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#ifndef FIXPOINT_ALGORITHM_HPP
#define FIXPOINT_ALGORITHM_HPP
#include "IdSet.hpp"
#include "IdMap.hpp"
#include "VariableAssignment.hpp"
#include "EquationSystem.hpp"
template<typename Domain>
struct FixpointAlgorithm {
virtual ~FixpointAlgorithm() { }
virtual void maxFixpoint(
const EquationSystem<Domain>& system,
StableVariableAssignment<Domain>& rho,
IdSet<Variable<Domain> >& changedIn,
IdSet<Variable<Domain> >& changedOut
) = 0;
};
template<typename Domain>
struct NaiveFixpointAlgorithm : public FixpointAlgorithm<Domain> {
NaiveFixpointAlgorithm(const EquationSystem<Domain>& system)
: _system(system) { }
virtual void maxFixpoint(
const EquationSystem<Domain>& system,
StableVariableAssignment<Domain>& rhoOut,
IdSet<Variable<Domain> >& changedIn,
IdSet<Variable<Domain> >& changedOut
) {
VariableAssignment<Domain>* rho = NULL;
VariableAssignment<Domain>* result = system.assignment(infinity<Domain>());
do {
if (rho) delete rho;
rho = result;
result = _system.eval(*rho);
} while (!_system.equalAssignments(*rho, *result));
if (rho) delete rho;
for (unsigned int i = 0, length = system.variableCount(); i < length; ++i) {
Variable<Domain> var = system.variable(i);
rhoOut[var] = (*result)[var];
}
}
private:
const EquationSystem<Domain>& _system;
};
template<typename Domain>
struct SmartFixpointAlgorithm : public FixpointAlgorithm<Domain> {
SmartFixpointAlgorithm(const EquationSystem<Domain>& system)
: _system(system),
_influence(system.variableCount(), IdSet<Variable<Domain> >(system.variableCount())){
}
struct DynamicVariableAssignment : public VariableAssignment<Domain> {
DynamicVariableAssignment(
const EquationSystem<Domain>& system,
IdMap<Variable<Domain>,IdSet<Variable<Domain> > >& influence,
StableVariableAssignment<Domain>& rho,
IdSet<Variable<Domain> >& stable,
IdSet<Variable<Domain> >& changed
) : _system(system),
_values(rho),
_stable(stable),
_changed(changed),
_influence(influence) { }
const Domain& operator[](const Variable<Domain>& var) const {
solve(var);
return _values[var];
}
private:
void solve(const Variable<Domain>& x) const {
if (!_stable.contains(x)) {
_stable.insert(x);
Domain val = _system[x]->eval(DependencyAssignment(*this, x));
if (val != _values[x]) {
IdSet<Variable<Domain> > oldInfluence = _influence[x];
_influence[x].clear();
_values[x] = val;
_changed.insert(x);
_stable.filter(oldInfluence);
for (typename IdSet<Variable<Domain> >::iterator it = oldInfluence.begin();
it != oldInfluence.end();
++it) {
solve(_system.variable(*it));
}
_influence[x] = oldInfluence;
}
}
}
struct DependencyAssignment : public VariableAssignment<Domain> {
DependencyAssignment(const DynamicVariableAssignment& assignment, const Variable<Domain>& var)
: _assignment(assignment), _var(var) { }
const Domain& operator[](const Variable<Domain>& x) const {
const Domain& result = _assignment[x];
_assignment._influence[x].insert(_var);
return result;
}
private:
const DynamicVariableAssignment& _assignment;
const Variable<Domain>& _var;
};
const EquationSystem<Domain>& _system;
StableVariableAssignment<Domain>& _values;
IdSet<Variable<Domain> >& _stable;
IdSet<Variable<Domain> >& _changed;
IdMap<Variable<Domain>,IdSet<Variable<Domain> > >& _influence;
};
void invalidate(const IdSet<Variable<Domain> >& set, IdSet<Variable<Domain> >& changed, StableVariableAssignment<Domain>& rho) const {
for (typename IdSet<Variable<Domain> >::iterator it = set.begin(),
end = set.end();
it != end;
++it) {
Variable<Domain>& var = _system.variable(*it);
if (!changed.contains(var)) {
rho[var] = infinity<Domain>();
changed.insert(var);
invalidate(_influence[var], changed, rho);
}
}
}
virtual void maxFixpoint(
const EquationSystem<Domain>& system,
StableVariableAssignment<Domain>& rhoOut,
IdSet<Variable<Domain> >& changedIn,
IdSet<Variable<Domain> >& changedOut
) {
for (typename IdSet<Variable<Domain> >::iterator it = changedIn.begin(),
end = changedIn.end();
it != end;
++it) {
//std::cout << *it << " ";
Variable<Domain>& var = _system.variable(*it);
rhoOut[var] = infinity<Domain>();
invalidate(_influence[var], changedIn, rhoOut);
}
changedIn.invert();
DynamicVariableAssignment rho(system, _influence, rhoOut, changedIn, changedOut);
for (unsigned int i = 0, length = system.variableCount(); i < length; ++i) {
rho[system.variable(i)];
}
/*std::cout << _influence << std::endl;
std::cout << std::endl;*/
}
private:
const EquationSystem<Domain>& _system;
IdMap<Variable<Domain>,IdSet<Variable<Domain> > > _influence;
};
#endif
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