Bug in ThreeValuedEquivalenceRelation#projectToConstraintsWith

[Heizmann]

While constructing seemingly a copy the above mentioned method in fact reuses data structure of the original.
I cannot understand its documentation but I guess the problem is a bug.

I did not want to change the original method (currently used in an evaluation) and added a new method ThreeValuedEquivalenceRelation#projectTo
68916df

Please check and delete the old method in case the new method fixes the problem.

[danieldietsch]

I'd like to add that if some adds a method to a class he or she should add an author tag. I did nothing with ThreeValuedEquivalenceRelation#projectToConstraintsWith, but perhaps @alexandernutz should take a look (the history indicates him as author).

[alexandernutz]

I agree with @Heizmann that the method leads to sharing of an underlying Set between two ThreeValuedEquivalenceRelations, which is clearly unintended.
However the new implementation does an additional intersection operation with the parameter set "elems" that is not intended.
I will update both the method and the documentation.

(The intended purpose is to keep all constraints where at least one side is in the given Set elems)

Can I delete the projectTo method after fixing projectToConstraintsWith? Eclipse shows me it is not referenced, but it has been wrong before..

[alexandernutz]

actually, I now believe it was not a bug -- at least the underlying sets were not shared.
The reason is that UnionFind#addEquivalenceClass makes a copy of its input set.
But I can see, that the code should make that clearer, so projectToConstraintsWith now makes a copy.

[Heizmann]

Can I delete the projectTo method

No. I need this method and it was not nice to comment the code.

[Heizmann]

But I can see, that the code should make that clearer,

It would be good if you could also update the documentation. If one can understand the documentation it might also become clear what your method does.

[alexandernutz]

sorry. I updated both documentation and method name (commits linked above in this thread), dont you like them?

[Heizmann]

I did no knew that you also updated the documentation.