Commit 1b9354c9 authored by Thibaud Michaud's avatar Thibaud Michaud Committed by Alexandre Duret-Lutz
Browse files

are_isomorphic: return the mapping found, not just true or false

* src/bin/ Here.
* src/tgbaalgos/, src/tgbaalgos/are_isomorphic.hh:
parent 97fdea9d
......@@ -415,12 +415,16 @@ namespace
// Do this first, because it is cheap and will help most
// algorithms.
if (opt_merge)
if (opt_are_isomorphic)
if (opt_product)
aut = spot::product(std::move(aut), opt_product);
if (opt_isomorph && !are_isomorphic(aut, opt_isomorph))
if (opt_isomorph && are_isomorphic(aut, opt_isomorph).empty())
return 0;
aut =, nullptr);
......@@ -187,12 +187,12 @@ namespace
namespace spot
are_isomorphic(const const_tgba_digraph_ptr a1,
const const_tgba_digraph_ptr a2)
if (are_trivially_different(a1, a2))
return false;
return std::vector<unsigned>();
unsigned n = a1->num_states();
assert(n == a2->num_states());
class2states_t a1_classes = map_class_states(a1);
......@@ -202,14 +202,14 @@ namespace spot
// 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;
return std::vector<unsigned>();
while (!is_isomorphism(mapping, a1, a2))
if (!next_class_permutation(a2_classes))
return false;
return std::vector<unsigned>();
mapping_from_classes(mapping, a1_classes, a2_classes);
return true;
return mapping;
......@@ -21,20 +21,16 @@
#include "tgba/tgbagraph.hh"
#include <vector>
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,
/// \brief Return an isomorphism between a1 and a2 if such an isomorphism
/// exists. Otherwise, return an empty vector.
/// The return value is a vector indexed by states of a1, and containing
/// states of a2.
SPOT_API std::vector<unsigned> are_isomorphic(const const_tgba_digraph_ptr a1,
const const_tgba_digraph_ptr a2);
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