CODEWITHSUNDEEP
prologsicstus-prologclpfd
MortenM
MortenM

Reputation: 522

Use of clpfd and fdbg

I have the following Prolog code which is using clpfd:

:- use_module(library(clpfd)).
:- use_module(library(fdbg)).   

go( X , Y  ) :-
X = [X1,X2],

X1 in 0..10,
X2 in 0..10,
Y  in -1..1,

X1 #= X2 #<=> IsNoChange,
X1 #> X2 #<=> IsDown,
X1 #< X2 #<=> IsUp,
( (IsNoChange #=1 #/\ Y #=0)  #\/ (IsDown #=1 #/\ Y #= -1) #\/ (IsUp #=1 #/\ Y #=1) ), 

labeling([], X).

If I run the go/2 predicate it works as expected:

| ?- go([1,2],Y).
Y = 1 ? 
yes
| ?- go([3,2],Y).
Y = -1 ? 
yes
| ?- 
| ?- go(X,Y).
X = [0,0],
Y = 0 ? 
yes
| ?-

But if I now enable the fdbg-debugger I don't get values for Y:

| ?- fdbg_on([file('fdbg.log',write) ]).
% The clp(fd) debugger is switched on
yes
% advice
| ?- go(X,Y).                           
X = [0,0],
Y in-1..1 ? 
yes
% advice

Is this a bug in the fdbg-library or am I doing something wrong?

Upvotes: 1

Views: 168

Answers (1)

Mats Carlsson
Mats Carlsson

Reputation: 1426

It's a bug in library(fdbg). It has been fixed for the upcoming SICStus 4.3.

Upvotes: 1

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