LinearCombinationFunction

construction:Undocumented Class

The LinearCombinationFunction has not been documented. The content listed below should be used as a starting point for documenting the class, which includes the typical automatic documentation associated with a MooseObject; however, what is contained is ultimately determined by what is necessary to make the documentation clear for users.


# LinearCombinationFunction

!syntax description /Functions/LinearCombinationFunction

## Overview

!! Replace these lines with information regarding the LinearCombinationFunction object.

## Example Input File Syntax

!! Describe and include an example of how to use the LinearCombinationFunction object.

!syntax parameters /Functions/LinearCombinationFunction

!syntax inputs /Functions/LinearCombinationFunction

!syntax children /Functions/LinearCombinationFunction

Returns the linear combination of the functions

Input Parameters

functionsThis function will return Sum_over_i(w_i * functions_i)
C++ Type:std::vector<FunctionName>
Options:
Description:This function will return Sum_over_i(w_i * functions_i)
wThis function will return Sum_over_i(w_i * functions_i)
C++ Type:std::vector<double>
Options:
Description:This function will return Sum_over_i(w_i * functions_i)

Required Parameters

control_tagsAdds user-defined labels for accessing object parameters via control logic.
C++ Type:std::vector<std::string>
Options:
Description:Adds user-defined labels for accessing object parameters via control logic.
enableTrueSet the enabled status of the MooseObject.
Default:True
C++ Type:bool
Options:
Description:Set the enabled status of the MooseObject.

Advanced Parameters

Input Files

(test/tests/functions/linear_combination_function/except1.i)
(test/tests/functions/linear_combination_function/lcf_grad.i)
(test/tests/functions/linear_combination_function/lcf1.i)
(python/peacock/tests/input_tab/InputTree/gold/lcf1.i)
(python/peacock/tests/common/lcf1.i)
(test/tests/functions/linear_combination_function/lcf_vector.i)

(test/tests/functions/linear_combination_function/except1.i)

# LinearCombinationFunction function test
# See [Functions] block for a description of the tests

[Mesh]
  type = GeneratedMesh
  dim = 1
  xmin = 0
  xmax = 2
  nx = 10
[]

[Variables]
  [./dummy]
  [../]
[]

[Kernels]
  [./dummy_u]
    type = TimeDerivative
    variable = dummy
  [../]
[]


[AuxVariables]
  [./the_linear_combo]
  [../]
[]

[AuxKernels]
  [./the_linear_combo]
    type = FunctionAux
    variable = the_linear_combo
    function = the_linear_combo
  [../]
[]


[Functions]
  [./twoxplus1]
    type = ParsedFunction
    value = 2*x+1
  [../]

  [./xsquared]
    type = ParsedFunction
    value = x*x
  [../]

  [./the_linear_combo]
    type = LinearCombinationFunction
    functions = 'x twoxplus1 xsquared'
    w = '0.5 5 0.4 0.3'
  [../]

  [./should_be_answer]
    type = ParsedFunction
    value = 0.5*x+5*(2*x+1)*0.4*x*x+0.3*7
  [../]
[]

[Postprocessors]
  [./should_be_zero]
    type = NodalL2Error
    function = should_be_answer
    variable = the_linear_combo
  [../]
[]

[Executioner]
  type = Transient
  dt = 0.5
  end_time = 1
[]

[Outputs]
  execute_on = 'timestep_end'
  hide = dummy
  exodus = false
  csv = true
[]

(test/tests/functions/linear_combination_function/lcf_grad.i)

# LinearCombinationFunction function test
# See [Functions] block for a description of the tests

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

[Variables]
  [./dummy]
  [../]
[]

[Kernels]
  [./dummy_u]
    type = TimeDerivative
    variable = dummy
  [../]
[]


[AuxVariables]
  [./the_linear_combo_x]
    order = CONSTANT
    family = MONOMIAL
  [../]
  [./the_linear_combo_y]
    order = CONSTANT
    family = MONOMIAL
  [../]
[]

