Problem with Model.intGeView()

In our non public Choco model we have code on the form:

final IntVar[] xs = model.intVarArray(10, 0, 9);
final BoolVar[] bs = Stream.of(xs).map(x -> model.intGeView(x, 1)).toArray(BoolVar[]::new);

final IntVar count = model.intVar(0, 10);
model.sum(bs, "=", count).post();

Our model produced wrong solutions, and after debugging we found out that:

• The domain size of all bs are 10, and not 2 that we had expected. It seems the domain size of the underlying IntVar is used.

• Replacing (only) the code model.intGeView(x, 1) above by model.arithm(x, ">", 0).reify() makes our model produce correct solutions. In addition the domain size of all bs are then 2, as expected.

• During debugging (and still using intGeView()), we replaced model.sum(bs, "=", count).post(); by model.sum(bs, "<=", count).post(); model.sum(bs, ">=", count).post();. This made the solver (from producing a solution within seconds) not producing any solution within reasonable time.

I apologise that this report does not contain a reproducing example of the bug that produce wrong solutions, but hope that it is still useful.

Choco version: 4.10.0 Java version: 11.0.1 Operating system: Linux Kernel 5.0.2

Best regards,

Magnus

[cprudhom]

I fix the issue (thank you for reporting it). This was related to a missing method implementation in views.

This should work now (you can try the snapshot version, or wait for a release).

Best, CP

[cprudhom]

Only eq and leq views were affected by the problem. The other ones (scale, offset, minus and not) act in a different way.