introduce partitioned_relabel_here

Function taking an automaton and trying to relabel
it by partitioning the old conditions and encode the
different subsets of the partition with new variables

* spot/priv/Makefile.am: Add
* spot/priv/partitioned_relabel.hh
, spot/priv/partitioned_relabel.cc: try_partition_me,
computes the partition of a given vector of bdds
* spot/twaalgos/relabel.hh
, spot/twaalgos/relabel.cc: Here. Adapt also relabel()
to cope with the different type of relabeling_maps
* tests/python/_partitioned_relabel.ipynb
, tests/python/except.py: Test and Usage
* tests/Makefile.am: Add test

tests/Makefile.am

@@ -436,6 +436,7 @@ TESTS_python = \
   python/origstate.py \
   python/otfcrash.py \
   python/parsetgba.py \
+  python/_partitioned_relabel.ipynb \
   python/parity.py \
   python/pdegen.py \
   python/prodexpt.py \

tests/python/except.py

@@ -359,3 +359,18 @@ except RuntimeError as e:
     tc.assertIn(filename, str(e))
 else:
     report_missing_exception()
+
+
+# Relabeling must use new variables
+aut = spot.make_twa_graph()
+aut.new_states(2)
+ap = buddy.bdd_ithvar(aut.register_ap("__nv0"))
+aut.new_edge(0,1,ap)
+
+try:
+    spot.partitioned_relabel_here(aut)
+except RuntimeError as e:
+    tc.assertIn("The given prefix for new variables",
+                str(e))
+else:
+    report_missing_exception()