evolution::dg::AtomicInboxBoundaryData< Dim > Struct Template Reference

Holds the data in the different directions for the nodegroup DgElementArray implementation. More...

#include <AtomicInboxBoundaryData.hpp>

Public Types
using	stored_type = evolution::dg::BoundaryData< Dim >

Public Member Functions
	AtomicInboxBoundaryData (const AtomicInboxBoundaryData &)=delete
AtomicInboxBoundaryData &	operator= (const AtomicInboxBoundaryData &)=delete
	AtomicInboxBoundaryData (AtomicInboxBoundaryData &&rhs) noexcept
AtomicInboxBoundaryData &	operator= (AtomicInboxBoundaryData &&) noexcept=delete
void	collect_messages ()
bool	set_missing_messages (size_t count)
void	pup (PUP::er &p)

Static Public Member Functions
static size_t	index (const DirectionalId< Dim > &directional_id)

Public Attributes
std::array< Parallel::StaticSpscQueue< std::tuple<::TimeStepId, stored_type, DirectionalId< Dim > >, 20 >, maximum_number_of_neighbors(Dim)>	boundary_data_in_directions {}
std::map< TimeStepId, DirectionalIdMap< Dim, stored_type > >	messages {}
std::atomic_int	missing_messages {}
int	processed_messages {}
int	passed_missing_messages {}

Detailed Description

template<size_t Dim>
struct evolution::dg::AtomicInboxBoundaryData< Dim >

Holds the data in the different directions for the nodegroup DgElementArray implementation.

The reason for this class is to reduce contention between cores and to allow the use of a Single-Producer-Single-Consumer (SPSC) queue instead of an MPMC queue. This has significant performance improvements since it drastically reduces contention.

Warning

Only AtomicInboxBoundaryData with zero messages can be move constructed or serialized. This is necessary in order to be able to serialize a std::unordered_map<Key,AtomicInboxBoundaryData>.

Member Function Documentation

collect_messages()

template<size_t Dim>

void evolution::dg::AtomicInboxBoundaryData< Dim >::collect_messages

(

)

Moves data from the SPSC queues into the messages map.

index()

template<size_t Dim>

static size_t evolution::dg::AtomicInboxBoundaryData< Dim >::index ( const DirectionalId< Dim > &  directional_id )

static

Computes the 1d index into the boundary_data_in_directions array for a specific directional_id that has been re-oriented using the OrientationMap to be put in the same block frame as the element that is receiving the data (i.e. that whose inbox this is being inserted into).

The hash is computed as

\begin{align} 2^D d + 2^{D-1} s + e \end{align}

where \(D\) is the number of spatial dimensions, \(d\) is the logical dimension of the direction to the neighbor from the element whose inbox this is, \(s\) is the side in the logical dimension \(d\) with a value of 1 for upper and 0 for lower, and \(e\) is a hash of the index of the SegmentId's of the neighbor's ElementId for the dimensions other than \(d\). In particular: for \(d=1\), \(e\) is 0 (1) if the SegmentId index along the face is even (odd); and for \(d = 3\) \(e\) is 0 (1, 2, 3) if the SegmentId indices along the face are both even (lower dim odd, higher dim odd, both dims odd). The element segment hash is computed as the logical and of the SegmentID's index in that direction, left shifted by which direction on the face it is.

set_missing_messages()

template<size_t Dim>

bool evolution::dg::AtomicInboxBoundaryData< Dim >::set_missing_messages

(

size_t

count

)

Set a lower bound on the number of messages required for the algorithm to make progress since the most recent call to collect_messages. After that number of new messages have been received, BoundaryCorrectionAndGhostCellsInbox will restart the algorithm.

Returns: whether enough messages have been received.

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

• src/Evolution/DiscontinuousGalerkin/AtomicInboxBoundaryData.hpp