A gravitational simulation in progress. More...

#include <orrery/sim/simulation.hpp>

Public Member Functions
	Simulation (core::ParticleData particles, std::unique_ptr< solvers::ForceSolver > solver, std::unique_ptr< integrators::Integrator > integrator, core::Real timestep, std::unique_ptr< backend::Executor > executor=nullptr, std::unique_ptr< RunOutput > output=nullptr)
	Take ownership of a configuration and the machinery to advance it.
	Simulation (const Simulation &)=delete
Simulation &	operator= (const Simulation &)=delete
	Simulation (Simulation &&) noexcept
Simulation &	operator= (Simulation &&) noexcept
void	step ()
	Advance by one step and count it.
void	run (core::Index steps)
	Record the current state, then take steps steps, recording as the output asks.
void	restore (core::ParticleData particles, core::Index step, bool accelerations_are_current=false)
	Replace the state and the step counter, as a resume does.
core::Index	step_index () const noexcept
core::Real	time () const noexcept
	The simulated time, step * timestep.
core::Real	timestep () const noexcept
const core::ParticleData &	particles () const noexcept
const solvers::ForceSolver &	solver () const noexcept
const integrators::Integrator &	integrator () const noexcept
core::Diagnostics	measure () const
	Measure the conserved quantities of the current state.

Detailed Description

A gravitational simulation in progress.

Constructor & Destructor Documentation

◆ Simulation()

orrery::sim::Simulation::Simulation	(	core::ParticleData	particles,
		std::unique_ptr< solvers::ForceSolver >	solver,
		std::unique_ptr< integrators::Integrator >	integrator,
		core::Real	timestep,
		std::unique_ptr< backend::Executor >	executor = nullptr,
		std::unique_ptr< RunOutput >	output = nullptr )

Take ownership of a configuration and the machinery to advance it.

executor may be null, and is only held so that it outlives the solver that refers to it. output may be null, which is a run that computes and records nothing and is what most of the test suite wants.

Establishes the acceleration invariant, which costs one force evaluation.

Member Function Documentation

◆ step()

void orrery::sim::Simulation::step ( )

Advance by one step and count it.

Does not record anything. run is what drives the output, and a caller that wants both writes the loop itself.

◆ run()

void orrery::sim::Simulation::run ( core::Index steps )

Record the current state, then take steps steps, recording as the output asks.

The initial state is recorded before the first step, so that a trajectory begins at the configuration the run started from rather than one step into it, and a diagnostics file has a row to be relative to.

◆ restore()

void orrery::sim::Simulation::restore	(	core::ParticleData	particles,
		core::Index	step,
		bool	accelerations_are_current = false )

Replace the state and the step counter, as a resume does.

The particle count may differ from the current one. Re-establishes the acceleration invariant from the state given rather than trusting the accelerations in it, unless accelerations_are_current says they came from a checkpoint and are already the accelerations at these positions, in which case they are kept exactly. That distinction is the whole of bitwise resume: recomputing would give the same answer for every solver in this project and is not guaranteed to for one added later (ADR-0032).

◆ measure()

core::Diagnostics orrery::sim::Simulation::measure ( ) const

nodiscard

Measure the conserved quantities of the current state.

Softened with whatever the solver softens with, asked of the solver rather than stored beside it, for the reason ADR-0008 gives: a potential energy computed with a different softening from the force kernel turns the conservation result into a measurement of the mismatch.

Costs an N^2 pass and shares no code with the solver, which is what makes it evidence rather than a restatement. A run measures it every few hundred steps rather than every step.

The documentation for this class was generated from the following file:

orrery/sim/simulation.hpp

Public Member Functions