gen: hide ks_cobuchi(), introduce aut_pattern()
* spot/gen/automata.hh, spot/gen/automata.cc: Hide ks_cobuchi() behind introduce aut_pattern(), as we have already done for the formulas. * bin/genaut.cc: Simplify using this interface. * python/spot/gen.i: Introduce aut_patterns(). * tests/python/gen.ipynb, tests/python/gen.py: Adjust.
This commit is contained in:
Alexandre Duret-Lutz
parent
ca7f72bb4b
commit
11ca2803c9
6 changed files with 216 additions and 122 deletions
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@ -17,75 +17,114 @@
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// You should have received a copy of the GNU General Public License
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// along with this program. If not, see <http://www.gnu.org/licenses/>.
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#include <spot/twa/twagraph.hh>
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#include <spot/gen/automata.hh>
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#include <spot/twa/formula2bdd.hh>
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#include <spot/tl/parse.hh>
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namespace spot
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{
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namespace gen
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{
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twa_graph_ptr
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ks_cobuchi(unsigned n)
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namespace
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{
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if (n == 0)
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throw std::runtime_error("ks_cobuchi() expects a positive argument");
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// the alphabet has four letters:
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// i, s (for sigma), p (for pi), h (for hash)
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// we encode this four letters alphabet thanks to two AP a and b
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// the exact encoding is not important
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// each letter is a permutation of the set {1..2n}
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// s = (1 2 .. 2n) the rotation
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// p = (1 2) the swap of the first two elements
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// i is the identity
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// d is the identity on {2..2n} but is undefined on 1
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static twa_graph_ptr
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ks_cobuchi(unsigned n)
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{
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if (n == 0)
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throw std::runtime_error("ks_cobuchi expects a positive argument");
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// the alphabet has four letters:
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// i, s (for sigma), p (for pi), h (for hash)
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// we encode this four letters alphabet thanks to two AP a and b
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// the exact encoding is not important
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// each letter is a permutation of the set {1..2n}
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// s = (1 2 .. 2n) the rotation
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// p = (1 2) the swap of the first two elements
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// i is the identity
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// d is the identity on {2..2n} but is undefined on 1
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// the automaton has 2n+1 states, numbered from 0 to 2n
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// 0 is the initial state and the only non-deterministic state
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// the automaton has 2n+1 states, numbered from 0 to 2n
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// 0 is the initial state and the only non-deterministic state
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auto dict = make_bdd_dict();
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auto aut = make_twa_graph(dict);
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auto dict = make_bdd_dict();
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auto aut = make_twa_graph(dict);
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// register aps
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aut->register_ap("a");
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aut->register_ap("b");
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// register aps
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bdd a = bdd_ithvar(aut->register_ap("a"));
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bdd b = bdd_ithvar(aut->register_ap("b"));
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// retrieve the four letters, and name them
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bdd i = formula_to_bdd(parse_formula("a&&b"), dict, aut);
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bdd s = formula_to_bdd(parse_formula("a&&!b"), dict, aut);
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bdd p = formula_to_bdd(parse_formula("!a&&b"), dict, aut);
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bdd h = formula_to_bdd(parse_formula("!a&&!b"), dict, aut);
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// name the four letters
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bdd i = a & b;
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bdd s = a & (!b);
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bdd p = (!a) & b;
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bdd h = (!a) & (!b);
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// actually build the automaton
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aut->new_states(2*n+1);
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aut->set_init_state(0);
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aut->set_acceptance(1, acc_cond::acc_code::cobuchi());
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// actually build the automaton
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aut->new_states(2*n+1);
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aut->set_init_state(0);
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aut->set_acceptance(1, acc_cond::acc_code::cobuchi());
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// from 0, we can non-deterministically jump to any state (except 0) with
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// any letter.
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for (unsigned q = 1; q <= 2*n; ++q)
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aut->new_edge(0, q, bddtrue, {0});
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// i is the identity
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for (unsigned q = 1; q <= 2*n; ++q)
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aut->new_edge(q, q, i);
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// p swaps 1 and 2, and leaves all other states invariant
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aut->new_edge(1, 2, p);
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aut->new_edge(2, 1, p);
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for (unsigned q = 3; q <= 2*n; ++q)
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aut->new_edge(q, q, p);
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// s does to next state (mod 2*n, 0 excluded)
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aut->new_edge(2*n, 1, s);
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for (unsigned q = 1; q < 2*n; ++q)
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aut->new_edge(q, q+1, s);
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// h is the same as i, except on 1 where it goes back to the initial state
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aut->new_edge(1, 0, h);
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for (unsigned q = 2; q <= 2*n; ++q)
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aut->new_edge(q, q, h);
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// from 0, we can non-deterministically jump to any state
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// (except 0) with any letter.
