134 lines
4.9 KiB
Python
134 lines
4.9 KiB
Python
# Licensed to the Apache Software Foundation (ASF) under one
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# or more contributor license agreements. See the NOTICE file
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# distributed with this work for additional information
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# regarding copyright ownership. The ASF licenses this file
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# to you under the Apache License, Version 2.0 (the
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# "License"); you may not use this file except in compliance
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# with the License. You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing,
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# software distributed under the License is distributed on an
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# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
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# KIND, either express or implied. See the License for the
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# specific language governing permissions and limitations
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# under the License.
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# pylint: disable=invalid-name
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"""searchsorted operator"""
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from tvm.script.ir_builder import IRBuilder
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from tvm.script.ir_builder import tirx as T
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from . import te, utils
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from .math import cast
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def binary_search(sequence_offset, search_range, sorted_sequence, value, right, out_dtype):
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"""Common IR generator for binary search used by CPU and GPU backends.
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Must be called within an active IRBuilder context.
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`sorted_sequence` is a N-D Buffer whose innermost dimension we want to search for `value`,
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and `search_range` is the size of the innermost dimension. `sequence_offset` is
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a 1-D linearlized offset specifying which of innermost sequences to search.
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So the search for `value` is performed over
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`sorted_sequence[sequence_offset:(sequence_offset + search_range)]`.
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Note that we index N-D Buffer by 1-D linearlized indices.
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"""
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lo_buf = T.decl_buffer([1], out_dtype, scope="local")
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hi_buf = T.decl_buffer([1], out_dtype, scope="local")
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lo = T.buffer_proxy(lo_buf)
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hi = T.buffer_proxy(hi_buf)
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lo[0] = cast(0, out_dtype)
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hi[0] = cast(search_range, out_dtype)
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# Reference: pytorch/aten/src/ATen/native/cuda/Bucketization.cu
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def condition(current_val, target_val):
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if right:
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return current_val <= target_val
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return current_val < target_val
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with T.While(lo[0] < hi[0]):
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mid = lo[0] + (hi[0] - lo[0] >> 1)
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with T.If(condition(sorted_sequence[sequence_offset + mid], value)):
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with T.Then():
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lo[0] = mid + 1
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with T.Else():
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hi[0] = mid
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return lo[0]
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def searchsorted(sorted_sequence, values, right=False, out_dtype="int64"):
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"""Find indices where elements should be inserted to maintain order.
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If `sorted_sequence` is N-dimensional, the innermost dimension of
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`values` are searched in the corresponding dimension of `sorted_sequence`.
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Parameters
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----------
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sorted_sequence : te.Tensor
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N-D or 1-D Tensor, containing monotonically increasing sequence
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on the innermost dimension.
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values : te.Tensor
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N-D Tensor containing the search values. When `sorted_sequence` is 1-D,
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the shape of `values` can be arbitrary. Otherwise, ranks of `sorted_sequence`
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and `values` must be the same, and outer N-1 axes must have the same size.
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right : bool, optional
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Controls which index is returned if a value lands exactly on one of sorted values. If
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False, the index of the first suitable location found is given. If true, return the
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last such index. If there is no suitable index, return either 0 or N (where N is the
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size of the innermost dimension).
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dtype : string, optional
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The data type of the output indices.
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Returns
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-------
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indices : te.Tensor
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Tensor with same shape as values, representing the indices of
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elements of `values` if they are inserted in `sorted_sequence`.
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"""
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def ir(sorted_sequence, values, indices):
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with IRBuilder() as ib:
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sorted_sequence_shape = sorted_sequence.shape
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values_shape = values.shape
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num_search = utils.prod(values_shape)
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search_range = sorted_sequence_shape[-1]
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sorted_sequence = T.buffer_proxy(sorted_sequence)
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values = T.buffer_proxy(values)
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indices = T.buffer_proxy(indices)
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with T.parallel(0, num_search) as i:
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if len(sorted_sequence_shape) == 1:
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sequence_offset = 0
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else:
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sequence_id = i // values_shape[-1]
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sequence_offset = sequence_id * search_range
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indices[i] = binary_search(
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sequence_offset,
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search_range,
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sorted_sequence,
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values[i],
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right,
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out_dtype,
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)
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return ib.get()
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return te.extern(
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values.shape,
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[sorted_sequence, values],
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lambda ins, outs: ir(ins[0], ins[1], outs[0]),
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name="searchsorted",
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dtype=out_dtype,
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)
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