diff --git a/CoMISo/NSolver/LinearConstraint.hh b/CoMISo/NSolver/LinearConstraint.hh
index 08031d2609bf1c8b37a1c24883f47d42e0e3da6c..7d03f6b4aaca1398682dcde8c6dd09acba5a750a 100644
--- a/CoMISo/NSolver/LinearConstraint.hh
+++ b/CoMISo/NSolver/LinearConstraint.hh
@@ -13,6 +13,7 @@
 
 #include <CoMISo/Config/CoMISoDefines.hh>
 #include "NConstraintInterface.hh"
+#include <gmm/gmm.h>
 
 //== FORWARDDECLARATIONS ======================================================
 
diff --git a/CoMISo/Solver/ConstrainedSolverT.cc b/CoMISo/Solver/ConstrainedSolverT.cc
index 0cdaeb56e2b28c5fc1aa26745f78cbe395039666..0bc2e9cffe0d34ba26f03109fc1865086e3c579a 100644
--- a/CoMISo/Solver/ConstrainedSolverT.cc
+++ b/CoMISo/Solver/ConstrainedSolverT.cc
@@ -914,7 +914,8 @@ eliminate_constraints(
     std::cerr << __FUNCTION__ << " Constraints eliminated " << sw.stop()/1000.0 << std::endl;
   sw.start();
   // init _new_idx vector
-  _new_idx.resize( mat_ncols(_constraints));
+//  _new_idx.resize( gmm::mat_ncols(_constraints));
+  _new_idx.resize( gmm::mat_ncols(_A)+1);
   for( unsigned int i=0; i<_new_idx.size(); ++i)
     _new_idx[i] = i;