Set up a simulation from a checkpoint. More...

Inheritance diagram for exahype2.api.blockstructured.LoadCheckpoint.LoadCheckpoint:

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Collaboration diagram for exahype2.api.blockstructured.LoadCheckpoint.LoadCheckpoint:

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Public Member Functions
	__init__ (self, Solver solver, str filename="checkpoint", str output_path=".", float time_stamp=None)

str	index_file_name (self)
	Path of the checkpoint's index file.

	construct_output (self, exahype2_project, peano_project, setup_simulation)
	Add the mesh construction and the loading of the data to the setup task graph.

Protected Attributes
	_filename

	_output_path

	_time_stamp

	_solver

Protected Attributes inherited from exahype2.api.Solver.Solver.GridConstruction
	_solver

Detailed Description

Set up a simulation from a checkpoint.

Alternative to the setups over a regular grid (exahype2.api.fv.SetupSimulationOverRegularGrid, exahype2.api.rkfd4.SetupSimulationOverRegularGrid): Instead of constructing a mesh and setting the initial condition, the setup reads a checkpoint written by exahype2.api.fv.WriteCheckpoint or exahype2.api.rkfd4.WriteCheckpoint and continues the simulation from there. It is available for both schemes as exahype2.api.fv.LoadCheckpoint and exahype2.api.rkfd4.LoadCheckpoint, as both use the same data layout.

The setup consists of three phases:

It reconstructs the checkpoint's mesh. The refinement sweep repeats until the mesh is stationary and the load balancing has stagnated, exactly as for the regular grid. Instead of refining down to a given mesh size, it refines the parents of all cells in the checkpoint (exahype2::CheckpointReader).
Once the mesh is complete, it switches off the load balancing and waits until the last splits have been carried out.
A last sweep loads the data. For every cell, it reads the patch with halo into the temporary solver._patch_with_halo, copies the patch into solver._patch and writes the patch with halo onto the overlaps of the faces (toolbox.blockstructured.api.ProjectPatchWithHaloOntoFaces). The faces hence also hold the ghost data along the domain boundary and the data at coarse-fine transitions as they have been at the time of the checkpoint. In unprepareTraversal(), the sweep restores the solver's time stamps, time step sizes and mesh sizes, plus the attributes the Python API has added, e.g. the time stamps of the next outputs of the plotters. Plotters which have written output at the time of the checkpoint move on to their next output, so the restarted simulation does not write them again (exahype2.api.Solver.Solver._add_checkpoint_meta_data_to_solver()).

The setup neither uses the initial condition nor the boundary conditions. The checkpoint has to be written by a solver with the same unknowns, auxiliary variables, patch size and halo, over the same domain. The code reads the checkpoint at runtime, i.e. the files have to exist when the simulation starts, but not when it is generated or built.

The time stamps of all solvers have to match, i.e. a project with several solvers has to load checkpoints of all of them, written at the same time.

Definition at line 191 of file LoadCheckpoint.py.

Constructor & Destructor Documentation

◆ init()

exahype2.api.blockstructured.LoadCheckpoint.LoadCheckpoint.__init__	(		self,
		Solver	solver,
		str	filename = `"checkpoint"`,
		str	output_path = `"."`,
		float	time_stamp = `None`
	)

Parameters

solver	exahype2.api.Solver The solver whose data is loaded.
filename	str File name of the checkpoint as passed to WriteCheckpoint. The setup reads the index file output_path/filename-SolverName.peano-patch-file.
output_path	str Directory of the checkpoint, relative to the directory the simulation is started from, or absolute.
time_stamp	float or None Time stamp of the checkpoint to load. If None, the setup loads the latest checkpoint in the index file. Otherwise, it loads the checkpoint whose time stamp is closest to time_stamp.

Reimplemented from exahype2.api.Solver.Solver.GridConstruction.

Definition at line 240 of file LoadCheckpoint.py.

References exahype2.api.blockstructured.LoadCheckpoint.LoadCheckpoint.__init__().

Referenced by exahype2.api.blockstructured.LoadCheckpoint.LoadCheckpoint.__init__().

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