 <OpenGeoSysProjectDiff base_file="../1d_decay_chain_GIA.prj">

   <add sel="/*/processes/process">

     <linear>true</linear>

   </add>

   <remove sel="/*/linear_solvers/linear_solver/eigen" />

   <add sel="/*/linear_solvers/linear_solver">

     <eigen>

       <solver_type>SparseLU</solver_type>

     </eigen>

   </add>

 </OpenGeoSysProjectDiff>