标签：exec info div protect eve pos sub notice access
1、定义，只有一个变量info，gecode中的常用技法，将多种信息存在一个变量中, info最后一位作为mask标识，其它位作为id标识。
/// Advisor with index and change information
class Idx : public Advisor {
protected:
/// Index and mark information
int _info;
public:
/// Constructor for creation
Idx(Space& home, Propagator& p, Council<Idx>& c, int i);
/// Constructor for cloning \a a
Idx(Space& home, bool share, Idx& a);
/// Mark advisor as modified
void mark(void);
/// Mark advisor as unmodified
void unmark(void);
/// Whether advisor‘s view has been marked
bool marked(void) const;
/// Get index of view
int idx(void) const;
};
2、实现
/*
* Advisor for activity recorder
*
*/
template<class View>
forceinline
Activity::Recorder<View>::Idx::Idx(Space& home, Propagator& p,
Council<Idx>& c, int i)
: Advisor(home,p,c), _info(i << 1) {}
template<class View>
forceinline
Activity::Recorder<View>::Idx::Idx(Space& home, bool share, Idx& a)
: Advisor(home,share,a), _info(a._info) {
}
template<class View>
forceinline void
Activity::Recorder<View>::Idx::mark(void) {
_info |= 1;
}
template<class View>
forceinline void
Activity::Recorder<View>::Idx::unmark(void) {
_info &= ~1;
}
template<class View>
forceinline bool
Activity::Recorder<View>::Idx::marked(void) const {
return (_info & 1) != 0;
}
template<class View>
forceinline int
Activity::Recorder<View>::Idx::idx(void) const {
return _info >> 1;
}
这个类从advisor继承，又进行这样的操作，是为了和recorder一起使用，当然也可以使用在其它地方，根据标记进行相应操作。 这里的使用方式值得借鉴，果然还是要从代码来入手,show me the code, 文档之类的始终太皮毛
/*
* Posting of activity recorder propagator
*
*/
template<class View>
forceinline
Activity::Recorder<View>::Recorder(Home home, ViewArray<View>& x,
Activity& a0)
: NaryPropagator<View,PC_GEN_NONE>(home,x), a(a0), c(home) {
home.notice(*this,AP_DISPOSE);
for (int i=x.size(); i--; )
if (!x[i].assigned())
x[i].subscribe(home,*new (home) Idx(home,*this,c,i));
}
template<class View>
forceinline ExecStatus
Activity::Recorder<View>::post(Home home, ViewArray<View>& x,
Activity& a) {
(void) new (home) Recorder<View>(home,x,a);
return ES_OK;
}
/*
* Propagation for activity recorder
*
*/
template<class View>
forceinline
Activity::Recorder<View>::Recorder(Space& home, bool share,
Recorder<View>& p)
: NaryPropagator<View,PC_GEN_NONE>(home,share,p) {
a.update(home, share, p.a);
c.update(home, share, p.c);
}
template<class View>
Propagator*
Activity::Recorder<View>::copy(Space& home, bool share) {
return new (home) Recorder<View>(home, share, *this);
}
template<class View>
inline size_t
Activity::Recorder<View>::dispose(Space& home) {
// Delete access to activity information
home.ignore(*this,AP_DISPOSE);
a.~Activity();
// Cancel remaining advisors
for (Advisors<Idx> as(c); as(); ++as)
x[as.advisor().idx()].cancel(home,as.advisor());
c.dispose(home);
(void) NaryPropagator<View,PC_GEN_NONE>::dispose(home);
return sizeof(*this);
}
template<class View>
PropCost
Activity::Recorder<View>::cost(const Space&, const ModEventDelta&) const {
return PropCost::record();
}
template<class View>
void
Activity::Recorder<View>::reschedule(Space& home) {
View::schedule(home,*this,ME_GEN_ASSIGNED);
}
template<class View>
ExecStatus
Activity::Recorder<View>::advise(Space&, Advisor& a, const Delta&) {
static_cast<Idx&>(a).mark();
return ES_NOFIX;
}
template<class View>
ExecStatus
Activity::Recorder<View>::propagate(Space& home, const ModEventDelta&) {
// Lock activity information
a.acquire();
for (Advisors<Idx> as(c); as(); ++as) {
int i = as.advisor().idx();
if (as.advisor().marked()) {
as.advisor().unmark();
a.update(i);
if (x[i].assigned())
as.advisor().dispose(home,c);
} else {
assert(!x[i].assigned());
a.decay(i);
}
}
a.release();
return c.empty() ? home.ES_SUBSUMED(*this) : ES_FIX;
}
标签：exec info div protect eve pos sub notice access
原文地址：http://www.cnblogs.com/crax/p/7468789.html
