Propagate without posting branching

[Oleg Zaikin]

Dear Gecode team.

In my program, I create a space and post all the needed constraints.

I do not need any branching to be done, only a result of the propagation is

needed, so I do not call the branch() function. The problem is that the status()

function always returns SS_SOLVED, even if in fact no solution is found.

1. Is it because the queue of branchers is empty, so the space’s status()

function terminates and reports that the space is solved?

2. If yes, then is it possible to post a trivial branching that does nothing?

Best regards, Oleg

[Mikael Zayenz Lagerkvist]

Hi,

In Gecode, if there are no branchers and propagation does not detect a failure, then the Space is considered solved for the purposes of search. This may include unassigned variables, but that may be desired in some situations.

A trivial branching that does nothing would not do anything, so I fail to see what effect iyou are trying to achieve.

Cheers

Zayenz

[Oleg Zaikin]

Dear Mikael.

We need it to run just our own propagation once and estimate the achieved effect.
We managed to do so by using a customised brancher that does no branching.

Best regards, Oleg.

понедельник, 23 мая 2022 г. в 14:58:04 UTC+1, Mikael Zayenz Lagerkvist:

[Mikael Zayenz Lagerkvist]

Hi,

If you have a Space you can run propagation on it by calling the
Space::status() function. no need for search engines or branchers.

Cheers,
Mikael

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Mikael Zayenz Lagerkvist