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1.8.3.1
gecode
int
bool
eqv.cpp
Go to the documentation of this file.
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/* -*- mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*- */
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/*
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* Main authors:
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* Christian Schulte <schulte@gecode.org>
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*
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* Copyright:
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* Christian Schulte, 2011
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*
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* Last modified:
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* $Date: 2011-10-07 20:28:27 +1100 (Fri, 07 Oct 2011) $ by $Author: schulte $
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* $Revision: 12427 $
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*
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* This file is part of Gecode, the generic constraint
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* development environment:
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* http://www.gecode.org
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*
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* Permission is hereby granted, free of charge, to any person obtaining
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* a copy of this software and associated documentation files (the
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* "Software"), to deal in the Software without restriction, including
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* without limitation the rights to use, copy, modify, merge, publish,
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* distribute, sublicense, and/or sell copies of the Software, and to
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* permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice shall be
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* included in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
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* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
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* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
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* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*
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*/
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#include <
gecode/int/bool.hh
>
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namespace
Gecode {
namespace
Int {
namespace
Bool {
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/*
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* N-ary Boolean equivalence propagator
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*
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*/
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PropCost
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NaryEqv::cost
(
const
Space
&,
const
ModEventDelta
&)
const
{
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return
PropCost::binary
(
PropCost::LO
);
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}
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Actor
*
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NaryEqv::copy
(
Space
& home,
bool
share) {
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return
new
(home)
NaryEqv
(home,share,*
this
);
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}
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ExecStatus
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NaryEqv::post
(
Home
home,
ViewArray<BoolView>
& x,
int
pm2) {
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int
n = x.
size
();
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for
(
int
i
=n;
i
--; )
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if
(x[
i
].
assigned
()) {
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pm2 ^= x[
i
].val();
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x[
i
] = x[--n];
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}
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if
(n == 0)
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return
(pm2 == 1) ?
ES_OK
:
ES_FAILED
;
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if
(n == 1) {
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GECODE_ME_CHECK
(x[0].eq(home,1^pm2));
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return
ES_OK
;
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}
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if
(n == 2) {
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if
(pm2 == 1) {
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return
Bool::Eq<BoolView,BoolView>::post
(home,x[0],x[1]);
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}
else
{
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NegBoolView
n(x[1]);
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return
Bool::Eq<BoolView,NegBoolView>::post
(home,x[0],n);
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}
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}
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x.
size
(n);
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(void)
new
(home)
NaryEqv
(home,x,pm2);
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return
ES_OK
;
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}
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ExecStatus
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NaryEqv::propagate
(
Space
& home,
const
ModEventDelta
&) {
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resubscribe
(home,
x0
);
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resubscribe
(home,
x1
);
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if
(
x
.
size
() == 0) {
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if
(
x0
.
assigned
() &&
x1
.
assigned
()) {
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return
(
pm2
== 1) ? home.
ES_SUBSUMED
(*
this
) :
ES_FAILED
;
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}
else
if
(
x0
.
assigned
()) {
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GECODE_ME_CHECK
(
x1
.
eq
(home,1^
pm2
));
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return
home.
ES_SUBSUMED
(*
this
);
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}
else
if
(
x1
.
assigned
()) {
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GECODE_ME_CHECK
(
x0
.
eq
(home,1^
pm2
));
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return
home.
ES_SUBSUMED
(*
this
);
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}
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}
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return
ES_FIX
;
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}
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}}}
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// STATISTICS: int-prop