PolycrystalHex

The PolycrystalHex object generates a set of points in 2D or 3D space such that hexagonal patterns are generated from a resulting Voronoi Tesselation. The number of grains must be choosen such that the $var element = document.getElementById("moose-equation-3387d2ae-3028-43d0-a9ef-81b9c2cba35e");katex.render("\\sqrt[dim]{n}", element, {displayMode:false,throwOnError:false,macros:{"\\pf":"\\frac{\\partial #1}{\\partial #2}"}});$ root is an integer. Furthermore, a suitable number must be chosen that is supported by the mesh resolution and grain boundary width. Once the grain structure has been generated, a coloring algorithm is used to assign order parameters to grains so that a reduced number of order parameters may be used. Typical numbers are given here:

Dimension	Recommended OPs
2D	8
3D	25

See Polycrystal Initial Conditions for more information.

Typical usage in an input file:

[UserObjects]
  [./voronoi]
    type = PolycrystalVoronoi
    grain_num = 100 # Number of grains
    rand_seed = 10
  [../]
  [./grain_tracker]
    type = GrainTracker
    threshold = 0.2
    connecting_threshold = 0.08
    compute_halo_maps = true # Only necessary for displaying HALOS
  [../]
[]

[ICs]
  [./PolycrystalICs]
    [./PolycrystalColoringIC]
      polycrystal_ic_uo = voronoi
    [../]
  [../]
[]

/opt/civet/build_0/moose/modules/phase_field/examples/grain_growth/grain_growth_2D_graintracker.i

# This simulation predicts GB migration of a 2D copper polycrystal with 100 grains represented with 18 order parameters
# Mesh adaptivity and time step adaptivity are used
# An AuxVariable is used to calculate the grain boundary locations
# Postprocessors are used to record time step and the number of grains

[Mesh]
  # Mesh block.  Meshes can be read in or automatically generated
  type = GeneratedMesh
  dim = 2 # Problem dimension
  nx = 11 # Number of elements in the x-direction
  ny = 11 # Number of elements in the y-direction
  xmin = 0    # minimum x-coordinate of the mesh
  xmax = 1000 # maximum x-coordinate of the mesh
  ymin = 0    # minimum y-coordinate of the mesh
  ymax = 1000 # maximum y-coordinate of the mesh
  elem_type = QUAD4  # Type of elements used in the mesh
  uniform_refine = 3 # Initial uniform refinement of the mesh

  parallel_type = replicated # Periodic BCs
[]

[GlobalParams]
  # Parameters used by several kernels that are defined globally to simplify input file
  op_num = 8 # Number of order parameters used
  var_name_base = gr # Base name of grains
[]

[Variables]
  # Variable block, where all variables in the simulation are declared
  [./PolycrystalVariables]
  [../]
[]

[UserObjects]
  [./voronoi]
    type = PolycrystalVoronoi
    grain_num = 100 # Number of grains
    rand_seed = 10
  [../]
  [./grain_tracker]
    type = GrainTracker
    threshold = 0.2
    connecting_threshold = 0.08
    compute_halo_maps = true # Only necessary for displaying HALOS
  [../]
[]

[ICs]
  [./PolycrystalICs]
    [./PolycrystalColoringIC]
      polycrystal_ic_uo = voronoi
    [../]
  [../]
[]

[AuxVariables]
  # Dependent variables
  [./bnds]
    # Variable used to visualize the grain boundaries in the simulation
  [../]
  [./unique_grains]
    order = CONSTANT
    family = MONOMIAL
  [../]
  [./var_indices]
    order = CONSTANT
    family = MONOMIAL
  [../]
  [./ghost_regions]
    order = CONSTANT
    family = MONOMIAL
  [../]
  [./halos]
    order = CONSTANT
    family = MONOMIAL
  [../]
[]

[Kernels]
  # Kernel block, where the kernels defining the residual equations are set up.
  [./PolycrystalKernel]
    # Custom action creating all necessary kernels for grain growth.  All input parameters are up in GlobalParams
  [../]
[]