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for (unsigned q = 1; q <= 2*n; ++q)
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aut->new_edge(0, q, bddtrue, {0});
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// i is the identity
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for (unsigned q = 1; q <= 2*n; ++q)
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aut->new_edge(q, q, i);
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// p swaps 1 and 2, and leaves all other states invariant
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aut->new_edge(1, 2, p);
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aut->new_edge(2, 1, p);
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for (unsigned q = 3; q <= 2*n; ++q)
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aut->new_edge(q, q, p);
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// s does to next state (mod 2*n, 0 excluded)
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aut->new_edge(2*n, 1, s);
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for (unsigned q = 1; q < 2*n; ++q)
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aut->new_edge(q, q+1, s);
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// h is the same as i, except on 1 where it goes back to the
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// initial state
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aut->new_edge(1, 0, h);
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for (unsigned q = 2; q <= 2*n; ++q)
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aut->new_edge(q, q, h);
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aut->merge_edges();
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aut->prop_state_acc(true);
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return aut;
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aut->merge_edges();
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aut->prop_state_acc(true);
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return aut;
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}
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}
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twa_graph_ptr aut_pattern(aut_pattern_id pattern, int n)
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{
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if (n < 0)
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{
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std::ostringstream err;
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err << "pattern argument for " << aut_pattern_name(pattern)
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<< " should be positive";
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throw std::runtime_error(err.str());
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}
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switch (pattern)
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{
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// Keep this alphabetically-ordered!
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case AUT_KS_COBUCHI:
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return ks_cobuchi(n);
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case AUT_END:
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break;
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}
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throw std::runtime_error("unsupported pattern");
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}
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const char* aut_pattern_name(aut_pattern_id pattern)
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{
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static const char* const class_name[] =
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{
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"ks-cobuchi",
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};
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// Make sure we do not forget to update the above table every
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// time a new pattern is added.
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static_assert(sizeof(class_name)/sizeof(*class_name)
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== AUT_END - AUT_BEGIN, "size mismatch");
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if (pattern < AUT_BEGIN || pattern >= AUT_END)
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throw std::runtime_error("unsupported pattern");
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return class_name[pattern - AUT_BEGIN];
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}
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}
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}
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@ -19,31 +19,48 @@
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#pragma once
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#include <spot/twa/twagraph.hh>
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#include <spot/misc/common.hh>
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#include <spot/twa/fwd.hh>
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namespace spot
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{
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namespace gen
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{
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/// \brief A family of co-Büchi automata.
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enum aut_pattern_id {
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AUT_BEGIN = 256,
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/// \brief A family of co-Büchi automata.
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///
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/// ks_cobuchi(n) is a co-Büchi automaton of size 2n+1 that is
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/// good-for-games and that has no equivalent deterministic co-Büchi
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/// automaton with less than 2^n / (2n+1) states.
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/// For details and other classes, see:
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///
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/// @InProceedings{kuperberg2015determinisation,
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/// author={Kuperberg, Denis and Skrzypczak, Micha{\l}},
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/// title={On Determinisation of Good-for-Games Automata},
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/// booktitle={International Colloquium on Automata, Languages, and
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/// Programming},
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/// pages={299--310},
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/// year={2015},
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/// organization={Springer}
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/// }
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///
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/// Only defined for n>0
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AUT_KS_COBUCHI = AUT_BEGIN,
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AUT_END
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};
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/// \brief generate an automaton from a known pattern
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///
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/// ks_cobuchi(n) is a co-Büchi automaton of size 2n+1 that is
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/// good-for-games and that has no equivalent deterministic co-Büchi
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/// automaton with less than 2^n / (2n+1) states.
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/// For details and other classes, see:
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/// The pattern is specified using one value from the aut_pattern_id
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/// enum. See the man page of the `genaut` binary for a
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/// description of those patterns, and bibliographic references.
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SPOT_API twa_graph_ptr aut_pattern(aut_pattern_id pattern, int n);
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/// \brief convert an aut_pattern_it value into a name
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///
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/// @InProceedings{kuperberg2015determinisation,
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/// author={Kuperberg, Denis and Skrzypczak, Micha{\l}},
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/// title={On Determinisation of Good-for-Games Automata},
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/// booktitle={International Colloquium on Automata, Languages, and
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/// Programming},
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/// pages={299--310},
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/// year={2015},
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/// organization={Springer}
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/// }
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///
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/// \pre n>0
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SPOT_API twa_graph_ptr
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ks_cobuchi(unsigned n);
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/// The returned name is suitable to be used as an option
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/// key for the genaut binary.
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SPOT_API const char* aut_pattern_name(aut_pattern_id pattern);
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}
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}
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