Open3D (C++ API)  0.18.0+252c867
InvertNeighborsList.h
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1 // ----------------------------------------------------------------------------
2 // - Open3D: www.open3d.org -
3 // ----------------------------------------------------------------------------
4 // Copyright (c) 2018-2023 www.open3d.org
5 // SPDX-License-Identifier: MIT
6 // ----------------------------------------------------------------------------
7 
8 #pragma once
9 
10 #include <tbb/parallel_for.h>
11 
12 #include "open3d/core/Atomic.h"
14 
15 namespace open3d {
16 namespace ml {
17 namespace impl {
18 
70 template <class TIndex, class TAttr>
71 void InvertNeighborsListCPU(const TIndex* const inp_neighbors_index,
72  const TAttr* const inp_neighbors_attributes,
73  const int num_attributes_per_neighbor,
74  const int64_t* const inp_neighbors_row_splits,
75  const size_t inp_num_queries,
76  TIndex* out_neighbors_index,
77  TAttr* out_neighbors_attributes,
78  const size_t index_size,
79  int64_t* out_neighbors_row_splits,
80  const size_t out_num_queries) {
81  using namespace open3d::utility;
82 
83  std::vector<uint32_t> tmp_neighbors_count(out_num_queries + 1, 0);
84 
85  // count how often an idx appears in inp_neighbors_index
86  tbb::parallel_for(tbb::blocked_range<size_t>(0, index_size),
87  [&](const tbb::blocked_range<size_t>& r) {
88  for (size_t i = r.begin(); i != r.end(); ++i) {
89  TIndex idx = inp_neighbors_index[i];
90  core::AtomicFetchAddRelaxed(
91  &tmp_neighbors_count[idx + 1], 1);
92  }
93  });
94 
95  InclusivePrefixSum(&tmp_neighbors_count[0],
96  &tmp_neighbors_count[tmp_neighbors_count.size()],
97  out_neighbors_row_splits);
98 
99  memset(tmp_neighbors_count.data(), 0,
100  sizeof(uint32_t) * tmp_neighbors_count.size());
101 
102  // fill the new index vector
103  tbb::parallel_for(
104  tbb::blocked_range<size_t>(0, inp_num_queries),
105  [&](const tbb::blocked_range<size_t>& r) {
106  for (size_t i = r.begin(); i != r.end(); ++i) {
107  TIndex query_idx = i;
108 
109  size_t begin_idx = inp_neighbors_row_splits[i];
110  size_t end_idx = inp_neighbors_row_splits[i + 1];
111  for (size_t j = begin_idx; j < end_idx; ++j) {
112  TIndex neighbor_idx = inp_neighbors_index[j];
113 
114  size_t list_offset =
115  out_neighbors_row_splits[neighbor_idx];
116  size_t item_offset = core::AtomicFetchAddRelaxed(
117  &tmp_neighbors_count[neighbor_idx], 1);
118  out_neighbors_index[list_offset + item_offset] =
119  query_idx;
120 
121  if (inp_neighbors_attributes) {
122  TAttr* attr_ptr =
123  out_neighbors_attributes +
124  num_attributes_per_neighbor *
125  (list_offset + item_offset);
126  for (int attr_i = 0;
127  attr_i < num_attributes_per_neighbor;
128  ++attr_i) {
129  attr_ptr[attr_i] = inp_neighbors_attributes
130  [num_attributes_per_neighbor * j +
131  attr_i];
132  }
133  }
134  }
135  }
136  });
137 }
138 
139 } // namespace impl
140 } // namespace ml
141 } // namespace open3d
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Definition: K4aPlugin.cpp:548
void InvertNeighborsListCPU(const TIndex *const inp_neighbors_index, const TAttr *const inp_neighbors_attributes, const int num_attributes_per_neighbor, const int64_t *const inp_neighbors_row_splits, const size_t inp_num_queries, TIndex *out_neighbors_index, TAttr *out_neighbors_attributes, const size_t index_size, int64_t *out_neighbors_row_splits, const size_t out_num_queries)
Definition: InvertNeighborsList.h:71
Definition: Dispatch.h:91
void InclusivePrefixSum(const Tin *first, const Tin *last, Tout *out)
Definition: ParallelScan.h:71
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