Aleph::CA::Block_Partition_2D Struct Reference

2D blocked partitioning into a grid of parts_y x parts_x. More...

#include <ca-tiling.H>

Static Public Member Functions
static constexpr Tile2D_Range	tile (const std::array< ca_size_t, 2 > &extents, const ca_size_t parts_y, const ca_size_t parts_x, const ca_size_t tile_index) noexcept
	Tile owned by tile_index over the parts_y * parts_x grid.
static constexpr std::array< ca_size_t, 2 >	factor_partitions (const std::array< ca_size_t, 2 > &extents, const ca_size_t parts) noexcept
	Pick a balanced (parts_y, parts_x) factorisation of parts.

Detailed Description

2D blocked partitioning into a grid of parts_y x parts_x.

Each tile is balanced along both axes, mirroring the structure of Synchronous_Engine's Tile<W,H> schedule. Useful when a lattice is wide enough that splitting along axis 0 alone leaves rows so long that they exceed the L2 working set.

Tiles are enumerated row-major over the tile grid:

tile_index = ty * parts_x + tx

with ty in [0, parts_y) and tx in [0, parts_x).

Definition at line 257 of file ca-tiling.H.

Member Function Documentation

factor_partitions()

static constexpr std::array< ca_size_t, 2 > Aleph::CA::Block_Partition_2D::factor_partitions ( const std::array< ca_size_t, 2 > &  extents, const ca_size_t  parts  )

inlinestaticconstexprnoexcept

Pick a balanced (parts_y, parts_x) factorisation of parts.

The factorisation prefers shapes whose aspect ratio matches the lattice aspect ratio: tall lattices get more parts_y, wide ones get more parts_x. The result is symmetric around sqrt(parts) when the lattice is roughly square.

Parameters

[in]	extents	2D lattice extents.
[in]	parts	total number of partitions.

Returns

{parts_y, parts_x} such that parts_y * parts_x == parts.

Definition at line 292 of file ca-tiling.H.

References Aleph::blossom_maximum_cardinality_matching(), cols, Aleph::diff(), rows, and y.

Referenced by TEST().

tile()

static constexpr Tile2D_Range Aleph::CA::Block_Partition_2D::tile ( const std::array< ca_size_t, 2 > &  extents, const ca_size_t  parts_y, const ca_size_t  parts_x, const ca_size_t  tile_index  )

inlinestaticconstexprnoexcept

Tile owned by tile_index over the parts_y * parts_x grid.

Parameters

[in]	extents	2D lattice extents (rows, cols).
[in]	parts_y	number of partitions along axis 0.
[in]	parts_x	number of partitions along axis 1.
[in]	tile_index	linear tile index.

Returns

the rectangle covered by tile_index.

Definition at line 266 of file ca-tiling.H.

References Aleph::blossom_maximum_cardinality_matching(), and Aleph::CA::split_range_balanced().

Referenced by TEST().

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

• ca-tiling.H