contact_preprocessing.hpp File Reference

dem — portable (Kokkos) contact->manifold reduction, replacing the thrust-based reduce_contacts_to_manifolds() in contact_preprocessing.cu. More...

#include <cstdint>
#include <Kokkos_Core.hpp>
#include <Kokkos_Sort.hpp>
#include "dem_portable.hpp"

Go to the source code of this file.

Classes
struct	peclet::dem::ContactC
	Portable mirror of ParticleSystem.cuh ContactConstraint (the fields this reduction touches). More...
struct	peclet::dem::ManifoldC
	Portable mirror of ManifoldConstraint. More...

Namespaces
namespace	peclet
namespace	peclet::dem

Typedefs
using	peclet::dem::CpExec = Kokkos::DefaultExecutionSpace
using	peclet::dem::CpMem = CpExec::memory_space

Functions
std::uint64_t	peclet::dem::pairKey (const ContactC &c)
	Canonical pair key: (min<<32)|max, or (idA<<32)|0xFFFFFFFF for a boundary (idB<0) contact.
void	peclet::dem::decodeKey (std::uint64_t key, int &bodyA, int &bodyB)
	Decode the canonical (bodyA, bodyB) from a pair key (bodyB = -1 for boundary).
ManifoldC	peclet::dem::transformContact (const ContactC &c)
	Per-contact transform to a single-point manifold, aligned to the canonical pair.
int	peclet::dem::reduceContactsToManifoldsKokkos (Kokkos::View< const ContactC *, CpMem > contacts, int n, Kokkos::View< ManifoldC *, CpMem > outManifolds, Kokkos::View< int, CpMem > outCount)
	Reduce n contacts to manifolds (one per unique canonical pair).

Detailed Description

dem — portable (Kokkos) contact->manifold reduction, replacing the thrust-based reduce_contacts_to_manifolds() in contact_preprocessing.cu.

Same pipeline: key each contact by its canonical pair, group by key, and within a group sum the aligned normals / torque arms / lever arms and count the points. thrust::sort_by_key + reduce_by_key become Kokkos::Experimental::sort_by_key + a scan-based segmented reduction (atomic accumulation), so no thrust/cub. The per-contact math (ContactToManifold / TransformAndFilter) is reused verbatim as KOKKOS_INLINE_FUNCTION and is shared with the host reference in the test.

One intentional change vs the thrust version: a manifold's (bodyA,bodyB) is decoded determinist -ically from the pair key (canonical min/max, or (idA,-1) for boundary), rather than taken from the first contact of an unstably-sorted run. The summed quantities are commutative, so they are unaffected. Decoupled from ParticleSystemData (portable POD mirrors) for standalone validation.

Definition in file contact_preprocessing.hpp.