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/* -*- mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*- */
/*
* Main authors:
* Christian Schulte <schulte@gecode.org>
*
* Copyright:
* Christian Schulte, 2012
*
* 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 <cfloat>
namespace Gecode {
/**
* \brief Class for action management
*
*/
class Action : public SharedHandle {
protected:
template<class View, bool p, bool f>
class Recorder;
/// Object for storing action values
class GECODE_VTABLE_EXPORT Storage : public SharedHandle::Object {
public:
/// Mutex to synchronize globally shared access
GECODE_KERNEL_EXPORT static Support::Mutex m;
/// Number of action values
int n;
/// Inverse decay factor
double invd;
/// Action values (more follow)
double* a;
/// Initialize action values
template<class View>
Storage(Home home, ViewArray<View>& x, double d,
typename BranchTraits<typename View::VarType>::Merit bm);
/// Update action value at position \a i
void update(int i);
/// Delete object
GECODE_KERNEL_EXPORT
~Storage(void);
};
/// Return object of correct type
Storage& object(void) const;
/// Set object to \a o
void object(Storage& o);
/// Update action value at position \a i
void update(int i);
/// Acquire mutex
void acquire(void);
/// Release mutex
void release(void);
public:
/// \name Constructors and initialization
//@{
/**
* \brief Construct as not yet intialized
*
* The only member functions that can be used on a constructed but not
* yet initialized action storage is init and the assignment operator.
*
*/
Action(void);
/// Copy constructor
GECODE_KERNEL_EXPORT
Action(const Action& a);
/// Assignment operator
GECODE_KERNEL_EXPORT
Action& operator =(const Action& a);
/**
* \brief Initialize for views \a x and decay factor \a d and action as defined by \a bm
*
* Count propagation if \a p is true, count failure if \a f is true.
*/
template<class View>
Action(Home home, ViewArray<View>& x, double d, bool p, bool f,
typename BranchTraits<typename View::VarType>::Merit bm);
/**
* \brief Initialize for views \a x and decay factor \a d and action as defined by \a bm
*
* Count propagation if \a p is true, count failure if \a f is true.
*/
template<class View>
void init(Home home, ViewArray<View>& x, double d, bool p, bool f,
typename BranchTraits<typename View::VarType>::Merit bm);
/// Default (empty) action information
GECODE_KERNEL_EXPORT static const Action def;
//@}
/// Destructor
GECODE_KERNEL_EXPORT
~Action(void);
/// \name Information access
//@{
/// Return action value at position \a i
double operator [](int i) const;
/// Return number of action values
int size(void) const;
//@}
/// \name Decay factor for aging
//@{
/// Set decay factor to \a d
GECODE_KERNEL_EXPORT
void decay(Space& home, double d);
/// Return decay factor
GECODE_KERNEL_EXPORT
double decay(const Space& home) const;
//@}
};
/// Propagator for recording action information
template<class View, bool p, bool f>
class Action::Recorder : public NaryPropagator<View,PC_GEN_NONE> {
protected:
using NaryPropagator<View,PC_GEN_NONE>::x;
/// Advisor with index and change information
class Idx : public Advisor {
protected:
/// Index and mark/failed information
unsigned int _info;
public:
/// Constructor for creation
Idx(Space& home, Propagator& r, Council<Idx>& c, int i);
/// Constructor for cloning \a a
Idx(Space& home, Idx& a);
/// Mark index as propagated
void propagate(void);
/// Mark index as failed
void fail(void);
/// Whether index has been propagated
bool propagated(void) const;
/// Whether index has been failed
bool failed(void) const;
