cuda::experimental::places::compute_block_owners

template<typename OwnerFn>
::std::vector<pos4> cuda::experimental::places::compute_block_owners(

OwnerFn &&owner_of,

size_t nblocks,

size_t block_size_bytes,

size_t elemsize,

size_t total_elems,

size_t probes,

localized_stats &stats

)

Decide the owner of each placement block by sampled majority vote.

For each block, probes elements are sampled (reproducibly: one seeded generator for the whole computation) and the most frequent owner wins. The majority vote is what tolerates partitions whose boundaries do not align with the block granularity: a block straddling two owners goes to the one owning most of it.

Parameters:

• owner_of – Callable mapping a linear element index to the pos4 of its owner in the grid

• nblocks – Number of placement blocks

• block_size_bytes – Size of a placement block in bytes (must be at least elemsize)

• elemsize – Size of one element in bytes (must be at least 1)

• total_elems – Total number of elements (probes are clipped to it)

• probes – Number of samples per block

• stats – Accumulates total/matching sample counts