diff --git a/src/deptree.cpp b/src/deptree.cpp
index 6f0de72..bd8b8a2 100644
--- a/src/deptree.cpp
+++ b/src/deptree.cpp
@@ -1,7 +1,7 @@
 #include <stack>
 #include "deptree.h"
 
-int DepTree::CreateNodeFromVar(const std::string& var, UsedType& used, CallStack& callstack)
+int DepTree::CreateNodeFromVar(const std::string& var, DepTreeVars& vars, CallStack& callstack)
 {
  COUT(DEBUG)<<"DepTree::CreateNodeFromVar "<<var<<std::endl;
  if(G_vars.count(var)==0)
@@ -12,22 +12,22 @@ int DepTree::CreateNodeFromVar(const std::string& var, UsedType& used, CallStack
 
  UsedType ids;
 
- used.insert(var);
+ vars[var]=this;
  G_vars[var]->UsedIdents(ids);
  type=DepTree::VAR;
  name=var;
 
- DepTree* d;
+ DepTreeVars::const_iterator d;
  int ret;
  callstack.insert(this);
  for(auto& i:ids)
  {
-  d=FindNodeByVar(i);
-  if(d==0)
+  d=vars.find(i);
+  if(d==vars.end())
   {
    auto n=*childrens.insert(new DepTree).first;
    n->parents.insert(this);
-   ret=n->CreateNodeFromVar(i,used,callstack);
+   ret=n->CreateNodeFromVar(i,vars,callstack);
    if(ret!=0)
    {
     COUT(ERROR)<<" in definition of variable "<<name<<std::endl;
@@ -36,13 +36,13 @@ int DepTree::CreateNodeFromVar(const std::string& var, UsedType& used, CallStack
   }
   else
   {
-   if(callstack.find(d)!=callstack.end())
+   if(callstack.find(d->second)!=callstack.end())
    {
     COUT(ERROR)<<"Circular dependency of variable "<<name<<" from variable "<<i<<std::endl;
     return 1;
    }
-   childrens.insert(d);
-   d->parents.insert(this);
+   childrens.insert(d->second);
+   d->second->parents.insert(this);
   }
  }
  callstack.erase(this);
@@ -51,7 +51,7 @@ int DepTree::CreateNodeFromVar(const std::string& var, UsedType& used, CallStack
 }
 
 
-int DepTree::CreateNodeFromSP(DepTree::NodeType list, G_toType::size_type ind, UsedType& used)
+int DepTree::CreateNodeFromSP(DepTree::NodeType list, G_toType::size_type ind, DepTreeVars& vars)
 {
  if(list!=DepTree::SAVE && list!=DepTree::PRINT)
  {
@@ -68,16 +68,16 @@ int DepTree::CreateNodeFromSP(DepTree::NodeType list, G_toType::size_type ind, U
 
  if(type==DepTree::SAVE) G_tosave[index]->UsedIdents(ids);
  else if(type==DepTree::PRINT) G_toprint[index]->UsedIdents(ids);
- DepTree* d;
+ DepTreeVars::const_iterator d;
  int ret;
  for(auto& i:ids)
  {
-  d=FindNodeByVar(i);
-  if(d==0)
+  d=vars.find(i);
+  if(d==vars.end())
   {
    auto n=*childrens.insert(new DepTree).first;
    n->parents.insert(this);
-   ret=n->CreateNodeFromVar(i,used,callstack);
+   ret=n->CreateNodeFromVar(i,vars,callstack);
    if(ret!=0)
    {
     COUT(ERROR)<<" in "<<((type==DepTree::SAVE)?"save":"print")<<" directive "<<((type==DepTree::SAVE)?G_tosave:G_toprint)[index]->Dump()<<"."<<std::endl;
@@ -86,8 +86,8 @@ int DepTree::CreateNodeFromSP(DepTree::NodeType list, G_toType::size_type ind, U
   }
   else
   {
-   childrens.insert(d);
-   d->parents.insert(this);
+   childrens.insert(d->second);
+   d->second->parents.insert(this);
   }
  }
 
@@ -103,48 +103,30 @@ int DepTree::CreateGlobalTree(UsedType& used)
   return 2;
  }
 
+ DepTreeVars vars;
+
  type=DepTree::ROOT;
  for(G_toType::size_type i=0; i<G_tosave.size(); i++)
  {
   auto n=*childrens.insert(new DepTree).first;
   n->parents.insert(this);
-  auto ret=n->CreateNodeFromSP(DepTree::SAVE,i,used);
+  auto ret=n->CreateNodeFromSP(DepTree::SAVE,i,vars);
   if(ret!=0) return ret;
  }
  for(G_toType::size_type i=0; i<G_toprint.size(); i++)
  {
   auto n=*childrens.insert(new DepTree).first;
   n->parents.insert(this);
-  auto ret=n->CreateNodeFromSP(DepTree::PRINT,i,used);
+  auto ret=n->CreateNodeFromSP(DepTree::PRINT,i,vars);
   if(ret!=0) return ret;
  }
 
- return 0;
-}
-
-
-DepTree* DepTree::FindNodeByVarFromCurrent(const std::string& var) const
-{
- if(type==DepTree::VAR && name==var) return const_cast<DepTree*>(this);
+ for(auto& i: vars) used.insert(i.first);
 
- DepTree* d;
- for(auto& i:childrens)
- {
-  d=i->FindNodeByVarFromCurrent(var);
-  if(d!=0) return d;
- }
  return 0;
 }
 
 
-DepTree* DepTree::FindNodeByVar(const std::string& var) const
-{
- const DepTree* curnode=this;
- while(curnode->parents.size()!=0) curnode=*(curnode->parents.begin());
- return curnode->FindNodeByVarFromCurrent(var);
-}
-
-
 DepTree::LeafVector DepTree::FindLeafNodes() const
 {
  LeafVector leafs;
diff --git a/src/deptree.h b/src/deptree.h
index a74e529..2928c1e 100644
--- a/src/deptree.h
+++ b/src/deptree.h
@@ -10,6 +10,7 @@
 class DepTree
 {
  typedef std::vector<DepTree*> LeafVector;
+ typedef std::map<std::string,DepTree*> DepTreeVars;
  enum NodeType {NOTDEF,ROOT,SAVE,PRINT,VAR};
 
  typedef std::set<DepTree*> NodeVector;
@@ -21,10 +22,8 @@ class DepTree
  std::string name;
  mutable bool visited;
 
- int CreateNodeFromVar(const std::string& var, UsedType& used, CallStack& callstack);
- int CreateNodeFromSP(NodeType list, G_toType::size_type ind, UsedType& used);
- DepTree* FindNodeByVarFromCurrent(const std::string& var) const;
- DepTree* FindNodeByVar(const std::string& var) const;
+ int CreateNodeFromVar(const std::string& var, DepTreeVars& vars, CallStack& callstack);
+ int CreateNodeFromSP(NodeType list, G_toType::size_type ind, DepTreeVars& vars);
  LeafVector FindLeafNodes() const;
 public:
  DepTree():type(DepTree::NOTDEF),visited(false) {}