Hi, This happens because matrix stores a copy of it's array. For variable-arrays it works as expected, since copy construction shares the elements. For argument arrays, it doesn't. Maybe we should consider using references instead of copies for matrices...
For your current problem, you could use the Matrix initialization and then use the get_array member function to get a copy of the contents. /Mikael On Mon, Sep 27, 2010 at 3:08 PM, Christian Schulte <[email protected]> wrote: > Denys, > > I also believed that this was the case: it is for variable arrays but not > for argument arrays (is that correct?). > > Mikael: can you shed some light on this, please? > > Christian > > -- > Christian Schulte, www.ict.kth.se/~cschulte/ > > > -----Original Message----- > From: [email protected] [mailto:[email protected]] On Behalf > Of Denys Duchier > Sent: Monday, September 27, 2010 1:21 PM > To: [email protected] > Subject: Re: [gecode-users] very odd bug in small program > > Chris Mears <[email protected]> writes: > > > I think the problem is that the Matrix constructor copies the IntArgs > > array, so that when you modify MC you aren't changing C itself. > > meh! I expected a matrix to be a view of the same underlying model, not > a copy. me not likey! > > > (Whether it ought to do this or not is another question.) One > > solution is to instead write: > > > > IntArgs C(4*4, 7, 1, 3, 4, 8, 2, 5, 1, 4, 3, 7, 2, 3, 1, 6, 8); > > ok, thank you, but... (sigh) > > --Denys > > _______________________________________________ > Gecode users mailing list > [email protected] > https://www.gecode.org/mailman/listinfo/gecode-users > > > _______________________________________________ > Gecode users mailing list > [email protected] > https://www.gecode.org/mailman/listinfo/gecode-users > -- Mikael Zayenz Lagerkvist, http://www.ict.kth.se/~zayenz/
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