[gecode-users] multiple non parallel search in different threads

[Christian Schulte]

Hi,

You should first try to make independent clones so that you can use them
with different threads:

a) Suppose you have a space s.
b) You compute the fixpoint by s->status(). If s->status() return SS_FAILED
you are done.
c) Create two clones c1 and c2 by c1 = s->clone(false) and c2 =
s->clone(false).
d) Now you can use c1 and c2 in two different threads with the normal DFS
engines.

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 TeXitoi
Sent: Wednesday, November 30, 2011 11:21 AM
To: users at gecode.org
Subject: [gecode-users] multiple non parallel search in different threads

Hi!

I use Gecode in a special way:
 - first I generate a problem
 - then I clone (using space->clone(false)) 2 times the problem
 - on each clone, I add some constraints and branching
 - then I launch simultaneously a DFS on each clone in parallel in 2
   differents threads. The options of the DFS is clone=false (to not
   manually delete my manual clone) and default threading mode (so
   sequencial search).

It (randomly) segfault inside Gecode (most of the time in _clone()). I
suspect that the search use clone(true), and that there is problems with my
2 simultaneous searchs. After reading MPG, I was thinking that it should
work, but I now suspect that each clone in DFS must use false.

Am I right? How to force clone(false) without doing parallel search in DFS?

Thanks.

-- 
Guillaume Pinot                               http://www.texitoi.eu

« Il semble que la perfection soit atteinte non quand il n'y a plus rien à
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