|  | OGS
    | 
 <OpenGeoSysProject>
   <mesh>quadratic_mesh.vtu</mesh>
   <geometry>quadratic_mesh_assembly_test.gml</geometry>
   <processes>
     <process>
       <name>LiquidFlow</name>
       <type>LIQUID_FLOW</type>
       <integration_order>4</integration_order>
       <process_variables>
         <process_variable>pressure</process_variable>
       </process_variables>
       <secondary_variables>
         <secondary_variable internal_name="darcy_velocity" output_name="v" />
       </secondary_variables>
       <specific_body_force>0.0 0.0 -9.81</specific_body_force>
     </process>
   </processes>
   <media>
     <medium id="0">
       <phases>
         <phase>
           <type>AqueousLiquid</type>
           <properties>
             <property>
               <name>viscosity</name>
               <type>Constant</type>
               <value>1.e-3</value>
             </property>
             <property>
               <name>density</name>
               <type>Constant</type>
               <value>1.e3</value>
             </property>
           </properties>
         </phase>
       </phases>
       <properties>
         <property>
           <name>permeability</name>
           <type>Constant</type>
           <value>1.e-8</value>
         </property>
         <property>
           <name>reference_temperature</name>
           <type>Constant</type>
           <value>293.15</value>
         </property>
         <property>
           <name>porosity</name>
           <type>Constant</type>
           <value>0.2</value>
         </property>
         <property>
           <name>storage</name>
           <type>Constant</type>
           <value>0.0</value>
         </property>
       </properties>
     </medium>
   </media>
   <time_loop>
     <processes>
       <process ref="LiquidFlow">
         <nonlinear_solver>basic_picard</nonlinear_solver>
         <convergence_criterion>
           <type>DeltaX</type>
           <norm_type>NORM2</norm_type>
           <abstol>1.e-6</abstol>
         </convergence_criterion>
         <time_discretization>
           <type>BackwardEuler</type>
         </time_discretization>
         <time_stepping>
           <type>FixedTimeStepping</type>
           <t_initial>0.0</t_initial>
           <t_end>1</t_end>
           <timesteps>
             <pair>
               <repeat>1</repeat>
               <delta_t>1</delta_t>
             </pair>
           </timesteps>
         </time_stepping>
       </process>
     </processes>
     <output>
       <type>VTK</type>
       <prefix>quadratic_mesh_assembly_test</prefix>
       <timesteps>
         <pair>
           <repeat>1</repeat>
           <each_steps>65</each_steps>
         </pair>
         <pair>
           <repeat>1</repeat>
           <each_steps>340</each_steps>
         </pair>
       </timesteps>
       <variables>
         <variable>pressure</variable>
         <variable>v</variable>
       </variables>
       <suffix>ts{:timestep}_t_{:time}</suffix>
     </output>
   </time_loop>
   <parameters>
     <parameter>
       <name>p0</name>
       <type>Constant</type>
       <value>1.e+5</value>
     </parameter>
     <parameter>
       <name>p_bc_in</name>
       <type>Constant</type>
       <value>1.0e+6</value>
     </parameter>
     <parameter>
       <name>p_bc_out</name>
       <type>Constant</type>
       <value>2.e+6</value>
     </parameter>
   </parameters>
   <process_variables>
     <process_variable>
       <name>pressure</name>
       <components>1</components>
       <order>2</order>
       <initial_condition>p0</initial_condition>
       <boundary_conditions>
         <boundary_condition>
           <geometrical_set>geometry</geometrical_set>
           <geometry>tp1</geometry>
           <type>Dirichlet</type>
           <parameter>p_bc_in</parameter>
         </boundary_condition>
         <boundary_condition>
           <geometrical_set>geometry</geometrical_set>
           <geometry>tp2</geometry>
           <type>Dirichlet</type>
           <parameter>p_bc_out</parameter>
         </boundary_condition>
         <boundary_condition>
           <geometrical_set>geometry</geometrical_set>
           <geometry>tp3</geometry>
           <type>Dirichlet</type>
           <parameter>p_bc_in</parameter>
         </boundary_condition>
         <boundary_condition>
           <geometrical_set>geometry</geometrical_set>
           <geometry>tp4</geometry>
           <type>Dirichlet</type>
           <parameter>p_bc_in</parameter>
         </boundary_condition>
         <boundary_condition>
           <geometrical_set>geometry</geometrical_set>
           <geometry>tp5</geometry>
           <type>Dirichlet</type>
           <parameter>p_bc_in</parameter>
         </boundary_condition>
       </boundary_conditions>
     </process_variable>
   </process_variables>
   <nonlinear_solvers>
     <nonlinear_solver>
       <name>basic_picard</name>
       <type>Picard</type>
       <max_iter>10</max_iter>
       <linear_solver>general_linear_solver</linear_solver>
     </nonlinear_solver>
   </nonlinear_solvers>
   <linear_solvers>
     <linear_solver>
       <name>general_linear_solver</name>
       <eigen>
         <solver_type>CG</solver_type>
         <precon_type>DIAGONAL</precon_type>
         <max_iteration_step>10000</max_iteration_step>
         <error_tolerance>1e-20</error_tolerance>
       </eigen>
     </linear_solver>
   </linear_solvers>
 </OpenGeoSysProject>