--- trunk/OOPSE/libmdtools/SimSetup.cpp	2003/08/27 19:23:29	733
+++ trunk/OOPSE/libmdtools/SimSetup.cpp	2003/08/28 21:09:47	736
@@ -1625,10 +1625,10 @@ void SimSetup::setupZConstraint(SimInfo& theInfo){
   else{
     sprintf(painCave.errMsg,
             "ZConstraint Warning: User does not set force substraction policy, "
-            "average force substraction policy is used\n");
+            "PolicyByMass is used\n");
     painCave.isFatal = 0;
     simError(); 
-    zconsForcePolicy->setData("BYNUMBER");
+    zconsForcePolicy->setData("BYMASS");
   }
 
   theInfo.addProperty(zconsForcePolicy);
@@ -1664,11 +1664,19 @@ void SimSetup::setupZConstraint(SimInfo& theInfo){
     tempParaItem.kRatio = zconStamp[i]->getKratio();
 
     zconsParaData->addItem(tempParaItem);
+  }
+
+  //check the uniqueness of index  
+  if(!zconsParaData->isIndexUnique()){
+    sprintf(painCave.errMsg,
+            "ZConstraint Error: molIndex is not unique\n");
+    painCave.isFatal = 1;
+    simError(); 
   }
 
   //sort the parameters by index of molecules
   zconsParaData->sortByIndex();
-
+  
   //push data into siminfo, therefore, we can retrieve later
   theInfo.addProperty(zconsParaData);
 }