Merge branch 'master' of ssh://bitbucket.org/czan/honours

1 files changed, 65 insertions, 45 deletions

diff --git a/impl/MaxStrategy.hpp b/impl/MaxStrategy.hpp
index d908c7b..5534597 100644
--- a/impl/MaxStrategy.hpp
+++ b/impl/MaxStrategy.hpp
@@ -9,7 +9,10 @@
 template<typename Domain>
 struct MaxStrategy {
   virtual ~MaxStrategy() { }
-  virtual unsigned int get(const MaxExpression<Domain>& e) = 0;
+  virtual unsigned int get(const MaxExpression<Domain>& e) {
+    return const_cast<const MaxStrategy<Domain>*>(this)->get(e);
+  }
+  virtual unsigned int get(const MaxExpression<Domain>& e) const = 0;
 };
 
 unsigned int stack_depth = 1;
@@ -39,44 +42,60 @@ struct DynamicMaxStrategy : public MaxStrategy<Domain> {
                  IdSet<MaxExpression<Domain> >(system.maxExpressionCount())),
       _var_influence(system.variableCount(),
                      IdSet<MaxExpression<Domain> >(system.maxExpressionCount())),
-      _frozen(false)
+      _changed(false)
   {}
 
-  void freeze() {
-    _frozen = true;
+  void setRho(DynamicVariableAssignment<Domain>& rho) {
+    _rho = &rho;
   }
 
-  void thaw() {
-    _frozen = false;
+  void hasChanged(bool c) {
+    _changed = c;
   }
 
-  bool is_frozen() {
-    return _frozen;
+  bool hasChanged() const {
+    return _changed;
   }
 
-  void setRho(DynamicVariableAssignment<Domain>& rho) {
-    _rho = &rho;
+  unsigned int get(const MaxExpression<Domain>& e) const {
+    log::strategy << indent() << "Look up " << e << std::endl;
+    return _values[e];
   }
 
   unsigned int get(const MaxExpression<Domain>& e) {
-    if (!_frozen)
-      solve(e);
+    log::strategy << indent() << "Solve for " << e << std::endl;
+    solve(e);
     return _values[e];
   }
 
   void invalidate(const Variable<Domain>& v) {
     log::strategy << indent() << "Invalidating " << v << " - " << *_system[v] << std::endl; 
-    _stable.filter(_var_influence[v]);
+    //log::debug << indent() << "  var-influence sets " << _var_influence << std::endl;
 
     IdSet<MaxExpression<Domain> > infl = _var_influence[v];
-    _var_influence[v].clear();
-
     for (typename IdSet<MaxExpression<Domain> >::iterator
            it = infl.begin(),
            end = infl.end();
          it != end;
          ++it) {
-      solve(_system.maxExpression(*it));
+      invalidate(_system.maxExpression(*it));
+    }
+  }
+
+  void invalidate(const MaxExpression<Domain>& v) {
+    if (_stable.contains(v)) {
+      log::strategy << indent() << "Invalidating " << v << std::endl; 
+      //log::debug << indent() << "  influence sets " << _influence << std::endl;
+      _stable.remove(v);
+      
+      IdSet<MaxExpression<Domain> > infl = _influence[v];
+      for (typename IdSet<MaxExpression<Domain> >::iterator
+             it = infl.begin(),
+             end = infl.end();
+           it != end;
+           ++it) {
+        invalidate(_system.maxExpression(*it));
+      }
     }
   }
 
@@ -96,16 +115,13 @@ private:
         log::strategy << x << " => " << *x.arguments()[val] << std::endl;
 
         IdSet<MaxExpression<Domain> > oldInfluence = _influence[x];
-        _influence[x].clear();
+        //_influence[x].clear();
         _values[x] = val;
+        _changed = true;
 
         _rho->invalidate(*_system.varFromExpr(x));
-
-	_rho->thaw();
-	this->freeze();
-	_rho->stabilise();
-	_rho->freeze();
-	this->thaw();
+        
+	//_rho->stabilise();
 
         _stable.filter(oldInfluence);
 
@@ -136,15 +152,11 @@ private:
 	_current(strat._system.variableCount()) {
     }
     const Domain operator[](const Variable<Domain>& var) {
+      // solve the strategy for this variable, too
+      _strat.solve(*_strat._system[var]);
       _strat._var_influence[var].insert(_expr);
-      if (_current.contains(var)) {
-	return _rho[var];
-      } else {
-	_current.insert(var);
-	Domain val = _strat._system[var]->eval(_rho, _strat);
-	_current.remove(var);
-	return val;
-      }
+      _strat._influence[*_strat._system[var]].insert(_expr);
+      return _rho[var];
     }
   private:
     DynamicMaxStrategy& _strat;
@@ -158,11 +170,13 @@ private:
       : _strat(strat),
         _expr(expr) {
     }
+    unsigned int get(const MaxExpression<Domain>& e) const {
+      _strat._influence[e].insert(_expr);
+      return _strat._values[e];
+    }
     unsigned int get(const MaxExpression<Domain>& e) {
       _strat.solve(e);
-      if (&_expr != &e) {
-        _strat._influence[e].insert(_expr);
-      }
+      _strat._influence[e].insert(_expr);
       return _strat._values[e];
     }
   private:
@@ -177,7 +191,7 @@ private:
   IdSet<MaxExpression<Domain> > _stable;
   IdMap<MaxExpression<Domain>,IdSet<MaxExpression<Domain> > > _influence;
   IdMap<Variable<Domain>,IdSet<MaxExpression<Domain> > > _var_influence;
-  bool _frozen;
+  bool _changed;
 };
 
 
@@ -193,19 +207,25 @@ struct Solver {
   Domain solve(Variable<Domain>& var) {
     MaxExpression<Domain>& rhs = *_system[var];
 
-    do {
-      _rho.has_changed(false);
+    // _rho automatically keeps up to date with changes made to the
+    // strategy, so you don't need to stabilise it
+
+    _strategy.get(rhs);
 
-      // improve strategy
-      _rho.freeze();
-      _strategy.thaw();
-      _strategy.get(rhs);
 
-      // iterate fixpoint
-      _strategy.freeze();
-      _rho.thaw();
+    /*
+    do {
+      _strategy.hasChanged(false);
+      
+      log::debug << "Stabilise assignment (toplevel)" << std::endl;
       _rho.stabilise();
-    } while (_rho.has_changed());
+      
+      log::debug << "Improve strategy (toplevel)" << std::endl;
+      // improve strategy
+      _strategy.get(rhs);
+      log::debug << (_strategy.hasChanged() ? "Strategy has changed - loop again" : "Strategy has not changed - terminate") << std::endl;
+    } while (_strategy.hasChanged());
+    */
 
     return _rho[var];
   }