Particle Sorter

class ParticleSorter

A helper class to sort particles according to their positions following a certain rule. This rule can be a morton hash, so the particle positions are sorted to follow a Z-order curve, a cell hash, particle ID…

template<class HashIterator>
void updateOrderWithCustomHash(HashIterator &hasher, uint N, uint maxHash = std::numeric_limits<uint>::max(), cudaStream_t st = 0);

Sets the current sorting according to the input hashes. The maximum possible hash (does not have to be included in the list) can be provided, which will improve performance.

template<class CellHasher = Sorter::MortonHash, class InputIterator>
void updateOrderByCellHash(InputIterator pos, uint N, Box box, int3 cellDim, cudaStream_t st = 0);

Sets the current sorting using the linear index of the cell of the given positions

void updateOrderById(int *id, int N, cudaStream_t st = 0);

Sets the current sorting using the input list of ids as hashes

template<class InputIterator, class OutputIterator>
void applyCurrentOrder(InputIterator d_property_unsorted, OutputIterator d_property_sorted, int N, cudaStream_t st = 0);

Applies the latest updated order to some input vector. WARNING: _unsorted and _sorted cannot be aliased!

int *getSortedIndexArray(int N);

uint *getSortedHashes();

Returns the current stored sorted hashes.

int *getIndexArrayById(int *id, int N, cudaStream_t st = 0);

Sort the sequence 0:N using a copy of the input id array as keys.

Example

//Create an instance of ParticleSorter:
ParticleSorter ps;
//Update/create a sorted index list from the positions using a certain hash
ps.updateOrderByHash<Sorter::MortonHash>(pos, numberParticles, BoxSize, cudaStream);
//Apply new order to some array
ps.applyCurrentOrder(array_in, array_out, numberParticles, cudaStream);

//Order the id array (without changing it) as keys and a 0..numberparticles array as values,
//return this device array. It does not affect the current order.
ps.getIndexArrayById(id, numberParticles, cudaStream);