ParsedODEKernel

This scalar kernel adds a source term : where is the variable the source acts upon, are other scalar variables, and are post-processor values.

The parameter expression is a string expression for the source term as it appears on the left-hand-side of the equation; thus it represents . The expression may use the following quantities:

  • the name of the scalar variable upon which the kernel acts,

  • the names of any scalar variables specified in the coupled_variables parameter,

  • the names of any post-processors specified in the postprocessors parameter, and

  • the names supplied in the constant_names parameter, defined to have the values provided by the constant_expressions parameters.

Currently, the function expression cannot be a function of time.

[ScalarKernels]
  [./td1]
    type = ODETimeDerivative
    variable = x
  [../]

  #
  # This parsed expression ODE Kernel behaves exactly as the ImplicitODEx kernel
  # in the main example. Checkout ImplicitODEx::computeQpResidual() in the
  # source code file ImplicitODEx.C to see the matching residual function.
  #
  # The ParsedODEKernel automaticaly generates the On- and Off-Diagonal Jacobian
  # entries.
  #
  [./ode1]
    type = ParsedODEKernel
    expression = '-3*x - 2*y'
    variable = x
    coupled_variables = y
  [../]

  [./td2]
    type = ODETimeDerivative
    variable = y
  [../]

  #
  # This parsed expression ODE Kernel behaves exactly as the ImplicitODEy Kernel
  # in the main example.
  #
  [./ode2]
    type = ParsedODEKernel
    expression = '-4*x - y'
    variable = y
    coupled_variables = x
  [../]
[]
(../moose/examples/ex18_scalar_kernel/ex18_parsed.i)

Input Parameters

  • expressionfunction expression

    C++ Type:FunctionExpression

    Controllable:No

    Description:function expression

  • variableThe name of the variable that this residual object operates on

    C++ Type:NonlinearVariableName

    Controllable:No

    Description:The name of the variable that this residual object operates on

Required Parameters

  • constant_expressionsVector of values for the constants in constant_names (can be an FParser expression)

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

    Controllable:No

    Description:Vector of values for the constants in constant_names (can be an FParser expression)

  • constant_namesVector of constants used in the parsed expression

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

    Controllable:No

    Description:Vector of constants used in the parsed expression

  • coupled_variablesScalar variables coupled in the parsed expression.

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

    Controllable:No

    Description:Scalar variables coupled in the parsed expression.

  • postprocessorsVector of postprocessor names used in the function expression

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

    Controllable:No

    Description:Vector of postprocessor names used in the function expression

Optional Parameters

  • absolute_value_vector_tagsThe tags for the vectors this residual object should fill with the absolute value of the residual contribution

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

    Controllable:No

    Description:The tags for the vectors this residual object should fill with the absolute value of the residual contribution

  • extra_matrix_tagsThe extra tags for the matrices this Kernel should fill

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

    Controllable:No

    Description:The extra tags for the matrices this Kernel should fill

  • extra_vector_tagsThe extra tags for the vectors this Kernel should fill

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

    Controllable:No

    Description:The extra tags for the vectors this Kernel should fill

  • matrix_tagssystemThe tag for the matrices this Kernel should fill

    Default:system

    C++ Type:MultiMooseEnum

    Options:nontime, system

    Controllable:No

    Description:The tag for the matrices this Kernel should fill

  • vector_tagsnontimeThe tag for the vectors this Kernel should fill

    Default:nontime

    C++ Type:MultiMooseEnum

    Options:nontime, time

    Controllable:No

    Description:The tag for the vectors this Kernel should fill

Tagging 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.

  • disable_fpoptimizerFalseDisable the function parser algebraic optimizer

    Default:False

    C++ Type:bool

    Controllable:No

    Description:Disable the function parser algebraic optimizer

  • enableTrueSet the enabled status of the MooseObject.

    Default:True

    C++ Type:bool

    Controllable:Yes

    Description:Set the enabled status of the MooseObject.

  • enable_ad_cacheTrueEnable caching of function derivatives for faster startup time

    Default:True

    C++ Type:bool

    Controllable:No

    Description:Enable caching of function derivatives for faster startup time

  • enable_auto_optimizeTrueEnable automatic immediate optimization of derivatives

    Default:True

    C++ Type:bool

    Controllable:No

    Description:Enable automatic immediate optimization of derivatives

  • enable_jitTrueEnable just-in-time compilation of function expressions for faster evaluation

    Default:True

    C++ Type:bool

    Controllable:No

    Description:Enable just-in-time compilation of function expressions for faster evaluation

  • evalerror_behaviornanWhat to do if evaluation error occurs. Options are to pass a nan, pass a nan with a warning, throw a error, or throw an exception

    Default:nan

    C++ Type:MooseEnum

    Options:nan, nan_warning, error, exception

    Controllable:No

    Description:What to do if evaluation error occurs. Options are to pass a nan, pass a nan with a warning, throw a error, or throw an exception

  • implicitTrueDetermines whether this object is calculated using an implicit or explicit form

    Default:True

    C++ Type:bool

    Controllable:No

    Description:Determines whether this object is calculated using an implicit or explicit form

  • 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