1 /* 2 * Copyright (C) 2018 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef FRAMEWORKS_ML_NN_INDEXED_SHAPE_WRAPPER_H 18 #define FRAMEWORKS_ML_NN_INDEXED_SHAPE_WRAPPER_H 19 20 #include "OperationsUtils.h" 21 22 namespace android { 23 namespace nn { 24 25 // A wrapper over a Shape class implementing some indexing logic for a wrapped 26 // shape. 27 // To get an offset for an element in a tensor from vector index, one needs to 28 // calculate strides first. This class removes the need to recalculate strides 29 // for every indexing and also provides some utility functions. 30 class IndexedShapeWrapper { 31 public: 32 IndexedShapeWrapper(const Shape& wrapped_shape); 33 34 // Calculates the next index in a lexicograpical order for a wrapped shape 35 // inplace. Only accepts valid index for a given shape as an input. 36 // Sets lastIndex to true if the received index was the last in a 37 // lexicographical order for a given shape. In this case, index stays the 38 // same. 39 bool nextIndexInplace(std::vector<uint32_t>* index, bool* lastIndex) const; 40 41 // Given an index as a vector with per-dimension indices, calculates an 42 // offset of the element in a flattened tensor. 43 bool indexToFlatIndex(const std::vector<uint32_t>& index, uint32_t* flatIndex) const; 44 45 // Same as indexToFlatIndex, only ignores first dimensions of an index if 46 // they are not present in the shape. Also ignores dimensions of a shape of 47 // size 1. 48 // For example: 49 // for shape: [3, 1, 2] 50 // and index: [4, 2, 5, 1] 51 // the function will ignore dimensions with indices 4 and 5 and set 52 // flatIndex to 5 as a result. 53 bool broadcastedIndexToFlatIndex(const std::vector<uint32_t>& index, uint32_t* flatIndex) const; 54 55 private: 56 const Shape* const shape; 57 std::vector<uint32_t> strides; 58 59 bool isValid(const std::vector<uint32_t>& index) const; 60 }; 61 62 } // namespace nn 63 } // namespace android 64 65 #endif // FRAMEWORKS_ML_NN_INDEXED_SHAPE_WRAPPER_H 66
