TCOLARGMIN

Tile Operation Diagram

TCOLARGMIN tile operation

Introduction

Get the row index of the minimum element for each column.

Math Interpretation

Let R = src.GetValidRow() and C = src.GetValidCol(). For 0 <= j < C:

\[ \mathrm{dst}_{0,j} = \underset{0 \le i < R}{\operatorname{argmin}} \; \mathrm{src}_{i,j} \]

Assembly Syntax

PTO-AS form: see docs/grammar/PTO-AS.md.

Synchronous form:

%dst = tcolargmin %src : !pto.tile<...> -> !pto.tile<...>

Lowering may introduce internal scratch tiles; the C++ intrinsic requires an explicit tmp operand.

IR Level 1 (SSA)

%dst = pto.tcolargmin %src, %tmp : (!pto.tile<...>, !pto.tile<...>) -> !pto.tile<...>

IR Level 2 (DPS)

pto.tcolargmin ins(%src, %tmp : !pto.tile_buf<...>, !pto.tile_buf<...>) outs(%dst : !pto.tile_buf<...>)

C++ Intrinsic

Declared in include/pto/common/pto_instr.hpp:

template <typename TileDataOut, typename TileDataIn, typename TileDataTmp, typename... WaitEvents>
PTO_INST RecordEvent TCOLARGMIN(TileDataOut& dst, TileDataIn& src, TileDataTmp& tmp, WaitEvents&... events);

Constraints

Implementation checks (NPU):

  • A2A3:
  • Tile location: dst and src must be TileType::Vec.
  • Tile layout of src: ND fractal (isRowMajor and SLayout::NoneBox).
  • Tile layout of dst: ND fractal (isRowMajor and SLayout::NoneBox).
  • Source data types: half, float, uint16_t, uint32_t.
  • Destination data types: uint32_t or int32_t.
  • tmp data type must be consistent with src data type.
  • Compile-time check: src.ValidCol must be 1 or -1 (dynamic).
  • Runtime valid checks:
    • srcValidCol != 0 and srcValidRow != 0.
    • dstValidRow == 1.
    • srcValidCol == dstValidCol.
  • A5:
  • Tile location: dst and src must be TileType::Vec.
  • Tile layout of src: ND fractal (isRowMajor and SLayout::NoneBox).
  • Tile layout of dst: ND fractal (isRowMajor and SLayout::NoneBox).
  • Source data types: int8_t, uint8_t, int16_t, uint16_t, int32_t, uint32_t, half, float.
  • Destination data types: uint32_t or int32_t.
  • Compile-time check: src.ValidCol must be 1 or -1 (dynamic).
  • Runtime valid checks:
    • srcValidCol != 0 and srcValidRow != 0.
    • dstValidRow == 1.
    • srcValidCol == dstValidCol.
  • tmp temporary tile is not used, only for compatibility.

About temporary tile tmp for A2A3

  • tmp is always used in the A2A3 implementation as scratch space for intermediate results (current index, argmin index, and current min elements).
  • tmp tile's data type must be the same as src's data type.
  • tmp tile is organized into three regions within a single row:
  • Region 0 ([0, tmpGapEles)): current row index counter (incremented per row).
  • Region 1 ([tmpGapEles, 2 * tmpGapEles)): current minimum elements for comparison.
  • Region 2 ([2 * tmpGapEles, 3 * tmpGapEles)): argmin index result (before final conversion to dst).
  • tmpGapEles is determined as follows:
  • When srcValidCol >= elemPerRpt: tmpGapEles = elemPerRpt.
  • When srcValidCol < elemPerRpt: tmpGapEles = ceil(srcValidCol / elemPerBlock) * elemPerBlock.
  • Simply set tmp tile size the same as src when src is small, or calculate the required stride based on src's validCol using the following formula:
repeats = ceil(validCol / elementPerRepeat)
stride = ceil(repeats * 2 / elementPerBlock) * elementPerBlock + ceil(repeats / elementPerBlock) * elementPerBlock

About temporary tile tmp for A5

  • tmp temporary tile is not used in the A5 implementation. The A5 uses vector register-based computation (__VEC_SCOPE__) and does not require scratch tile storage.
  • tmp is retained in the C++ intrinsic signature solely for API compatibility with A2A3.

Examples

Auto

#include <pto/pto-inst.hpp>

using namespace pto;

void example_auto() {
  using SrcT = Tile<TileType::Vec, float, 16, 256, BLayout::RowMajor, -1, -1>;
  using DstT = Tile<TileType::Vec, uint32_t, 1, 256, BLayout::RowMajor, -1, -1>;
  using TmpT = Tile<TileType::Vec, float, 1, 32, BLayout::RowMajor, -1, -1>;
  SrcT src(16, 255);
  DstT dst(1, 255);
  TmpT tmp(1, 32);
  TCOLARGMIN(dst, src, tmp);
}

Manual

#include <pto/pto-inst.hpp>

using namespace pto;

void example_manual() {
  using SrcT = Tile<TileType::Vec, float, 16, 256, BLayout::RowMajor, -1, -1>;
  using DstT = Tile<TileType::Vec, uint32_t, 1, 256, BLayout::RowMajor, -1, -1>;
  using TmpT = Tile<TileType::Vec, float, 1, 32, BLayout::RowMajor, -1, -1>;
  SrcT src(16, 255);
  DstT dst(1, 255);
  TmpT tmp(1, 32);
  TASSIGN(src, 0x0);
  TASSIGN(dst, 0x1000);
  TASSIGN(tmp, 0x2000);
  TCOLARGMIN(dst, src, tmp);
}

ASM Form Examples

Auto Mode

# Auto mode: compiler/runtime-managed placement and scheduling.
%dst = pto.tcolargmin %src, %tmp : (!pto.tile<...>, !pto.tile<...>) -> !pto.tile<...>

Manual Mode

# Manual mode: bind resources explicitly before issuing the instruction.
# Optional for tile operands:
# pto.tassign %arg0, @tile(0x1000)
# pto.tassign %arg1, @tile(0x2000)
%dst = pto.tcolargmin %src, %tmp : (!pto.tile<...>, !pto.tile<...>) -> !pto.tile<...>

PTO Assembly Form

%dst = tcolargmin %src : !pto.tile<...> -> !pto.tile<...>
# IR Level 2 (DPS)
pto.tcolargmin ins(%src, %tmp : !pto.tile_buf<...>, !pto.tile_buf<...>) outs(%dst : !pto.tile_buf<...>)

- [x] Write tcolargmin English documentation (docs/isa/TCOLARGMIN.md) - [ ] Write tcolargmin Chinese documentation (docs/isa/TCOLARGMIN_zh.md)