Index: tol/btol/vmatrix_type/tol_bvmat_bsr_impl.h
===================================================================
--- tol/btol/vmatrix_type/tol_bvmat_bsr_impl.h	(revision dac8deb31c5107f80eec918f0200049bcb3a39d7)
+++ tol/btol/vmatrix_type/tol_bvmat_bsr_impl.h	(revision 8fd1737a0b8771d3e2e10c09a42f63dda5cd167f)
@@ -266,4 +266,27 @@
   void  operator()(IteratorT first, IteratorT last) const { action(); }
 };
+
+///////////////////////////////////////////////////////////////////////////////
+class trace_msg
+///////////////////////////////////////////////////////////////////////////////
+{
+  const std::string& msg_;
+public:
+  trace_msg(std::string& msg) : msg_(msg) {}
+  void action(const std::string& str) const
+  {
+    Std(BSR()+"TRACE "+msg_.c_str()+" : '"+str.c_str()+"'");
+  }
+  void operator()(const std::string& str) const
+  {
+    action(str);
+  }
+  template<typename IteratorT>
+  void operator()(IteratorT first, IteratorT last) const
+  {
+    std::string str;
+    str.assign(first, last);
+    action(str);
+  }};