Create track initializers on device from secondary particles. More...

#include <ExtendFromSecondariesAction.hh>

Inheritance diagram for celeritas::ExtendFromSecondariesAction:

[legend]

Public Member Functions
	ExtendFromSecondariesAction (ActionId id)
	Construct with explicit Id.

Action interface
ID of the action
ActionId	action_id () const final
	Short name for the action.

std::string_view	label () const final
	Short name for the action.

std::string_view	description () const final
	Get a long description of the action.

StepActionOrder	order () const final
	Dependency ordering of the action.

ExplicitAction interface
void	step (CoreParams const &, CoreStateHost &) const final
	Execute the action with host data.

void	step (CoreParams const &, CoreStateDevice &) const final
	Execute the action with device data.

BeginRunAction interface
void	begin_run (CoreParams const &, CoreStateHost &) final
	Warm up asynchronous allocation. More...

void	begin_run (CoreParams const &, CoreStateDevice &) final
	Warm up asynchronous allocation. More...

Public Member Functions inherited from celeritas::StepActionInterface< P, S >
virtual void	step (P const &, S< MemSpace::host > &) const =0
	Execute the action with host data.

virtual void	step (P const &, S< MemSpace::device > &) const =0
	Execute the action with device data.

Public Member Functions inherited from celeritas::ActionInterface
virtual	~ActionInterface () noexcept=0
	Default destructor.

Public Member Functions inherited from celeritas::BeginRunActionInterface< P, S >
virtual void	begin_run (P const &, S< MemSpace::host > &)=0
	Set host data at the beginning of a run.

virtual void	begin_run (P const &, S< MemSpace::device > &)=0
	Set device data at the beginning of a run.

Additional Inherited Members
Public Types inherited from celeritas::ActionTypeTraits< P, S >
using	CoreParams = P

using	CoreStateHost = S< MemSpace::host >

using	CoreStateDevice = S< MemSpace::device >

using	SpanCoreStateHost = Span< S< MemSpace::host > *const >

using	SpanCoreStateDevice = Span< S< MemSpace::device > *const >

Protected Member Functions inherited from celeritas::ActionInterface
	ActionInterface ()=default

	CELER_DEFAULT_COPY_MOVE (ActionInterface)

Detailed Description

Create track initializers on device from secondary particles.

Secondaries produced by each track are ordered arbitrarily in memory, and the memory may be fragmented if not all secondaries survived cutoffs. For example, after the interactions have been processed and cutoffs applied, the track states and their secondaries might look like the following (where 'X' indicates a track or secondary that did not survive):

 thread ID   | 0   1 2           3       4   5 6           7       8   9
 track ID    | 10  X 8           7       X   5 4           X       2   1
 secondaries | [X]   [X, 11, 12] [13, X] [X]   [14, X, 15] [X, 16] [X]

Because the order in which threads receive a chunk of memory from the secondary allocator is nondeterministic, the actual ordering of the secondaries in memory is unpredictable; for instance:

secondary storage | [X, 13, X, X, 11, 12, X, X, 16, 14, X, 15, X]

When track initializers are created from secondaries, they are ordered by thread ID to ensure reproducibility. If a track that produced secondaries has died (e.g., thread ID 7 in the example above), one of its secondaries is immediately used to fill that track slot:

 thread ID   | 0   1 2           3       4   5 6           7       8   9
 track ID    | 10  X 8           7       X   5 4           16      2   1
 secondaries | [X]   [X, 11, 12] [13, X] [X]   [14, X, 15] [X, X]  [X]

This way, the geometry state is reused rather than initialized from the position (which is expensive). This also prevents the geometry state from being overwritten by another track's secondary, so if the track produced multiple secondaries, the rest are still able to copy the parent's state.

Track initializers are created from the remaining secondaries and are added to the back of the vector. The thread ID of each secondary's parent is also stored, so any new tracks initialized from secondaries produced in this step can copy the geometry state from the parent. The indices of the empty slots in the track vector are identified and stored as a sorted vector of vacancies.

 track initializers | 11 12 13 14 15
 parent             | 2  2  3  6  6
 vacancies          | 1  4

Member Function Documentation

◆ begin_run() [1/2]

void celeritas::ExtendFromSecondariesAction::begin_run	(	CoreParams const &	,
		CoreStateDevice &	core_state
	)

final

Warm up asynchronous allocation.

This just calls MallocAsync before the first step, since it's used by detail::remove_if_alive under the hood.

◆ begin_run() [2/2]

void celeritas::ExtendFromSecondariesAction::begin_run	(	CoreParams const &	,
		CoreStateHost &
	)

inlinefinal

Warm up asynchronous allocation.

This just calls MallocAsync before the first step, since it's used by detail::remove_if_alive under the hood.

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

Public Member Functions

Additional Inherited Members

Detailed Description

Member Function Documentation

◆ begin_run() [1/2]

◆ begin_run() [2/2]