From 1d53b6414e0cd81043d7c76aa89f4f97da5e479f Mon Sep 17 00:00:00 2001
From: Joseph Redmon <pjreddie@gmail.com>
Date: Thu, 23 Jan 2014 19:24:37 +0000
Subject: [PATCH] Stable on MNIST, about to change a lot
---
src/maxpool_layer.c | 32 +++++++++++++++++++++++++++++++-
1 files changed, 31 insertions(+), 1 deletions(-)
diff --git a/src/maxpool_layer.c b/src/maxpool_layer.c
index f58a22f..ccf9bee 100644
--- a/src/maxpool_layer.c
+++ b/src/maxpool_layer.c
@@ -9,9 +9,17 @@
return double_to_image(h,w,c,layer.output);
}
+image get_maxpool_delta(maxpool_layer layer)
+{
+ int h = (layer.h-1)/layer.stride + 1;
+ int w = (layer.w-1)/layer.stride + 1;
+ int c = layer.c;
+ return double_to_image(h,w,c,layer.delta);
+}
+
maxpool_layer *make_maxpool_layer(int h, int w, int c, int stride)
{
- printf("Maxpool Layer: %d x %d x %d image, %d stride\n", h,w,c,stride);
+ fprintf(stderr, "Maxpool Layer: %d x %d x %d image, %d stride\n", h,w,c,stride);
maxpool_layer *layer = calloc(1, sizeof(maxpool_layer));
layer->h = h;
layer->w = w;
@@ -39,3 +47,25 @@
}
}
+void backward_maxpool_layer(const maxpool_layer layer, double *in, double *delta)
+{
+ image input = double_to_image(layer.h, layer.w, layer.c, in);
+ image input_delta = double_to_image(layer.h, layer.w, layer.c, delta);
+ image output_delta = get_maxpool_delta(layer);
+ image output = get_maxpool_image(layer);
+ int i,j,k;
+ for(k = 0; k < input.c; ++k){
+ for(i = 0; i < input.h; ++i){
+ for(j = 0; j < input.w; ++j){
+ double val = get_pixel(input, i, j, k);
+ double cur = get_pixel(output, i/layer.stride, j/layer.stride, k);
+ double d = get_pixel(output_delta, i/layer.stride, j/layer.stride, k);
+ if(val == cur) {
+ set_pixel(input_delta, i, j, k, d);
+ }
+ else set_pixel(input_delta, i, j, k, 0);
+ }
+ }
+ }
+}
+
--
Gitblit v1.10.0