[PPL-devel] PIP and SWI-Prolog, bug?

[Fred Mesnard]

Le 4 mai 2012 à 12:33, Enea Zaffanella a écrit :

> On 05/02/2012 10:51 AM, Fred Mesnard wrote:
>> I am using PPL 1.0pre1 (GIT version) with SWI-Prolog  6.1.3 and I think I find a bug wrt PIP:
>> 
>>    Call: (8) ppl_new_PIP_Problem_from_space_dimension(6, _G10879) ? skip
>>    Exit: (8) ppl_new_PIP_Problem_from_space_dimension(6, 935460) ? creep
>> 
>>    Call: (8) ppl_PIP_Problem_add_constraints(935460, [A-B-C+D>=0, F= -A+B+E, D= -1-A+B+C]) ? creep
>>    Exit: (8) ppl_PIP_Problem_add_constraints(935460, []) ?
>> 
>>    Call: (8) ppl_PIP_Problem_is_satisfiable(935460) ? skip
>>    Exit: (8) ppl_PIP_Problem_is_satisfiable(935460) ?
>> 
>> IMO, this last call should fail because the [A-B-C+D>=0, F= -A+B+E, D= -1-A+B+C] is not satisfiable.
>> Note that [A-B-C+D>=0, D= -1-A+B+C] is correctly reported as unsatisfiable.
>> 
>> Do you confirm it's a bug from PIP?
>> 
> 
> I confirm it is a bug in PIP_Problem (nothing to do with the Prolog interface itself). The bug was due to lack of update for the `sign' of the special equality row after this row is modified (when elaborating equality constraints after the first one).
> 
> I have already committed the correction on master.
> Can you please have a try on it?

It's ok now. Thank you! 

Fred