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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(
EquationSystem<Domain>& system,
ConcreteMaxStrategy<Domain>& strat,
StableVariableAssignment<Domain>& rho,
IdSet<Variable<Domain> >& changedIn,
IdSet<Variable<Domain> >& changedOut
) const = 0;
};
template<typename Domain>
struct NaiveImprovementOperator : public ImprovementOperator<Domain> {
bool improve(
EquationSystem<Domain>& system,
ConcreteMaxStrategy<Domain>& strat,
StableVariableAssignment<Domain>& rho,
IdSet<Variable<Domain> >&,
IdSet<Variable<Domain> >&
) const {
bool changed = false;
for (unsigned int i = 0, length = system.maxExpressionCount();
i < length;
++i) {
MaxExpression<Domain>& expr = system.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 = expr.bestStrategy(rho, strat);
if (index != strat.get(expr)) {
changed = true;
strat.set(expr, index);
}
}
//log::strategy << strat << std::endl;
return changed;
}
};
template<typename Domain>
struct RepeatedImprovementOperator : public ImprovementOperator<Domain> {
RepeatedImprovementOperator(const ImprovementOperator<Domain>& op)
: _subImprovement(op) { }
bool improve(
EquationSystem<Domain>& system,
ConcreteMaxStrategy<Domain>& strat,
StableVariableAssignment<Domain>& rho,
IdSet<Variable<Domain> >& changedIn,
IdSet<Variable<Domain> >& changedOut
) const {
if (_subImprovement.improve(system, strat, rho, changedIn, changedOut)) {
StableVariableAssignment<Domain>* rho2 = system.eval(rho, strat);
improve(system, strat, *rho2, changedIn, changedOut);
delete rho2;
return true;
}
return false;
}
private:
const ImprovementOperator<Domain>& _subImprovement;
};
#endif
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