FloatOptimize supports step value

git-svn-id: file:///Users/tack/GecodeGitMigration/gecode-svn-mirror/gecode/trunk@14445 e85b7adc-8362-4630-8c63-7469d557c915

Author: Christian Schulte

gecode/minimodel.hh

@@ -2220,9 +2220,12 @@ namespace Gecode {
     /// Baseclass for float-based cost-based optimization
     template<FloatRelType frt>
     class FloatOptimizeSpace : public Space {
+    protected:
+      /// Step to increment for next better solution
+      FloatNum step;
     public:
-      /// Default constructor
-      FloatOptimizeSpace(void);
+      /// Constructor with step \a s
+      FloatOptimizeSpace(FloatNum s=0.0);
       /// Constructor for cloning
       FloatOptimizeSpace(bool share, FloatOptimizeSpace& s);
       /// Member function constraining according to cost

gecode/minimodel/optimize.hpp

@@ -60,13 +60,14 @@ namespace Gecode { namespace MiniModel {
 
   template<FloatRelType frt>
   forceinline
-  FloatOptimizeSpace<frt>::FloatOptimizeSpace(void) {}
+  FloatOptimizeSpace<frt>::FloatOptimizeSpace(FloatNum s)
+    : step(s) {}
 
   template<FloatRelType frt>
   forceinline
   FloatOptimizeSpace<frt>::FloatOptimizeSpace(bool share, 
                                               FloatOptimizeSpace& s)
-    : Space(share,s) {}
+    : Space(share,s), step(s.step) {}
 
   template<FloatRelType frt>
   void
@@ -75,7 +76,18 @@ namespace Gecode { namespace MiniModel {
       dynamic_cast<const FloatOptimizeSpace<frt>*>(&_best);
     if (best == NULL)
       throw DynamicCastFailed("FloatOptimizeSpace::constrain");
-    rel(*this, cost(), frt, best->cost().val());
+    switch (frt) {
+    case FRT_LE:
+      // Minimize cost variable
+      rel(*this, cost(), FRT_LE, best->cost().val()-step);
+      break;
+    case FRT_GR:
+      // Maximize cost variable
+      rel(*this, cost(), FRT_GR, best->cost().val()+step);
+      break;
+    default:
+      GECODE_NEVER;
+    }
   }
 
 #endif