[AuxKernels]
  [./the_linear_combo_x]
    type = FunctionDerivativeAux
    component = x
    variable = the_linear_combo_x
    function = the_linear_combo
  [../]
  [./the_linear_combo_y]
    type = FunctionDerivativeAux
    component = y
    variable = the_linear_combo_y
    function = the_linear_combo
  [../]
[]


[Functions]
  [./xtimes]
    type = ParsedGradFunction
    value = '1.1*x+y'
    grad_x = '1.1'
    grad_y = '1'
  [../]

  [./twoxplus1]
    type = ParsedGradFunction
    value = '2*x+1'
    grad_x = '2'
  [../]

  [./tover2]
    type = ParsedGradFunction
    value = '0.5*t-y*7'
    grad_y = '-7'
  [../]

  [./the_linear_combo]
    type = LinearCombinationFunction
    functions = 'xtimes twoxplus1 tover2'
    w = '3 -1.2 3'
  [../]

  [./should_be_answer_x]
    type = ParsedFunction
    value = '3*1.1-1.2*2'
  [../]
  [./should_be_answer_y]
    type = ParsedFunction
    value = '3*1+3*(-7)'
  [../]
[]

[Postprocessors]
  [./should_be_zero_x]
    type = ElementL2Error
    function = should_be_answer_x
    variable = the_linear_combo_x
  [../]
  [./should_be_zero_y]
    type = ElementL2Error
    function = should_be_answer_y
    variable = the_linear_combo_y
  [../]
[]

[Executioner]
  type = Transient
  dt = 0.5
  end_time = 1
[]

[Outputs]
  execute_on = 'timestep_end'
  file_base = lcf_grad
  hide = dummy
  exodus = false
  csv = true
[]

(test/tests/functions/linear_combination_function/lcf1.i)

# LinearCombinationFunction function test
# See [Functions] block for a description of the tests

[Mesh]
  type = GeneratedMesh
  dim = 1
  xmin = 0
  xmax = 2
  nx = 10
[]

[Variables]
  [./dummy]
  [../]
[]

[Kernels]
  [./dummy_u]
    type = TimeDerivative
    variable = dummy
  [../]
[]


[AuxVariables]
  [./the_linear_combo]
  [../]
[]

[AuxKernels]
  [./the_linear_combo]
    type = FunctionAux
    variable = the_linear_combo
    function = the_linear_combo
  [../]
[]


[Functions]
  [./xtimes]
    type = ParsedFunction
    value = 1.1*x
  [../]

  [./twoxplus1]
    type = ParsedFunction
    value = 2*x+1
  [../]

  [./xsquared]
    type = ParsedFunction
    value = (x-2)*x
  [../]

  [./tover2]
    type = ParsedFunction
    value = 0.5*t
  [../]

  [./the_linear_combo]
    type = LinearCombinationFunction
    functions = 'xtimes twoxplus1 xsquared tover2'
    w = '3 -1.2 0.4 3'
  [../]

  [./should_be_answer]
    type = ParsedFunction
    value = 3*1.1*x-1.2*(2*x+1)+0.4*(x-2)*x+3*0.5*t
  [../]
[]

[Postprocessors]
  [./should_be_zero]
    type = NodalL2Error
    function = should_be_answer
    variable = the_linear_combo
  [../]
[]

[Executioner]
  type = Transient
  dt = 0.5
  end_time = 1
[]

[Outputs]
  execute_on = 'timestep_end'
  file_base = lcf1
  hide = dummy
  exodus = false
  csv = true
[]

(python/peacock/tests/input_tab/InputTree/gold/lcf1.i)

# LinearCombinationFunction function test
# See [Functions] block for a description of the tests
[Mesh]
  type = GeneratedMesh
  dim = 1
  xmin = 0
  xmax = 2
  nx = 10
[]

[Variables]
  [dummy]
  []
[]

[Kernels]
  [dummy_u]
    type = TimeDerivative
    variable = dummy
  []
[]

[AuxVariables]
  [the_linear_combo]
  []
[]

[AuxKernels]
  [the_linear_combo]
    type = FunctionAux
    variable = the_linear_combo
    function = the_linear_combo
  []
[]

