Hi Andrea,
This is due to recomputation. Please check Tip 8.4 whether this explains the behaviour. Cheers Christian -- Christian Schulte, Professor of Computer Science, KTH, www.gecode.org/~schulte/ From: users-boun...@gecode.org [mailto:users-boun...@gecode.org] On Behalf Of Andrea Peano Sent: Tuesday, September 23, 2014 1:23 PM To: users@gecode.org Subject: [gecode-users] Strange branching behaviour when using FunctionBrancher Hello, I've implemented a search strategy by splitting the search into three levels. I think the code may explain better this strategy. void MyModel::post(Space& home) { static_cast<MyModel&>(home).second_level(); } void MyModel::second_level() { status(); //do something with the partial solution //print "second level" branch(*this, BoolBranchDirection, INT_VAL_MIN()); branch(*this, post2); } void MyModel::post2(Space& home) { static_cast<MyModel&>(home).third_level(); } void MyModel::third_level() { if(BoolBranchDirection.val()==0) { //print third level left //left branch behaviour (install further branches) } else { //print third level right //right branch behaviour (install further branches) } } Imagine now we are fixing the partial solution before the "post" calling, so the solver goes only once into the "post" function (and it's confirmed by GIST). The strange fact is that "second_level" is called more than once! Instead I expect one call for "second_level" and two calls for "third_level", which executes two different paths of the code. These are the prints I read: second level third level left second level third level right second level third level right But I expected: second level third level left third level right Can you clarify this behaviour please? Furthermore, I experienced that I need to call "status()" within the second level, to ground some variables I expected to be already ground. Is this normal? I'm using Gecode 4.2.1 Thanks, Andrea -- Andrea Peano - PhD student Department of Engineering - University of Ferrara Tel: +39 0532 97 4827
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