1 files changed, 105 insertions, 21 deletions

diff --git a/impl/MaxStrategy.hpp b/impl/MaxStrategy.hpp
index 21a6420..8f40c99 100644
--- a/impl/MaxStrategy.hpp
+++ b/impl/MaxStrategy.hpp
@@ -12,42 +12,126 @@ struct MaxStrategy {
   virtual unsigned int get(const MaxExpression<Domain>& e) const = 0;
 };
 
+#include "VariableAssignment.hpp"
+
+template<typename Domain>
+struct DynamicVariableAssignment;
+
 template<typename Domain>
-struct ConcreteMaxStrategy : public MaxStrategy<Domain> {
-  ConcreteMaxStrategy(const EquationSystem<Domain>& system)
-    : _system(system),
-      _strategy(system.maxExpressionCount(), 0) {
+struct DynamicMaxStrategy : public MaxStrategy<Domain> {
+  DynamicMaxStrategy(
+    const EquationSystem<Domain>& system
+  ) : _system(system),
+      _rho(NULL),
+      _values(system.maxExpressionCount(), 0),
+      _stable(system.maxExpressionCount()),
+      _influence(system.maxExpressionCount(),
+                 IdSet<MaxExpression<Domain>>(system.maxExpressionCount())),
+      _var_influence(system.variableCount(),
+                     IdSet<MaxExpression<Domain>>(system.maxExpressionCount()))
+  {}
+
+  void setRho(DynamicVariableAssignment<Domain>& rho) {
+    _rho = &rho;
   }
 
   unsigned int get(const MaxExpression<Domain>& e) const {
-    return _strategy[e];
+    solve(e);
+    return _values[e];
   }
-  unsigned int set(const MaxExpression<Domain>& e, unsigned int i) {
-    _strategy[e] = i;
-    return i;
+
+  void invalidate(const Variable<Domain>& v) const {
+    log::strategy << "\tInvalidating " << v << " - " << *_system[v] << std::endl;
+    _stable.filter(_var_influence[v]);
+
+    for (auto it = _var_influence[v].begin();
+         it != _var_influence[v].end();
+         ++it) {
+      solve(_system.maxExpression(*it));
+    }
   }
 
-  void print(std::ostream& cout) const {
-    for (unsigned int i = 0, length = _system.maxExpressionCount();
-         i < length;
-         ++i) {
-      auto expr = _system.maxExpression(i);
-      unsigned int subExpression = get(expr);
-      cout << expr
-           << " --[" << subExpression << "]-> "
-           << *expr.arguments()[subExpression] << std::endl;
+private:
+  void solve(const MaxExpression<Domain>& x) const {
+    if (!_stable.contains(x)) {
+      _stable.insert(x);
+      log::strategy << "\tStabilise " << x << std::endl;
+
+      unsigned int val = x.bestStrategy(DependencyAssignment(*this, *_rho, x),
+                                        DependencyStrategy(*this, x));
+
+      if (val != _values[x]) {
+        log::strategy << x << " => " << *x.arguments()[val] << std::endl;
+
+        auto oldInfluence = _influence[x];
+        _influence[x].clear();
+        _values[x] = val;
+
+        _rho->invalidate(*_system.varFromExpr(x));
+
+        _stable.filter(oldInfluence);
+
+        for (auto it = oldInfluence.begin();
+             it != oldInfluence.end();
+             ++it) {
+          solve(_system.maxExpression(*it));
+        }
+      } else {
+        log::strategy << "\t" << x << " did not change" << std::endl;
+      }
+    } else {
+      log::strategy << "\t" << x << " is stable" << std::endl;
     }
   }
 
+  struct DependencyAssignment : public VariableAssignment<Domain>{
+    DependencyAssignment(const DynamicMaxStrategy& strat,
+                         VariableAssignment<Domain>& rho,
+                         const MaxExpression<Domain>& expr)
+      : _strat(strat),
+        _rho(rho),
+        _expr(expr) {
+    }
+    const Domain& operator[](const Variable<Domain>& var) const {
+      _strat._var_influence[var].insert(_expr);
+      return _rho[var];
+    }
+  private:
+    const DynamicMaxStrategy& _strat;
+    VariableAssignment<Domain>& _rho;
+    const MaxExpression<Domain>& _expr;
+  };
+
+  struct DependencyStrategy : public MaxStrategy<Domain> {
+    DependencyStrategy(const DynamicMaxStrategy& strat, const MaxExpression<Domain>& expr)
+      : _strat(strat),
+        _expr(expr) {
+    }
+    unsigned int get(const MaxExpression<Domain>& e) const {
+      _strat.solve(e);
+      if (&_expr != &e) {
+        _strat._influence[e].insert(_expr);
+      }
+      return _strat._values[e];
+    }
   private:
+    const DynamicMaxStrategy& _strat;
+    const MaxExpression<Domain>& _expr;
+  };
+
+private:
   const EquationSystem<Domain>& _system;
-  IdMap<MaxExpression<Domain>,unsigned int> _strategy;
+  mutable DynamicVariableAssignment<Domain>* _rho;
+  mutable IdMap<MaxExpression<Domain>,unsigned int> _values;
+  mutable IdSet<MaxExpression<Domain>> _stable;
+  mutable IdMap<MaxExpression<Domain>,IdSet<MaxExpression<Domain>>> _influence;
+  mutable IdMap<Variable<Domain>,IdSet<MaxExpression<Domain>>> _var_influence;
 };
 
-template<typename Domain>
-std::ostream& operator<<(std::ostream& cout, const ConcreteMaxStrategy<Domain>& strat) {
+/*template<typename Domain>
+std::ostream& operator<<(std::ostream& cout, const MaxStrategy<Domain>& strat) {
   strat.print(cout);
   return cout;
-}
+}*/
 
 #endif