MultiAppInterpolationTransfer

The MultiAppInterpolationTransfer transfers the nearest node's source variables to the nearest node on the target mesh using mesh interpolation, including the ability to utilize the displaced configuration for either or both the source and target. The MultiAppInterpolationTransfer also offers extrapolation on non-overlapping domains where the target data can be computed from source nodes not inside the target mesh. Other interpolation transfers like the MultiAppMeshFunctionTransfer are not able to extrapolate data and will only work for fully overlapping domains.

Nodal transfers using the default settings for this interpolation scheme, interp_type=inverse_distance and num_points=3, will find the three closest points on the source mesh to a node on the target mesh. The source data from the three closest nodes will then be interpolated to the target node using inverse distance weighting. Inverse distance interpolation is best suited for the interpolation of point cloud data in the source mesh onto a target mesh.

note

The MultiAppMeshFunctionTransfer may be a better choice for nodal transfers between two meshes with fully overlapping domains because the element shape functions will be used in the transfer. However, as mentioned above, only the MultiAppInterpolationTransfer can be used to extrapolate data between meshes on domains that do not fully overlap.

Using MultiAppInterpolationTransfer with the default interpolation settings for mesh to mesh nodal transfers of data is not deterministic when the point being interpolated to on the target mesh is exactly the same distance away from more than num_points on the source mesh. This nondeterministic behavior in the MultiAppInterpolationTransfer node-to-node transfer can lead to different data being transferred when the numerics of a problem are changed by something like the parallel decomposition or compiler settings.

This inconsistency can occur on structured meshes when the target mesh is a refined version of the source mesh. In this scenario, a target node will be placed equidistant from several source nodes. For a 2D structured mesh of quadrilaterals, the refined mesh's target node would be equidistant from 4 nodes on the source mesh. With the default num_points=3, the three points chosen from the four equidistant nodes on the source mesh will be arbitrary and has been shown to be dependent on the parallel decomposition of the mesh. This problem can be made deterministic by increasing num_points=4 so that all of the nodes in the element are used for the interpolation.

Example Syntax

[Transfers]
  [./fromsub]
    type = MultiAppInterpolationTransfer
    direction = from_multiapp
    multi_app = sub
    source_variable = u
    variable = from_sub
  [../]
[]

Input Parameters

directionWhether this Transfer will be 'to' or 'from' a MultiApp, or bidirectional, by providing both FROM_MULTIAPP and TO_MULTIAPP.
C++ Type:MultiMooseEnum
Options:to_multiapp, from_multiapp
Description:Whether this Transfer will be 'to' or 'from' a MultiApp, or bidirectional, by providing both FROM_MULTIAPP and TO_MULTIAPP.
multi_appThe name of the MultiApp to use.
C++ Type:MultiAppName
Options:
Description:The name of the MultiApp to use.
source_variableThe variable to transfer from.
C++ Type:std::vector<VariableName>
Options:
Description:The variable to transfer from.
variableThe auxiliary variable to store the transferred values in.
C++ Type:std::vector<AuxVariableName>
Options:
Description:The auxiliary variable to store the transferred values in.

Required Parameters

allow_skipped_adjustmentFalseIf set to true, the transfer skips adjustment when from or to postprocessor values are either zero or have different signs. If set to false, an error is thrown when encountering these conditions.
Default:False
C++ Type:bool
Options:
Description:If set to true, the transfer skips adjustment when from or to postprocessor values are either zero or have different signs. If set to false, an error is thrown when encountering these conditions.
check_multiapp_execute_onTrueWhen false the check between the multiapp and transfer execute on flags is not preformed.
Default:True
C++ Type:bool
Options:
Description:When false the check between the multiapp and transfer execute on flags is not preformed.
displaced_source_meshFalseWhether or not to use the displaced mesh for the source mesh.
Default:False
C++ Type:bool
Options:
Description:Whether or not to use the displaced mesh for the source mesh.
displaced_target_meshFalseWhether or not to use the displaced mesh for the target mesh.
Default:False
C++ Type:bool
Options:
Description:Whether or not to use the displaced mesh for the target mesh.
distance_tol1e-10If the distance between two points is smaller than distance_tol, two points will be considered as identical
Default:1e-10
C++ Type:double
Options:
Description:If the distance between two points is smaller than distance_tol, two points will be considered as identical
exclude_gap_blocksGap subdomains we want to exclude when constructing/using virtually translated points
C++ Type:std::vector<SubdomainName>
Options:
Description:Gap subdomains we want to exclude when constructing/using virtually translated points
execute_onSAME_AS_MULTIAPPThe list of flag(s) indicating when this object should be executed, the available options include NONE, INITIAL, LINEAR, NONLINEAR, TIMESTEP_END, TIMESTEP_BEGIN, FINAL, CUSTOM, SAME_AS_MULTIAPP.
Default:SAME_AS_MULTIAPP
C++ Type:ExecFlagEnum
Options:NONE, INITIAL, LINEAR, NONLINEAR, TIMESTEP_END, TIMESTEP_BEGIN, FINAL, CUSTOM, SAME_AS_MULTIAPP
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, FINAL, CUSTOM, SAME_AS_MULTIAPP.
from_postprocessors_to_be_preservedThe name of the Postprocessor in the from-app to evaluate an adjusting factor.
C++ Type:std::vector<PostprocessorName>
Options:
Description:The name of the Postprocessor in the from-app to evaluate an adjusting factor.
from_solution_tagThe tag of the solution vector to be transferred (default to the solution)
C++ Type:TagName
Options:
Description:The tag of the solution vector to be transferred (default to the solution)
interp_typeinverse_distanceThe algorithm to use for interpolation.
Default:inverse_distance
C++ Type:MooseEnum
Options:inverse_distance, radial_basis
Description:The algorithm to use for interpolation.
num_points3The number of nearest points to use for interpolation.
Default:3
C++ Type:unsigned int
Options:
Description:The number of nearest points to use for interpolation.
power2The polynomial power to use for calculation of the decay in the interpolation.
Default:2
C++ Type:double
Options:
Description:The polynomial power to use for calculation of the decay in the interpolation.
radius-1Radius to use for radial_basis interpolation. If negative then the radius is taken as the max distance between points.
Default:-1
C++ Type:double
Options:
Description:Radius to use for radial_basis interpolation. If negative then the radius is taken as the max distance between points.
shrink_gap_width0gap width with which we want to temporarily shrink mesh in transfering solution
Default:0
C++ Type:double
Options:
Description:gap width with which we want to temporarily shrink mesh in transfering solution
shrink_meshSOURCEWhich mesh we want to shrink
Default:SOURCE
C++ Type:MooseEnum
Options:SOURCE, TARGET
Description:Which mesh we want to shrink
to_postprocessors_to_be_preservedThe name of the Postprocessor in the to-app to evaluate an adjusting factor.
C++ Type:std::vector<PostprocessorName>
Options:
Description:The name of the Postprocessor in the to-app to evaluate an adjusting factor.
to_solution_tagThe tag of the solution vector to be transferred to (default to the solution)
C++ Type:TagName
Options:
Description:The tag of the solution vector to be transferred to (default to the solution)

