[gecode-users] Cutting holes within a view optimally

[Zaremby, David]

Thanks. That did the trick.  I knew it was easy.  I just couldn't seem to find it...

virtual ExecStatus propagate(Space& home, const ModEventDelta&)  {
            if (x0.assigned())
            {
                  Iter::Ranges::Singleton r0(x0.val() - offset1 > 0 ? x0.val() - offset1 : 0, x0.val() + offset0);
                  GECODE_ME_CHECK(x1.minus_r(home, r0, false));
            }
            else if (x1.assigned())
            {
                  Iter::Ranges::Singleton r1(x1.val() - offset0 > 0 ? x1.val() - offset0 : 0, x1.val() + offset1);
                  GECODE_ME_CHECK(x0.minus_r(home, r1, false));
            }

            if (x0.max() + offset0 < x1.min() || x1.max() + offset1 < x0.min())
                  return home.ES_SUBSUMED(*this);
            else
                  return ES_FIX;
      }

David Zaremby
Senior Software Engineer
LSS / Strategic Products

Lockheed Martin Simulation, Training & Support
12506 Lake Underhill Road, MP-823
Orlando, FL 32825
From: Christian Schulte [mailto:cschulte at kth.se]
Sent: Tuesday, April 13, 2010 2:11 PM
To: Zaremby, David; users at gecode.org
Subject: RE: [gecode-users] Cutting holes within a view optimally

Check the minus_r member function and the range iterator
                Iter::Ranges::Singleton
The latter allows to specify a single range.

That should do the trick!

Cheers
Christian

--
Christian Schulte, web.ict.kth.se/~cschulte/

From: users-bounces at gecode.org [mailto:users-bounces at gecode.org] On Behalf Of Zaremby, David
Sent: Tuesday, April 13, 2010 7:34 PM
To: users at gecode.org gecode
Subject: [gecode-users] Cutting holes within a view optimally

Gecoders,

I am struggling with finding the best way to cut a hole in a view during propegation without doing a simple for loop. I originally thought I should use a Range and Iterator and execute the minus_v method, but I can't find an easy way to construct one easily using specific values other than using a value array of ints but I would still need a loop to initialize the array. What is the best way to do this with the least computation?

The end goal of this propagator is to put a gap between two domains however there is no guarantee that x0 < x1  so you really can't reduce much on the domain until one is assigned a start. Additionally you can't use an offset view because you only want the offset to apply if the task is the earlier one one.

virtual ExecStatus propagate(Space& home, const ModEventDelta&)  {
            if (x0.assigned())
            {
                  //create a range that x1 cant equal over (x0.val - offset1, x0.val + offset0)
                  for (int i = x0.val() - offset1; i < x0.val() + offset0; ++i)
                  {
                        GECODE_ME_CHECK(x1.nq(home, i));
                  }
            }
            else if (x1.assigned())
            {
                  //create a range that x0 cant equal over (x1.val - offset0, x1.val + offset1)
                  for (int i = x1.val() - offset0; i < x1.val() + offset1; ++i)
                  {
                        GECODE_ME_CHECK(x0.nq(home, i));
                  }
            }

            if (x0.max() + offset0 <= x1.min() || x1.max() + offset1 <= x0.min())
                  return home.ES_SUBSUMED(*this);
            else
                  return ES_FIX;
      }

David Zaremby
Senior Software Engineer
LSS / Strategic Products

Lockheed Martin Simulation, Training & Support
12506 Lake Underhill Road, MP-823
Orlando, FL 32825
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.gecode.org/pipermail/users/attachments/20100413/cb3a4d25/attachment-0001.htm>