[PPL-devel] difference on pointset powerset

[j.c.vandepol at utwente.nl]

Dear Enea,

Thanks, this is going to help a lot! Where can I find a list of all PPL-Prolog predicates?
I didn’t find this particular one in
http://bugseng.com/products/ppl/documentation//user/ppl-user-prolog-interface-1.2-html/domains_predicates.html
(well, apparently I can replace “Polyhedron” in ppl_Polyhedron_difference_assign by anything I need?)

Kind regards,
Jaco van de Pol

On 14 Aug 2017, at 18:53, Enea Zaffanella <zaffanella at cs.unipr.it<mailto:zaffanella at cs.unipr.it>> wrote:


Hello.

The Pointset_Powerset domain has a difference_assign operator.
If I remember correctly, when instantiated to used NNC_Polyhedron,
the operator should be precise.

For instance:

pset1 = { A >= 0 }
pset2 = { B = 0, A = 0 }
pset1.difference_assign(pset2) = { A >= 0, B > 0 }, { A >= 0, -B > 0 }, { B = 0, A > 0 }

Examples of its use (in the C++ interface) can be seen in

   tests/Powerset/difference1.cc<http://difference1.cc>

where, however, it is instantiated with the C_Polyhedron class.

As for the Prolog interface, this should be the foreign predicate to call:

extern "C" Prolog_foreign_return_type
  ppl_Pointset_Powerset_NNC_Polyhedron_difference_assign
  (Prolog_term_ref t_lhs, Prolog_term_ref t_rhs);

Let us know if it works as expected.

Cheers,
Enea.


On 08/08/2017 02:39 PM, j.c.vandepol at utwente.nl<mailto:j.c.vandepol at utwente.nl> wrote:
Dear developers of PPL,

Is it possible to directly compute the set-difference of two pointset powersets?

In particular, I’m interested in the precise complement;
convex difference approximations are not sufficient for my case.

Kind regards,
Jaco van de Pol


--
Prof. Jaco van de Pol
University of Twente (NL)
Formal Methods and Tools
http://www.cs.utwente.nl/~vdpol<http://www.cs.utwente.nl/%7Evdpol>




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--
Prof. Jaco van de Pol
University of Twente (NL)
Formal Methods and Tools
http://www.cs.utwente.nl/~vdpol

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