ImageSubdomainGenerator

The ImageSubdomainGenerator uses the coordinates of each element's centroid to sample a location of an image. It then uses the resulting color value of the pixel to determine the subdomain ID.

Samples an image at the coordinates of each element centroid using the resulting value as each element's subdomain ID

Input Parameters

inputThe mesh we want to modify
C++ Type:MeshGeneratorName
Options:
Description:The mesh we want to modify

Required Parameters

componentThe image RGB-component to return, leaving this blank will result in a greyscale value for the image to be created. The component number is zero based, i.e. 0 returns the first (RED) component of the image.
C++ Type:unsigned int
Options:
Description:The image RGB-component to return, leaving this blank will result in a greyscale value for the image to be created. The component number is zero based, i.e. 0 returns the first (RED) component of the image.
dimensionsx,y,z dimensions of the image (defaults to mesh dimensions)
C++ Type:libMesh::Point
Options:
Description:x,y,z dimensions of the image (defaults to mesh dimensions)
fileName of single image file to extract mesh parameters from. If provided, a 2D mesh is created.
C++ Type:FileName
Options:
Description:Name of single image file to extract mesh parameters from. If provided, a 2D mesh is created.
file_baseImage file base to open, use this option when a stack of images must be read (ignored if 'file' is given)
C++ Type:FileNameNoExtension
Options:
Description:Image file base to open, use this option when a stack of images must be read (ignored if 'file' is given)
file_rangeRange of images to analyze, used with 'file_base' (ignored if 'file' is given)
C++ Type:std::vector
Options:
Description:Range of images to analyze, used with 'file_base' (ignored if 'file' is given)
file_suffixSuffix of the file to open, e.g. 'png'
C++ Type:std::string
Options:
Description:Suffix of the file to open, e.g. 'png'
originOrigin of the image (defaults to mesh origin)
C++ Type:libMesh::Point
Options:
Description:Origin of the image (defaults to mesh origin)

Optional Parameters

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.

Advanced Parameters

flip_xFalseFlip the image along the x-axis
Default:False
C++ Type:bool
Options:
Description:Flip the image along the x-axis
flip_yFalseFlip the image along the y-axis
Default:False
C++ Type:bool
Options:
Description:Flip the image along the y-axis
flip_zFalseFlip the image along the z-axis
Default:False
C++ Type:bool
Options:
Description:Flip the image along the z-axis

Flip Parameters

lower_value0The value to set for data less than the threshold value
Default:0
C++ Type:double
Options:
Description:The value to set for data less than the threshold value
thresholdThe threshold value
C++ Type:double
Options:
Description:The threshold value
upper_value1The value to set for data greater than the threshold value
Default:1
C++ Type:double
Options:
Description:The value to set for data greater than the threshold value

Threshold Parameters

scale1Multiplier to apply to all pixel values; occurs after shifting
Default:1
C++ Type:double
Options:
Description:Multiplier to apply to all pixel values; occurs after shifting
shift0Value to add to all pixels; occurs prior to scaling
Default:0
C++ Type:double
Options:
Description:Value to add to all pixels; occurs prior to scaling

Rescale Parameters

Input Files

test/tests/preconditioners/fsp/fsp_test_image.i

test/tests/preconditioners/fsp/fsp_test_image.i

[Mesh]
  [gen]
    type = GeneratedMeshGenerator
    dim = 2
    nx = 41
    ny = 41
  []
  [./image]
    input = gen
    type = ImageSubdomainGenerator
    file = kitten.png
    threshold = 100
  [../]
[]

[Variables]
  [./u]
    order = FIRST
    family = LAGRANGE
    block = 1
  [../]
  [./v]
    order = FIRST
    family = LAGRANGE
    block = 1
  [../]
[]

[Kernels]
  [./diff_u]
    type = Diffusion
    variable = u
  [../]
  [./conv_v]
    type = CoupledForce
    variable = v
    v = u
  [../]
  [./diff_v]
    type = Diffusion
    variable = v
  [../]
[]

[BCs]
  active = 'left_u left_v right_u'
  [./left_u]
    type = DirichletBC
    variable = u
    boundary = left
    value = 0
  [../]
  [./right_u]
    type = DirichletBC
    variable = u
    boundary = right
    value = 100
  [../]
  [./left_v]
    type = DirichletBC
    variable = v
    boundary = left
    value = 0
  [../]
  [./right_v]
    type = DirichletBC
    variable = v
    boundary = right
    value = 0
  [../]
[]

[Problem]
  type = FEProblem
  material_coverage_check = false
  kernel_coverage_check = false
[]

[Executioner]
  # This is setup automatically in MOOSE (SetupPBPAction.C)
  # petsc_options = '-snes_mf_operator'
  # petsc_options_iname = '-pc_type'
  # petsc_options_value =  'asm'
  type = Steady
[]

[Preconditioning]
  [./FSP]
    # It is the starting point of splitting
    type = FSP
    topsplit = 'uv' # 'uv'
    [./uv]
      # Generally speaking, there are four types of splitting we could choose
      # <additive,multiplicative,symmetric_multiplicative,schur>
      # An approximate solution to the original system
      # | A_uu  A_uv | | u | _ |f_u|
      # |  0    A_vv | | v | - |f_v|
      # is obtained by solving the following subsystems
      # A_uu u = f_u and A_vv v = f_v
      # If splitting type is specified as schur, we may also want to set more options to
      # control how schur works using PETSc options
      # petsc_options_iname = '-pc_fieldsplit_schur_fact_type -pc_fieldsplit_schur_precondition'
      # petsc_options_value = 'full selfp'
      splitting = 'u v' # 'u' and 'v'
      splitting_type = additive
    [../]
    [./u]
      # PETSc options for this subsolver
      # A prefix will be applied, so just put the options for this subsolver only
      vars = u
      petsc_options_iname = '-pc_type -ksp_type'
      petsc_options_value = '     hypre preonly'
    [../]
    [./v]
      # PETSc options for this subsolver
      vars = v
      petsc_options_iname = '-pc_type -ksp_type'
      petsc_options_value = '     hypre  preonly'
    [../]
  [../]
[]

[Outputs]
  file_base = kitten_out
  exodus = true
[]

Input Parameters
Input Files

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