- dt_initialThe initial time step size
C++ Type:double
Controllable:No
Description:The initial time step size
- target_iterationsThe target number of fixed point iterations
C++ Type:unsigned int
Controllable:No
Description:The target number of fixed point iterations
- target_windowThe number of iterations added to and subtracted from 'target_iterations' to determine the iteration window; the time step size will increase if the iterations were below 'target_iterations' - 'target_window' and will decrease if the iterations were above 'target_iterations' + 'target_window'.
C++ Type:unsigned int
Controllable:No
Description:The number of iterations added to and subtracted from 'target_iterations' to determine the iteration window; the time step size will increase if the iterations were below 'target_iterations' - 'target_window' and will decrease if the iterations were above 'target_iterations' + 'target_window'.
FixedPointIterationAdaptiveDT
Description
This time stepper adjusts the time step size according to a target number of fixed point iterations . This can only be used in apps having one or more MultiApps.
The time step size for step , , is computed as the product of the old time step size, , and a multiplier , which varies based on the old time step number of fixed point iterations, :
where
is the target number of fixed point iterations, provided by "target_iterations",
is the target window, provided by "target_window",
is the increase factor, provided by "increase_factor", and
is the decrease factor, provided by "decrease_factor".
The time step size of the first step is provided by "dt_initial".
Input 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.
- decrease_factor0.8Factor by which the previous time step size will decrease if the previous number of fixed point iterations was above the target window maximum ('target_iterations' + 'target_window').
Default:0.8
C++ Type:double
Controllable:No
Description:Factor by which the previous time step size will decrease if the previous number of fixed point iterations was above the target window maximum ('target_iterations' + 'target_window').
- increase_factor1.2Factor by which the previous time step size will increase if the previous number of fixed point iterations was below the target window minimum ('target_iterations' - 'target_window').
Default:1.2
C++ Type:double
Controllable:No
Description:Factor by which the previous time step size will increase if the previous number of fixed point iterations was below the target window minimum ('target_iterations' - 'target_window').
- 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.
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