ElementLpNormAux

Compute an elemental field variable (single value per element) equal to the Lp-norm of a coupled Variable.

This can be used to average variables on elements, to make a copy that is constant on each element, a monomial of order 0. The desired Lp-norm is natural conserved in this process.

This is also typically used on a variable representing an error or a difference to a known solution, to turn an error on each quadrature point to an element-wise error.

Alternative objects and kernels

To compute the Lp or Hp error directly from a variable and a known reference solution, use ElementL2ErrorFunctionAux or ElementH1ErrorFunctionAux respectively.

For computing a global norm (error) metric, the NodalL2Norm and the ElementL2Norm (respectively NodalL2Error and the ElementL2Error) postprocessors may be considered.

Example syntax

In this example, we display several ways of creating fields computing local element-wise norms and errors of field variables.

[AuxKernels]
  [./l2_norm_aux]
    type = ElementLpNormAux
    variable = element_l2_norm
    coupled_variable = u
  [../]
  [./l2_error_aux]
    type = ElementL2ErrorFunctionAux
    variable = element_l2_error
    # A function representing the exact solution for the solution
    function = exact_fn
    # The nonlinear variable representing the FEM solution
    coupled_variable = u
  [../]
  [./h1_error_aux]
    type = ElementH1ErrorFunctionAux
    variable = element_h1_error
    # A function representing the exact solution for the solution
    function = exact_fn
    # The nonlinear variable representing the FEM solution
    coupled_variable = u
  [../]
[]
(../moose/test/tests/auxkernels/error_function_aux/error_function_aux.i)

Input Parameters

  • coupled_variableThe variable to compute the norm of.

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

    Controllable:No

    Description:The variable to compute the norm of.

  • variableThe name of the variable that this object applies to

    C++ Type:AuxVariableName

    Controllable:No

    Description:The name of the variable that this object applies to

Required Parameters

  • blockThe list of blocks (ids or names) that this object will be applied

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

    Controllable:No

    Description:The list of blocks (ids or names) that this object will be applied

  • boundaryThe list of boundaries (ids or names) from the mesh where this object applies

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

    Controllable:No

    Description:The list of boundaries (ids or names) from the mesh where this object applies

  • check_boundary_restrictedTrueWhether to check for multiple element sides on the boundary in the case of a boundary restricted, element aux variable. Setting this to false will allow contribution to a single element's elemental value(s) from multiple boundary sides on the same element (example: when the restricted boundary exists on two or more sides of an element, such as at a corner of a mesh

    Default:True

    C++ Type:bool

    Controllable:No

    Description:Whether to check for multiple element sides on the boundary in the case of a boundary restricted, element aux variable. Setting this to false will allow contribution to a single element's elemental value(s) from multiple boundary sides on the same element (example: when the restricted boundary exists on two or more sides of an element, such as at a corner of a mesh

  • execute_onLINEAR TIMESTEP_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, PRE_DISPLACE.

    Default:LINEAR 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, PRE_DISPLACE

    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, PRE_DISPLACE.

  • p2The exponent used in the norm.

    Default:2

    C++ Type:double

    Controllable:No

    Description:The exponent used in the norm.

  • 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.

Optional Parameters

  • 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.

  • seed0The seed for the master random number generator

    Default:0

    C++ Type:unsigned int

    Controllable:No

    Description:The seed for the master random number generator

  • 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