Index: kernel/include/IMP/score_states/BondDecoratorListScoreState.h
===================================================================
--- kernel/include/IMP/score_states/BondDecoratorListScoreState.h	(revision 400)
+++ kernel/include/IMP/score_states/BondDecoratorListScoreState.h	(working copy)
@@ -50,6 +50,10 @@
   BondIterator bonds_end() const {
     return bonds_.end();
   }
+
+  unsigned int number_of_bonds() const {
+    return bonds_.size();
+  }
 };
 
 } // namespace IMP
Index: kernel/src/restraints/BondDecoratorRestraint.cpp
===================================================================
--- kernel/src/restraints/BondDecoratorRestraint.cpp	(revision 400)
+++ kernel/src/restraints/BondDecoratorRestraint.cpp	(working copy)
@@ -54,6 +54,7 @@
 {
   out << "Bond decorator restraint with unary function ";
   f_->show(out);
+  out << " on " << bl_->number_of_bonds() << " bonds";
   out << std::endl;
 }