Optional 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.
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
Options:
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

Input Files

(test/tests/restart/restart_transient_from_steady/restart_trans_with_2subs.i)
(test/tests/transfers/transfer_interpolation/master.i)
(test/tests/transfers/multiapp_transfer_transformation/transfer_transformation.i)
(modules/porous_flow/examples/multiapp_fracture_flow/fracture_diffusion/matrix_app_nonconforming.i)
(test/tests/restart/restart_transient_from_transient/pseudo_trans_with_2subs.i)
(modules/porous_flow/examples/multiapp_fracture_flow/3dFracture/matrix_app.i)
(test/tests/restart/restart_transient_from_transient/restart_trans_with_2subs.i)
(modules/porous_flow/examples/multiapp_fracture_flow/fracture_diffusion/matrix_app_dirac.i)
(modules/porous_flow/examples/multiapp_fracture_flow/single_fracture_heat_transfer/matrix_app.i)
(test/tests/transfers/multiapp_interpolation_transfer/fromsub_master.i)
(test/tests/transfers/multiapp_interpolation_transfer/fromrestrictedsub_master.i)
(test/tests/restart/restart_transient_from_steady/steady_with_2subs.i)
(test/tests/transfers/multiapp_interpolation_transfer/tosub_master.i)

(test/tests/transfers/multiapp_interpolation_transfer/fromsub_master.i)

###########################################################
# This is a test of the Transfer System. This test
# uses the Multiapp System to solve independent problems
# related geometrically. Solutions are then interpolated
# and transferred from a non-aligned domain.
#
# @Requirement F7.20
###########################################################


[Mesh]
  type = GeneratedMesh
  dim = 2
  nx = 10
  ny = 10
  displacements = 'disp_x disp_y'
  # The MultiAppInterpolationTransfer object only works with ReplicatedMesh
  parallel_type = replicated
[]

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

[AuxVariables]
  [./from_sub]
  [../]
  [./elemental_from_sub]
    order = CONSTANT
    family = MONOMIAL
  [../]
  [./radial_from_sub]
  [../]
  [./radial_elemental_from_sub]
    order = CONSTANT
    family = MONOMIAL
  [../]
  [./disp_x]
    initial_condition = 0.2
  [../]
  [./disp_y]
  [../]
  [./displaced_target_from_sub]
  [../]
  [./displaced_source_from_sub]
  [../]
  [./nodal_from_sub_elemental]
  [../]
  [./elemental_from_sub_elemental]
    order = CONSTANT
    family = MONOMIAL
  [../]
[]

[Kernels]
  [./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
  num_steps = 1
  dt = 1

  solve_type = 'PJFNK'

  petsc_options_iname = '-pc_type -pc_hypre_type'
  petsc_options_value = 'hypre boomeramg'
[]

[Outputs]
  exodus = true
[]

[MultiApps]
  [./sub]
    type = TransientMultiApp
    app_type = MooseTestApp
    positions = '0 0 0 0.6 0 0'
    input_files = fromsub_sub.i
  [../]
[]

[Transfers]
  [./fromsub]
    type = MultiAppInterpolationTransfer
    direction = from_multiapp
    multi_app = sub
    source_variable = u
    variable = from_sub
  [../]
  [./elemental_fromsub]
    type = MultiAppInterpolationTransfer
    direction = from_multiapp
    multi_app = sub
    source_variable = u
    variable = elemental_from_sub
  [../]
  [./radial_fromsub]
    type = MultiAppInterpolationTransfer
    direction = from_multiapp
    multi_app = sub
    source_variable = u
    variable = radial_from_sub
    interp_type = radial_basis
  [../]
  [./radial_elemental_fromsub]
    type = MultiAppInterpolationTransfer
    direction = from_multiapp
    multi_app = sub
    source_variable = u
    variable = radial_elemental_from_sub
    interp_type = radial_basis
  [../]
  [./displaced_target_fromsub]
    type = MultiAppInterpolationTransfer
    direction = from_multiapp
    multi_app = sub
    source_variable = u
    variable = displaced_target_from_sub
    displaced_target_mesh = true
  [../]
  [./displaced_source_fromsub]
    type = MultiAppInterpolationTransfer
    direction = from_multiapp
    multi_app = sub
    source_variable = u
    variable = displaced_source_from_sub
    displaced_source_mesh = true
  [../]
  [./elemental_from_sub_elemental]
    type = MultiAppInterpolationTransfer
    direction = from_multiapp
    multi_app = sub
    source_variable = elemental
    variable = elemental_from_sub_elemental
  [../]
  [./nodal_from_sub_elemental]
    type = MultiAppInterpolationTransfer
    direction = from_multiapp
    multi_app = sub
    source_variable = elemental
    variable = nodal_from_sub_elemental
  [../]
[]

(test/tests/restart/restart_transient_from_steady/restart_trans_with_2subs.i)

[Mesh]
  type = GeneratedMesh
  dim = 2
  nx = 10
  ny = 10
  parallel_type = 'replicated'
[]

[Problem]
  restart_file_base = steady_with_2subs_out_cp/LATEST
  skip_additional_restart_data = true
[]

[AuxVariables]
  [Tf]
  []
[]

[Variables]
  [power_density]
  []
[]

[Functions]
  [pwr_func]
    type = ParsedFunction
    value = '1e3*x*(1-x)+5e2' # increase this function to drive transient
  []
[]

[Kernels]
  [timedt]
    type = TimeDerivative
    variable = power_density
  []

  [diff]
    type = Diffusion
    variable = power_density
  []

  [coupledforce]
    type = BodyForce
    variable = power_density
    function = pwr_func
  []
[]

[BCs]
  [left]
    type = DirichletBC
    variable = power_density
    boundary = left
    value = 50
  []
  [right]
    type = DirichletBC
    variable = power_density
    boundary = right
    value = 1e3
  []
[]

