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split: add a new split_edge variant

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* spot/twaalgos/split.cc, spot/twaalgos/split.hh: Here.
* tests/python/splitedge.py: New file.
* tests/Makefile.am: Add it.
This commit is contained in:
Jonah Romero 2023-08-03 11:54:49 +02:00 • committed by Alexandre Duret-Lutz
parent d96796121a
commit c2832cabfc
4 changed files with 479 additions and 5 deletions
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251
spot/twaalgos/split.cc
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@ -1,6 +1,6 @@
// -*- coding: utf-8 -*-
// Copyright (C) 2017-2021 Laboratoire de Recherche et Développement
// de l'Epita.
// Copyright (C) 2017-2023 Laboratoire de Recherche et Développement
// de l'Epita. IMDEA Software Institute.
//
// This file is part of Spot, a model checking library.
//
@ -25,9 +25,200 @@
#include <algorithm>
#include <map>
#include <unordered_set>
namespace std
{
template<>
struct hash<::bdd>
{
size_t operator()(::bdd const& instance) const noexcept
{
return ::spot::bdd_hash{}(instance);
}
};
template<>
struct hash<pair<bdd, bdd>>
{
size_t operator()(pair<bdd, bdd> const& x) const noexcept
{
size_t first_hash = std::hash<bdd>()(x.first);
size_t second_hash = std::hash<bdd>()(x.second);
size_t sum = second_hash
+ 0x9e3779b9
+ (first_hash << 6)
+ (first_hash >> 2);
return first_hash ^ sum;
}
};
}
namespace spot
{
// We attempt to add a potentially new set of symbols defined as "value" to
// our current set of edge partitions, "current_set". We also specify a set
// of valid symbols considered
static void add_to_lower_bound_set_helper(
std::unordered_set<bdd>& current_set,
bdd valid_symbol_set,
bdd value)
{
// This function's correctness is defined by the invariant, that we never
// add a bdd to our current set unless the bdd is disjoint from every other
// element in the current_set. In other words, we will only reach the final
// set.insert(value), if we can iterate over the whole of current_set
// without finding some set intersections
if (value == bddfalse) // Don't add empty sets, as they subsume everything
{
return;
}
for (auto sym : current_set)
{
// If a sym is a subset of value, recursively add the set of symbols
// defined in value, but not in sym. This ensures the two elements
// are disjoint.
if (bdd_implies(sym, value))
{
add_to_lower_bound_set_helper(
current_set, valid_symbol_set, (value - sym) & valid_symbol_set);
return;
}
// If a sym is a subset of the value we're trying to add, then we
// remove the symbol and add the two symbols created by partitioning
// the sym with value.
else if (bdd_implies(value, sym))
{
current_set.erase(sym);
add_to_lower_bound_set_helper(current_set,
valid_symbol_set,
sym & value);
add_to_lower_bound_set_helper(current_set,
valid_symbol_set,
sym - value);
return;
}
}
// This line is only reachable if value is not a subset and doesn't
// subsume any element currently in our set
current_set.insert(value);
}
static std::array<bdd, 4> create_possible_intersections(
bdd valid_symbol_set,
std::pair<bdd, bdd> const& first,
std::pair<bdd, bdd> const& second)
{
auto intermediate = second.first & valid_symbol_set;
auto intermediate2 = second.second & valid_symbol_set;
return {
first.first & intermediate,
first.second & intermediate,
first.first & intermediate2,
first.second & intermediate2,
};
}
using bdd_set = std::unordered_set<bdd>;
using bdd_pair_set = std::unordered_set<std::pair<bdd, bdd>>;
// Transforms each element of the basis into a complement pair,
// with a valid symbol set specified
static bdd_pair_set create_complement_pairs(std::vector<bdd> const& basis,
bdd valid_symbol_set)
{
bdd_pair_set intersections;
for (auto& sym : basis)
{
auto intersection = sym & valid_symbol_set;
if (intersection != bddfalse)
{
auto negation = valid_symbol_set - intersection;
intersections.insert(std::make_pair(intersection, negation));
}
}
return intersections;
}
template<typename Callable>
void iterate_possible_intersections(bdd_pair_set const& complement_pairs,
bdd valid_symbol_set,
Callable callable)
{
for (auto it = complement_pairs.begin(); it != complement_pairs.end(); ++it)
{
for (auto it2 = std::next(it); it2 != complement_pairs.end(); ++it2)
{
auto intersections = create_possible_intersections(
valid_symbol_set, *it, *it2);
for (auto& intersection : intersections)
{
callable(intersection);
}
}
}
}
// Compute the lower set bound of a set. A valid symbol set is also
// provided to make sure that no symbol exists in the output if it is
// not also included in the valid symbol set
static bdd_set lower_set_bound(std::vector<bdd> const& basis,
bdd valid_symbol_set)
{
auto complement_pairs = create_complement_pairs(basis, valid_symbol_set);
if (complement_pairs.size() == 1)
{
bdd_set lower_bound;
auto& pair = *complement_pairs.begin();
if (pair.first != bddfalse
&& bdd_implies(pair.first, valid_symbol_set))
{
lower_bound.insert(pair.first);
}
if (pair.second != bddfalse
&& bdd_implies(pair.second, valid_symbol_set))
{
lower_bound.insert(pair.second);
}
return lower_bound;
}
else
{
bdd_set lower_bound;
iterate_possible_intersections(complement_pairs, valid_symbol_set,
[&](auto intersection)
{
add_to_lower_bound_set_helper(lower_bound,
valid_symbol_set,
intersection);
});
return lower_bound;
}
}
// Partitions a symbol based on a list of other bdds called the basis.
// The resulting partition will have the property that for any paritioned
// element and any element element in the basis, the partitioned element will
// either by completely contained by that element of the basis, or completely
// disjoint.
static bdd_set generate_contained_or_disjoint_symbols(bdd sym,
std::vector<bdd> const& basis)
{
auto lower_bound = lower_set_bound(basis, sym);
// If the sym was disjoint from everything in the basis, we'll be left with
// an empty lower_bound. To fix this, we will simply return a singleton,
// with sym as the only element. Notice, this singleton will satisfy the
// requirements of a return value from this function. Additionally, if the
// sym is false, that means nothing can traverse it, so we simply are left
// with no edges.
if (lower_bound.empty() && sym != bddfalse)
{
lower_bound.insert(sym);
}
return lower_bound;
}
twa_graph_ptr split_edges(const const_twa_graph_ptr& aut)
{
twa_graph_ptr out = make_twa_graph(aut->get_dict());
@ -77,4 +268,60 @@ namespace spot
}
return out;
}
twa_graph_ptr split_edges(const const_twa_graph_ptr& aut,
std::vector<bdd> const& basis)
{
twa_graph_ptr out = make_twa_graph(aut->get_dict());
out->copy_acceptance_of(aut);
out->copy_ap_of(aut);
out->prop_copy(aut, twa::prop_set::all());
out->new_states(aut->num_states());
out->set_init_state(aut->get_init_state_number());
// We use a cache to avoid the costly loop around minterms_of().
// Cache entries have the form (id, [begin, end]) where id is the
// number of a BDD that as been (or will be) split, and begin/end
// denotes a range of existing transition numbers that cover the
// split.
using cached_t = std::pair<unsigned, unsigned>;
std::unordered_map<unsigned, cached_t> split_cond;
internal::univ_dest_mapper<twa_graph::graph_t> uniq(out->get_graph());
for (auto& e: aut->edges())
{
bdd const& cond = e.cond;
unsigned dst = e.dst;
if (cond == bddfalse)
continue;
if (aut->is_univ_dest(dst))
{
auto d = aut->univ_dests(dst);
dst = uniq.new_univ_dests(d.begin(), d.end());
}
auto& [begin, end] = split_cond[cond.id()];
if (begin == end)
{
begin = out->num_edges() + 1;
auto split = generate_contained_or_disjoint_symbols(cond,
basis);
for (bdd minterm : split)
{
out->new_edge(e.src, dst, minterm, e.acc);
}
end = out->num_edges() + 1;
}
else
{
auto& g = out->get_graph();
for (unsigned i = begin; i < end; ++i)
{
out->new_edge(e.src, dst, g.edge_storage(i).cond, e.acc);
}
}
}
return out;
}
}

