eclipse-clp

I have the following conditions over two variable A and B : [A,B] #:: 1..10, (A #= 3) or (B #= 3), ((A #> 3 or B #>3) -> % expression 1 ; % expression 2 ) %cntd The problem is in line 2, the solver doesn't know about the value of A and B , how to decide which branch of condition will be continued without specifying the value of the variables at line 2? The reasonable act is to decide on this branch based on the value of the variables when the solver traverse the possible values for the variables. But, As I found it goes through one of these expressions before knowing the value of the variables

I have to solve Sudoku puzzles in the format of a vector containing 9 vectors (of length 9 each). Seeing as vectors are linked lists in Prolog, I figured the search would go faster if I transformed the puzzles in a 2D array format first. Example puzzle: puzzle(P) :- P = [[_,_,8,7,_,_,_,_,6], [4,_,_,_,_,9,_,_,_], [_,_,_,5,4,6,9,_,_], [_,_,_,_,_,3,_,5,_], [_,_,3,_,_,7,6,_,_], [_,_,_,_,_,_,_,8,9], [_,7,_,4,_,2,_,_,5], [8,_,_,9,_,5,_,2,3], [2,_,9,3,_,8,7,6,_]]. I'm using ECLiPSe CLP to implement a solver. The best I've come up with so far is to write a domain like this: domain(P):- dim(P,[9,9]), P

Can someone provide a simple example of channelling constraints? Channelling constraints are used to combine viewpoints of a constraint problem. Handbook of Constraint Programming gives a good explanation of how it works and why it can be useful: The search variables can be the variables of one of the viewpoints, say X1 (this is discussed further below). As search proceeds, propagating the constraints C1 removes values from the domains of the variables in X1. The channelling constraints may then allow values to be removed from the domains of the variables in X2. Propagating these value