[Postprocessors]
  [pwr_avg]
    type = ElementAverageValue
    block = '0'
    variable = power_density
    execute_on = 'initial timestep_end'
  []
  [temp_avg]
    type = ElementAverageValue
    variable = Tf
    block = '0'
    execute_on = 'initial timestep_end'
  []
  [temp_max]
    type = ElementExtremeValue
    value_type = max
    variable = Tf
    block = '0'
    execute_on = 'initial timestep_end'
  []
  [temp_min]
    type = ElementExtremeValue
    value_type = min
    variable = Tf
    block = '0'
    execute_on = 'initial timestep_end'
  []
[]

[Executioner]
  type = Transient
  start_time = 0
  end_time = 3
  dt = 1.0

  petsc_options_iname = '-pc_type -pc_hypre_type -ksp_gmres_restart '
  petsc_options_value = 'hypre boomeramg 100'

  nl_abs_tol = 1e-8
  nl_rel_tol = 1e-7

  fixed_point_rel_tol = 1e-7
  fixed_point_abs_tol = 1e-07
  fixed_point_max_its = 4

  line_search = none
[]

[MultiApps]
  [./sub]
    type = TransientMultiApp
    app_type = MooseTestApp
    positions = '0   0 0
                 0.5 0 0'
    input_files  = restart_trans_with_sub_sub.i
    execute_on = 'timestep_end'
  [../]
[]

[Transfers]
  [p_to_sub]
    type = MultiAppProjectionTransfer
    direction = to_multiapp
    source_variable = power_density
    variable = power_density
    multi_app = sub
    execute_on = 'timestep_end'
  []
  [t_from_sub]
    type = MultiAppInterpolationTransfer
    direction = from_multiapp
    source_variable = temp
    variable = Tf
    multi_app = sub
    execute_on = 'timestep_end'
  []
[]

[Outputs]
  exodus = true
  csv = true
  perf_graph = true
[]

(test/tests/transfers/transfer_interpolation/master.i)

[Mesh]
  type = GeneratedMesh
  dim = 2
  nx = 10
  ny = 10
  # This test currently diffs when run in parallel with DistributedMesh enabled,
  # most likely due to the fact that it uses some geometric search stuff.
  # For more information, see #2121.
  parallel_type = replicated
[]

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

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

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

[UserObjects]
  [./layered_average]
    type = LayeredAverage
    variable = u
    direction = x
    num_layers = 3
  [../]
[]

[Executioner]
  type = Transient
  num_steps = 1
  dt = 1
  nl_rel_tol = 1e-10

  solve_type = 'PJFNK'

  petsc_options_iname = '-pc_type -pc_hypre_type'
  petsc_options_value = 'hypre boomeramg'
[]

[Outputs]
  exodus = true
[]
[MultiApps]
  [./sub]
    type = TransientMultiApp
    app_type = MooseTestApp
    execute_on = timestep_end
    positions = '0 0 0'
    input_files = sub.i
    sub_cycling = true
    interpolate_transfers = true
    output_sub_cycles = true
  [../]
[]

[Transfers]
  [./nearest_node]
    type = MultiAppNearestNodeTransfer
    direction = to_multiapp
    multi_app = sub
    source_variable = u
    variable = nearest_node
  [../]
  [./mesh_function]
    type = MultiAppMeshFunctionTransfer
    direction = to_multiapp
    multi_app = sub
    source_variable = u
    variable = mesh_function
  [../]
  [./user_object]
    type = MultiAppUserObjectTransfer
    direction = to_multiapp
    multi_app = sub
    variable = user_object
    user_object = layered_average
  [../]
  [./interpolation]
    type = MultiAppInterpolationTransfer
    direction = to_multiapp
    multi_app = sub
    source_variable = u
    variable = interpolation
  [../]
[]

(test/tests/transfers/multiapp_transfer_transformation/transfer_transformation.i)

[Mesh]
  [./gmg]
    type = GeneratedMeshGenerator
    dim = 2
    nx = 3
    ny = 5
    nz = 0
    xmax = 0.8
    xmin = 0.2
    zmin = 0
    zmax = 0
    elem_type = QUAD4
  []

  [./subdomain_id]
    type = ElementSubdomainIDGenerator
    input = gmg
    subdomain_ids = '0 1 2
                     0 1 2
                     0 1 2
                     0 1 2
                     0 1 2'
  []

  [./boundary01]
    type = SideSetsBetweenSubdomainsGenerator
    input = subdomain_id
    primary_block = '0'
    paired_block = '1'
    new_boundary = 'boundary01'
  []

  [./boundary10]
    type = SideSetsBetweenSubdomainsGenerator
    input = boundary01
    primary_block = '1'
    paired_block = '0'
    new_boundary = 'boundary10'
  []

  [./boundary12]
    type = SideSetsBetweenSubdomainsGenerator
    input = boundary10
    primary_block = '1'
    paired_block = '2'
    new_boundary = 'boundary12'
  []

  [./boundary21]
    type = SideSetsBetweenSubdomainsGenerator
    input = boundary12
    primary_block = '2'
    paired_block = '1'
    new_boundary = 'boundary21'
  []

  uniform_refine = 3
[]

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

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

[AuxVariables]
  [./fromsubelem]
    order = constant
    family = monomial
  [../]

  [./fromsub]
  []
[]

[BCs]
  [./left0]
    type = DirichletBC
    variable = u
    boundary = left
    value = 0
  [../]

  [./right0]
    type = DirichletBC
    variable = u
    boundary = boundary01
    value = 1
  [../]

  [./right1]
    type = DirichletBC
    variable = u
    boundary = boundary12
    value = 0
  [../]

  [./right2]
    type = DirichletBC
    variable = u
    boundary = right
    value = 1
  [../]
[]

[Executioner]
  type = Steady
  solve_type = 'NEWTON'
[]

[Outputs]
  exodus = true
[]

[MultiApps]
  [sub]
    type = FullSolveMultiApp
    app_type = MooseTestApp
    positions = '0.0  0.0  0.0'
    execute_on = 'timestep_end'
    input_files = transfer_transformation_sub.i
  []
[]

[Transfers]
  [from_sub]
    type = MultiAppInterpolationTransfer
    direction = from_multiapp
    multi_app = sub
    num_points = 1
    shrink_gap_width = 0.2
    shrink_mesh = 'source'
    source_variable = 'u'
    variable = 'fromsub'
    exclude_gap_blocks = '1 3'
  []