17
spot/twaalgos/split.hh
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@ -1,6 +1,6 @@
// -*- coding: utf-8 -*-
// Copyright (C) 2017, 2018, 2020 Laboratoire de Recherche et Développement
// de l'Epita.
// Copyright (C) 2017, 2018, 2020, 2023 Laboratoire de Recherche
// et Développement de l'Epita. IMDEA Software Institute.
//
// This file is part of Spot, a model checking library.
//
@ -20,6 +20,7 @@
#pragma once
#include <spot/twa/twagraph.hh>
#include <vector>
namespace spot
{
@ -28,7 +29,17 @@ namespace spot
///
/// Create a new version of the automaton where all edges are split
/// so that they are all labeled by a conjunction of all atomic
/// propositions. After this we can consider that each edge of the
/// propositions. After this we can consider that each edge of the
/// automate is a transition labeled by one letter.
SPOT_API twa_graph_ptr split_edges(const const_twa_graph_ptr& aut);
/// \ingroup twa_misc
/// \brief transform edges into transitions based on set of bdds
///
/// Create a new version of the automaton where all edges are split
/// such that, for any transformed edge and any set of symbols in
/// the basis, the transformed edge is either completely disjoint
/// from the set of symbols, or it is a subset of them.
SPOT_API twa_graph_ptr split_edges(
const const_twa_graph_ptr& aut, std::vector<bdd> const& basis);
}

