text: [Mesh]
    type = GeneratedMesh
    dim = 3
    nx = 15
    ny = 15
    nz = 15
    xmin = 0
    xmax = 100
    ymin = 0
    ymax = 100
    zmin = 0
    zmax = 100
    elem_type = HEX8
  []
  
  [Variables]
    [./c]
      order = FIRST
      family = LAGRANGE
    [../]
  []
  
  [ICs]
    [./c]
      type = MultiSmoothCircleIC
      variable = c
      invalue = 1.0
      outvalue = 0.0001
      bubspac = 30.0 # This spacing is from bubble center to bubble center
      numbub = 10
      radius = 10.0
      int_width = 12.0
      rand_seed = 2000
      radius_variation = 2 #This is the standard deviation
      radius_variation_type = normal
    [../]
  []
  
  [Kernels]
    [./ie_c]
      type = TimeDerivative
      variable = c
    [../]
    [./diff]
      type = MatDiffusion
      variable = c
      diffusivity = D_v
    [../]
  []
  
  [BCs]
    [./Periodic]
      [./all]
        auto_direction = 'x y z'
      [../]
    [../]
  []
  
  [Materials]
    [./Dv]
      type = GenericConstantMaterial
      prop_names = D_v
      prop_values = 0.074802
    [../]
  []
  
  [Postprocessors]
    [./bubbles]
      type = FeatureFloodCount
      variable = c
      execute_on = 'initial timestep_end'
    [../]
  []
  
  [Executioner]
    type = Transient
    scheme = bdf2
    solve_type = PJFNK
    petsc_options_iname = '-pc_type -pc_hypre_type -ksp_gmres_restart -mat_mffd_type'
    petsc_options_value = 'hypre boomeramg 101 ds'
    l_max_its = 20
    l_tol = 1e-4
    nl_max_its = 20
    nl_rel_tol = 1e-9
    nl_abs_tol = 1e-11
    start_time = 0.0
    num_steps = 1
    dt = 100.0
  []
  
  [Outputs]
    exodus = true
  []
  