[gecode-users] Stability of a solution

[Christian Schulte]

Hi Philippe,

I assume from what you write that you the variables of your problem(s) stay the same while the constraints change. Is tthat correct?

Then, what you can do is to take a space for the new problem (with the new constraints) and assign the variables in the new problem to the values of the old problem. If the space fails, the old solution is not any longer valid. The cost can be accessed as always...

Hope that helps
Christian

--
Christian Schulte, www.ict.kth.se/~cschulte

-----Original Message-----
From: users-bounces at gecode.org [mailto:users-bounces at gecode.org] On Behalf Of Philippe
Sent: Wednesday, October 16, 2013 12:09 AM
To: users at gecode.org
Subject: [gecode-users] Stability of a solution

Hi all,

I have a constraint satisfaction problem correctly solved by gecode using a Branch &  Bound engine. However, I have a stability issue : 
This problem should be solved frequently with minor changes and I get a different solution each time I solve it (I solve it from scratch  every 3 s and the search is time constrained to 10 ms)

Thus, to have a stable solution, I have to know if the previous solution  is still valid and I have to compare its cost (relatively the updated problem) to the best new solution. Unfortunately, this previous solution is not always  analyzed (even if this solution is  probably still relevant) since I am time constrained.

Is there an elegant way to check if the previous solution is still valid and to  compute its cost?

Thanks for tips,
Cheers,
Philippe


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