TimeSequenceStepper

This time stepper derives from TimeSequenceStepperBase and provides the sequence of time values from a user-specified list, given by "time_sequence".

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

Example input syntax

In this example, the numerical problem is solved at four specified points in time using a TimeSequenceStepper.

[Executioner]
  type = Transient
  end_time = 4.0
  [./TimeStepper]
    type = TimeSequenceStepper
    time_sequence = '0   0.85 1.3 2 4'
  [../]
[]

Input Parameters

time_sequenceThe values of t
C++ Type:std::vector<double>
Controllable:No
Description:The values of t

Required Parameters

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.
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

(../moose/test/tests/time_steppers/timesequence_stepper/timesequence.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 = TimeSequenceStepper
    time_sequence  = '0   0.85 1.3 2 4'
  [../]
[]

[Outputs]
  exodus = true
[]