[Functions]
  [xtimes]
    type = ParsedFunction
    value = '1.1*x'
  []
  [twoxplus1]
    type = ParsedFunction
    value = '2*x+1'
  []
  [xsquared]
    type = ParsedFunction
    value = '(x-2)*x'
  []
  [tover2]
    type = ParsedFunction
    value = '0.5*t'
  []
  [the_linear_combo]
    type = LinearCombinationFunction
    functions = 'xtimes twoxplus1 xsquared tover2'
    w = '3 -1.2 0.4 3'
  []
  [should_be_answer]
    type = ParsedFunction
    value = '3*1.1*x-1.2*(2*x+1)+0.4*(x-2)*x+3*0.5*t'
  []
[]

[Postprocessors]
  [should_be_zero]
    type = NodalL2Error
    function = should_be_answer
    variable = 'the_linear_combo'
  []
[]

[Executioner]
  type = Transient
  dt = 0.5
  end_time = 1
[]

[Outputs]
  execute_on = 'timestep_end'
  file_base = lcf1
  hide = 'dummy'
  exodus = false
  csv = true
[]

(python/peacock/tests/common/lcf1.i)

# LinearCombinationFunction function test
# See [Functions] block for a description of the tests

[Mesh]
  type = GeneratedMesh
  dim = 1
  xmin = 0
  xmax = 2
  nx = 10
[]

[Variables]
  [./dummy]
  [../]
[]

[Kernels]
  [./dummy_u]
    type = TimeDerivative
    variable = dummy
  [../]
[]


[AuxVariables]
  [./the_linear_combo]
  [../]
[]

[AuxKernels]
  [./the_linear_combo]
    type = FunctionAux
    variable = the_linear_combo
    function = the_linear_combo
  [../]
[]


[Functions]
  [./xtimes]
    type = ParsedFunction
    value = 1.1*x
  [../]

  [./twoxplus1]
    type = ParsedFunction
    value = 2*x+1
  [../]

  [./xsquared]
    type = ParsedFunction
    value = (x-2)*x
  [../]

  [./tover2]
    type = ParsedFunction
    value = 0.5*t
  [../]

  [./the_linear_combo]
    type = LinearCombinationFunction
    functions = 'xtimes twoxplus1 xsquared tover2'
    w = '3 -1.2 0.4 3'
  [../]

  [./should_be_answer]
    type = ParsedFunction
    value = 3*1.1*x-1.2*(2*x+1)+0.4*(x-2)*x+3*0.5*t
  [../]
[]

[Postprocessors]
  [./should_be_zero]
    type = NodalL2Error
    function = should_be_answer
    variable = the_linear_combo
  [../]
[]

[Executioner]
  type = Transient
  dt = 0.5
  end_time = 1
[]

[Outputs]
  execute_on = 'timestep_end'
  file_base = lcf1
  hide = dummy
  exodus = false
  csv = true
[]

(test/tests/functions/linear_combination_function/lcf_vector.i)

# use the vectorValue of a LinearCombinationFunction
[Mesh]
  type = GeneratedMesh
  dim = 2
  nx = 10
  ny = 10
  uniform_refine = 1
[]

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

[Functions]
  [./conductivity_1]
    type = ParsedVectorFunction
    value_y = '0.1+x'
    value_x = '0.5*(1+x*y)'
  [../]
  [./conductivity_2]
    type = ParsedVectorFunction
    value_y = '0.1+2*x'
    value_x = '0.2+x*y'
  [../]
  [./conductivity]
    type = LinearCombinationFunction # yields value_y=0.1, value_x=0.8
    functions = 'conductivity_1 conductivity_2'
    w = '2 -1'
  [../]
[]

[Kernels]
  [./diff]
    type = DiffTensorKernel
    variable = u
    conductivity = conductivity
  [../]
[]

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

[Executioner]
  type = Steady
  solve_type = 'PJFNK'
  petsc_options_iname = '-pc_type -pc_hypre_type'
  petsc_options_value = 'hypre boomeramg'
[]

[Outputs]
  exodus = true
[]

Input Parameters
Input Files

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LinearCombinationFunction

Input Parameters

Required Parameters

Advanced Parameters

Input Files