Re: [Info-gnuprologjava] GPJ gives different results than GNU-Prolog

[Burak Emir]

Hey,

No, indeed I was using 0.2.5, sorry for the confusion.

- Burak

On Sat, Sep 15, 2012 at 12:46 PM, Daniel Thomas <address@hidden> wrote:
> Hmm slightly confused as the more minimal test case works fine for me
> though the original one fails:
>
> $ java -jar 
> '/home/daniel/dev/gnuprolog/releases/0.2.6/gnuprologjava-0.2.6.jar' test.pl 
> "run"
> GNU Prolog for Java (0.2.6) Goal runner (c) Constantine Plotnikov, 1997-1999.
> subs is able to create cert(subs) and to send it to subsender
> subs can send message subscriptionConfirmation to subsender
> subsender can send cert(subs) to sender
> subsender can send message create to sender
> time = 48ms
>
> SUCCESS. redo (y/n/a)?y
> subsender can send cert(subs) to sender
> gnu.prolog.vm.PrologException: error(existence_error(procedure,msg / 6),error)
> [snip stacktrace]
>
> The existence_error is to be expected as the reduced test case is
> missing msg/6 and GNU Prolog gives the same result:
> $ gprolog
> GNU Prolog 1.3.0
> By Daniel Diaz
> Copyright (C) 1999-2007 Daniel Diaz
> | ?- [test].
> compiling /home/daniel/dev/gnuprolog/support/cheung/test.pl for byte
> code...
> /home/daniel/dev/gnuprolog/support/cheung/test.pl compiled, 46 lines
> read - 5902 bytes written, 14 ms
>
> (4 ms) yes
> | ?- run.
> subs is able to create cert(subs) and to send it to subsender
> subs can send message subscriptionConfirmation to subsender
> subsender can send cert(subs) to sender
> subsender can send message create to sender
>
> true ? ;
> subsender can send cert(subs) to sender
> uncaught exception: error(existence_error(procedure,msg/6),(\+)/1)
>
> I recall fixing some bugs with dynamic predicates for the 0.2.6 relase.
> Burak Emir: are you using 0.2.6?
>
>
> I put some more debugging into sendCert to give:
> sendCert(Sender, Receiver, Cert):-
>         write('seeing if have cert: '),write(Sender),write(',
> '),write(Cert),write('\n'),write('certs:'),findall(hasCert(X,Y),hasCert(X,Y),List),write(List),write('\n'),
>         hasCert(Sender, Cert),write(hasCert(Sender,Cert)),write('\n'),
>         assert(hasCert(Receiver, Cert)),
>         write(Sender), write(' can send '), write(Cert),
>      write(' to '), write(Receiver), write('\n').
> as the first predicate of sendCert
>
> This gives the illuminating output:
> seeing if have cert: subsender, cert(subs,null,perm(fors,forward),null,-1,-1)
> certs:[hasCert(subs,cert(subreceiver,null,perm(receiver,receive),null,-1,-1)),
>  hasCert(subsender,cert(subs,null,perm(fors,forward),null,-1,-1))]
> ERROR: subsender is not able to send 
> cert(subs,null,perm(fors,forward),null,-1,-1) to sender
>
> Which indicates that hasCert(Sender, Cert) is failing even though
> findall(hasCert(X,Y),hasCert(X,Y),List) finds something which is at
> least textually equivalent to hasCert(Sender, Cert).
>
> So yes looks like a bug, some sort of incorrect caching of what
> predicate exist or similar, unfortunately it looks to be a more subtle
> flaw than the one fixed in 0.2.6 as we have simple test cases that
> assert something and then check that it exits.
> Assistance with finding a minimal test case greatly appreciated as
> presently it is rather difficult to debug where things are going wrong.
>
> Daniel
>
> On Thu, 2012-09-13 at 03:00 +0200, John Cheung wrote:
>> Hello,
>>
>> first thank you for your answer. You could be right.
>> There could be a problem with dynamic(hasCert/2),
>> but does GPJ not supports the dynamic command?
>>
>> John C.
>>
>> -----Ursprüngliche Nachricht-----
>> From: Burak Emir
>> Sent: Wednesday, September 12, 2012 11:49 PM
>> To: John Cheung
