TransientProblemInterface

class TransientProblemInterface

Interface for transient simulations.

Subclassed by godzilla::ExplicitProblemInterface, godzilla::ImplicitFENonlinearProblem

Public Types

enum class TimeScheme

Time stepping schemes.

Values:

enumerator BEULER

Backward Euler.

enumerator CN

Crank-Nicolson.

enumerator EULER

Forward Euler.

enumerator RK_2

Runge-Kutta 2 (midpoint)

enumerator HEUN

Heun’s.

enumerator SSP_RK_2

Strong stability preserving RK-2.

enumerator SSP_RK_3

Strong stability preserving RK-3.

Public Functions

void set_time_stepping_adaptor(TimeSteppingAdaptor *adaptor)

Set time stepping adaptivity using an adaptor class.

Parameters:

adaptor – Time stepping adaptor object

TimeSteppingAdaptor *get_time_stepping_adaptor() const

Get time stepping adaptor.

Returns:

Time stepping adaptor

TS get_ts() const

Get TS object.

Returns:

PETSc TS object

Real get_time_step() const

Get the current timestep size.

Returns:

the current timestep size

void set_time_step(Real dt) const

Allows one to reset the timestep at any time, useful for simple pseudo-timestepping codes.

Parameters:

dt – The size of the timestep

void set_max_time(Real max_time)

Sets the maximum (or final) time for time-stepping.

Parameters:

max_time – Final time to step to

Real get_max_time() const

Gets the maximum (or final) time for time-stepping.

Returns:

Final time to step to

void set_converged_reason(TSConvergedReason reason)

Sets the reason for handling the convergence.

Parameters:

reason – Converged reason

TSConvergedReason get_converged_reason() const

Gets the reason the time iteration was stopped.

NOTE: Can only be called after the call to solve() is complete.

Returns:

Converged reason

void set_scheme(TimeScheme scheme)

Set time-stepping scheme.

void set_scheme(const std::string &scheme_name)

Set time-stepping scheme.

std::string get_scheme() const

Get the name of time stepping scheme.

void set_time(Real t)

Set simulation time.

Parameters:

t – New simulation time

virtual void pre_step()

Called before the time step solve.

virtual void post_step()

Called after the time step is done solving.

virtual void pre_stage(Real stage_time)

Runs the user-defined pre-stage function.

Parameters:

stage_time – The absolute time of the current stage

virtual void post_stage(Real stage_time, Int stage_index, const std::vector<Vector> &Y)

Runs the user-defined post-stage function.

Parameters:

• stage_time – The absolute time of the current stage

• stage_index – Stage number

• Y – Array of vectors (of size = total number of stages) with the stage solutions

void compute_rhs(Real time, const Vector &x, Vector &F)

Compute right-hand side.

Parameters:

• time – Current time

• x – Solution at time time

• F – Right-hand side vector