I was having a problem with finding all my solutions while using BAB. I finally created a very simple model that demonstrated my problem and using that model, I was able to find a solution to the problem.
I could not find this issue discussed anywhere, so I am going to describe it here in case any one else runs into it and is looking for a solution to it. This is the scenario: IntVar X(0,1); branch(X, INT_VAL_MIN()); IntVar Y(0,2); branch(Y, INT_VAL_MIN()); IntArgs C(1,2); IntVarArray V(2, 0, 2); rel(V[0] == X); rel(V[1] == Y); IntVar Cost(0,5); linear(C, X, V, IRT_EQ, Cost); If I solve this with DFS, I get 6 solutions. If I solve this with BAB and in the constrain function say rel(cost > b.cost); I only get 4 solutions. Note: If I run with GIST and expand the nodes in the correct order, I can cause BAB to display all 6 solutions, but the normal search order does not find all of them. To have BAB find all 6 solutions, I removed the above two branch statements and replaced them with branch(Cost, INT_VAL_MIN()); So, the general rule I would conclude from this test is that when using linear to create a cost function for BAB, always branch on the output of the equation rather than on the terms making up the equation. I don't know if this holds true for other uses of linear. Dean _______________________________________________ Gecode users mailing list users@gecode.org https://www.gecode.org/mailman/listinfo/gecode-users