[AuxKernels]
  # AuxKernel block, defining the equations used to calculate the auxvars
  [./bnds_aux]
    # AuxKernel that calculates the GB term
    type = BndsCalcAux
    variable = bnds
    execute_on = 'initial timestep_end'
  [../]
  [./unique_grains]
    type = FeatureFloodCountAux
    variable = unique_grains
    flood_counter = grain_tracker
    field_display = UNIQUE_REGION
    execute_on = 'initial timestep_end'
  [../]
  [./var_indices]
    type = FeatureFloodCountAux
    variable = var_indices
    flood_counter = grain_tracker
    field_display = VARIABLE_COLORING
    execute_on = 'initial timestep_end'
  [../]
  [./ghosted_entities]
    type = FeatureFloodCountAux
    variable = ghost_regions
    flood_counter = grain_tracker
    field_display = GHOSTED_ENTITIES
    execute_on = 'initial timestep_end'
  [../]
  [./halos]
    type = FeatureFloodCountAux
    variable = halos
    flood_counter = grain_tracker
    field_display = HALOS
    execute_on = 'initial timestep_end'
  [../]
[]

[BCs]
  # Boundary Condition block
  [./Periodic]
    [./top_bottom]
      auto_direction = 'x y' # Makes problem periodic in the x and y directions
    [../]
  [../]
[]

[Materials]
  [./CuGrGr]
    # Material properties
    type = GBEvolution
    T = 450 # Constant temperature of the simulation (for mobility calculation)
    wGB = 14 # Width of the diffuse GB
    GBmob0 = 2.5e-6 #m^4(Js) for copper from Schoenfelder1997
    Q = 0.23 #eV for copper from Schoenfelder1997
    GBenergy = 0.708 #J/m^2 from Schoenfelder1997
  [../]
[]

[Postprocessors]
  # Scalar postprocessors
  [./dt]
    # Outputs the current time step
    type = TimestepSize
  [../]
[]

[Executioner]
  type = Transient # Type of executioner, here it is transient with an adaptive time step
  scheme = bdf2 # Type of time integration (2nd order backward euler), defaults to 1st order backward euler

  #Preconditioned JFNK (default)
  solve_type = 'PJFNK'

  # Uses newton iteration to solve the problem.
  petsc_options_iname = '-pc_type -pc_hypre_type -ksp_gmres_restart -mat_mffd_type'
  petsc_options_value = 'hypre boomeramg 101 ds'

  l_max_its = 30 # Max number of linear iterations
  l_tol = 1e-4 # Relative tolerance for linear solves
  nl_max_its = 40 # Max number of nonlinear iterations
  nl_rel_tol = 1e-10 # Absolute tolerance for nonlienar solves

  start_time = 0.0
  end_time = 4000

  [./TimeStepper]
    type = IterationAdaptiveDT
    dt = 25 # Initial time step.  In this simulation it changes.
    optimal_iterations = 6 # Time step will adapt to maintain this number of nonlinear iterations
  [../]

  [./Adaptivity]
    # Block that turns on mesh adaptivity. Note that mesh will never coarsen beyond initial mesh (before uniform refinement)
    initial_adaptivity = 2 # Number of times mesh is adapted to initial condition
    refine_fraction = 0.7 # Fraction of high error that will be refined
    coarsen_fraction = 0.1 # Fraction of low error that will coarsened
    max_h_level = 4 # Max number of refinements used, starting from initial mesh (before uniform refinement)
  [../]
[]

[Outputs]
  exodus = true # Exodus file will be outputted
  csv = true
  [./console]
    type = Console
    max_rows = 20 # Will print the 20 most recent postprocessor values to the screen
  [../]
[]

Description and Syntax

PolycrystalHex

Perturbed hexagonal polycrystal

Input Parameters

variableArray of coupled variables
C++ Type:std::vector
Options:
Description:Array of coupled variables

