zhanghang1989 commented on a change in pull request #10852: [MXNET-411] Add ROI Align URL: https://github.com/apache/incubator-mxnet/pull/10852#discussion_r189138585
########## File path: src/operator/contrib/roi_align.cc ########## @@ -0,0 +1,586 @@ +/* + * 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. + */ +/*! + * Copyright (c) 2018 by Contributors + * \file roi_align.cc + * \brief roi align operator + * \author Hang Zhang + * Adapted from Caffe2 +*/ +#include "./roi_align-inl.h" + + +namespace mxnet { +namespace op { + +template <typename T> +struct PreCalc { + int pos1; + int pos2; + int pos3; + int pos4; + T w1; + T w2; + T w3; + T w4; +}; + +template <typename T> +void pre_calc_for_bilinear_interpolate( + const int height, + const int width, + const int pooled_height, + const int pooled_width, + const int iy_upper, + const int ix_upper, + T roi_start_h, + T roi_start_w, + T bin_size_h, + T bin_size_w, + int roi_bin_grid_h, + int roi_bin_grid_w, + std::vector<PreCalc<T>>* pre_calc) { + int pre_calc_index = 0; + for (int ph = 0; ph < pooled_height; ph++) { + for (int pw = 0; pw < pooled_width; pw++) { + for (int iy = 0; iy < iy_upper; iy++) { + const T yy = roi_start_h + ph * bin_size_h + + static_cast<T>(iy + .5f) * bin_size_h / + static_cast<T>(roi_bin_grid_h); // e.g., 0.5, 1.5 + for (int ix = 0; ix < ix_upper; ix++) { + const T xx = roi_start_w + pw * bin_size_w + + static_cast<T>(ix + .5f) * bin_size_w / + static_cast<T>(roi_bin_grid_w); + + T x = xx; + T y = yy; + // deal with: inverse elements are out of feature map boundary + if (y < -1.0 || y > height || x < -1.0 || x > width) { + // empty + PreCalc<T> pc; + pc.pos1 = 0; + pc.pos2 = 0; + pc.pos3 = 0; + pc.pos4 = 0; + pc.w1 = 0; + pc.w2 = 0; + pc.w3 = 0; + pc.w4 = 0; + pre_calc->at(pre_calc_index) = pc; + pre_calc_index += 1; + continue; + } + + if (y <= 0) { + y = 0; + } + if (x <= 0) { + x = 0; + } + + int y_low = static_cast<int>(y); + int x_low = static_cast<int>(x); + int y_high; + int x_high; + + if (y_low >= height - 1) { + y_high = y_low = height - 1; + y = (T)y_low; + } else { + y_high = y_low + 1; + } + + if (x_low >= width - 1) { + x_high = x_low = width - 1; + x = (T)x_low; + } else { + x_high = x_low + 1; + } + + T ly = y - y_low; + T lx = x - x_low; + T hy = 1. - ly, hx = 1. - lx; + T w1 = hy * hx, w2 = hy * lx, w3 = ly * hx, w4 = ly * lx; + + // save weights and indeces + PreCalc<T> pc; + pc.pos1 = y_low * width + x_low; + pc.pos2 = y_low * width + x_high; + pc.pos3 = y_high * width + x_low; + pc.pos4 = y_high * width + x_high; + pc.w1 = w1; + pc.w2 = w2; + pc.w3 = w3; + pc.w4 = w4; + pre_calc->at(pre_calc_index) = pc; + + pre_calc_index += 1; + } + } + } + } +} + +template <typename T> +void ROIAlignForward( + const int nthreads, + const T* bottom_data, + const T& spatial_scale, + const int channels, + const int height, + const int width, + const int pooled_height, + const int pooled_width, + const int sampling_ratio, + const T* bottom_rois, + int roi_cols, + T* top_data) { + DCHECK(roi_cols == 4 || roi_cols == 5); + + int n_rois = nthreads / channels / pooled_width / pooled_height; + // (n, c, ph, pw) is an element in the pooled output + // can be parallelized using omp + int n; +#pragma omp parallel for private(n) \ +num_threads(engine::OpenMP::Get()->GetRecommendedOMPThreadCount()) + for (n = 0; n < n_rois; n++) { + int index_n = n * channels * pooled_width * pooled_height; + + // roi could have 4 or 5 columns + const T* offset_bottom_rois = bottom_rois + n * roi_cols; + int roi_batch_ind = 0; + if (roi_cols == 5) { + roi_batch_ind = offset_bottom_rois[0]; + offset_bottom_rois++; + } + + // Do not using rounding; this implementation detail is critical + T roi_start_w = offset_bottom_rois[0] * spatial_scale; + T roi_start_h = offset_bottom_rois[1] * spatial_scale; + T roi_end_w = offset_bottom_rois[2] * spatial_scale; + T roi_end_h = offset_bottom_rois[3] * spatial_scale; + + // Force malformed ROIs to be 1x1 + T roi_width = std::max(roi_end_w - roi_start_w, (T)1.); + T roi_height = std::max(roi_end_h - roi_start_h, (T)1.); + T bin_size_h = static_cast<T>(roi_height) / static_cast<T>(pooled_height); + T bin_size_w = static_cast<T>(roi_width) / static_cast<T>(pooled_width); + + // We use roi_bin_grid to sample the grid and mimic integral + int roi_bin_grid_h = (sampling_ratio > 0) + ? sampling_ratio + : ceil(roi_height / pooled_height); // e.g., = 2 + int roi_bin_grid_w = + (sampling_ratio > 0) ? sampling_ratio : ceil(roi_width / pooled_width); + + // We do average (integral) pooling inside a bin + const T count = roi_bin_grid_h * roi_bin_grid_w; // e.g. = 4 + + // we want to precalculate indeces and weights shared by all chanels, + // this is the key point of optimiation + std::vector<PreCalc<T>> pre_calc( + roi_bin_grid_h * roi_bin_grid_w * pooled_width * pooled_height); + pre_calc_for_bilinear_interpolate( + height, + width, + pooled_height, + pooled_width, + roi_bin_grid_h, + roi_bin_grid_w, + roi_start_h, + roi_start_w, + bin_size_h, + bin_size_w, + roi_bin_grid_h, + roi_bin_grid_w, + &pre_calc); + + int c; +#pragma omp parallel for private(c) \ Review comment: keeping this ? ---------------------------------------------------------------- This is an automated message from the Apache Git Service. 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