Re: [eclipse-clp-users] bb_min problem

From: Bogdan Tanasa <g-bogta_at_...107...>
Date: Tue, 5 Apr 2011 13:48:24 +0200
I am also investigating this problem, although I don't have so many
information about how the CLP engine works inside. I have to say that I
suspect the suspend statements.


-----Original Message-----
From: Joachim Schimpf [mailto:joachim.schimpf@...269...] 
Sent: 5 aprilie 2011 13:27
Subject: Re: [eclipse-clp-users] bb_min problem

Bogdan Tanasa wrote:
> Hi,
> I have a piece of CLP which is designed to do some kind of bin packing. 
> If I use bb_min with continue strategy the same solution is printed 
> several times. Can someone please have a look on my code am give me some 
> hints ?

I had a look, but haven't quite yet tracked down why you get
repeated solutions with the same objective value - this should
not happen with branch-and-bound, and might be a bug with the
implementation of bb_min's continue-strategy.

If you change the strategy to 'restart', the multiple-solution
effect does not occur.  However, bb_min still takes a long time
to return AFTER finding the optimum.  This seems to be due to
slow fixpoint conversion when instantiating the variables to
their optimal solution, which is probably a side effect of your
use of very large integer domains and/or real-valued variables.

I don't have more information at the moment.

-- Joachim

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Received on Tue Apr 05 2011 - 11:48:33 CEST

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