| #------------------------------------------------------------- |
| # |
| # 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. |
| # |
| #------------------------------------------------------------- |
| args <- commandArgs(TRUE) |
| library("Matrix") |
| imgSize=as.integer(args[1]) |
| numImg=as.integer(args[2]) |
| numChannels=as.integer(args[3]) |
| numFilters=as.integer(args[4]) |
| filterSize=as.integer(args[5]) |
| stride=as.integer(args[6]) |
| pad=as.integer(args[7]) |
| P=as.integer(args[8]) |
| Q=as.integer(args[9]) |
| |
| # Assumption: NCHW image format |
| w=matrix(seq(1, numFilters*numChannels*filterSize*filterSize), numFilters, numChannels*filterSize*filterSize, byrow=TRUE) |
| dout=matrix(seq(1, numImg*numFilters*P*Q), numImg, numFilters*P*Q, byrow=TRUE) |
| |
| if(as.logical(args[11])) { |
| zero_mask = (w - mean(w)) > 0 |
| w = w * zero_mask |
| } else { |
| w = w - mean(w) |
| } |
| if(as.logical(args[12])) { |
| zero_mask = (dout - mean(dout)) > 0 |
| dout = dout * zero_mask |
| } else { |
| dout = dout - mean(dout) |
| } |
| col2im <- function(img_cols, C, Hin, Win, Hf, Wf, |
| strideh, stridew, reduction) { |
| |
| Hout = as.integer((Hin - Hf) / strideh + 1) |
| Wout = as.integer((Win - Wf) / stridew + 1) |
| |
| img = matrix(0, C, Hin*Win, byrow=TRUE) # zeros |
| for (hout in 1:Hout) { # all output rows |
| hin = (hout-1) * strideh + 1 |
| for (wout in 1:Wout) { # all output columns |
| win = (wout-1) * stridew + 1 |
| # Extract a local patch of the input image corresponding spatially to the filter sizes. |
| img_patch = matrix(img_cols[,(hout-1)*Wout + wout], C, Hf*Wf, byrow=TRUE) # zeros |
| for (c in 1:C) { # all channels |
| img_patch_slice = matrix(img_patch[c,], Hf, Wf, byrow=TRUE) # reshape |
| if (reduction == "add") { |
| img_slice = matrix(0, Hin, Win, byrow=TRUE) |
| img_slice[hin:(hin+Hf-1), win:(win+Wf-1)] = img_patch_slice |
| img[c,] = img[c,] + matrix(t(img_slice), 1, Hin*Win) |
| } else { |
| img_slice = matrix(img[c,], Hin, Win, byrow=TRUE) |
| img_slice[hin:(hin+Hf-1), win:(win+Wf-1)] = img_patch_slice |
| img[c,] = matrix(t(img_slice), 1, Hin*Win) |
| } |
| } |
| } |
| } |
| img |
| } |
| |
| unpad_image <- function(img_padded, Hin, Win, padh, padw) { |
| C = nrow(img_padded) |
| img = matrix(0, C, Hin*Win, byrow=TRUE) |
| for (c in 1:C) { |
| img_padded_slice = matrix(img_padded[c,], (Hin+2*padh), (Win+2*padw), byrow=TRUE) |
| img_slice = img_padded_slice[(padh+1):(padh+Hin), (padw+1):(padw+Win)] |
| img[c,] = matrix(t(img_slice), 1, Hin*Win) |
| } |
| img |
| } |
| |
| conv2d_backward_data <- function(dout, Hout, Wout, |
| W, N, C, Hin, Win, Hf, Wf, |
| strideh, stridew, padh, padw) { |
| |
| F = nrow(W) |
| |
| # Create gradient volumes |
| dX = matrix(0, N, C*Hin*Win, byrow=TRUE) |
| |
| # Partial derivatives for convolution - im2col implementation |
| for (n in 1:N) { # all examples |
| doutn = matrix(dout[n,], F, Hout*Wout, byrow=TRUE) |
| |
| # Compute dX |
| dXn_padded_cols = t(W) %*% doutn # shape (C*Hf*Wf, Hout*Wout) |
| dXn_padded = col2im(dXn_padded_cols, C, Hin+2*padh, Win+2*padw, Hf, Wf, strideh, stridew, "add") |
| dXn = unpad_image(dXn_padded, Hin, Win, padh, padw) |
| dX[n,] = matrix(t(dXn), 1, C*Hin*Win) # reshape |
| } |
| |
| dX |
| } |
| |
| dx = conv2d_backward_data(dout, P, Q, w, numImg, numChannels, imgSize, imgSize, filterSize, filterSize, stride, stride, pad, pad); |
| |
| writeMM(as(dx,"CsparseMatrix"), paste(args[10], "B", sep="")) |
