<OpenGeoSysProject>
  <mesh>cube_1x1x1_hex_1e4.vtu</mesh>
  <geometry>cube_1x1x1.gml</geometry>
  <processes>
    <process>
      <name>SteadyStateDiffusion</name>
      <type>STEADY_STATE_DIFFUSION</type>
      <integration_order>2</integration_order>
      <process_variables>
        <process_variable>pressure</process_variable>
      </process_variables>
      <secondary_variables>
        <secondary_variable internal_name="darcy_velocity" output_name="v" />
      </secondary_variables>
    </process>
    <include file="SteadyStateDiffusion.xml" />
  </processes>
  <media>
    <medium id="0">
      <phases />
      <properties>
        <property>
          <name>diffusion</name>
          <type>Constant</type>
          <value>1</value>
        </property>
        <property>
          <name>reference_temperature</name>
          <type>Constant</type>
          <value>293.15</value>
        </property>
      </properties>
    </medium>
  </media>
  <time_loop>
    <processes>
      <process ref="SteadyStateDiffusion">
        <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>SingleStep</type>
        </time_stepping>
      </process>
    </processes>
    <output>
      <type>VTK</type>
      <prefix>cube_1e4_neumann</prefix>
      <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>0</value>
    </parameter>
    <parameter>
      <name>p_neumann</name>
      <type>Constant</type>
      <value>1</value>
    </parameter>
    <parameter>
      <name>p_Dirichlet</name>
      <type>Constant</type>
      <value>1</value>
    </parameter>
  </parameters>
  <process_variables>
    <process_variable>
      <name>pressure</name>
      <components>1</components>
      <order>1</order>
      <initial_condition>p0</initial_condition>
      <boundary_conditions>
        <boundary_condition>
          <geometrical_set>cube_1x1x1_geometry</geometrical_set>
          <geometry>left</geometry>
          <type>Dirichlet</type>
          <parameter>p_Dirichlet</parameter>
        </boundary_condition>
        <boundary_condition>
          <geometrical_set>cube_1x1x1_geometry</geometrical_set>
          <geometry>front</geometry>
          <type>Dirichlet</type>
          <parameter>p_Dirichlet</parameter>
        </boundary_condition>
        <boundary_condition>
          <geometrical_set>cube_1x1x1_geometry</geometrical_set>
          <geometry>right</geometry>
          <type>Neumann</type>
          <parameter>p_neumann</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>
      <lis>-i cg -p jacobi -tol 1e-16 -maxiter 10000</lis>
      <eigen>
        <solver_type>CG</solver_type>
        <precon_type>DIAGONAL</precon_type>
        <max_iteration_step>10000</max_iteration_step>
        <error_tolerance>1e-16</error_tolerance>
      </eigen>
      <petsc>
        <prefix>gw</prefix>
        <parameters>-gw_ksp_type cg -gw_pc_type bjacobi -gw_ksp_rtol 1e-16 -gw_ksp_max_it 10000</parameters>
      </petsc>
    </linear_solver>
  </linear_solvers>
</OpenGeoSysProject>