Simulation¶

Introduction¶

Simulation is the top-level object of a μfem analysis. It owns the geometry, the physics models, the runner that drives execution, and the supporting managers used to query coefficients, collect reports, monitor metrics, and export fields.

A simulation is created through the Simulation.New factory, configured with a runner and one or more models, and then executed with run().

Creating a Simulation¶

import mufem

sim = mufem.Simulation.New("My Example", "data/geometry.mesh")

Simulation.New accepts:

Parameter	Description
`name`	Display name of the simulation.
`mesh_path`	Optional path to the mesh file. If omitted, load the mesh later via `sim.get_domain().load_mesh(...)`.

Lifecycle¶

A simulation runs in three phases:

Initialization — sim.initialize() prepares the domain, models, materials, and the initial solution. It is called automatically by sim.run() and rarely needs to be invoked directly.
Run — sim.run() hands control to the configured runner, which advances the simulation until it completes.
Reset — sim.reset() returns the runner to its starting state so the simulation can be replayed.

Accessors¶

The simulation exposes the managers that hold the rest of the state:

Method	Returns
`get_domain()`	The computational domain (mesh, regions).
`get_model_manager()`	Registry of the active physics models.
`get_coefficient_manager()`	Coefficient functions available as inputs to models.
`get_report_manager()`	Reports collected during the run.
`get_monitor_manager()`	Monitors emitted during the run.
`get_field_exporter()`	Field exporter for visualization output.
`get_runner()`	The currently configured runner.
`get_machine()`	Machine context (e.g. MPI process information).
`get_name()`	The simulation name.

Lifecycle Events¶

Components attach callbacks to Event instances so that work runs at well-defined points in the simulation lifecycle. The most common use is configuring the field exporter to write at run completion (see Runners and the field exporter documentation).

The built-in events are:

Event	Fires
`Event.Initialization`	Once after `sim.initialize()` completes.
`Event.RunCompletion`	Once when the runner's main loop finishes.
`Event.TimeStep`	At the end of each time step (unsteady runs).
`Event.Iteration`	At the end of each inner iteration.

Two policies are available to thin out a stream of events:

# Fire on every 10th time step.
every_ten = mufem.Event.TimeStep(10)

# Fire when the simulation passes specific times.
checkpoints = mufem.Event.AtTimes([0.1, 0.5, 1.0])

Example¶

import mufem

sim = mufem.Simulation.New("My Example", "data/geometry.mesh")

runner = mufem.SteadyRunner(total_iterations=3)
sim.set_runner(runner)

# Configure models, materials, exports here ...

sim.run()