Required Parameters

boundaryThe list of boundary IDs from the mesh where this boundary condition applies
C++ Type:std::vector
Options:
Description:The list of boundary IDs from the mesh where this boundary condition applies
coloring_algorithmjpThe grain neighbor graph coloring algorithm to use: "jp" (DEFAULT) Jones and Plassmann, an efficient coloring algorithm, "power" an alternative stochastic algorithm, "greedy", a greedy assignment algorithm with stochastic updates to guarantee a valid coloring, "bt", a back tracking algorithm that produces good distributions but may experience exponential run time in the worst case scenario (works well on medium to large 2D problems)
Default:jp
C++ Type:MooseEnum
Options:jp power greedy bt
Description:The grain neighbor graph coloring algorithm to use: "jp" (DEFAULT) Jones and Plassmann, an efficient coloring algorithm, "power" an alternative stochastic algorithm, "greedy", a greedy assignment algorithm with stochastic updates to guarantee a valid coloring, "bt", a back tracking algorithm that produces good distributions but may experience exponential run time in the worst case scenario (works well on medium to large 2D problems)
columnar_3DFalse3D microstructure will be columnar in the z-direction?
Default:False
C++ Type:bool
Options:
Description:3D microstructure will be columnar in the z-direction?
compute_halo_mapsFalseInstruct the Postprocessor to communicate proper halo information to all ranks
Default:False
C++ Type:bool
Options:
Description:Instruct the Postprocessor to communicate proper halo information to all ranks
compute_var_to_feature_mapFalseInstruct the Postprocessor to compute the active vars to features map
Default:False
C++ Type:bool
Options:
Description:Instruct the Postprocessor to compute the active vars to features map
connecting_thresholdThe threshold for which an existing feature may be extended (defaults to "threshold")
C++ Type:double
Options:
Description:The threshold for which an existing feature may be extended (defaults to "threshold")
enable_var_coloringFalseInstruct the Postprocessor to populate the variable index map.
Default:False
C++ Type:bool
Options:
Description:Instruct the Postprocessor to populate the variable index map.
execute_onINITIALThe 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.
Default:INITIAL
C++ Type:ExecFlagEnum
Options:NONE INITIAL LINEAR NONLINEAR TIMESTEP_END TIMESTEP_BEGIN FINAL CUSTOM
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.
file_nameFile containing grain centroids, if file_name is provided, the centroids from the file will be used.
C++ Type:FileName
Options:
Description:File containing grain centroids, if file_name is provided, the centroids from the file will be used.
flood_entity_typeELEMENTALDetermines whether the flood algorithm runs on nodes or elements
Default:ELEMENTAL
C++ Type:MooseEnum
Options:NODAL ELEMENTAL
Description:Determines whether the flood algorithm runs on nodes or elements
grain_num0Number of grains being represented by the order parameters
Default:0
C++ Type:unsigned int
Options:
Description:Number of grains being represented by the order parameters
int_width0Width of diffuse interfaces
Default:0
C++ Type:double
Options:
Description:Width of diffuse interfaces
op_numArray of coupled variables (num_name)
C++ Type:unsigned int
Options:
Description:Array of coupled variables (num_name)
output_adjacency_matrixFalseOutput the Grain Adjacency Matrix used in the coloring algorithms. Additionally, the grain to OP assignments will be printed
Default:False
C++ Type:bool
Options:
Description:Output the Grain Adjacency Matrix used in the coloring algorithms. Additionally, the grain to OP assignments will be printed
perturbation_percent0The percent to randomly perturb centers of grains relative to the size of the grain
Default:0
C++ Type:double
Options:
Description:The percent to randomly perturb centers of grains relative to the size of the grain
rand_seed0The random seed
Default:0
C++ Type:unsigned int
Options:
Description:The random seed
secondary_percolation_boundariesPaired boundaries with "primaryary_percolation_boundaries" parameter
C++ Type:std::vector
Options:
Description:Paired boundaries with "primaryary_percolation_boundaries" parameter
specified_boundariesAn optional list of boundaries; if supplied, each feature is checked to determine whether it intersects any of the specified boundaries in this list.
C++ Type:std::vector
Options:
Description:An optional list of boundaries; if supplied, each feature is checked to determine whether it intersects any of the specified boundaries in this list.
threshold0.5The threshold value for which a new feature may be started
Default:0.5
C++ Type:double
Options:
Description:The threshold value for which a new feature may be started
use_less_than_threshold_comparisonTrueControls whether features are defined to be less than or greater than the threshold value.
Default:True
C++ Type:bool
Options:
Description:Controls whether features are defined to be less than or greater than the threshold value.
var_name_baseArray of coupled variables (base_name)
C++ Type:std::string
Options:
Description:Array of coupled variables (base_name)
x_offset0.5Specifies offset of hexagon grid in x-direction
Default:0.5
C++ Type:double
Options:
Description:Specifies offset of hexagon grid in x-direction

