second.find(guard_2);
if (sat_result != sat_cache_element->second.end())
return sat_result->second;
}
LtlFormula* f = &And::construct(*guard_1, *guard_2);
const bool result = f->satisfiable();
LtlFormula::destruct(f);
sat_cache_element->second.insert(make_pair(guard_2, result));
return result;
}
}