qimpy.transport.TimeEvolution

class TimeEvolution(*, i_step=0, t=0.0, dt=0.0, dt_save, t_max, n_collate, integrator='RK2', checkpoint_in=(None, ''), geometry)

Bases: TreeNode

Time evolution parameters.

Parameters:

i_step (int)
t (float)
dt (float)
dt_save (float)
t_max (float)
n_collate (int)
integrator (str)
checkpoint_in (CheckpointPath)
geometry (Geometry)

__init__(*, i_step=0, t=0.0, dt=0.0, dt_save, t_max, n_collate, integrator='RK2', checkpoint_in=(None, ''), geometry)

Initialize time evolution parameters

Parameters:

i_step (int) – Initial step index, used for continuing from checkpoint.
t (float) – Initial time, used for continuing from checkpoint.
dt (float) – [Input file] Time step for evolution. If zero, this is set to the maximum stable time step for advection.
dt_save (float) – [Input file] Time interval at which to save results. This will be rounded to the nearest multiple of dt to ensure that the results are written at uniform intervals.
t_max (float) – [Input file] Stop evolution at this time.
n_collate (int) – [Input file] Number of save-steps to collect into each checkpoint file. Collecting together several saves can substantially improve performance by amortizing the latency associated with disk I/O and GPU transfers. The results in the checkpoint have an additional outermost dimension corresponding to the number of collated steps.
integrator (str) – [Input file] Integrator for time-stepping: RK2 or RK4.
geometry (Geometry) – Corresponding geometry from which maximum time step is determined
checkpoint_in (CheckpointPath)

Return type:

None

Methods

`__init__`	Initialize time evolution parameters
`add_child`	Construct child object self.`attr_name` of type cls.
`add_child_one_of`	Invoke add_child on one of several child options in args.
`run`	Run time evolution loop, checkpointing at regular intervals.
`save_checkpoint`	Save self and all children in hierarchy to cp_path.
`time_step`	Second-order correct time step.

Attributes

`t`	Current time
`dt`	Time step (set automatically if zero)
`i_step`	Current step number
`i_step_initial`	Initial step number for current job (not zero if continued)
`n_steps`	Number of steps
`save_interval`	Save results every so many steps
`n_collate`	Collect these many save steps into a single checkpoint
`integrator`	Time-step style used for integration
`child_names`	Names of attributes with child objects.
`variant_name`	Version of children having variants (if any)

run(transport)

Run time evolution loop, checkpointing at regular intervals.

Parameters:: transport (Transport)
Return type:: None

time_step(geometry)

Second-order correct time step.

Parameters:: geometry (Geometry)
Return type:: None

dt: float: Time step (set automatically if zero)

i_step: int: Current step number

i_step_initial: int: Initial step number for current job (not zero if continued)

integrator: str: Time-step style used for integration

n_collate: int: Collect these many save steps into a single checkpoint

n_steps: int: Number of steps

save_interval: int: Save results every so many steps

t: float: Current time