Optional Parameters

allow_duplicate_execution_on_initialTrueIn the case where this UserObject is depended upon by an initial condition, allow it to be executed twice during the initial setup (once before the IC and again after mesh adaptivity (if applicable).
Default:True
C++ Type:bool
Options:
Description:In the case where this UserObject is depended upon by an initial condition, allow it to be executed twice during the initial setup (once before the IC and again after mesh adaptivity (if applicable).
condense_map_infoFalseDetermines whether we condense all the node values when in multimap mode (default: false)
Default:False
C++ Type:bool
Options:
Description:Determines whether we condense all the node values when in multimap mode (default: false)
control_tagsAdds user-defined labels for accessing object parameters via control logic.
C++ Type:std::vector
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.
force_preauxFalseForces the GeneralUserObject to be executed in PREAUX
Default:False
C++ Type:bool
Options:
Description:Forces the GeneralUserObject to be executed in PREAUX
outputsnone Vector of output names were you would like to restrict the output of variables(s) associated with this object
Default:none
C++ Type:std::vector
Options:
Description:Vector of output names were you would like to restrict the output of variables(s) associated with this object
primary_percolation_boundariesA list of boundaries used in conjunction with the corresponding "secondary_percolation_boundaries" parameter for determining if a feature creates a path connecting any pair of boundaries
C++ Type:std::vector
Options:
Description:A list of boundaries used in conjunction with the corresponding "secondary_percolation_boundaries" parameter for determining if a feature creates a path connecting any pair of boundaries
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.
use_global_numberingTrueDetermine whether or not global numbers are used to label features on multiple maps (default: true)
Default:True
C++ Type:bool
Options:
Description:Determine whether or not global numbers are used to label features on multiple maps (default: true)
use_single_mapTrueDetermine whether information is tracked per coupled variable or consolidated into one (default: true)
Default:True
C++ Type:bool
Options:
Description:Determine whether information is tracked per coupled variable or consolidated into one (default: true)

Advanced Parameters

Input Files

modules/phase_field/test/tests/grain_growth/hex.i
modules/phase_field/test/tests/initial_conditions/HexPolycrystalIC.i
modules/combined/examples/phase_field-mechanics/hex_grain_growth_2D_eldrforce.i

modules/phase_field/test/tests/grain_growth/hex.i

[Mesh]
  type = GeneratedMesh
  dim = 2
  nx = 40
  ny = 40
  nz = 0
  xmin = 0
  xmax = 1000
  ymin = 0
  ymax = 1000
  zmin = 0
  zmax = 0
  elem_type = QUAD4
[]

[GlobalParams]
  op_num = 4
  var_name_base = gr
[]

[Variables]
  [./PolycrystalVariables]
  [../]
[]

[UserObjects]
  [./hex_ic]
    type = PolycrystalHex
    coloring_algorithm = bt
    x_offset = .5
    grain_num = 4
  [../]
[]

[ICs]
  [./PolycrystalICs]
    [./PolycrystalColoringIC]
      polycrystal_ic_uo = hex_ic
    [../]
  [../]
[]

[AuxVariables]
  [./bnds]
    order = FIRST
    family = LAGRANGE
  [../]
[]

[Kernels]
  [./PolycrystalKernel]
  [../]
[]

[AuxKernels]
  [./BndsCalc]
    type = BndsCalcAux
    variable = bnds
    execute_on = timestep_end
  [../]
[]

[BCs]
  [./Periodic]
    [./All]
      auto_direction = 'x y'
    [../]
  [../]
[]

[Materials]
  [./Copper]
    type = GBEvolution
    T = 500 # K
    wGB = 60 # nm
    GBmob0 = 2.5e-6 #m^4/(Js) from Schoenfelder 1997
    Q = 0.23 #Migration energy in eV
    GBenergy = 0.708 #GB energy in J/m^2
  [../]
[]

[Preconditioning]
  active = ''
  [./SMP]
    type = SMP
    full = true
  [../]
[]

[Executioner]
  type = Transient
  scheme = 'bdf2'
  solve_type = 'PJFNK'

  petsc_options_iname = '-pc_type -pc_hypre_type -ksp_gmres_restart'
  petsc_options_value = 'hypre boomeramg 31'

  l_tol = 1.0e-4
  l_max_its = 30
  nl_max_its = 20
  nl_rel_tol = 1.0e-9
  start_time = 0.0
  num_steps = 2
  dt = 80.0
[]