  [from_sub_elem]
    type = MultiAppInterpolationTransfer
    direction = from_multiapp
    multi_app = sub
    num_points = 4
    shrink_gap_width = 0.2
    shrink_mesh = 'source'
    source_variable = 'u'
    variable = 'fromsubelem'
    exclude_gap_blocks = '1 3'
  []

  [from_master]
    type = MultiAppInterpolationTransfer
    direction = to_multiapp
    multi_app = sub
    num_points = 1
    shrink_gap_width = 0.2
    shrink_mesh = 'target'
    source_variable = 'u'
    exclude_gap_blocks = '1 3'
    variable = 'frommaster'
  []

  [from_master_elem]
    type = MultiAppInterpolationTransfer
    direction = to_multiapp
    multi_app = sub
    num_points = 4
    shrink_gap_width = 0.2
    shrink_mesh = 'target'
    source_variable = 'u'
    exclude_gap_blocks = '1 3'
    variable = 'frommasterelem'
  []
[]

(modules/porous_flow/examples/multiapp_fracture_flow/fracture_diffusion/matrix_app_nonconforming.i)

# A fracture, which is a 1D line of elements, is embedded in a matrix, which is a 2D surface of elements.
# The meshes conform: all fracture nodes are also matrix nodes (the fracture elements are sides of matrix elements).
#
# The heat equation governs temperature in the fracture and matrix system, and heat energy is transferred between the two using a MultiApp approach
[Mesh]
  [generate]
    type = GeneratedMeshGenerator
    dim = 2
    nx = 20
    xmin = 0
    xmax = 10.0
    ny = 20
    ymin = -1.9
    ymax = 2.1
  []
[]

[Variables]
  [matrix_T]
  []
[]

[Kernels]
  [dot]
    type = TimeDerivative
    variable = matrix_T
  []
  [matrix_diffusion]
    type = AnisotropicDiffusion
    variable = matrix_T
    tensor_coeff = '1E-3 0 0 0 1E-3 0 0 0 1E-3'
  []
[]

[DiracKernels]
  [heat_from_fracture]
    type = ReporterPointSource
    variable = matrix_T
    value_name = heat_transfer_rate/transferred_joules_per_s
    x_coord_name = heat_transfer_rate/x
    y_coord_name = heat_transfer_rate/y
    z_coord_name = heat_transfer_rate/z
  []
[]

[VectorPostprocessors]
  [heat_transfer_rate]
    type = ConstantVectorPostprocessor
    vector_names = 'transferred_joules_per_s x y z'
    value = '0; 0; 0; 0'
    outputs = none
  []
[]

[Preconditioning]
  [entire_jacobian]
    type = SMP
    full = true
  []
[]

[Executioner]
  type = Transient
  solve_type = NEWTON
  dt = 100
  end_time = 100
[]


[Outputs]
  print_linear_residuals = false
  exodus = false
[]

[MultiApps]
  [fracture_app]
    type = TransientMultiApp
    input_files = fracture_app_dirac.i
    cli_args = 'Kernels/toMatrix/transfer_coefficient=0.01'
    execute_on = TIMESTEP_BEGIN
  []
[]

[Transfers]
  [T_to_fracture]
    type = MultiAppInterpolationTransfer
    direction = to_multiapp
    multi_app = fracture_app
    source_variable = matrix_T
    variable = transferred_matrix_T
  []
  [heat_from_fracture]
    type = MultiAppReporterTransfer
    direction = from_multiapp
    multi_app = fracture_app
    from_reporters = 'heat_transfer_rate/joules_per_s heat_transfer_rate/x heat_transfer_rate/y heat_transfer_rate/z'
    to_reporters = 'heat_transfer_rate/transferred_joules_per_s heat_transfer_rate/x heat_transfer_rate/y heat_transfer_rate/z'
  []
[]

(test/tests/restart/restart_transient_from_transient/pseudo_trans_with_2subs.i)

[Mesh]
  type = GeneratedMesh
  dim = 2
  nx = 10
  ny = 10
  parallel_type = 'replicated'
[]

[AuxVariables]
  [Tf]
  []
[]

[Variables]
  [power_density]
  []
[]

[Functions]
  [pwr_func]
    type = ParsedFunction
    value = '1e3*x*(1-x)+5e2'
  []
[]

[Kernels]
  [timedt]
    type = TimeDerivative
    variable = power_density
  []
  [diff]
    type = Diffusion
    variable = power_density
  []
  [coupledforce]
    type = BodyForce
    variable = power_density
    function = pwr_func
  []
[]

[BCs]
  [left]
    type = DirichletBC
    variable = power_density
    boundary = left
    value = 50
  []
  [right]
    type = DirichletBC
    variable = power_density
    boundary = right
    value = 1e3
  []
[]

[Postprocessors]
  [pwr_avg]
    type = ElementAverageValue
    variable = power_density
    execute_on = 'initial timestep_end'
  []
  [temp_avg]
    type = ElementAverageValue
    variable = Tf
    execute_on = 'initial timestep_end'
  []
  [temp_max]
    type = ElementExtremeValue
    value_type = max
    variable = Tf
    execute_on = 'initial timestep_end'
  []
  [temp_min]
    type = ElementExtremeValue
    value_type = min
    variable = Tf
    execute_on = 'initial timestep_end'
  []
[]

[Executioner]
  type = Transient
  petsc_options_iname = '-pc_type -pc_hypre_type -ksp_gmres_restart '
  petsc_options_value = 'hypre boomeramg 100'

  nl_abs_tol = 1e-8
  nl_rel_tol = 1e-12

  end_time = 20
  dt = 2.0
[]

[MultiApps]
  [sub]
    type = TransientMultiApp
    app_type = MooseTestApp
    positions = '0   0 0
                 0.5 0 0'
    input_files  = pseudo_trans_with_2subs_sub.i
    execute_on = 'timestep_end'
  []
[]

[Transfers]
  [p_to_sub]
    type = MultiAppProjectionTransfer
    direction = to_multiapp
    source_variable = power_density
    variable = power_density
    multi_app = sub
    execute_on = 'timestep_end'
  []
  [t_from_sub]
    type = MultiAppInterpolationTransfer
    direction = from_multiapp
    source_variable = temp
    variable = Tf
    multi_app = sub
    execute_on = 'timestep_end'
  []
[]

