RE: Counting backtracks

Dear Karen,

I have also tried all the initialisations before calling minimize/2 this way:

init_backtracks :-
        setval(backtracks,0).

	get_backtracks(B) :-
        	getval(backtracks,B).
        
	count_backtracks :-
        	setval(deep_fail,false).

	count_backtracks :-
        	getval(deep_fail,false),        % may fail
        	setval(deep_fail,true),
        	incval(backtracks),
        	fail.
minimize((
	    mylabeling(SearchVars),
            get_backtracks(B),
            printf("Backtracks to this point = %d \n \n", [B])
	), OptimalNumber).

Yet I received the same message.

Regards,

Farouk


-----Original Message-----
From: Karen Petrie [mailto:scomkep@zeus.hud.ac.uk]
Sent: 02 May 2003 15:46
To: eclipse-users@icparc.ic.ac.uk; f.aminu@lancaster.ac.uk
Subject: RE: [eclipse-users] Counting backtracks


Farouk,

Are you remembering to count the backtracks in your labelling code? As it 
looks as if the B is uninstantiated. If so, can you send me a bigger 
fragment of code to study.

Karen

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>Subject: RE: [eclipse-users] Counting backtracks
>Date: Fri, 2 May 2003 15:32:31 +0100
>Thread-Topic: [eclipse-users] Counting backtracks
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>From: "Aminu, Farouk" <f.aminu@lancaster.ac.uk>
>To: Joachim Schimpf <j.schimpf@icparc.ic.ac.uk>, eclipse-users 
<eclipse-users@icparc.ic.ac.uk>
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>Hello,
>
>I used: 
>
> minimize((
>	    mylabeling(SearchVars),
>            get_backtracks(B),
>            printf("Backtracks to this point = %d \n \n", [B])
>	), OptimalNumber)
>
>but I am getting the following message:
>
>'type error in printf("%d \n \n", [B])'
>
>am I doing something wrong?
>
>Farouk
>
>Umaru Farouk Aminu
>Department of Management Science,
>Lancaster University,
>Lancaster,
>LA1 4YX,
>UK.
>Tel: +44 1524 383619 (Home)
>      +44 1524 593865 (School)
>      +44 1524 844885 (Fax)
>
>
>
>
>-----Original Message-----
>From: Joachim Schimpf [mailto:j.schimpf@icparc.ic.ac.uk]
>Sent: 02 May 2003 12:40
>To: eclipse-users@icparc.ic.ac.uk
>Subject: Re: [eclipse-users] Counting backtracks
>
>
>Karen Petrie (scomkep@zeus.hud.ac.uk) wrote
>>...
>> Then you need to redefine the event handler:
>> 
>> write_info(_Error, Predicate):-
>>         arg(1, Predicate, Minimum),
>>         printf("Found a solution with cost %d \n", [Minimum]),
>>         get_backtracks(B),
>>         printf("Backtracks to this point = %d \n \n", [B]).
>> 
>> %set event handler
>> :- set_event_handler(280, write_info/2).
>> 
>> Then all you do is call minimize on your labelling:
>> 
>> minimize(mylabeling(SearchVars), OptimalNumber)
>
>
>There is actually no need to use this obscure event handler.
>You can simply write:
>
>    minimize((
>	    mylabeling(SearchVars),
>            get_backtracks(B),
>            printf("Backtracks to this point = %d \n \n", [B])
>	), OptimalNumber)
>
>Whenever mylabeling/1 succeeds, you have a better solution.
>
>
>-- 
> Joachim Schimpf              /             phone: +44 20 7594 8187
> IC-Parc                     /      mailto:J.Schimpf@imperial.ac.uk
> Imperial College London    /    http://www.icparc.ic.ac.uk/eclipse
>
>