ChangeOverFixedPointPostprocessor

Description

This post-processor computes the change or relative change in a post-processor value over a fixed point iterations. It may be used to track the convergence of the fixed point algorithm. where is the relative change at iteration , is the value of post-processor at iteration , and is the reference value for the change (either the previous iteration value, , or the initial value at the beginning of the iteration process, . Relative change is computed as Optionally, the user may specify to return the absolute value of the change.

Example Syntax

The following example demonstrates how this post-processor is used:

# This test tests the ChangeOverTimePostprocessor, which computes the change
# in a postprocessor value with respect to the previous value or with respect to
# the initial value. This test creates a time-dependent function postprocessor
# and then computes its change over a timestep. The FE problem used here is a
# dummy problem and has no effect on the test.

[Mesh]
  type = GeneratedMesh
  dim = 1
  nx = 5
[]

[Variables]
  [./u]
  [../]
[]

[Kernels]
  [./time_derivative]
    type = TimeDerivative
    variable = u
  [../]
  [./diff]
    type = Diffusion
    variable = u
  [../]
[]

[BCs]
  [./left]
    type = DirichletBC
    variable = u
    boundary = left
    value = 0
  [../]
  [./right]
    type = DirichletBC
    variable = u
    boundary = right
    value = 1
  [../]
[]

[Executioner]
  type = Transient

  start_time = 0.0
  dt = 1.0
  num_steps = 2
[]

[Functions]
  [./my_function]
    type = ParsedFunction
    expression = '1 + t * t'
  [../]
[]

[Postprocessors]
  [./my_postprocessor]
    type = FunctionValuePostprocessor
    function = my_function
    execute_on = 'initial timestep_end'
  [../]
  [./change_over_time]
    type = ChangeOverTimePostprocessor
    postprocessor = my_postprocessor
    change_with_respect_to_initial = false
    execute_on = 'initial timestep_end'
  [../]
[]

[Outputs]
  file_base = 'change_over_time_previous'
  csv = true
[]
(../moose/test/tests/postprocessors/change_over_time/change_over_time.i)

Input Parameters

  • postprocessorThe name of the postprocessor

    C++ Type:PostprocessorName

    Controllable:No

    Description:The name of the postprocessor

Required Parameters

  • change_with_respect_to_initialFalseCompute change with respect to value at the beginning of the FixedPoint iterations instead of previous value

    Default:False

    C++ Type:bool

    Controllable:No

    Description:Compute change with respect to value at the beginning of the FixedPoint iterations instead of previous value

  • compute_relative_changeFalseCompute magnitude of relative change instead of change

    Default:False

    C++ Type:bool

    Controllable:No

    Description:Compute magnitude of relative change instead of change

  • execute_onTIMESTEP_ENDThe list of flag(s) indicating when this object should be executed, the available options include NONE, INITIAL, LINEAR, NONLINEAR, TIMESTEP_END, TIMESTEP_BEGIN, MULTIAPP_FIXED_POINT_END, MULTIAPP_FIXED_POINT_BEGIN, FINAL, CUSTOM, ALWAYS.

    Default:TIMESTEP_END

    C++ Type:ExecFlagEnum

    Options:NONE, INITIAL, LINEAR, NONLINEAR, TIMESTEP_END, TIMESTEP_BEGIN, MULTIAPP_FIXED_POINT_END, MULTIAPP_FIXED_POINT_BEGIN, FINAL, CUSTOM, ALWAYS, TRANSFER

    Controllable:No

    Description:The list of flag(s) indicating when this object should be executed, the available options include NONE, INITIAL, LINEAR, NONLINEAR, TIMESTEP_END, TIMESTEP_BEGIN, MULTIAPP_FIXED_POINT_END, MULTIAPP_FIXED_POINT_BEGIN, FINAL, CUSTOM, ALWAYS.

  • prop_getter_suffixAn optional suffix parameter that can be appended to any attempt to retrieve/get material properties. The suffix will be prepended with a '_' character.

    C++ Type:MaterialPropertyName

    Controllable:No

    Description:An optional suffix parameter that can be appended to any attempt to retrieve/get material properties. The suffix will be prepended with a '_' character.

  • take_absolute_valueFalseOption to take absolute value of change

    Default:False

    C++ Type:bool

    Controllable:No

    Description:Option to take absolute value of change

Optional Parameters

  • allow_duplicate_execution_on_initialFalseIn the case where this UserObject is depended upon by an initial condition, allow it to be executed twice during the initial setup (once before the IC and again after mesh adaptivity (if applicable).

    Default:False

    C++ Type:bool

    Controllable:No

    Description:In the case where this UserObject is depended upon by an initial condition, allow it to be executed twice during the initial setup (once before the IC and again after mesh adaptivity (if applicable).

  • control_tagsAdds user-defined labels for accessing object parameters via control logic.

    C++ Type:std::vector<std::string>

    Controllable:No

    Description:Adds user-defined labels for accessing object parameters via control logic.

  • enableTrueSet the enabled status of the MooseObject.

    Default:True

    C++ Type:bool

    Controllable:Yes

    Description:Set the enabled status of the MooseObject.

  • execution_order_group0Execution order groups are executed in increasing order (e.g., the lowest number is executed first). Note that negative group numbers may be used to execute groups before the default (0) group. Please refer to the user object documentation for ordering of user object execution within a group.

    Default:0

    C++ Type:int

    Controllable:No

    Description:Execution order groups are executed in increasing order (e.g., the lowest number is executed first). Note that negative group numbers may be used to execute groups before the default (0) group. Please refer to the user object documentation for ordering of user object execution within a group.

  • force_postauxFalseForces the UserObject to be executed in POSTAUX

    Default:False

    C++ Type:bool

    Controllable:No

    Description:Forces the UserObject to be executed in POSTAUX

  • force_preauxFalseForces the UserObject to be executed in PREAUX

    Default:False

    C++ Type:bool

    Controllable:No

    Description:Forces the UserObject to be executed in PREAUX

  • force_preicFalseForces the UserObject to be executed in PREIC during initial setup

    Default:False

    C++ Type:bool

    Controllable:No

    Description:Forces the UserObject to be executed in PREIC during initial setup

  • outputsVector of output names where you would like to restrict the output of variables(s) associated with this object

    C++ Type:std::vector<OutputName>

    Controllable:No

    Description:Vector of output names where you would like to restrict the output of variables(s) associated with this object

  • use_displaced_meshFalseWhether or not this object should use the displaced mesh for computation. Note that in the case this is true but no displacements are provided in the Mesh block the undisplaced mesh will still be used.

    Default:False

    C++ Type:bool

    Controllable:No

    Description:Whether or not this object should use the displaced mesh for computation. Note that in the case this is true but no displacements are provided in the Mesh block the undisplaced mesh will still be used.

Advanced Parameters