[Outputs]
  exodus = true
  csv = true
  perf_graph = true
  checkpoint = true
  execute_on = 'INITIAL TIMESTEP_END FINAL'
[]

(modules/porous_flow/examples/multiapp_fracture_flow/3dFracture/matrix_app.i)

# 3D matrix app doing thermo-hydro PorousFlow and receiving heat energy via a VectorPostprocessor from the 2D fracture App
[Mesh]
  uniform_refine = 0
  [generate]
    type = GeneratedMeshGenerator
    dim = 3
    nx = 11
    xmin = -10
    xmax = 210
    ny = 9
    ymin = -10
    ymax = 160
    nz = 11
    zmin = -10
    zmax = 210
  []
[]

[GlobalParams]
  PorousFlowDictator = dictator
[]

[Variables]
  [matrix_P]
    scaling = 1E6
  []
  [matrix_T]
    initial_condition = 473
  []
[]

[ICs]
  [frac_P]
    type = FunctionIC
    variable = matrix_P
    function = insitu_pp
  []
[]

[Functions]
  [insitu_pp]
    type = ParsedFunction
    value = '10 - 0.847E-2 * z' # Approximate hydrostatic in MPa
  []
[]

[PorousFlowFullySaturated]
  coupling_type = ThermoHydro
  porepressure = matrix_P
  temperature = matrix_T
  fp = water
  gravity = '0 0 -9.81E-6' # Note the value, because of pressure_unit
  pressure_unit = MPa
[]

[DiracKernels]
  [heat_from_fracture]
    type = ReporterPointSource
    variable = matrix_T
    value_name = heat_transfer_rate/transferred_joules_per_s
    x_coord_name = heat_transfer_rate/x
    y_coord_name = heat_transfer_rate/y
    z_coord_name = heat_transfer_rate/z
  []
[]

[Modules]
  [FluidProperties]
    [water]
      type = SimpleFluidProperties # this is largely irrelevant here since we care about heat conduction only
      thermal_expansion = 0 # to prevent depressurization as the reservoir is cooled
    []
  []
[]

[Materials]
  [porosity]
    type = PorousFlowPorosityConst
    porosity = 1E-3 # small porosity of rock
  []
  [permeability]
    type = PorousFlowPermeabilityConst
    permeability = '1E-18 0 0   0 1E-18 0   0 0 1E-18'
  []
  [internal_energy]
    type = PorousFlowMatrixInternalEnergy
    density = 2700 # kg/m^3
    specific_heat_capacity = 800 # rough guess at specific heat capacity
  []
  [aq_thermal_conductivity]
    type = PorousFlowThermalConductivityIdeal
    dry_thermal_conductivity = '5 0 0  0 5 0  0 0 5'
  []
[]

[VectorPostprocessors]
  [heat_transfer_rate]
    type = ConstantVectorPostprocessor
    vector_names = 'transferred_joules_per_s x y z'
    value = '0; 0; 0; 0'
    outputs = none
  []
[]

[AuxVariables]
  [normal_thermal_conductivity]
    family = MONOMIAL
    order = CONSTANT
  []
  [fracture_normal_x]
    family = MONOMIAL
    order = CONSTANT
    initial_condition = 0
  []
  [fracture_normal_y]
    family = MONOMIAL
    order = CONSTANT
    initial_condition = 1
  []
  [fracture_normal_z]
    family = MONOMIAL
    order = CONSTANT
    initial_condition = 0
  []
  [element_normal_length]
    family = MONOMIAL
    order = CONSTANT
  []
[]

[AuxKernels]
  [normal_thermal_conductivity_auxk]
    type = ConstantAux
    variable = normal_thermal_conductivity
    value = 5 # very simple in this case
  []
  [element_normal_length_auxk]
    type = PorousFlowElementLength
    variable = element_normal_length
    direction = 'fracture_normal_x fracture_normal_y fracture_normal_z'
  []
[]

[Preconditioning]
  [entire_jacobian]
    type = SMP
    full = true
    petsc_options_iname = '-pc_type'
    petsc_options_value = 'lu'
  []
[]

[Executioner]
  type = Transient
  solve_type = NEWTON
  [TimeStepper]
    type = IterationAdaptiveDT
    dt = 1
    growth_factor = 1.1
    optimal_iterations = 4
    timestep_limiting_postprocessor = 1E8
  []
  end_time = 1E8
  nl_abs_tol = 1E-2
[]

[Outputs]
  print_linear_residuals = false
  exodus = false
[]

[MultiApps]
  [fracture_app]
    type = TransientMultiApp
    input_files = fracture_only_aperture_changing.i
    cli_args = 'Outputs/ex/sync_only=false'
    execute_on = TIMESTEP_BEGIN
    sub_cycling = true
### catch_up = true
### max_catch_up_steps = 100
  []
[]

[Transfers]
  [element_normal_length_to_fracture]
    type = MultiAppNearestNodeTransfer
    direction = to_multiapp
    multi_app = fracture_app
    source_variable = element_normal_length
    variable = enclosing_element_normal_length
  []
  [element_normal_thermal_cond_to_fracture]
    type = MultiAppNearestNodeTransfer
    direction = to_multiapp
    multi_app = fracture_app
    source_variable = normal_thermal_conductivity
    variable = enclosing_element_normal_thermal_cond
  []
  [T_to_fracture]
    type = MultiAppInterpolationTransfer
    direction = to_multiapp
    multi_app = fracture_app
    source_variable = matrix_T
    variable = transferred_matrix_T
  []
  [normal_x_from_fracture]
    type = MultiAppNearestNodeTransfer
    direction = from_multiapp
    multi_app = fracture_app
    source_variable = normal_dirn_x
    variable = fracture_normal_x
  []
  [normal_y_from_fracture]
    type = MultiAppNearestNodeTransfer
    direction = from_multiapp
    multi_app = fracture_app
    source_variable = normal_dirn_y
    variable = fracture_normal_y
  []
  [normal_z_from_fracture]
    type = MultiAppNearestNodeTransfer
    direction = from_multiapp
    multi_app = fracture_app
    source_variable = normal_dirn_z
    variable = fracture_normal_z
  []
  [heat_from_fracture]
    type = MultiAppReporterTransfer
    direction = from_multiapp
    multi_app = fracture_app
    from_reporters = 'heat_transfer_rate/joules_per_s heat_transfer_rate/x heat_transfer_rate/y heat_transfer_rate/z'
    to_reporters = 'heat_transfer_rate/transferred_joules_per_s heat_transfer_rate/x heat_transfer_rate/y heat_transfer_rate/z'
  []
[]