>> Cc: address@hidden
>> Subject: Re: [Info-gnuprologjava] GPJ gives different results than
>> GNU-Prolog
>>
>> P.S. I have reduced it to the following.
>> I guess one can reduce it further.
>> Could it be that something is wrong with the dynamic(hasCert/2) ?
>>
>> -- Burak
>>
>> /// code:
>>
>> msg(2, subs, subsender, 'subscriptionConfirmation', [cert(subs)] ).
>> msg(3, subsender, sender, 'create', [cert(subs)] ).
>>
>> :- dynamic(hasCert/2).
>>
>> sendCert(Sender, Receiver, Cert):-
>>         hasCert(Sender, Cert),
>>         assertz(hasCert(Receiver, Cert)),
>>         write(Sender), write(' can send '), write(Cert),
>>      write(' to '), write(Receiver), write('\n').
>>
>> sendCert(Sender, Receiver, cert(Sender)):-
>>         assertz(hasCert(Receiver, cert(Sender))),
>>         write(Sender), write(' is able to create '),
>>         write(cert(Sender)),
>>         write(' and to send it to '), write(Receiver), write('\n').
>>
>> sendAllCerts(_, _, _, []).
>>
>> sendAllCerts(Step, From, To, [F_Cert|Rest]):-
>>         sendCert(From, To, F_Cert),
>>         sendAllCerts(Step, From, To, Rest).
>>
>> sendAllCerts(Step, From, To, [F_Cert|Rest]):-
>>         \+(sendCert(From, To, F_Cert)),
>>         sendAllCerts(Step, From, To, Rest),
>>         write('ERROR: '),
>>         write(From), write(' is not able to send '),
>>         write(F_Cert), write(' to '),
>>         write(To), write('\n').
>>
>> run(Step, MaxSteps):- Step < MaxSteps,
>>         msg(Step, Sender, Receiver, Name , C_List),
>>         sendAllCerts(Step, Sender, Receiver, C_List),
>>         write(Sender), write(' can send message '),
>>         write(Name), write(' to '), write(Receiver), write('\n'),
>>         IPlus1 is Step + 1, run(IPlus1, MaxSteps).
>>
>> run(Step, MaxSteps):-
>>         Step < MaxSteps,
>>     \+(msg(Step, _, _, _, _,_ )),
>>         IPlus1 is Step + 1, run(IPlus1, MaxSteps).
>>
>> run(MaxSteps, MaxSteps).
>>
>> run:-run(2,4).
>>
>> /// GPJ output:
>> subs is able to create cert(subs) and to send it to subsender
>> subs can send message subscriptionConfirmation to subsender
>> ERROR: subsender is not able to send cert(subs) to sender
>> subsender can send message create to sender
>>
>> /// GNU Prolog output:
>> subs is able to create cert(subs) and to send it to subsender
>> subs can send message subscriptionConfirmation to subsender
>> subsender can send cert(subs) to sender
>> subsender can send message create to sender
>>
>>
>>
>> On Wed, Sep 12, 2012 at 7:33 PM, Burak Emir <address@hidden> wrote:
>> > Hey John,
>> >
>> > Looks interesting, probably a bug!
>> >
>> > Your example is still quite long though - is it possible to find a
>> > smaller program that still produces two different results?
>> >
>> > At the risk of stating the obvious, having the shortest program
>> > possible makes it much easier to debug.
>> >
>> > -- Burak Emir
>> >
>> > On Tue, Sep 11, 2012 at 3:19 PM, John Cheung <address@hidden>
>> > wrote:
>> >> Hello,
>> >>
>> >> i'm trying to run my prolog programm from Java with GPJ.
>> >>
>> >> The programm gives the correct result in GNU-Prolog, but GNU Prolog for
>> >> Java
>> >> gives another
>> >> result. Can it be that GNU Prolog supports more or other commands than
>> >> GPJ?
>> >> I don't see what's causing this problem.
>> >>
>> >>
>> >> I've attached the program and the different results for you. You can
>> >> start
>> >> the Programm by
>> >> invorking "run." .
>> >>
>> >> I need this for my thesis, so I would be very grateful if you could help
>> >> me.
>> >>
>> >> Thank You,
>> >>
>> >> John C.
>> >
>> >
>> >
>> > --
>> > Burak Emir
>> > --
>> > http://burak.emir.googlepages.com
>>
>>
>>
>