Re: [gecode-users] About posting Boolean expression

[Yong]

Hi Christian, Thanks for your prompt reply. The code I wrote was following the example from Section 6.2 Boolean expressions and relations of <<Modeling with Gecode>>(for Gecode3.1.0). The original example is: " For example, the Boolean _expression_ x && imp(y,z) (to be read as x ? (y ? z)) for Boolean variables x, y, and z is posted by:     BoolVar b=post(home, x && imp(y,z)); " So, is it my inaccurate understanding of this example or the example itself is not expressed in an accurate way? Yong Christian Schulte wrote: Write instead:   BoolVar tmp =post(*this, ~(a[j]==(i+1)),ICL_DEF);   What you did is posting the constraint that (a[j] == (i+1)) (and hence the return type of post is void as the compiler tells you). What you apparently wanted to do is to post a reified constraint which you get with ~ (and hence the return type is BoolVar).   Cheers Christian   -- Christian Schulte, www.ict.kth.se/~cschulte/   From: users-boun...@gecode.org [mailto:users-boun...@gecode.org] On Behalf Of Yong Sent: Monday, October 19, 2009 3:26 PM To: us...@gecode.org Subject: [gecode-users] About posting Boolean _expression_   Hi group, A question about posting Boolean _expression_ here. Any hint will be appreciated! My compiler will give "cannot convert from 'void' to 'Gecode::BoolVar'" error on below code: BoolVar tmp =post(*this,(a[j]==(i+1)),ICL_DEF); Yong ps: I'm using Gecode3.2.0 + VC++ 2008 Express Edition

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