Adding function to test if two büchi automata are isomorphic.

And add the corresponding --isomorphic=FILENAME option to autfilt.

* src/tgbaalgos/are_isomorphic.cc, src/tgbaalgos/are_isomorphic.hh:
New.
* src/tgbaalgos/Makefile.am: Add it.
* src/bin/autfilt.cc: Add --isomorphic option.
* src/tgbatest/isomorph.test: Test it.
* src/tgbatest/Makefile.am: Add it.
This commit is contained in:
Thibaud Michaud 2014-12-03 17:54:22 +01:00 committed by Alexandre Duret-Lutz
parent 61edf7f41d
commit 97fdea9d71
6 changed files with 434 additions and 1 deletions

View file

@ -28,6 +28,7 @@ AM_CXXFLAGS = $(WARNING_CXXFLAGS)
tgbaalgosdir = $(pkgincludedir)/tgbaalgos
tgbaalgos_HEADERS = \
are_isomorphic.hh \
bfssteps.hh \
closure.hh \
complete.hh \
@ -80,6 +81,7 @@ tgbaalgos_HEADERS = \
noinst_LTLIBRARIES = libtgbaalgos.la
libtgbaalgos_la_SOURCES = \
are_isomorphic.cc \
bfssteps.cc \
closure.cc \
complete.cc \

