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#ifndef IMPROVEMENT_OPERATOR_HPP
#define IMPROVEMENT_OPERATOR_HPP
#include "IdSet.hpp"
#include "MaxStrategy.hpp"
template<typename Domain>
struct ImprovementOperator {
virtual ~ImprovementOperator() { }
virtual bool improve(
ConcreteMaxStrategy<Domain>& strat,
const VariableAssignment<Domain>& rho,
IdSet<Variable<Domain> >& changedIn,
IdSet<Variable<Domain> >& changedOut
) const = 0;
};
template<typename Domain>
unsigned int bestStrategy(const MaxStrategy<Domain>& strat, const MaxExpression<Domain>& expr, const VariableAssignment<Domain>& rho) {
Domain bestValue = MaxStrategyExpression<Domain>(expr, strat).eval(rho);
unsigned int bestIndex = strat.get(expr);
const std::vector<Expression<Domain>*>& args = expr.arguments();
for (unsigned int j = 0, length = args.size();
j < length;
++j) {
const Domain value = MaxStrategyExpression<Domain>(*args[j], strat).eval(rho);
std::cout << bestValue << " < " << value << ": ";
if (bestValue < value) {
std::cout << "change!" << std::endl;
bestValue = value;
bestIndex = j;
}
std::cout << std::endl;
}
return bestIndex;
}
template<typename Domain>
struct NaiveImprovementOperator : public ImprovementOperator<Domain> {
bool improve(
ConcreteMaxStrategy<Domain>& strat,
const VariableAssignment<Domain>& rho,
IdSet<Variable<Domain> >& changedIn,
IdSet<Variable<Domain> >& changedOut
) const {
bool changed = false;
for (unsigned int i = 0, length = strat.maxExpressionCount();
i < length;
++i) {
MaxExpression<Domain>& expr = strat.maxExpression(i);
// this relies on the fact that an expression will only be proessed after the expressions
// it depends on (which should always be true, as they form a DAG)
unsigned int index = bestStrategy(strat, expr, rho);
if (index != strat.get(expr)) {
changed = true;
strat.set(expr, index);
}
}
return changed;
}
};
template<typename Domain>
struct RepeatedImprovementOperator : public ImprovementOperator<Domain> {
RepeatedImprovementOperator(const ImprovementOperator<Domain>& op)
: _subImprovement(op) { }
bool improve(
ConcreteMaxStrategy<Domain>& strat,
const VariableAssignment<Domain>& rho,
IdSet<Variable<Domain> >& changedIn,
IdSet<Variable<Domain> >& changedOut
) const {
if (_subImprovement.improve(strat, rho, changedIn, changedOut)) {
VariableAssignment<Domain>* rho2 = strat.eval(rho);
improve(strat, *rho2, changedIn, changedOut);
delete rho2;
return true;
}
return false;
}
private:
const ImprovementOperator<Domain>& _subImprovement;
};
template<typename Domain>
struct SmartImprovementOperator : public ImprovementOperator<Domain> {
SmartImprovementOperator(const ConcreteEquationSystem<Domain>& system)
: _system(system),
_influence(system.maxExpressionCount(), IdSet<MaxExpression<Domain> >(system.maxExpressionCount())) {
}
struct DynamicMaxStrategy : public MaxStrategy<Domain> {
DynamicMaxStrategy(
ConcreteMaxStrategy<Domain>& strat,
IdMap<MaxExpression<Domain>,IdSet<MaxExpression<Domain> > >& influence,
const VariableAssignment<Domain>& rho,
IdSet<MaxExpression<Domain> >& stable,
IdSet<MaxExpression<Domain> >& changed
) : MaxStrategy<Domain>(strat),
_rho(rho),
_values(strat),
_stable(stable),
_changed(changed),
_influence(influence) {
}
unsigned int get(const MaxExpression<Domain>& e) const {
solve(e);
return _values.get(e);
}
private:
void solve(const MaxExpression<Domain>& x) const {
if (!_stable.contains(x)) {
_stable.insert(x);
unsigned int val = bestStrategy(DependencyStrategy(*this, x), x, _rho);
//MaxStrategyExpression(x, DependencyStrategy(_values, x));
if (val != _values.get(x)) {
IdSet<MaxExpression<Domain> > oldInfluence = _influence[x];
_influence[x].clear();
_values.set(x, val);
_changed.insert(x);
std::cout << x << std::endl;
_stable.filter(oldInfluence);
for (typename IdSet<MaxExpression<Domain> >::iterator it = oldInfluence.begin();
it != oldInfluence.end();
++it) {
solve(_values.maxExpression(*it));
}
_influence[x] = oldInfluence;
}
}
}
struct DependencyStrategy : public MaxStrategy<Domain> {
DependencyStrategy(const DynamicMaxStrategy& strat, const MaxExpression<Domain>& expr)
: MaxStrategy<Domain>(strat),
_strat(strat),
_expr(expr) {
}
unsigned int get(const MaxExpression<Domain>& e) const {
_strat.solve(e);
_strat._influence[e].insert(_expr);
return _strat._values.get(e);
}
private:
const DynamicMaxStrategy& _strat;
const MaxExpression<Domain>& _expr;
};
private:
const VariableAssignment<Domain>& _rho;
ConcreteMaxStrategy<Domain>& _values;
IdSet<MaxExpression<Domain> >& _stable;
IdSet<MaxExpression<Domain> >& _changed;
IdMap<MaxExpression<Domain>,IdSet<MaxExpression<Domain> > >& _influence;
};
void invalidate(IdSet<MaxExpression<Domain> >& set, MaxExpression<Domain>& expr) const {
for (typename IdSet<MaxExpression<Domain> >::iterator it = _influence[expr].begin(),
end = _influence[expr].end();
it != end;
++it) {
set.insert(_system.maxExpression(*it));
invalidate(set, expr);
}
}
bool improve(
ConcreteMaxStrategy<Domain>& stratOut,
const VariableAssignment<Domain>& rho,
IdSet<Variable<Domain> >& changedIn,
IdSet<Variable<Domain> >& changedOut
) const {
IdSet<MaxExpression<Domain> > invalidSet(_system.maxExpressionCount());
IdSet<MaxExpression<Domain> > changedSet(_system.maxExpressionCount());
for (typename IdSet<Variable<Domain> >::iterator it = changedIn.begin(),
end = changedIn.end();
it != end;
++it) {
invalidate(invalidSet, *_system[_system.variable(*it)]);
}
invalidSet.invert();
std::cout << std::endl;
DynamicMaxStrategy strat(stratOut, _influence, rho, invalidSet, changedSet);
std::cout << std::endl;
for (typename IdSet<MaxExpression<Domain> >::iterator it = changedSet.begin(),
end = changedSet.end();
it != end;
++it) {
Variable<Domain>* var = strat.varFromExpr(_system.maxExpression(*it));
if (var) {
changedOut.insert(*var);
}
}
std::cout << changedSet << std::endl;
std::cout << changedOut << std::endl;
return changedOut.size() != 0;
}
private:
const ConcreteEquationSystem<Domain>& _system;
mutable IdMap<MaxExpression<Domain>,IdSet<MaxExpression<Domain> > > _influence;
};
#endif
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