CSVTimeSequenceStepper

This time stepper derives from TimeSequenceStepperBase and provides the sequence of time values from a CSV file or similarly delimited text file. A DelimitedFileReader is used to read the CSV file.

The file is always read in columns. The column can either be accessed by name (using the "column_name" parameter, provided that the CSV file has a header containing the names of the different columns) or by index (using the "column_index" parameter, with 0 the index of the first column).

See Failed solves for information on the behavior of this time stepper for failed time steps.

Input Parameters

file_namename of the file in which the time sequence is read
C++ Type:FileName
Controllable:No
Description:name of the file in which the time sequence is read

Required Parameters

column_indexindex of the column which contains the time sequence
C++ Type:unsigned int
Controllable:No
Description:index of the column which contains the time sequence
column_nametimename of the column which contains the time sequence
Default:time
C++ Type:std::string
Controllable:No
Description:name of the column which contains the time sequence
cutback_factor_at_failure0.5Factor to apply to timestep if a time step fails to converge.
Default:0.5
C++ Type:double
Controllable:No
Description:Factor to apply to timestep if a time step fails to converge.
delimiter,delimiter used to parse the file
Default:,
C++ Type:std::string
Controllable:No
Description:delimiter used to parse the file
headerFalseindicates whether the file contains a header with the column names
Default:False
C++ Type:bool
Controllable:No
Description:indicates whether the file contains a header with the column names
reset_dtFalseUse when restarting a calculation to force a change in dt.
Default:False
C++ Type:bool
Controllable:No
Description:Use when restarting a calculation to force a change in dt.
use_last_dt_after_last_tFalseIf true, uses the final time step size for times after the last time in the sequence, instead of taking a single step directly to the simulation end time
Default:False
C++ Type:bool
Controllable:No
Description:If true, uses the final time step size for times after the last time in the sequence, instead of taking a single step directly to the simulation end time

Optional Parameters

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.
enableTruewhether or not to enable the time stepper
Default:True
C++ Type:bool
Controllable:Yes
Description:whether or not to enable the time stepper

Advanced Parameters

Input Files

(test/tests/time_steppers/timesequence_stepper/csvtimesequence.i)
(test/tests/time_steppers/time_stepper_system/multiple_timesequences.i)

(test/tests/time_steppers/timesequence_stepper/csvtimesequence.i)

[Mesh]
  type = GeneratedMesh
  dim = 2
  xmin = -1
  xmax =  1
  ymin = -1
  ymax =  1
  nx = 2
  ny = 2
  elem_type = QUAD9
[]

[Functions]
  [./exact_fn]
    type = ParsedFunction
    expression = t*t*(x*x+y*y)
  [../]

  [./forcing_fn]
    type = ParsedFunction
    expression = 2*t*(x*x+y*y)-4*t*t
  [../]
[]

[Variables]
  [./u]
    family = LAGRANGE
    order = SECOND
  [../]
[]

[ICs]
  [./u_var]
    type = FunctionIC
    variable = u
    function = exact_fn
  [../]
[]

[Kernels]
  [./td]
    type = TimeDerivative
    variable = u
  [../]

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

  [./ffn]
    type = BodyForce
    variable = u
    function = forcing_fn
  [../]
[]

[BCs]
  [./all]
    type = FunctionDirichletBC
    variable = u
    boundary = 'left right top bottom'
    function = exact_fn
  [../]
[]

[Executioner]
  type = Transient
  end_time = 10
  [./TimeStepper]
    type = CSVTimeSequenceStepper
    file_name = timesequence.csv
    column_name = time1
  [../]
[]

[Outputs]
  exodus = true
[]

(test/tests/time_steppers/time_stepper_system/multiple_timesequences.i)

[Mesh]
  type = GeneratedMesh
  dim = 2
  nx = 10
  ny = 10
[]

[Variables]
  [u]
  []
[]

[Kernels]
  [diff]
    type = CoefDiffusion
    variable = u
    coef = 0.1
  []
  [time]
    type = TimeDerivative
    variable = u
  []
[]

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

[Executioner]
  type = Transient
  end_time = 0.8
  solve_type = PJFNK
  petsc_options_iname = '-pc_type -pc_hypre_type'
  petsc_options_value = 'hypre boomeramg'
  # Use as many different time sequence steppers as we could to test the compositionDT
  [TimeSteppers]
    [ConstDT1]
      type = ConstantDT
      dt = 0.2
    []

    [ConstDT2]
      type = ConstantDT
      dt = 0.1
    []

    [LogConstDT]
      type = LogConstantDT
      log_dt = 0.2
      first_dt = 0.1
    []

    [Timesequence1]
      type = TimeSequenceStepper
      time_sequence  = '0  0.25 0.3 0.5 0.8'
    []

    [Timesequence2]
      type = CSVTimeSequenceStepper
      file_name = timesequence.csv
      column_name = time
    []

    [Timesequence3]
      type = ExodusTimeSequenceStepper
      mesh = timesequence.e
    []
  []
[]

[Postprocessors]
  [timestep]
    type = TimePostprocessor
    execute_on = 'timestep_end'
  []
[]

[Outputs]
  csv = true
  file_base='multiple_timesequences'
[]

Input Parameters
Input Files