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
    from_multi_app = sub
    source_variable = u
    variable = from_sub
  [../]
[]

Input Parameters

source_variableThe variable to transfer from.
C++ Type:std::vector<VariableName>
Controllable:No
Description:The variable to transfer from.
variableThe auxiliary variable to store the transferred values in.
C++ Type:std::vector<AuxVariableName>
Controllable:No
Description:The auxiliary variable to store the transferred values in.

Required Parameters

check_multiapp_execute_onTrueWhen false the check between the multiapp and transfer execute on flags is not preformed.
Default:True
C++ Type:bool
Controllable:No
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
Controllable:No
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
Controllable:No
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
Controllable:No
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>
Controllable:No
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, ALWAYS.
Default:SAME_AS_MULTIAPP
C++ Type:ExecFlagEnum
Options:NONE, INITIAL, LINEAR, NONLINEAR, TIMESTEP_END, TIMESTEP_BEGIN, FINAL, CUSTOM, SAME_AS_MULTIAPP, ALWAYS
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, FINAL, CUSTOM, SAME_AS_MULTIAPP, ALWAYS.
from_multi_appThe name of the MultiApp to receive data from
C++ Type:MultiAppName
Controllable:No
Description:The name of the MultiApp to receive data from
from_solution_tagThe tag of the solution vector to be transferred (default to the solution)
C++ Type:TagName
Controllable:No
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
Controllable:No
Description:The algorithm to use for interpolation.
num_points3The number of nearest points to use for interpolation.
Default:3
C++ Type:unsigned int
Controllable:No
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
Controllable:No
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
Controllable:No
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
Controllable:No
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
Controllable:No
Description:Which mesh we want to shrink
to_multi_appThe name of the MultiApp to transfer the data to
C++ Type:MultiAppName
Controllable:No
Description:The name of the MultiApp to transfer the data to
to_solution_tagThe tag of the solution vector to be transferred to (default to the solution)
C++ Type:TagName
Controllable:No
Description:The tag of the solution vector to be transferred to (default to the solution)

Optional Parameters

_called_legacy_paramsTrue
Default:True
C++ Type:bool
Controllable:No
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.
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

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
Controllable:No
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.
from_postprocessors_to_be_preservedThe name of the Postprocessor in the from-app to evaluate an adjusting factor.
C++ Type:std::vector<PostprocessorName>
Controllable:No
Description:The name of the Postprocessor in the from-app to evaluate an adjusting factor.
to_postprocessors_to_be_preservedThe name of the Postprocessor in the to-app to evaluate an adjusting factor.
C++ Type:std::vector<PostprocessorName>
Controllable:No
Description:The name of the Postprocessor in the to-app to evaluate an adjusting factor.

Conservative Transfer Parameters

(../../../SoftwareDownloads/moose/test/tests/transfers/multiapp_interpolation_transfer/fromsub_parent.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
    from_multi_app = sub
    source_variable = u
    variable = from_sub
  [../]
  [./elemental_fromsub]
    type = MultiAppInterpolationTransfer
    from_multi_app = sub
    source_variable = u
    variable = elemental_from_sub
  [../]
  [./radial_fromsub]
    type = MultiAppInterpolationTransfer
    from_multi_app = sub
    source_variable = u
    variable = radial_from_sub
    interp_type = radial_basis
  [../]
  [./radial_elemental_fromsub]
    type = MultiAppInterpolationTransfer
    from_multi_app = sub
    source_variable = u
    variable = radial_elemental_from_sub
    interp_type = radial_basis
  [../]
  [./displaced_target_fromsub]
    type = MultiAppInterpolationTransfer
    from_multi_app = sub
    source_variable = u
    variable = displaced_target_from_sub
    displaced_target_mesh = true
  [../]
  [./displaced_source_fromsub]
    type = MultiAppInterpolationTransfer
    from_multi_app = sub
    source_variable = u
    variable = displaced_source_from_sub
    displaced_source_mesh = true
  [../]
  [./elemental_from_sub_elemental]
    type = MultiAppInterpolationTransfer
    from_multi_app = sub
    source_variable = elemental
    variable = elemental_from_sub_elemental
  [../]
  [./nodal_from_sub_elemental]
    type = MultiAppInterpolationTransfer
    from_multi_app = sub
    source_variable = elemental
    variable = nodal_from_sub_elemental
  [../]
[]

Example Syntax
Input Parameters