/// Clear any information
void clear(void);
/// Get index of view
int idx(void) const;
};
/// Access to action information
Action a;
/// The advisor council
Council<Idx> c;
/// Constructor for cloning \a r
Recorder(Space& home, Recorder<View,p,f>& r);
public:
/// Constructor for creation
Recorder(Home home, ViewArray<View>& x, Action& a);
/// Copy propagator during cloning
virtual Propagator* copy(Space& home);
/// Cost function (record so that propagator runs last)
virtual PropCost cost(const Space& home, const ModEventDelta& med) const;
/// Schedule function
virtual void reschedule(Space& home);
/// Give advice to propagator
virtual ExecStatus advise(Space& home, Advisor& a, const Delta& d);
/// Give advice to propagator when \a home has failed
virtual void advise(Space& home, Advisor& a);
/// Perform propagation
virtual ExecStatus propagate(Space& home, const ModEventDelta& med);
/// Delete propagator and return its size
virtual size_t dispose(Space& home);
/// Post action recorder propagator
static ExecStatus post(Home home, ViewArray<View>& x, Action& a);
};
/**
* \brief Print action values enclosed in curly brackets
* \relates Action
*/
template<class Char, class Traits>
std::basic_ostream<Char,Traits>&
operator <<(std::basic_ostream<Char,Traits>& os,
const Action& a);
/*
* Advisor for action recorder
*
*/
template<class View, bool p, bool f>
forceinline
Action::Recorder<View,p,f>::Idx::Idx(Space& home, Propagator& r,
Council<Idx>& c, int i)
: Advisor(home,r,c), _info(static_cast<unsigned int>(i) << 2U) {}
template<class View, bool p, bool f>
forceinline
Action::Recorder<View,p,f>::Idx::Idx(Space& home, Idx& a)
: Advisor(home,a), _info(a._info) {
}
template<class View, bool p, bool f>
forceinline void
Action::Recorder<View,p,f>::Idx::propagate(void) {
_info |= 1U;
}
template<class View, bool p, bool f>
forceinline void
Action::Recorder<View,p,f>::Idx::fail(void) {
_info |= 2U;
}
template<class View, bool p, bool f>
forceinline bool
Action::Recorder<View,p,f>::Idx::propagated(void) const {
return (_info & 1U) != 0;
}
template<class View, bool p, bool f>
forceinline bool
Action::Recorder<View,p,f>::Idx::failed(void) const {
return (_info & 2U) != 0;
}
template<class View, bool p, bool f>
forceinline void
Action::Recorder<View,p,f>::Idx::clear(void) {
_info &= ~3U;
}
template<class View, bool p, bool f>
forceinline int
Action::Recorder<View,p,f>::Idx::idx(void) const {
return static_cast<int>(_info >> 2);
}
/*
* Posting of action recorder propagator
*
*/
template<class View, bool p, bool f>
forceinline
Action::Recorder<View,p,f>::Recorder(Home home, ViewArray<View>& x,
Action& a0)
: NaryPropagator<View,PC_GEN_NONE>(home,x), a(a0), c(home) {
home.notice(*this,AP_DISPOSE);
for (int i=0; i<x.size(); i++)
if (!x[i].assigned())
x[i].subscribe(home,*new (home) Idx(home,*this,c,i), true);
}
template<class View, bool p, bool f>
forceinline ExecStatus
Action::Recorder<View,p,f>::post(Home home, ViewArray<View>& x, Action& a) {
(void) new (home) Recorder<View,p,f>(home,x,a);
return ES_OK;
}
/*
* Action value storage
*
*/
template<class View>
forceinline
Action::Storage::Storage(Home home, ViewArray<View>& x, double d,
typename
BranchTraits<typename View::VarType>::Merit bm)
: n(x.size()), invd(1.0 / d), a(heap.alloc<double>(x.size())) {
if (bm)
for (int i=0; i<n; i++) {
typename View::VarType xi(x[i].varimp());
a[i] = bm(home,xi,i);
}
else
for (int i=0; i<n; i++)
a[i] = 1.0;
}
forceinline void
Action::Storage::update(int i) {
/*
* The trick to inverse decay is from: An Extensible SAT-solver,
* Niklas Eén, Niklas Sörensson, SAT 2003.
