/usr/include/gecode/int/arithmetic/argmax.hpp is in libgecode-dev 5.1.0-2build1.
This file is owned by root:root, with mode 0o644.
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/*
* Main authors:
* Christian Schulte <schulte@gecode.org>
*
* Copyright:
* Christian Schulte, 2015
*
* Last modified:
* $Date: 2016-11-08 17:23:24 +0100 (Tue, 08 Nov 2016) $ by $Author: schulte $
* $Revision: 15253 $
*
* This file is part of Gecode, the generic constraint
* development environment:
* http://www.gecode.org
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
*/
#include <gecode/int/rel.hh>
namespace Gecode { namespace Int { namespace Arithmetic {
template<class VA, class VB, bool tiebreak>
forceinline
ArgMax<VA,VB,tiebreak>::ArgMax(Home home, IdxViewArray<VA>& x0, VB y0)
: Propagator(home), x(x0), y(y0) {
x.subscribe(home,*this,PC_INT_BND);
y.subscribe(home,*this,PC_INT_DOM);
}
template<class VA, class VB, bool tiebreak>
ExecStatus
ArgMax<VA,VB,tiebreak>::post(Home home, IdxViewArray<VA>& x, VB y) {
assert(x.size() > 0);
if (x.size() == 1) {
GECODE_ME_CHECK(y.eq(home,x[0].idx));
} else if (y.assigned()) {
int max=0;
while (x[max].idx < y.val())
max++;
assert(x[max].idx == y.val());
if (tiebreak)
for (int i=0; i<max; i++)
GECODE_ES_CHECK((Rel::Le<VA,VA>::post(home,
x[i].view,x[max].view)));
else
for (int i=0; i<max; i++)
GECODE_ES_CHECK((Rel::Lq<VA,VA>::post(home,
x[i].view,x[max].view)));
for (int i=max+1; i<x.size(); i++)
GECODE_ES_CHECK((Rel::Lq<VA,VA>::post(home,
x[i].view,x[max].view)));
} else {
(void) new (home) ArgMax<VA,VB,tiebreak>(home,x,y);
}
return ES_OK;
}
template<class VA, class VB, bool tiebreak>
forceinline
ArgMax<VA,VB,tiebreak>::ArgMax(Space& home, bool share,
ArgMax<VA,VB,tiebreak>& p)
: Propagator(home,share,p) {
x.update(home,share,p.x);
y.update(home,share,p.y);
}
template<class VA, class VB, bool tiebreak>
Actor*
ArgMax<VA,VB,tiebreak>::copy(Space& home, bool share) {
return new (home) ArgMax<VA,VB,tiebreak>(home,share,*this);
}
template<class VA, class VB, bool tiebreak>
PropCost
ArgMax<VA,VB,tiebreak>::cost(const Space&,
const ModEventDelta&) const {
return PropCost::linear(PropCost::LO,x.size()+1);
}
template<class VA, class VB, bool tiebreak>
void
ArgMax<VA,VB,tiebreak>::reschedule(Space& home) {
x.reschedule(home,*this,PC_INT_BND);
y.reschedule(home,*this,PC_INT_DOM);
}
template<class VA, class VB, bool tiebreak>
ExecStatus
ArgMax<VA,VB,tiebreak>::propagate(Space& home, const ModEventDelta&) {
/*
* A key invariant is as follows: for each value i in the domain
* of y there is an index-value pair with index i in x.
*/
// Compute lower and upper bounds for the maximum and its first position.
int p = x[0].idx;
int l = x[0].view.min();
int u = x[0].view.max();
for (int i=1; i<x.size(); i++) {
if (l < x[i].view.min()) {
p = x[i].idx; l = x[i].view.min();
}
if (u < x[i].view.max())
u = x[i].view.max();
}
// Eliminate elements from x and y that are too small
{
Region r(home);
// Values to delete from y
int* d=r.alloc<int>(y.size());
// Number of values to delete
int n = 0;
int i=0, j=0;
ViewValues<VB> iy(y);
while ((i < x.size()) && iy()) {
if (x[i].idx == iy.val()) {
if (x[i].view.max() < l) {
x[i].view.cancel(home,*this,PC_INT_BND);
d[n++]=x[i].idx;
} else {
x[j++]=x[i];
}
++iy;
} else {
assert(x[i].idx < iy.val());
if (x[i].view.max() < l) {
x[i].view.cancel(home,*this,PC_INT_BND);
} else {
x[j++]=x[i];
}
}
i++;
}
while (i < x.size())
if (x[i].view.max() < l) {
x[i].view.cancel(home,*this,PC_INT_BND); i++;
} else {
x[j++]=x[i++];
}
x.size(j);
if (static_cast<unsigned int>(n) == y.size())
return ES_FAILED;
Iter::Values::Array id(d,n);
GECODE_ME_CHECK(y.minus_v(home,id,false));
}
/*
* Now the following invariant holds:
* - for all q in y: u >= x(q).max() >= l
* - if l==u, then exists q in y: x(q).max = u
*/
if (tiebreak && (l == u))
GECODE_ME_CHECK(y.lq(home,p));
if (y.assigned()) {
int max=0;
while (x[max].idx < y.val())
max++;
assert(x[max].idx == y.val());
if (tiebreak)
for (int i=0; i<max; i++)
GECODE_ES_CHECK((Rel::Le<VA,VA>::post(home(*this),
x[i].view,x[max].view)));
else
for (int i=0; i<max; i++)
GECODE_ES_CHECK((Rel::Lq<VA,VA>::post(home(*this),
x[i].view,x[max].view)));
for (int i=max+1; i<x.size(); i++)
GECODE_ES_CHECK((Rel::Lq<VA,VA>::post(home(*this),
x[i].view,x[max].view)));
return home.ES_SUBSUMED(*this);
}
// Recompute the upper bound for elements in y
{
ViewValues<VB> iy(y);
int i=0;
// Skip smaller elements
while (x[i].idx < y.min())
i++;
u=x[i].view.max();
// Skip the minimal element
i++; ++iy;
while (iy()) {
if (x[i].idx == iy.val()) {
u = std::max(u,x[i].view.max());
++iy;
} else {
assert(x[i].idx < iy.val());
}
i++;
}
}
// Constrain elements in x but not in y
{
int i = 0;
// Elements which must be smaller (for tiebreaking)
if (tiebreak)
while ((i < x.size()) && (x[i].idx < y.min())) {
GECODE_ME_CHECK(x[i].view.le(home,u));
i++;
}
else
while ((i < x.size()) && (x[i].idx < y.min())) {
GECODE_ME_CHECK(x[i].view.lq(home,u));
i++;
}
assert(x[i].idx == y.min());
// Elements which cannot be larger
ViewValues<VB> iy(y);
// Skip the minimal element
i++; ++iy;
while ((i < x.size()) && iy()) {
if (x[i].idx == iy.val()) {
++iy;
} else {
assert(x[i].idx < iy.val());
GECODE_ME_CHECK(x[i].view.lq(home,u));
}
i++;
}
while (i < x.size()) {
assert(x[i].idx > y.max());
GECODE_ME_CHECK(x[i].view.lq(home,u));
i++;
}
}
return tiebreak ? ES_NOFIX : ES_FIX;
}
template<class VA, class VB, bool tiebreak>
forceinline size_t
ArgMax<VA,VB,tiebreak>::dispose(Space& home) {
x.cancel(home,*this,PC_INT_BND);
y.cancel(home,*this,PC_INT_DOM);
(void) Propagator::dispose(home);
return sizeof(*this);
}
}}}
// STATISTICS: int-prop
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