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@ -0,0 +1,215 @@
// -*- coding: utf-8 -*-
// Copyright (C) 2014 Laboratoire de Recherche et
// Développement de l'Epita (LRDE).
// Copyright (C) 2004, 2005 Laboratoire d'Informatique de Paris 6 (LIP6),
// département Systèmes Répartis Coopératifs (SRC), Université Pierre
// et Marie Curie.
//
// 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 "tgba/tgbagraph.hh"
#include "tgbaalgos/are_isomorphic.hh"
#include <unordered_map>
#include <vector>
#include <algorithm>
#include "misc/hashfunc.hh"
namespace
{
typedef size_t class_t;
typedef std::vector<unsigned> states_t;
typedef std::unordered_map<class_t, states_t> class2states_t;
typedef std::vector<class_t> state2class_t;
typedef spot::tgba_digraph::graph_t::trans_storage_t trans_storage_t;
bool
trans_lessthan(trans_storage_t ts1, trans_storage_t ts2)
{
return
ts1.src != ts2.src ?
ts1.src < ts2.src :
ts1.dst != ts2.dst ?
ts1.dst < ts2.dst :
ts1.acc != ts2.acc ?
ts1.acc < ts2.acc :
ts1.cond.id() < ts2.cond.id();
}
std::function<bool(trans_storage_t ts1, trans_storage_t ts2)>
trans_lessthan_mapped(const std::vector<unsigned>& mapping)
{
return [mapping](trans_storage_t ts1,
trans_storage_t ts2)
{
return
mapping[ts1.src] != mapping[ts2.src] ?
mapping[ts1.src] < mapping[ts2.src] :
mapping[ts1.dst] != mapping[ts2.dst] ?
mapping[ts1.dst] < mapping[ts2.dst] :
ts1.acc != ts2.acc ?
ts1.acc < ts2.acc :
ts1.cond.id() < ts2.cond.id();
};
}
state2class_t
map_state_class(const spot::const_tgba_digraph_ptr a)
{
state2class_t hashin(a->num_states(), 0);
state2class_t hashout(a->num_states(), 0);
state2class_t state2class(a->num_states());
for (auto& t: a->transitions())
{
if (!a->is_dead_transition(t))
{
hashout[t.src] ^= spot::wang32_hash(t.cond.id());
hashout[t.src] ^= spot::wang32_hash(t.acc);
hashin[t.dst] ^= spot::wang32_hash(t.cond.id());
hashin[t.dst] ^= spot::wang32_hash(t.acc);
}
}
for (unsigned i = 0; i < a->num_states(); ++i)
// Rehash the ingoing transitions so that the total hash differs for
// different (in, out) pairs of ingoing and outgoing transitions, even if
// the union of in and out is the same.
state2class[i] = spot::wang32_hash(hashin[i]) ^ hashout[i];
return state2class;
}
class2states_t
map_class_states(const spot::const_tgba_digraph_ptr a)
{
unsigned n = a->num_states();
std::vector<states_t> res;
class2states_t class2states;
auto state2class = map_state_class(a);
for (unsigned s = 0; s < n; ++s)
{
class_t c1 = state2class[s];
(*(class2states.emplace(c1, std::vector<unsigned>()).first)).second.
emplace_back(s);
}
return class2states;
}
bool
mapping_from_classes(std::vector<unsigned>& mapping,
class2states_t classes1,
class2states_t classes2)
{
if (classes1.size() != classes2.size())
return false;
for (auto& p : classes1)
{
if (p.second.size() != classes2[p.first].size())
return false;
for (unsigned j = 0; j < p.second.size(); ++j)
mapping[p.second[j]] = classes2[p.first][j];
}
return true;
}
bool
next_class_permutation(class2states_t& classes)
{
for (auto& p : classes)
if (std::next_permutation(p.second.begin(), p.second.end()))
return true;
return false;
}
bool
is_isomorphism(const std::vector<unsigned>& mapping,
const spot::const_tgba_digraph_ptr a1,
const spot::const_tgba_digraph_ptr a2)
{
unsigned n = a1->num_states();
assert(n == a2->num_states());
std::vector<trans_storage_t> trans1;
std::vector<trans_storage_t> trans2;
for (auto& t: a1->transitions())
if (!(a1->is_dead_transition(t)))
trans1.push_back(t);
for (auto& t: a2->transitions())
if (!(a2->is_dead_transition(t)))
trans2.push_back(t);
// Sort the vectors of transitions so that they can be compared.
// To use the same metric, the transitions of a1 have to be mapped to
// a2.
std::sort(trans1.begin(), trans1.end(), trans_lessthan_mapped(mapping));
std::sort(trans2.begin(), trans2.end(), trans_lessthan);
for (unsigned i = 0; i < trans1.size(); ++i)
{
auto ts1 = trans1[i];
auto ts2 = trans2[i];
if (!(ts2.src == mapping[ts1.src] &&
ts2.dst == mapping[ts1.dst] &&
ts1.acc == ts2.acc &&
ts1.cond.id() == ts2.cond.id()))
{
return false;
}
}
return true;
}
bool
are_trivially_different(const spot::const_tgba_digraph_ptr a1,
const spot::const_tgba_digraph_ptr a2)
{
return (a1->num_states() != a2->num_states() ||
a1->num_transitions() != a2->num_transitions());
}
}
namespace spot
{
bool
are_isomorphic(const const_tgba_digraph_ptr a1,
const const_tgba_digraph_ptr a2)
{
if (are_trivially_different(a1, a2))
return false;
unsigned n = a1->num_states();
assert(n == a2->num_states());
class2states_t a1_classes = map_class_states(a1);
class2states_t a2_classes = map_class_states(a2);
std::vector<unsigned> mapping(n);
// Get the first possible mapping between a1 and a2, or return false if
// the number of class or the size of the classes do not match.
if (!(mapping_from_classes(mapping, a1_classes, a2_classes)))
return false;
while (!is_isomorphism(mapping, a1, a2))
{
if (!next_class_permutation(a2_classes))
return false;
mapping_from_classes(mapping, a1_classes, a2_classes);
}
return true;
}
}

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@ -0,0 +1,41 @@
// -*- coding: utf-8 -*-
// Copyright (C) 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/>.
#ifndef SPOT_TGBAALGOS_ARE_ISOMORPHIC_HH
# define SPOT_TGBAALGOS_ARE_ISOMORPHIC_HH
#include "tgba/tgbagraph.hh"
namespace spot
{
/// \ingroup tgba_misc
/// \brief Check whether two automata are isomorphic.
/// Two automata a1 and a2 are said to be isomorphic if there is a bijection
/// f between the states of a1 and a2 such that for every pair of state (s1,
/// s2) of a1:
/// - there is a transition from s1 to s2 iff there is a transition from f(s1)
/// to f(s2)
/// - if there is such a transition, then the acceptance set and acceptance
/// condition are the same on the transition from s1 to s2 and from f(s1) to
/// f(s2)
SPOT_API bool are_isomorphic(const const_tgba_digraph_ptr a1,
const const_tgba_digraph_ptr a2);
}
#endif