(test/tests/restart/restart_transient_from_transient/restart_trans_with_2subs.i)

[Mesh]
  type = GeneratedMesh
  dim = 2
  nx = 10
  ny = 10
  parallel_type = 'replicated'
[]

[Problem]
  restart_file_base = pseudo_trans_with_2subs_out_cp/LATEST
[]

[AuxVariables]
  [Tf]
  []
[]

[Variables]
  [power_density]
  []
[]

[Functions]
  [pwr_func]
    type = ParsedFunction
    value = '1e3*x*(1-x)+5e2' # increase this function to drive transient
  []
[]

[Kernels]
  [timedt]
    type = TimeDerivative
    variable = power_density
  []

  [diff]
    type = Diffusion
    variable = power_density
  []

  [coupledforce]
    type = BodyForce
    variable = power_density
    function = pwr_func
  []
[]

[BCs]
  [left]
    type = DirichletBC
    variable = power_density
    boundary = left
    value = 50
  []
  [right]
    type = DirichletBC
    variable = power_density
    boundary = right
    value = 1e3
  []
[]

[Postprocessors]
  [pwr_avg]
    type = ElementAverageValue
    block = '0'
    variable = power_density
    execute_on = 'initial timestep_end'
  []
  [temp_avg]
    type = ElementAverageValue
    variable = Tf
    block = '0'
    execute_on = 'initial timestep_end'
  []
  [temp_max]
    type = ElementExtremeValue
    value_type = max
    variable = Tf
    block = '0'
    execute_on = 'initial timestep_end'
  []
  [temp_min]
    type = ElementExtremeValue
    value_type = min
    variable = Tf
    block = '0'
    execute_on = 'initial timestep_end'
  []
[]

[Executioner]
  type = Transient
  start_time = 0
  end_time = 3
  dt = 1.0

  petsc_options_iname = '-pc_type -pc_hypre_type -ksp_gmres_restart '
  petsc_options_value = 'hypre boomeramg 100'

  nl_abs_tol = 1e-8
  nl_rel_tol = 1e-12

  line_search = none
[]

[MultiApps]
  [./sub]
    type = TransientMultiApp
    app_type = MooseTestApp
    positions = '0   0 0
                 0.5 0 0'
    input_files  = restart_trans_with_2subs_sub.i
    execute_on = 'timestep_end'
  [../]
[]

[Transfers]
  [p_to_sub]
    type = MultiAppProjectionTransfer
    direction = to_multiapp
    source_variable = power_density
    variable = power_density
    multi_app = sub
    execute_on = 'timestep_end'
  []
  [t_from_sub]
    type = MultiAppInterpolationTransfer
    direction = from_multiapp
    source_variable = temp
    variable = Tf
    multi_app = sub
    execute_on = 'timestep_end'
  []
[]

[Outputs]
  exodus = true
  csv = true
  perf_graph = true
[]

(modules/porous_flow/examples/multiapp_fracture_flow/fracture_diffusion/matrix_app_dirac.i)

# A fracture, which is a 1D line of elements, is embedded in a matrix, which is a 2D surface of elements.
# The meshes conform: all fracture nodes are also matrix nodes (the fracture elements are sides of matrix elements).
#
# The heat equation governs temperature in the fracture and matrix system, and heat energy is transferred between the two using a MultiApp approach
[Mesh]
  [generate]
    type = GeneratedMeshGenerator
    dim = 2
    nx = 20
    xmin = 0
    xmax = 10.0
    ny = 20 # anything less than this produces over/under-shoots
    ymin = -2
    ymax = 2
  []
[]

[Variables]
  [matrix_T]
  []
[]

[Kernels]
  [dot]
    type = TimeDerivative
    variable = matrix_T
  []
  [matrix_diffusion]
    type = AnisotropicDiffusion
    variable = matrix_T
    tensor_coeff = '1E-3 0 0 0 1E-3 0 0 0 1E-3'
  []
[]

[DiracKernels]
  [heat_from_fracture]
    type = ReporterPointSource
    variable = matrix_T
    value_name = heat_transfer_rate/transferred_joules_per_s
    x_coord_name = heat_transfer_rate/x
    y_coord_name = heat_transfer_rate/y
    z_coord_name = heat_transfer_rate/z
  []
[]

[VectorPostprocessors]
  [heat_transfer_rate]
    type = ConstantVectorPostprocessor
    vector_names = 'transferred_joules_per_s x y z'
    value = '0; 0; 0; 0'
    outputs = none
  []
[]

[Preconditioning]
  [entire_jacobian]
    type = SMP
    full = true
  []
[]

[Executioner]
  type = Transient
  solve_type = NEWTON
  dt = 100
  end_time = 100
  nl_rel_tol = 1e-8
  petsc_options_iname = '-pc_type  -pc_factor_mat_solver_package'
  petsc_options_value = 'lu        superlu_dist'
[]


[Outputs]
  print_linear_residuals = false
  exodus = false
  csv=true
[]

[MultiApps]
  [fracture_app]
    type = TransientMultiApp
    input_files = fracture_app_dirac.i
    execute_on = TIMESTEP_BEGIN
  []
[]

[Transfers]
  [T_to_fracture]
    type = MultiAppInterpolationTransfer
    direction = to_multiapp
    multi_app = fracture_app
    source_variable = matrix_T
    variable = transferred_matrix_T
  []
  [heat_from_fracture]
    type = MultiAppReporterTransfer
    direction = from_multiapp
    multi_app = fracture_app
    from_reporters = 'heat_transfer_rate/joules_per_s heat_transfer_rate/x heat_transfer_rate/y heat_transfer_rate/z'
    to_reporters = 'heat_transfer_rate/transferred_joules_per_s heat_transfer_rate/x heat_transfer_rate/y heat_transfer_rate/z'
  []
[]

(modules/porous_flow/examples/multiapp_fracture_flow/single_fracture_heat_transfer/matrix_app.i)

# Matrix physics, which is just heat conduction.  Heat energy comes from the fracture App
[Mesh]
  [generate]
    type = GeneratedMeshGenerator
    dim = 2
    nx = 20
    xmin = 0
    xmax = 100.0
    ny = 9
    ymin = -9
    ymax = 9
  []
[]

[Variables]
  [matrix_T]
    initial_condition = 40 # degC
  []
[]