*/
assert((i >= 0) && (i < n));
a[i] = invd * (a[i] + 1.0);
if (a[i] > Kernel::Config::rescale_limit)
for (int j=0; j<n; j++)
a[j] *= Kernel::Config::rescale;
}
/*
* Action
*
*/
forceinline Action::Storage&
Action::object(void) const {
return static_cast<Action::Storage&>(*SharedHandle::object());
}
forceinline void
Action::object(Action::Storage& o) {
SharedHandle::object(&o);
}
forceinline void
Action::update(int i) {
object().update(i);
}
forceinline double
Action::operator [](int i) const {
assert((i >= 0) && (i < object().n));
return object().a[i];
}
forceinline int
Action::size(void) const {
return object().n;
}
forceinline void
Action::acquire(void) {
object().m.acquire();
}
forceinline void
Action::release(void) {
object().m.release();
}
forceinline
Action::Action(void) {}
template<class View>
forceinline
Action::Action(Home home, ViewArray<View>& x, double d,
bool p, bool f,
typename BranchTraits<typename View::VarType>::Merit bm) {
assert(!*this);
if (!p && !f)
return;
object(*new Storage(home,x,d,bm));
if (p && f)
(void) Recorder<View,true,true>::post(home,x,*this);
else if (p && !f)
(void) Recorder<View,true,false>::post(home,x,*this);
else if (!p && f)
(void) Recorder<View,false,true>::post(home,x,*this);
}
template<class View>
forceinline void
Action::init(Home home, ViewArray<View>& x, double d,
bool p, bool f,
typename BranchTraits<typename View::VarType>::Merit bm) {
assert(!*this);
if (!p && !f)
return;
object(*new Storage(home,x,d,bm));
if (p && f)
(void) Recorder<View,true,true>::post(home,x,*this);
else if (p && !f)
(void) Recorder<View,true,false>::post(home,x,*this);
else if (!p && f)
(void) Recorder<View,false,true>::post(home,x,*this);
}
template<class Char, class Traits>
std::basic_ostream<Char,Traits>&
operator <<(std::basic_ostream<Char,Traits>& os,
const Action& a) {
std::basic_ostringstream<Char,Traits> s;
s.copyfmt(os); s.width(0);
s << '{';
if (a.size() > 0) {
s << a[0];
for (int i=1; i<a.size(); i++)
s << ", " << a[i];
}
s << '}';
return os << s.str();
}
/*
* Propagation for action recorder
*
*/
template<class View, bool p, bool f>
forceinline
Action::Recorder<View,p,f>::Recorder(Space& home, Recorder<View,p,f>& r)
: NaryPropagator<View,PC_GEN_NONE>(home,r), a(r.a) {
c.update(home, r.c);
}
template<class View, bool p, bool f>
Propagator*
Action::Recorder<View,p,f>::copy(Space& home) {
return new (home) Recorder<View,p,f>(home, *this);
}
template<class View, bool p, bool f>
inline size_t
Action::Recorder<View,p,f>::dispose(Space& home) {
// Delete access to action information
home.ignore(*this,AP_DISPOSE);
a.~Action();
// Cancel remaining advisors
for (Advisors<Idx> as(c); as(); ++as)
x[as.advisor().idx()].cancel(home,as.advisor(),true);
c.dispose(home);
(void) NaryPropagator<View,PC_GEN_NONE>::dispose(home);
return sizeof(*this);
}
template<class View, bool p, bool f>
PropCost
Action::Recorder<View,p,f>::cost(const Space&, const ModEventDelta&) const {
return PropCost::record();
}
template<class View, bool p, bool f>
void
Action::Recorder<View,p,f>::reschedule(Space& home) {
View::schedule(home,*this,ME_GEN_ASSIGNED);
}
template<class View, bool p, bool f>
ExecStatus
Action::Recorder<View,p,f>::advise(Space& home, Advisor& _a, const Delta&) {
Idx& a = static_cast<Idx&>(_a);
if (p) {
a.propagate();
return ES_NOFIX;
} else {
return x[a.idx()].assigned() ? home.ES_FIX_DISPOSE(c,a) : ES_FIX;
}
}
template<class View, bool p, bool f>
void
Action::Recorder<View,p,f>::advise(Space&, Advisor& _a) {
Idx& a = static_cast<Idx&>(_a);
if (f)
a.fail();
}
template<class View, bool p, bool f>
ExecStatus
Action::Recorder<View,p,f>::propagate(Space& home, const ModEventDelta&) {
// Lock action information
a.acquire();
for (Advisors<Idx> as(c); as(); ++as) {
int i = as.advisor().idx();
if (p && as.advisor().propagated()) {
as.advisor().clear();
a.update(i);
if (x[i].assigned())
as.advisor().dispose(home,c);
}
if (f && as.advisor().failed()) {
as.advisor().clear();
a.update(i);
if (x[i].assigned())
as.advisor().dispose(home,c);
}
}
a.release();
return c.empty() ? home.ES_SUBSUMED(*this) : ES_FIX;
}
}
// STATISTICS: kernel-branch