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submission 67845

rex_cz · python · License unknown
Kernel source · 64 lines ↓

Use it

Vendorable · source mirrored · license unknownView source →

No package. Vendor the mirrored source: 64 lines, June 9 Researcher Reciprocity License v1.0.

a.py
curl "https://kernelindex.com/api/v1/implementations/kernelbot-grayscale-v2-67845?include=source"
interfacepython
Compatibility
measured onNVIDIA H100
declared hardwareNVIDIA H100
architecturessm_90
dtypesfp32

Benchmark evidence

1 measurement across 1 GPU, fastest first.

Operation / workload
Hardware
Latency
Rank
Observed
RGB to grayscalesuite of 6 cases
NVIDIA H100
1.39ms
#28 of 36
2025-11-08
Run →

Reported · How evidence levels are derived →

Source and license

sourceavailable
revision digestsha256:e58122b5e959dc8115d0ebd4fae19140f9ab10a467742a5d88a02813ecc46848
license declaredunknown
license concludedunknown
authorsrex_cz
imported2026-08-15

Techniques

Extracted from the mirrored source by pattern, never inferred. Each row cites its line.

num-warps = 4num_warps=4,
stages = 1num_stages=1,

Kernel source

a.py64 lines
#!POPCORN leaderboard grayscale_v2

from task import input_t, output_t
from utils import DeterministicContext
import triton
import triton.language as tl


@triton.jit
def _grayscale_kernel(
    rgb_ptr,
    output_ptr,
    width: tl.int32,
    stride_h: tl.int32,
    stride_w: tl.int32,
    stride_c: tl.int32,
    out_stride_h: tl.int32,
    out_stride_w: tl.int32,
    BLOCK_SIZE: tl.constexpr,
):
    pid = tl.program_id(0)

    offsets = pid * BLOCK_SIZE + tl.arange(0, BLOCK_SIZE)

    rows = offsets // width
    cols = offsets % width

    rgb_index = rows * stride_h + cols * stride_w

    r = tl.load(rgb_ptr + rgb_index + 0 * stride_c)
    g = tl.load(rgb_ptr + rgb_index + 1 * stride_c)
    b = tl.load(rgb_ptr + rgb_index + 2 * stride_c)

    grayscale = 0.2989 * r + 0.5870 * g + 0.1140 * b

    out_index = rows * out_stride_h + cols * out_stride_w
    tl.store(output_ptr + out_index, grayscale)


def custom_kernel(data: input_t) -> output_t:
    with DeterministicContext():
        rgb, output = data
        height, width, channels = rgb.shape
        if channels != 3:
            raise ValueError(f"Expected last dimension to be 3, got {channels}")

        BLOCK_SIZE = 1024

        grid = (triton.cdiv(height * width, BLOCK_SIZE),)

        _grayscale_kernel[grid](
            rgb,
            output,
            width,
            rgb.stride(0),
            rgb.stride(1),
            rgb.stride(2),
            output.stride(0),
            output.stride(1),
            BLOCK_SIZE=BLOCK_SIZE,
            num_warps=4,
            num_stages=1,
        )
        return output
scrolls · 64 lines total

Source code from GPU Mode and the KernelBot dataset · June 9 Researcher Reciprocity License v1.0

Changes from previous submission

Against this author's previous submission submission 67844.

  ⋯ 58 unchanged lines
              output.stride(1),
              BLOCK_SIZE=BLOCK_SIZE,
              num_warps=4,
-             num_stages=2,
+             num_stages=1,
          )
          return output
   No newline at end of file

Best evidence level for this revision: reported

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