[Kernels]
  [dot]
    type = CoefTimeDerivative
    variable = matrix_T
    Coefficient = 1E5
  []
  [matrix_diffusion]
    type = AnisotropicDiffusion
    variable = matrix_T
    tensor_coeff = '1 0 0 0 1 0 0 0 1'
  []
[]

[DiracKernels]
  [heat_from_fracture]
    type = ReporterPointSource
    variable = matrix_T
    value_name = heat_transfer_rate/transferred_joules_per_s
    x_coord_name = heat_transfer_rate/x
    y_coord_name = heat_transfer_rate/y
    z_coord_name = heat_transfer_rate/z
  []
[]

[VectorPostprocessors]
  [heat_transfer_rate]
    type = ConstantVectorPostprocessor
    vector_names = 'transferred_joules_per_s x y z'
    value = '0; 0; 0; 0'
    outputs = none
  []
[]

[Preconditioning]
  [entire_jacobian]
    type = SMP
    full = true
  []
[]

[Executioner]
  type = Transient
  solve_type = NEWTON
  dt = 1
  end_time = 100
  nl_abs_tol = 1E-3
[]


[Outputs]
  print_linear_residuals = false
  exodus = true
  csv=true
[]

[MultiApps]
  [fracture_app]
    type = TransientMultiApp
    input_files = fracture_app.i
    execute_on = TIMESTEP_BEGIN
  []
[]

[Transfers]
  [T_to_fracture]
    type = MultiAppInterpolationTransfer
    direction = to_multiapp
    multi_app = fracture_app
    source_variable = matrix_T
    variable = transferred_matrix_T
  []
  [heat_from_fracture]
    type = MultiAppReporterTransfer
    direction = from_multiapp
    multi_app = fracture_app
    from_reporters = 'heat_transfer_rate/joules_per_s heat_transfer_rate/x heat_transfer_rate/y heat_transfer_rate/z'
    to_reporters = 'heat_transfer_rate/transferred_joules_per_s heat_transfer_rate/x heat_transfer_rate/y heat_transfer_rate/z'
  []
[]

(test/tests/transfers/multiapp_interpolation_transfer/fromsub_master.i)

###########################################################
# This is a test of the Transfer System. This test
# uses the Multiapp System to solve independent problems
# related geometrically. Solutions are then interpolated
# and transferred from a non-aligned domain.
#
# @Requirement F7.20
###########################################################


[Mesh]
  type = GeneratedMesh
  dim = 2
  nx = 10
  ny = 10
  displacements = 'disp_x disp_y'
  # The MultiAppInterpolationTransfer object only works with ReplicatedMesh
  parallel_type = replicated
[]

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

[AuxVariables]
  [./from_sub]
  [../]
  [./elemental_from_sub]
    order = CONSTANT
    family = MONOMIAL
  [../]
  [./radial_from_sub]
  [../]
  [./radial_elemental_from_sub]
    order = CONSTANT
    family = MONOMIAL
  [../]
  [./disp_x]
    initial_condition = 0.2
  [../]
  [./disp_y]
  [../]
  [./displaced_target_from_sub]
  [../]
  [./displaced_source_from_sub]
  [../]
  [./nodal_from_sub_elemental]
  [../]
  [./elemental_from_sub_elemental]
    order = CONSTANT
    family = MONOMIAL
  [../]
[]

[Kernels]
  [./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
  num_steps = 1
  dt = 1

  solve_type = 'PJFNK'

  petsc_options_iname = '-pc_type -pc_hypre_type'
  petsc_options_value = 'hypre boomeramg'
[]

[Outputs]
  exodus = true
[]

[MultiApps]
  [./sub]
    type = TransientMultiApp
    app_type = MooseTestApp
    positions = '0 0 0 0.6 0 0'
    input_files = fromsub_sub.i
  [../]
[]

[Transfers]
  [./fromsub]
    type = MultiAppInterpolationTransfer
    direction = from_multiapp
    multi_app = sub
    source_variable = u
    variable = from_sub
  [../]
  [./elemental_fromsub]
    type = MultiAppInterpolationTransfer
    direction = from_multiapp
    multi_app = sub
    source_variable = u
    variable = elemental_from_sub
  [../]
  [./radial_fromsub]
    type = MultiAppInterpolationTransfer
    direction = from_multiapp
    multi_app = sub
    source_variable = u
    variable = radial_from_sub
    interp_type = radial_basis
  [../]
  [./radial_elemental_fromsub]
    type = MultiAppInterpolationTransfer
    direction = from_multiapp
    multi_app = sub
    source_variable = u
    variable = radial_elemental_from_sub
    interp_type = radial_basis
  [../]
  [./displaced_target_fromsub]
    type = MultiAppInterpolationTransfer
    direction = from_multiapp
    multi_app = sub
    source_variable = u
    variable = displaced_target_from_sub
    displaced_target_mesh = true
  [../]
  [./displaced_source_fromsub]
    type = MultiAppInterpolationTransfer
    direction = from_multiapp
    multi_app = sub
    source_variable = u
    variable = displaced_source_from_sub
    displaced_source_mesh = true
  [../]
  [./elemental_from_sub_elemental]
    type = MultiAppInterpolationTransfer
    direction = from_multiapp
    multi_app = sub
    source_variable = elemental
    variable = elemental_from_sub_elemental
  [../]
  [./nodal_from_sub_elemental]
    type = MultiAppInterpolationTransfer
    direction = from_multiapp
    multi_app = sub
    source_variable = elemental
    variable = nodal_from_sub_elemental
  [../]
[]

(test/tests/transfers/multiapp_interpolation_transfer/fromrestrictedsub_master.i)

[Mesh]
  type = GeneratedMesh
  dim = 2
  nx = 10
  ny = 10
  # The MultiAppInterpolationTransfer object only works with ReplicatedMesh
  parallel_type = replicated
[]

[Variables]
  [u]
  []
[]

[AuxVariables]
  [elemental_from_sub]
    order = CONSTANT
    family = MONOMIAL
  []
  [nodal_from_sub]
  []
[]

[Kernels]
  [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
  num_steps = 1
  dt = 1

  petsc_options_iname = '-pc_type -pc_hypre_type'
  petsc_options_value = 'hypre boomeramg'
[]

[Outputs]
  exodus = true
[]

[MultiApps]
  [sub]
    type = TransientMultiApp
    app_type = MooseTestApp
    positions = '0.05 0.5 0 0.55 0.5 0'
    input_files = fromrestrictedsub_sub.i
    output_in_position = true
  []
[]