[Outputs]
  exodus = true
[]

modules/phase_field/test/tests/initial_conditions/HexPolycrystalIC.i

[Mesh]
  type = GeneratedMesh
  dim = 2
  nx = 19
  ny = 19
[]

[GlobalParams]
  op_num = 9
  var_name_base = gr
  grain_num = 36
[]

[Variables]
  [./PolycrystalVariables]
  [../]
[]

[UserObjects]
  [./hex_ic]
    type = PolycrystalHex
    coloring_algorithm = bt
  [../]
[]

[ICs]
  [./PolycrystalICs]
    [./PolycrystalColoringIC]
      polycrystal_ic_uo = hex_ic
    [../]
  [../]
[]

[BCs]
  [./Periodic]
    [./all]
      auto_direction = 'x'
    [../]
  [../]
[]

[Executioner]
  type = Transient
  num_steps = 1
[]

[Problem]
  solve = false
  kernel_coverage_check = false
[]

[Outputs]
  [./out]
    type = Exodus
    execute_on = final
  [../]
[]

modules/combined/examples/phase_field-mechanics/hex_grain_growth_2D_eldrforce.i

[Mesh]
  type = GeneratedMesh
  dim = 2
  nx = 20
  ny = 17
  nz = 0
  xmax = 1000
  ymax = 866
  zmax = 0
  elem_type = QUAD4
  uniform_refine = 2
[]

[GlobalParams]
  op_num = 3
  var_name_base = gr
[]

[Variables]
  [./PolycrystalVariables]
  [../]
  [./disp_x]
    order = FIRST
    family = LAGRANGE
  [../]
  [./disp_y]
    order = FIRST
    family = LAGRANGE
  [../]
[]

[UserObjects]
  [./hex_ic]
    type = PolycrystalHex
    coloring_algorithm = bt
    grain_num = 36
    x_offset = 0.0
    output_adjacency_matrix = true
  [../]
  [./euler_angle_file]
    type = EulerAngleFileReader
    file_name = grn_36_test2_2D.tex
  [../]
  [./grain_tracker]
    type = GrainTrackerElasticity
    threshold = 0.2
    compute_var_to_feature_map = true
    execute_on = 'initial timestep_begin'
    flood_entity_type = ELEMENTAL

    fill_method = symmetric9
    C_ijkl = '1.27e5 0.708e5 0.708e5 1.27e5 0.708e5 1.27e5 0.7355e5 0.7355e5 0.7355e5'
    euler_angle_provider = euler_angle_file
  [../]
[]

[ICs]
  [./PolycrystalICs]
    [./PolycrystalColoringIC]
      polycrystal_ic_uo = hex_ic
    [../]
  [../]
[]

[AuxVariables]
  [./bnds]
    order = FIRST
    family = LAGRANGE
  [../]
  [./elastic_strain11]
    order = CONSTANT
    family = MONOMIAL
  [../]
  [./elastic_strain22]
    order = CONSTANT
    family = MONOMIAL
  [../]
  [./elastic_strain12]
    order = CONSTANT
    family = MONOMIAL
  [../]
  [./unique_grains]
    order = CONSTANT
    family = MONOMIAL
  [../]
  [./var_indices]
    order = CONSTANT
    family = MONOMIAL
  [../]
  [./C1111]
    order = CONSTANT
    family = MONOMIAL
  [../]
  [./vonmises_stress]
    order = CONSTANT
    family = MONOMIAL
  [../]
  [./euler_angle]
    order = CONSTANT
    family = MONOMIAL
  [../]
[]

[Kernels]
  [./PolycrystalKernel]
  [../]
  [./PolycrystalElasticDrivingForce]
  [../]
  [./TensorMechanics]
    displacements = 'disp_x disp_y'
  [../]
[]

