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apache--tvm/python/tvm/topi/gpu/scatter_nd.py
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chore: import upstream snapshot with attribution
2026-07-13 13:36:25 +08:00

130 lines
5.8 KiB
Python

# Licensed to the Apache Software Foundation (ASF) under one
# or more contributor license agreements. See the NOTICE file
# distributed with this work for additional information
# regarding copyright ownership. The ASF licenses this file
# to you under the Apache License, Version 2.0 (the
# "License"); you may not use this file except in compliance
# with the License. You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing,
# software distributed under the License is distributed on an
# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
# KIND, either express or implied. See the License for the
# specific language governing permissions and limitations
# under the License.
# pylint: disable=invalid-name
# ruff: noqa: E741
"""scatter_nd related operators"""
import tvm
from tvm import te, tirx # hide redefinition of min and max
from tvm.script.ir_builder import IRBuilder
from tvm.script.ir_builder import tirx as T
from ..math import cast
from ..scatter import _verify_scatter_nd_inputs
from ..utils import ceil_div
def scatter_nd(data, indices, updates, mode):
"""GPU implementation of scatter_nd with explicit thread bindings."""
_verify_scatter_nd_inputs(data, indices, updates)
def gen_ir(data_ptr, indices_ptr, updates_ptr, out_ptr):
# pylint: disable=invalid-name
data = T.buffer_proxy(data_ptr)
indices = T.buffer_proxy(indices_ptr)
updates = T.buffer_proxy(updates_ptr)
out = T.buffer_proxy(out_ptr)
# We combine all the indices dimensions but the first one into a single
# dimension so we can iterate it in single loop instead of an arbitrary
# number of loops. We do the same thing for all the update dimensions.
fused_indices_dimension = 1
for i in indices_ptr.shape[1:]:
fused_indices_dimension *= i
fused_updates_dimension = 1
for i in updates_ptr.shape[len(indices_ptr.shape) - 1 :]:
fused_updates_dimension *= i
fused_shape = 1
for i in data_ptr.shape:
fused_shape *= i
max_threads = int(tvm.target.Target.current(allow_none=False).attrs["max_num_threads"])
with IRBuilder() as ib:
with T.seq_scope():
# Init
nthread_bx_init = cast(ceil_div(fused_shape, max_threads), "int32")
tx_init = te.thread_axis("threadIdx.x")
bx_init = te.thread_axis("blockIdx.x")
with T.frame_scope(
[
T.attr(bx_init, "thread_extent", nthread_bx_init),
T.attr(tx_init, "thread_extent", max_threads),
]
):
tid = bx_init * max_threads + tx_init
with T.If(tid < fused_shape):
with T.Then():
out[tid] = data[tid]
# Scatter
nthread_bx_scat = cast(ceil_div(fused_updates_dimension, max_threads), "int32")
tx_scat = te.thread_axis("threadIdx.x")
bx_scat = te.thread_axis("blockIdx.x")
with T.frame_scope(
[
T.attr(bx_scat, "thread_extent", nthread_bx_scat),
T.attr(tx_scat, "thread_extent", max_threads),
]
):
j = bx_scat * max_threads + tx_scat
with T.If(j < fused_updates_dimension):
with T.Then():
with T.serial(0, fused_indices_dimension) as i:
offset = fused_updates_dimension
index = j # x_M, .. x_{N-1} part of the index into out.
# Build up the indices[0, y_0, ..], ..,
# indices[M-1, y_0, ..] part of the index into out.
for l in reversed(range(indices_ptr.shape[0].value)):
# indices[l, y_0, ... y_{k-1}]
index += offset * indices[i + l * fused_indices_dimension]
offset *= data_ptr.shape[l]
if mode == "update":
out[index] = updates[i * fused_updates_dimension + j]
elif mode == "add":
out[index] += updates[i * fused_updates_dimension + j]
elif mode == "mul":
out[index] *= updates[i * fused_updates_dimension + j]
elif mode == "min":
out[index] = tirx.min(
out[index], updates[i * fused_updates_dimension + j]
)
elif mode == "max":
out[index] = tirx.max(
out[index], updates[i * fused_updates_dimension + j]
)
else:
raise NotImplementedError(
"scatter_nd mode not in [update, add, mul, min, max]:",
mode,
)
return ib.get()
out_buf = tirx.decl_buffer(data.shape, data.dtype, "out_buf", layout=None)
return te.extern(
[data.shape],
[data, indices, updates],
lambda ins, outs: gen_ir(ins[0], ins[1], ins[2], outs[0]),
dtype=data.dtype,
out_buffers=[out_buf],
name="scatter_nd.gpu",
tag="scatter_nd.gpu",
)