1
tests/Makefile.am
View file

@ -461,6 +461,7 @@ TESTS_python = \
python/simstate.py \
python/sonf.py \
python/split.py \
python/splitedge.py \
python/streett_totgba.py \
python/streett_totgba2.py \
python/stutter.py \

215
tests/python/splitedge.py Normal file
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@ -0,0 +1,215 @@
#!/usr/bin/python3
# -*- mode: python; coding: utf-8 -*-
# Copyright (C) 2020-2022 Laboratoire de Recherche et Développement de
# l'EPITA.
#
# 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/>.
import spot, buddy
from unittest import TestCase
tc = TestCase()
def create_aps(aut):
return [buddy.bdd_ithvar(aut.register_ap(ap.ap_name())) for ap in aut.ap()]
def do_edge_test(aut, aps, edges_before, edges_after):
tc.assertEqual(aut.num_edges(), edges_before)
aut = spot.split_edges(aut, aps)
tc.assertEqual(aut.num_edges(), edges_after)
aut = spot.automaton("""
HOA: v1
States: 1
Start: 0
AP: 2 "a" "b"
Acceptance: 1 Inf(0)
--BODY--
State: 0
[t] 0
--END--""")
aps = create_aps(aut)
do_edge_test(aut, aps, 1, 4)
aut = spot.automaton("""
HOA: v1
States: 2
Start: 0
AP: 2 "a" "b"
Acceptance: 1 Inf(0)
--BODY--
State: 0
[t] 0
State: 1
[0&1] 1
--END--""")
aps = create_aps(aut)
do_edge_test(aut, aps, 2, 5)
aut = spot.automaton("""
HOA: v1
States: 1
Start: 0
AP: 1 "a"
Acceptance: 1 Inf(0)
--BODY--
State: 0
[f] 0
--END--""")
aps = create_aps(aut)
do_edge_test(aut, aps, 0, 0)
aut = spot.automaton("""
HOA: v1
States: 3
Start: 0
AP: 2 "a" "b"
Acceptance: 1 Inf(0)
--BODY--
State: 0
[0|1] 1
[!1] 2
State: 1
State: 2
--END--""")
# Before:
# State: 0
# {a, b, c, d}
# {a, b}
# After:
# State : 0
# {a, b, c}, {d}
# {a, b}
# a = 00
# b = 10
# c = 01
# d = 11
aps = create_aps(aut)
# [{a, b, c}]
aps = [buddy.bdd_not(aps[0]) | buddy.bdd_not(aps[1])]
do_edge_test(aut, aps, 2, 3)
aut = spot.automaton("""
HOA: v1
States: 3
Start: 0
AP: 2 "a" "b"
Acceptance: 1 Inf(0)
--BODY--
State: 0
[t] 1
[!0] 2
State: 1
State: 2
--END--""")
# Before:
# State: 0
# {a, b, c, d}
# {a, c}
# After:
# State : 0
# {a, b}, {c, d}
# {a}, {c}
# a = 00
# b = 10
# c = 01
# d = 11
aps = create_aps(aut)
# [{a, b}, {c, d}]
aps = [buddy.bdd_not(aps[1]), aps[1]]
do_edge_test(aut, aps, 2, 4)
aut = spot.automaton("""
HOA: v1
States: 3
Start: 0
AP: 2 "a" "b"
Acceptance: 1 Inf(0)
--BODY--
State: 0
[t] 1
[!0&!1 | !0&1] 2
State: 1
State: 2
--END--""")
# Before:
# State: 0
# {a, b, c, d}
# {a, c}
# After:
# State : 0
# {a},{b},{c},{d}
# {a},{c}
# a = 00
# b = 10
# c = 01
# d = 11
aps = create_aps(aut)
neg_aps = [buddy.bdd_not(a) for a in aps]
# [{a},{b},{c},{d}]
aps = [
neg_aps[0] & neg_aps[1],
neg_aps[0] & aps[1],
aps[0] & neg_aps[1],
aps[0] & aps[1]
]
do_edge_test(aut, aps, 2, 6)
aut = spot.automaton("""
HOA: v1
States: 3
Start: 0
AP: 2 "a" "b"
Acceptance: 1 Inf(0)
--BODY--
State: 0
[t] 1
[!0&!1 | 0&!1] 2
State: 1
State: 2
--END--""")
# Before
# State: 0
# {a, b, c, d}
# {a, b}
# After:
# State : 0
# {a, b, c}, {d}
# {a, b}
# a = 00
# b = 10
# c = 01
# d = 11
aps = create_aps(aut)
neg_aps = [buddy.bdd_not(a) for a in aps]
# [{a, b, c}, {d}]
aps = [
neg_aps[0] | neg_aps[1],
aps[0] & aps[1]
]
do_edge_test(aut, aps, 2, 3)