[AuxKernels]
  [./BndsCalc]
    type = BndsCalcAux
    variable = bnds
    execute_on = 'initial timestep_end'
  [../]
  [./elastic_strain11]
    type = RankTwoAux
    variable = elastic_strain11
    rank_two_tensor = elastic_strain
    index_i = 0
    index_j = 0
    execute_on = timestep_end
  [../]
  [./elastic_strain22]
    type = RankTwoAux
    variable = elastic_strain22
    rank_two_tensor = elastic_strain
    index_i = 1
    index_j = 1
    execute_on = timestep_end
  [../]
  [./elastic_strain12]
    type = RankTwoAux
    variable = elastic_strain12
    rank_two_tensor = elastic_strain
    index_i = 0
    index_j = 1
    execute_on = timestep_end
  [../]
  [./unique_grains]
    type = FeatureFloodCountAux
    variable = unique_grains
    execute_on = timestep_end
    flood_counter = grain_tracker
    field_display = UNIQUE_REGION
  [../]
  [./var_indices]
    type = FeatureFloodCountAux
    variable = var_indices
    execute_on = timestep_end
    flood_counter = grain_tracker
    field_display = VARIABLE_COLORING
  [../]
  [./C1111]
    type = RankFourAux
    variable = C1111
    rank_four_tensor = elasticity_tensor
    index_l = 0
    index_j = 0
    index_k = 0
    index_i = 0
    execute_on = timestep_end
  [../]
  [./vonmises_stress]
    type = RankTwoScalarAux
    variable = vonmises_stress
    rank_two_tensor = stress
    scalar_type = VonMisesStress
  [../]
  [./euler_angle]
    type = OutputEulerAngles
    variable = euler_angle
    euler_angle_provider = euler_angle_file
    grain_tracker = grain_tracker
    output_euler_angle = 'phi1'
  [../]
[]

[BCs]
  [./Periodic]
    [./All]
      auto_direction = 'x y'
      variable = 'gr0 gr1 gr2'
    [../]
  [../]
  [./top_displacement]
    type = DirichletBC
    variable = disp_y
    boundary = top
    value = -50.0
  [../]
  [./x_anchor]
    type = DirichletBC
    variable = disp_x
    boundary = 'left right'
    value = 0.0
  [../]
  [./y_anchor]
    type = DirichletBC
    variable = disp_y
    boundary = bottom
    value = 0.0
  [../]
[]

[Materials]
  [./Copper]
    type = GBEvolution
    block = 0
    T = 500 # K
    wGB = 15 # nm
    GBmob0 = 2.5e-6 # m^4/(Js) from Schoenfelder 1997
    Q = 0.23 # Migration energy in eV
    GBenergy = 0.708 # GB energy in J/m^2
  [../]
  [./ElasticityTensor]
    type = ComputePolycrystalElasticityTensor
    block = 0
    grain_tracker = grain_tracker
  [../]
  [./strain]
    type = ComputeSmallStrain
    block = 0
    displacements = 'disp_x disp_y'
  [../]
  [./stress]
    type = ComputeLinearElasticStress
    block = 0
  [../]
[]

[Postprocessors]
  [./dofs]
    type = NumDOFs
  [../]
  [./dt]
    type = TimestepSize
  [../]
  [./run_time]
    type = PerfGraphData
    section_name = "Root"
    data_type = total
  [../]
  [./bnd_length]
    type = GrainBoundaryArea
  [../]
[]

[Preconditioning]
  [./SMP]
    type = SMP
    off_diag_row = 'disp_x disp_y'
    off_diag_column = 'disp_y disp_x'
  [../]
[]

[Executioner]
  type = Transient
  scheme = bdf2
  solve_type = PJFNK
  petsc_options_iname = '-pc_type -pc_hypre_type -ksp_gmres_restart -pc_hypre_boomeramg_strong_threshold'
  petsc_options_value = 'hypre boomeramg 31 0.7'
  l_tol = 1.0e-4
  l_max_its = 30
  nl_max_its = 40
  nl_rel_tol = 1.0e-7
  start_time = 0.0
  num_steps = 50
  [./TimeStepper]
    type = IterationAdaptiveDT
    dt = 1.5
    growth_factor = 1.2
    cutback_factor = 0.8
    optimal_iterations = 8
  [../]
  [./Adaptivity]
    initial_adaptivity = 2
    refine_fraction = 0.8
    coarsen_fraction = 0.05
    max_h_level = 3
  [../]
[]

[Outputs]
  exodus = true
[]

Typical usage in an input file :
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MOOSEDocs

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PolycrystalHex

Typical usage in an input file:

Description and Syntax

PolycrystalHex

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