Creating an automaton by adding states and transitions
This example demonstrates how to create an automaton and then print it.
C++
#include <iostream>
#include <spot/twaalgos/hoa.hh>
#include <spot/twa/twagraph.hh>
int main(void)
{
// The bdd_dict is used to maintain the correspondence between the
// atomic propositions and the BDD variables that label the edges of
// the automaton.
spot::bdd_dict_ptr dict = spot::make_bdd_dict();
// This creates an empty automaton that we have yet to fill.
spot::twa_graph_ptr aut = make_twa_graph(dict);
// Since a BDD is associated to every atomic proposition, the
// register_ap() function returns a BDD variable number
// that can be converted into a BDD using bdd_ithvar().
bdd p1 = bdd_ithvar(aut->register_ap("p1"));
bdd p2 = bdd_ithvar(aut->register_ap("p2"));
// Set the acceptance condition of the automaton to Inf(0)&Inf(1)
aut->set_generalized_buchi(2);
// States are numbered from 0.
aut->new_states(3);
// The default initial state is 0, but it is always better to
// specify it explicitely.
aut->set_init_state(0U);
// new_edge() takes 3 mandatory parameters: source state,
// destination state, and label. A last optional parameter can be
// used to specify membership to acceptance sets.
aut->new_edge(0, 1, p1);
aut->new_edge(1, 1, p1 & p2, {0});
aut->new_edge(1, 2, p2, {1});
aut->new_edge(2, 1, p1 | p2, {0, 1});
// Print the resulting automaton.
print_hoa(std::cout, aut);
return 0;
}
HOA: v1
States: 3
Start: 0
AP: 2 "p1" "p2"
acc-name: generalized-Buchi 2
Acceptance: 2 Inf(0)&Inf(1)
properties: trans-labels explicit-labels trans-acc
--BODY--
State: 0
[0] 1
State: 1
[0&1] 1 {0}
[1] 2 {1}
State: 2
[0 | 1] 1 {0 1}
--END--
Python
import spot
import buddy
# The bdd_dict is used to maintain the correspondence between the
# atomic propositions and the BDD variables that label the edges of
# the automaton.
bdict = spot.make_bdd_dict();
# This creates an empty automaton that we have yet to fill.
aut = spot.make_twa_graph(bdict)
# Since a BDD is associated to every atomic proposition, the register_ap()
# function returns a BDD variable number that can be converted into a BDD using
# bdd_ithvar() from the BuDDy library.
p1 = buddy.bdd_ithvar(aut.register_ap("p1"))
p2 = buddy.bdd_ithvar(aut.register_ap("p2"))
# Set the acceptance condition of the automaton to Inf(0)&Inf(1)
aut.set_generalized_buchi(2)
# States are numbered from 0.
aut.new_states(3)
# The default initial state is 0, but it is always better to
# specify it explicitely.
aut.set_init_state(0)
# new_edge() takes 3 mandatory parameters: source state, destination state, and
# label. A last optional parameter can be used to specify membership to
# acceptance sets. In the Python version, the list of acceptance sets the
# transition belongs to should be specified as a list.
aut.new_edge(0, 1, p1)
aut.new_edge(1, 1, p1 & p2, [0])
aut.new_edge(1, 2, p2, [1]);
aut.new_edge(2, 1, p1 | p2, [0, 1]);
# Print the resulting automaton.
print(aut.to_str('hoa'))