ExodusTimeSequenceStepper

This time stepper derives from TimeSequenceStepperBase and provides the sequence of time values from an Exodus file.

The Exodus file is read by the first process (rank 0), and the time step sequence is then broadcast to all other processes.

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

Example input file

In this example, the time stepper extracts the time sequence from an exodus output file. This exodus file may not necessarily have been generated using the same input file. The starting and end time of the simulation may still be set independently.

[Executioner]
  type = Transient
  end_time = 4.0
  [./TimeStepper]
    type = ExodusTimeSequenceStepper
    mesh = timesequence_no_start_time.e
  [../]
[]

Input Parameters

meshThe name of the mesh file to extract the time sequence from (must be an exodusII file).
C++ Type:MeshFileName
Unit:(no unit assumed)
Controllable:No
Description:The name of the mesh file to extract the time sequence from (must be an exodusII file).

Required Parameters

cutback_factor_at_failure0.5Factor to apply to timestep if a time step fails to converge.
Default:0.5
C++ Type:double
Unit:(no unit assumed)
Controllable:No
Description:Factor to apply to timestep if a time step fails to converge.
reset_dtFalseUse when restarting a calculation to force a change in dt.
Default:False
C++ Type:bool
Unit:(no unit assumed)
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
Unit:(no unit assumed)
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>
Unit:(no unit assumed)
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
Unit:(no unit assumed)
Controllable:Yes
Description:whether or not to enable the time stepper

Advanced Parameters

(moose/test/tests/time_steppers/timesequence_stepper/exodustimesequence.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 = 4.0
  [./TimeStepper]
    type = ExodusTimeSequenceStepper
    mesh = timesequence_no_start_time.e
  [../]
[]

[Outputs]
  exodus = true
[]