<OpenGeoSysProject>
  <meshes>
    <mesh>domain.vtu</mesh>
    <mesh>left.vtu</mesh>
    <mesh>right.vtu</mesh>
  </meshes>
  <processes>
    <process>
      <name>HeatConduction</name>
      <type>HEAT_CONDUCTION</type>
      <integration_order>2</integration_order>
      <process_variables>
        <process_variable>temperature</process_variable>
      </process_variables>
      <secondary_variables>
        <secondary_variable internal_name="heat_flux" output_name="heat_flux" />
      </secondary_variables>
    </process>
  </processes>
  <time_loop>
    <processes>
      <process ref="HeatConduction">
        <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>8.6400e+4</t_end>
          <timesteps>
            <pair>
              <repeat>10</repeat>
              <delta_t>8.6400e+3</delta_t>
            </pair>
          </timesteps>
        </time_stepping>
      </process>
    </processes>
    <output>
      <type>VTK</type>
      <prefix>time_decay_bc</prefix>
      <timesteps>
        <pair>
          <repeat>10</repeat>
          <each_steps>1</each_steps>
        </pair>
      </timesteps>
      <variables>
        <variable>temperature</variable>
        <variable>heat_flux</variable>
      </variables>
      <suffix>ts{:timestep}_t_{:time}</suffix>
    </output>
  </time_loop>
  <media>
    <medium id="4">
      <phases />
      <properties>
        <property>
          <name>thermal_conductivity</name>
          <type>Constant</type>
          <value>5</value>
        </property>
        <property>
          <name>specific_heat_capacity</name>
          <type>Constant</type>
          <value>1000</value>
        </property>
        <property>
          <name>density</name>
          <type>Constant</type>
          <value>2500</value>
        </property>
      </properties>
    </medium>
  </media>
  <parameters>
    <parameter>
      <name>T0</name>
      <type>Function</type>
      <expression>320.0 + 30 * y;</expression>
    </parameter>
    <parameter>
      <name>decay_function</name>
      <type>Function</type>
      <expression>if (t>4.32e+4) 0.0; else 1 - t/ 4.32e+4;</expression>
    </parameter>
  </parameters>
  <process_variables>
    <process_variable>
      <name>temperature</name>
      <components>1</components>
      <order>1</order>
      <initial_condition>T0</initial_condition>
      <boundary_conditions>
        <boundary_condition>
          <mesh>right</mesh>
          <type>Dirichlet</type>
          <parameter>T0</parameter>
        </boundary_condition>
        <boundary_condition>
          <mesh>left</mesh>
          <type>TimeDecayDirichlet</type>
          <time_decay_parameter>decay_function</time_decay_parameter>
          <lower_limit>290</lower_limit>
        </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>
  <test_definition>
    <vtkdiff>
      <file>time_decay_bc_ts_5_t_43200.000000.vtu</file>
      <field>temperature</field>
      <absolute_tolerance>1e-8</absolute_tolerance>
      <relative_tolerance>0</relative_tolerance>
    </vtkdiff>
    <vtkdiff>
      <file>time_decay_bc_ts_10_t_86400.000000.vtu</file>
      <field>temperature</field>
      <absolute_tolerance>1e-8</absolute_tolerance>
      <relative_tolerance>0</relative_tolerance>
    </vtkdiff>
  </test_definition>
</OpenGeoSysProject>