add one function

Solver/dofManager.h

@@ -358,6 +358,14 @@ class dofManager : public dofManagerBase{
     }
   }
 
+  virtual inline void sparsityDof(const std::vector<Dof> &keys){
+    for (int itR=0; itR< keys.size(); itR++){
+      for (int itC=0; itC<keys.size(); itC++){
+        insertInSparsityPattern(keys[itR],keys[itC]);
+      }
+    }
+  }
+
   virtual inline void assemble(const Dof &R, const Dof &C, const dataMat &value)
   {
     if (_isParallel && !_parallelFinalized) _parallelFinalize();