[Transfers]
  [elemental_fromsub]
    type = MultiAppInterpolationTransfer
    direction = from_multiapp
    multi_app = sub
    source_variable = elemental
    variable = elemental_from_sub
  []
  [nodal_fromsub]
    type = MultiAppInterpolationTransfer
    direction = from_multiapp
    multi_app = sub
    source_variable = nodal
    variable = nodal_from_sub
  []
[]

(test/tests/restart/restart_transient_from_steady/steady_with_2subs.i)

[Mesh]
  type = GeneratedMesh
  dim = 2
  nx = 10
  ny = 10
  parallel_type = 'replicated'
[]

[AuxVariables]
  [Tf]
  []
[]

[Variables]
  [power_density]
  []
[]

[Functions]
  [pwr_func]
    type = ParsedFunction
    value = '1e3*x*(1-x)+5e2'
  []
[]

[Kernels]
  [diff]
    type = Diffusion
    variable = power_density
  []

  [coupledforce]
    type = BodyForce
    variable = power_density
    function = pwr_func
  []
[]

[BCs]
  [left]
    type = DirichletBC
    variable = power_density
    boundary = left
    value = 50
  []
  [right]
    type = DirichletBC
    variable = power_density
    boundary = right
    value = 1e3
  []
[]

[Postprocessors]
  [pwr_avg]
    type = ElementAverageValue
    variable = power_density
    execute_on = 'initial timestep_end'
  []
  [temp_avg]
    type = ElementAverageValue
    variable = Tf
    execute_on = 'initial final'
  []
  [temp_max]
    type = ElementExtremeValue
    value_type = max
    variable = Tf
    execute_on = 'initial final'
  []
  [temp_min]
    type = ElementExtremeValue
    value_type = min
    variable = Tf
    execute_on = 'initial final'
  []
[]

[Executioner]
  type = Steady
  petsc_options_iname = '-pc_type -pc_hypre_type -ksp_gmres_restart '
  petsc_options_value = 'hypre boomeramg 100'

  nl_abs_tol = 1e-8
  nl_rel_tol = 1e-12

  fixed_point_rel_tol = 1E-7
  fixed_point_abs_tol = 1.0e-07
  fixed_point_max_its = 12
[]

[MultiApps]
  [sub]
    type = FullSolveMultiApp
    app_type = MooseTestApp
    positions = '0   0 0
                 0.5 0 0'
    input_files  = steady_with_sub_sub.i
    execute_on = 'timestep_end'
  []
[]

[Transfers]
  [p_to_sub]
    type = MultiAppProjectionTransfer
    direction = to_multiapp
    source_variable = power_density
    variable = power_density
    multi_app = sub
    execute_on = 'timestep_end'
  []
  [t_from_sub]
    type = MultiAppInterpolationTransfer
    direction = from_multiapp
    source_variable = temp
    variable = Tf
    multi_app = sub
    execute_on = 'timestep_end'
  []
[]

[Outputs]
  exodus = true
  csv = true
  perf_graph = true
  checkpoint = true
  execute_on = 'INITIAL TIMESTEP_END FINAL'
[]

(test/tests/transfers/multiapp_interpolation_transfer/tosub_master.i)

###########################################################
# This is a test of the Transfer System. This test
# uses the Multiapp System to solve independent problems
# related geometrically. Solutions are then interpolated
# and transferred to a non-aligned domain.
#
# @Requirement F7.20
###########################################################


[Mesh]
  type = GeneratedMesh
  dim = 2
  nx = 10
  ny = 10
  xmin = .21
  xmax = .79
  displacements = 'disp_x disp_y'
  # The MultiAppInterpolationTransfer object only works with ReplicatedMesh
  parallel_type = replicated
[]

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

[AuxVariables]
  [./disp_x]
    initial_condition = 0.4
  [../]
  [./disp_y]
  [../]
  [./elemental]
    order = CONSTANT
    family = MONOMIAL
  [../]
[]

[Functions]
  [./x_func]
    type = ParsedFunction
    value = x
  [../]
[]

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

[AuxKernels]
  [./x_func_aux]
    type = FunctionAux
    variable = elemental
    function = x_func
    execute_on = initial
  [../]
[]

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

[Executioner]
  type = Transient
  num_steps = 1
  dt = 1

  solve_type = 'PJFNK'

  petsc_options_iname = '-pc_type -pc_hypre_type'
  petsc_options_value = 'hypre boomeramg'
[]

[Outputs]
  exodus = true
[]

[MultiApps]
  [./sub]
    type = TransientMultiApp
    app_type = MooseTestApp
    execute_on = timestep_end
    positions = '0.2 0 0'
    input_files = tosub_sub.i
  [../]
[]

[Transfers]
  [./tosub]
    type = MultiAppInterpolationTransfer
    direction = to_multiapp
    multi_app = sub
    source_variable = u
    variable = from_master
  [../]
  [./elemental_tosub]
    type = MultiAppInterpolationTransfer
    direction = to_multiapp
    multi_app = sub
    source_variable = u
    variable = elemental_from_master
  [../]
  [./radial_tosub]
    type = MultiAppInterpolationTransfer
    direction = to_multiapp
    multi_app = sub
    source_variable = u
    variable = radial_from_master
    interp_type = radial_basis
  [../]
  [./radial_elemental_tosub]
    type = MultiAppInterpolationTransfer
    direction = to_multiapp
    multi_app = sub
    source_variable = u
    variable = radial_elemental_from_master
    interp_type = radial_basis
  [../]
  [./displaced_target_tosub]
    type = MultiAppInterpolationTransfer
    direction = to_multiapp
    multi_app = sub
    source_variable = u
    variable = displaced_target_from_master
    displaced_target_mesh = true
  [../]
  [./displaced_source_tosub]
    type = MultiAppInterpolationTransfer
    direction = to_multiapp
    multi_app = sub
    source_variable = u
    variable = displaced_source_from_master
    displaced_source_mesh = true
  [../]
  [./elemental_to_sub_elemental]
    type = MultiAppInterpolationTransfer
    direction = to_multiapp
    multi_app = sub
    source_variable = elemental
    variable = elemental_from_master_elemental
  [../]
  [./elemental_to_sub_nodal]
    type = MultiAppInterpolationTransfer
    direction = to_multiapp
    multi_app = sub
    source_variable = elemental
    variable = nodal_from_master_elemental
  [../]
[]

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