SplineFunction

Define a spline function from interpolated data defined by input parameters.

The SplineFunction defines a 1D spline (1D shape, it is defined everywhere in the domain by translation) along one of the x, y, z directions (specified by the component parameter). The spline is defined by

its value (ordinates, y) at several abscissa (x) through which the function passes
its first derivative at the first abscissa
its first derivative at the last abscissa

From this information the spline is automatically generated. Both the first and second order derivatives of the spline are defined.

Example input syntax

In this example, we define a spline going through 4 points defined by the x and y parameters.

[Functions]
  [./spline_function]
    type = SplineFunction
    x = '0 1 2 3'
    y = '0 1 0 1'
  [../]
[]

Input Parameters

xThe abscissa values
C++ Type:std::vector<double>
Controllable:No
Description:The abscissa values
yThe ordinate values
C++ Type:std::vector<double>
Controllable:No
Description:The ordinate values

Required Parameters

componentxThe component of the geometry point to interpolate with
Default:x
C++ Type:MooseEnum
Options:x, y, z
Controllable:No
Description:The component of the geometry point to interpolate with
execute_onLINEARThe list of flag(s) indicating when this object should be executed, the available options include FORWARD, ADJOINT, HOMOGENEOUS_FORWARD, ADJOINT_TIMESTEP_BEGIN, ADJOINT_TIMESTEP_END, NONE, INITIAL, LINEAR, NONLINEAR, POSTCHECK, TIMESTEP_END, TIMESTEP_BEGIN, MULTIAPP_FIXED_POINT_END, MULTIAPP_FIXED_POINT_BEGIN, FINAL, CUSTOM.
Default:LINEAR
C++ Type:ExecFlagEnum
Options:FORWARD, ADJOINT, HOMOGENEOUS_FORWARD, ADJOINT_TIMESTEP_BEGIN, ADJOINT_TIMESTEP_END, NONE, INITIAL, LINEAR, NONLINEAR, POSTCHECK, TIMESTEP_END, TIMESTEP_BEGIN, MULTIAPP_FIXED_POINT_END, MULTIAPP_FIXED_POINT_BEGIN, FINAL, CUSTOM
Controllable:No
Description:The list of flag(s) indicating when this object should be executed, the available options include FORWARD, ADJOINT, HOMOGENEOUS_FORWARD, ADJOINT_TIMESTEP_BEGIN, ADJOINT_TIMESTEP_END, NONE, INITIAL, LINEAR, NONLINEAR, POSTCHECK, TIMESTEP_END, TIMESTEP_BEGIN, MULTIAPP_FIXED_POINT_END, MULTIAPP_FIXED_POINT_BEGIN, FINAL, CUSTOM.
yp11e+30The value of the first derivative of the interpolating function at point 1
Default:1e+30
C++ Type:double
Controllable:No
Description:The value of the first derivative of the interpolating function at point 1
ypn1e+30The value of the first derivative of the interpolating function at point n
Default:1e+30
C++ Type:double
Controllable:No
Description:The value of the first derivative of the interpolating function at point n

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:No
Description:Set the enabled status of the MooseObject.

Advanced Parameters

Input Files

(test/tests/ics/function_ic/spline_function.i)
(test/tests/utils/spline_interpolation/spline_interpolation.i)

(test/tests/ics/function_ic/spline_function.i)

#
# Test the gradient calculation in spline function and the gradient pass-through in FunctionIC
#

[Mesh]
  type = GeneratedMesh
  dim = 2
  xmin = 0
  xmax = 3
  ymin = 0
  ymax = 1
  nx = 10
  ny = 2
[]

[Variables]
  [./u]
    order = THIRD
    family = HERMITE
  [../]
[]

[Functions]
  [./spline_function]
    type = SplineFunction
    x = '0 1 2 3'
    y = '0 1 0 1'
  [../]
[]

[ICs]
  [./u_ic]
    type = FunctionIC
    variable = 'u'
    function = spline_function
  [../]
[]

[Executioner]
  type = Steady
[]

[Problem]
  solve = false
[]

[Outputs]
  file_base = spline
  [./OverSampling]
    type = Exodus
    refinements = 3
  [../]
[]

(test/tests/ics/function_ic/spline_function.i)

#
# Test the gradient calculation in spline function and the gradient pass-through in FunctionIC
#

[Mesh]
  type = GeneratedMesh
  dim = 2
  xmin = 0
  xmax = 3
  ymin = 0
  ymax = 1
  nx = 10
  ny = 2
[]

[Variables]
  [./u]
    order = THIRD
    family = HERMITE
  [../]
[]

[Functions]
  [./spline_function]
    type = SplineFunction
    x = '0 1 2 3'
    y = '0 1 0 1'
  [../]
[]

[ICs]
  [./u_ic]
    type = FunctionIC
    variable = 'u'
    function = spline_function
  [../]
[]

[Executioner]
  type = Steady
[]

[Problem]
  solve = false
[]

[Outputs]
  file_base = spline
  [./OverSampling]
    type = Exodus
    refinements = 3
  [../]
[]

(test/tests/utils/spline_interpolation/spline_interpolation.i)

[Mesh]
  type = GeneratedMesh
  dim = 1
  nx = 4
  xmin = -1
  xmax = 3
  elem_type = EDGE2
[]

[Functions]
  [./spline_fn]
    type = SplineFunction
    x = '-1  0 3'
    y = '0.5 0 3'
  [../]
[]

[Variables]
  [./u]
    order = THIRD
    family = HERMITE
  [../]
[]

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

  [./ufn]
    type = SplineFFn
    variable = u
    function = spline_fn
  [../]
[]

[BCs]
  [./sides]
    type = FunctionDirichletBC
    variable = u
    boundary = '0 1'
    function = spline_fn
  [../]
[]

[Postprocessors]
  [./l2_err]
    type = ElementL2Error
    variable = u
    function = spline_fn
    execute_on = 'initial timestep_end'
  [../]
[]

[Executioner]
  type = Steady
  solve_type = NEWTON
[]

[Outputs]
  exodus = true
[]

Example input syntax
Input Parameters
Input Files