abs.hpp

00001 /* -*- mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*- */
00002 /*
00003  *  Main authors:
00004  *     Christian Schulte <schulte@gecode.org>
00005  *     Guido Tack <tack@gecode.org>
00006  *     Vincent Barichard <Vincent.Barichard@univ-angers.fr>
00007  *
00008  *  Copyright:
00009  *     Christian Schulte, 2004
00010  *     Guido Tack, 2006
00011  *     Vincent Barichard, 2012
00012  *
00013  *  This file is part of Gecode, the generic constraint
00014  *  development environment:
00015  *     http://www.gecode.org
00016  *
00017  *  Permission is hereby granted, free of charge, to any person obtaining
00018  *  a copy of this software and associated documentation files (the
00019  *  "Software"), to deal in the Software without restriction, including
00020  *  without limitation the rights to use, copy, modify, merge, publish,
00021  *  distribute, sublicense, and/or sell copies of the Software, and to
00022  *  permit persons to whom the Software is furnished to do so, subject to
00023  *  the following conditions:
00024  *
00025  *  The above copyright notice and this permission notice shall be
00026  *  included in all copies or substantial portions of the Software.
00027  *
00028  *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
00029  *  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
00030  *  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
00031  *  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
00032  *  LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
00033  *  OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
00034  *  WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
00035  *
00036  */
00037 
00038 namespace Gecode { namespace Float { namespace Arithmetic {
00039 
00040   template<class A, class B>
00041   forceinline
00042   Abs<A,B>::Abs(Home home, A x0, B x1)
00043     : MixBinaryPropagator<A,PC_FLOAT_BND,B,PC_FLOAT_BND>(home,x0,x1) {}
00044 
00045   template<class A, class B>
00046   ExecStatus
00047   Abs<A,B>::post(Home home, A x0, B x1) {
00048     GECODE_ME_CHECK(x1.eq(home,abs(x0.val())));
00049     if (x0.min() >= 0)
00050       GECODE_ME_CHECK(x0.eq(home,FloatVal(x1.min(), x1.max())));
00051     else if (x0.max() <= 0)
00052       GECODE_ME_CHECK(x0.eq(home,FloatVal(-x1.max(), -x1.min())));
00053     else
00054       GECODE_ME_CHECK(x0.eq(home,FloatVal(-x1.max(), x1.max())));
00055     (void) new (home) Abs<A,B>(home,x0,x1);
00056     return ES_OK;
00057   }
00058 
00059   template<class A, class B>
00060   forceinline
00061   Abs<A,B>::Abs(Space& home, Abs<A,B>& p)
00062     : MixBinaryPropagator<A,PC_FLOAT_BND,B,PC_FLOAT_BND>(home,p) {}
00063 
00064   template<class A, class B>
00065   Actor*
00066   Abs<A,B>::copy(Space& home) {
00067     return new (home) Abs<A,B>(home,*this);
00068   }
00069 
00070   template<class A, class B>
00071   ExecStatus
00072   Abs<A,B>::propagate(Space& home, const ModEventDelta&) {
00073     GECODE_ME_CHECK(x1.eq(home,abs(x0.val())));
00074     if (x0.min() >= 0)
00075       GECODE_ME_CHECK(x0.eq(home,FloatVal(x1.min(), x1.max())));
00076     else if (x0.max() <= 0)
00077       GECODE_ME_CHECK(x0.eq(home,FloatVal(-x1.max(), -x1.min())));
00078     else
00079       GECODE_ME_CHECK(x0.eq(home,FloatVal(-x1.max(), x1.max())));
00080     return (x0.assigned() && x1.assigned()) ? home.ES_SUBSUMED(*this) : ES_FIX;
00081   }
00082 
00083 }}}
00084 
00085 // STATISTICS: float-prop
00086