diff --git a/Solver/linearSystemPETSc.hpp b/Solver/linearSystemPETSc.hpp
index f5216ebdb3a16d1ae4aee8b8f3dfddb7ad9812c1..7c525816067dfc10f6fc1025633f4a2c9472fb62 100644
--- a/Solver/linearSystemPETSc.hpp
+++ b/Solver/linearSystemPETSc.hpp
@@ -280,7 +280,7 @@ int linearSystemPETSc<scalar>::systemSolve()
     _try(KSPSetOperators(_ksp, _a, _a, SAME_NONZERO_PATTERN));
   else
     _try(KSPSetOperators(_ksp, _a, _a, DIFFERENT_NONZERO_PATTERN));
-  if (_matrixModified && _parameters["matrix_reuse"]!="same_matrix"){
+  if (_matrixModified && linearSystem<scalar>::_parameters["matrix_reuse"]!="same_matrix"){
     _try(MatAssemblyBegin(_a, MAT_FINAL_ASSEMBLY));
     _try(MatAssemblyEnd(_a, MAT_FINAL_ASSEMBLY));
   }