[gecode-users] Rewriting propagators into more than one propagator

[Christian Schulte]

Dear David,

That is quite simple: in fact, rewriting a propagator p into a propagator q
is nothing but posting q and returning that p is subsumed. The reason why
there is in fact a special macro is that the macro firsts calls the
dispose() member function of p, then posts q, and then p returns E_SUBSUMED
(check the definition of GECODE_REWRITE in gecode/kernel/macros.hpp). But
this is an optimization.

So what you can do: 
 - just post all propagators (make sure to pass home(*this) as first
argument to the post function, this makes sure that some information is
inherited from the propagator to be rewritten).
 - return ES_SUBSUMED of the propagator to be rewritten.

That's all!

Cheers
Christian

--
Christian Schulte, www.gecode.org/~schulte
Professor of Computer Science, KTH, cschulte at kth.se
Expert Researcher, SICS, cschulte at sics.se


-----Original Message-----
From: users-bounces at gecode.org [mailto:users-bounces at gecode.org] On Behalf
Of David Rijsman
Sent: Wednesday, March 04, 2015 9:23 AM
To: users at gecode.org
Subject: [gecode-users] Rewriting propagators into more than one propagator

Dear All,

How can I rewrite a propagator during cloning (or propagation) into more
than one propagator? 

The example in the MPG all rewrite propagators into one other propagator.

Reason for wanting is that I have a propagator P with complexity n-square so
it pays of to rewrite into two or more P propagators if by value of the
variables the propagators become independent. 


David J. Rijsman
R&D Optimization Lead
Quintiq
T +31 73 691 0739
M +31 6 2127 6829
Skype: quintiq.david
www.quintiq.com



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