[PPL-devel] PPL ranking functions

[Kafle, Bishoksan (ARC-TI)[SGT, INC]]

Hello Roberto,

Thanks for getting back to me and pointing to the paper. 

Let me put it simply like this:

ppl_all_affine_ranking_functions_MS_C_Polyhedron(H,RFs),

is there any built in predicates in PPL in which I can ask for singleRanking function(RFs, SingleRF) from the space of ranking functions.

If SingleRF does not serve my purpose can I ask for the next (something like backtracking in prolog)?

I read that it is expensive but is doable. I hope this clears up the misunderstanding.

Many thanks for bearing with me and thank you in advance

Best regards
Bishoksan




________________________________________
From: Roberto Bagnara [bagnara at cs.unipr.it]
Sent: Monday, May 18, 2015 10:15 AM
To: Kafle, Bishoksan (ARC-TI)[SGT, INC]
Cc: The Parma Polyhedra Library developers' list
Subject: Re: [PPL-devel] PPL ranking functions

On 05/16/15 15:09, Kafle, Bishoksan (ARC-TI)[SGT, INC] wrote:
> I have a question about ranking functions, which hopefully you can clarify me. I am using PPL-ciao prolog interface.
>
> The predicate *ppl_one_affine_ranking_function_MS_C_Polyhedron(H,RF)* gives a single ranking function if there exists one.
>
> But I would like to have the possibility of getting more than one ranking functions.
>
> The predicate *ppl_all_affine_ranking_functions_MS_C_Polyhedron(H,RFs)* gives a polyhedron which represent a space of all affine ranking functions but how can one generate or enumerate them systematically?
>
> Any help on this would be highly appreciated.

Hello Bishoksan.

I am not sure I understand the question.  If a linear ranking function
exists, then there exist infinitely many ranking functions.
What do tou mean to "generate or enumerate them systematically"?
Perhaps the answer to your question is at page 27 of this paper:

  http://bugseng.com/automatic-synthesis-linear-ranking-functions-complete-unabridged-version

Please do not hesitate to come back to use if I have misunderstood
your question.
Kind regards,

  Roberto

--
     Prof. Roberto Bagnara

Applied Formal Methods Laboratory - University of Parma, Italy
mailto:bagnara at cs.unipr.it
                              BUGSENG srl - http://bugseng.com
                              mailto:roberto.bagnara at bugseng.com