Dear Gustavo,
Thanks for your detailed reply.
On 19.12.2009, at 03:47, Gustavo Gutierrez wrote:
2009/12/18 Maity, Ashis K <[email protected]>
However, improved recomputation using Gecode functionalities might
help?
The current design of the integration only consider constraint
propagation in gecode and search is done in mozart. This means that
we don't inherit neither the existing search engines in gecode nor
the search stop objects. Allowing the direct use of the serch
engines is not straight forward but we have some ideas on how to
handle it.
Ah, that is good to know. I assume that one of the advantages of this
design is that Geoz (i.e. Mozart with Gecode interface) distributor
strategies (branching strategies) can employ arbitrary Mozart code.
Nevertheless, does that also mean that Gecode features like batch
recomputation are not available? If not, could that be reimplemented
on the Mozart side?
Also, I understand that for this reason the performance figures
reported for Gecode cannot be reached with Geoz?
Any comment on this is appreciated! Also, when are we expecting
this release (of Mozart-Gecode interface)-- in days, weeks or
months? There is a project website called GeOz (seems defunct now)
-- is it the same thing?
It is hard to say when this is going to be finished. We are facing
different issues on this integration that are still unsolved from
the design point of view. To give you an idea on one of the main
problems: you should know that mozart supports several programming
paradigms including logic programming. To support this we have the
concept of space combinators (or, not, etc.) for this to work we
relay on a gecode feature called reflection. This feature was
removed from gecode in version 3.0 and we don't have a clear idea on
how to handle combinators without it.
Sorry, I don't understand. Since Gecode 3 you cannot ask a Gecode
space anymore whether it is entailed or failed etc.? Gecode itself
does not provide combinators (anymore)? How does Gecode then implement
solvers, don't these rely on this information as well?
I really like the flexibility allowed by something like
Combinator.reify, it allows for a very high-level control to defined
complex CSP. On the other hand, such an approach can lead to weak
propagation...
Thank you!
Best wishes,
Torsten
--
Torsten Anders
Interdisciplinary Centre for Computer Music Research
University of Plymouth
Office: +44-1752-586219
Private: +44-1752-558917
http://strasheela.sourceforge.net
http://www.torsten-anders.de
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