1/*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing,
13 * software distributed under the License is distributed on an
14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15 * KIND, either express or implied. See the License for the
16 * specific language governing permissions and limitations
17 * under the License.
18 */
19
20/*!
21 * \brief Softmax op constructions
22 * \file nn/flatten.h
23 */
24#ifndef TVM_TOPI_NN_FLATTEN_H_
25#define TVM_TOPI_NN_FLATTEN_H_
26
27#include <tvm/te/operation.h>
28#include <tvm/topi/detail/constant_utils.h>
29#include <tvm/topi/tags.h>
30
31#include <string>
32#include <vector>
33
34namespace tvm {
35namespace topi {
36namespace nn {
37
38using namespace tvm::te;
39
40/*!
41 * \brief Flattens the input tensor into a 2-D tensor by collapsing higher dimensions.
42 * This requires the input tensor to have constant sized dimensions.
43 *
44 * \param x The input tensor.
45 * \param name The name of the operation
46 * \param tag The tag to mark the operation
47 *
48 * \return A 2-D tensor.
49 */
50inline Tensor flatten(const Tensor& x, std::string name = "tensor", std::string tag = kInjective) {
51 auto ishape = x->shape;
52 PrimExpr dim = 1;
53 for (size_t i = 1; i < ishape.size(); ++i) {
54 dim = dim * ishape[i];
55 }
56
57 Array<PrimExpr> oshape({ishape[0], dim});
58
59 std::vector<PrimExpr> extra_shape;
60 for (size_t i = 1; i < ishape.size(); ++i) {
61 extra_shape.push_back(ishape[i]);
62 }
63 std::reverse(extra_shape.begin(), extra_shape.end());
64
65 return tvm::te::compute(
66 oshape,
67 [&](Var i, Var j) {
68 PrimExpr idx = j;
69 std::vector<PrimExpr> index;
70 for (auto s : extra_shape) {
71 index.push_back(indexmod(idx, s));
72 idx = indexdiv(idx, s);
73 }
74 index.push_back(i);
75 std::reverse(index.begin(), index.end());
76 return x(index);
77 },
78 name, tag);
79}
80
81} // namespace nn
82} // namespace topi
83} // namespace tvm
84#endif // TVM_TOPI_NN_FLATTEN_H_
85