add arithm preprocessing to detect trivial cases

[jgFages]

No description provided.

[ArthurGodet]

I agree on the proposed preprocessing. But why are some tests failing due to these changes ?

[jgFages]

I agree on the proposed preprocessing. But why are some tests failing due to these changes ?

Ah, those optimization are no longer possible within a dynamic context...
So even the already existing prepocessing below was wrong actually :

default Constraint arithm(IntVar var1, String op, IntVar var2) {
            if (var2.isInstantiated()) {
                return arithm(var1, op, var2.getValue());
            }
            if (var1.isInstantiated()) {
                return arithm(var2, Operator.getFlip(op), var1.getValue());
            }
...

[cprudhom]

Wouldn't be better to move this simplification to IntConstraintFactory ?
That's where preprocessing are commonly applied.

[jgFages]

Wouldn't be better to move this simplification to IntConstraintFactory ? That's where preprocessing are commonly applied.

It is already in IIntConstraintFactory, perhaps you meant PreProcessing.java ?

[cprudhom]

I used to use solver.getSearchState() == SearchState.NEW for instance in cstr.impliedBy(bvar).
I would suggest either to call this method or to create a new method with an accurate name that indicates that such preprocessing can be done safely.

[cprudhom]

Well, there exists a method like that: solver.isSolving()