From d9f1b0b16edeb59281355a855e18a8be343fc33c Mon Sep 17 00:00:00 2001
From: Joseph Redmon <pjreddie@gmail.com>
Date: Fri, 08 Aug 2014 19:04:15 +0000
Subject: [PATCH] probably how maxpool layers should be
---
src/maxpool_layer.c | 79 +++++++++++++++++++++++++++++++--------
1 files changed, 62 insertions(+), 17 deletions(-)
diff --git a/src/maxpool_layer.c b/src/maxpool_layer.c
index 54a734a..08c9f2f 100644
--- a/src/maxpool_layer.c
+++ b/src/maxpool_layer.c
@@ -17,14 +17,15 @@
return float_to_image(h,w,c,layer.delta);
}
-maxpool_layer *make_maxpool_layer(int batch, int h, int w, int c, int stride)
+maxpool_layer *make_maxpool_layer(int batch, int h, int w, int c, int size, int stride)
{
- fprintf(stderr, "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 size, %d stride\n", h,w,c,size,stride);
maxpool_layer *layer = calloc(1, sizeof(maxpool_layer));
layer->batch = batch;
layer->h = h;
layer->w = w;
layer->c = c;
+ layer->size = size;
layer->stride = stride;
layer->output = calloc(((h-1)/stride+1) * ((w-1)/stride+1) * c*batch, sizeof(float));
layer->delta = calloc(((h-1)/stride+1) * ((w-1)/stride+1) * c*batch, sizeof(float));
@@ -40,6 +41,32 @@
layer->delta = realloc(layer->delta, ((h-1)/layer->stride+1) * ((w-1)/layer->stride+1) * c * layer->batch*sizeof(float));
}
+float get_max_region(image im, int h, int w, int c, int size)
+{
+ int i,j;
+ int lower = (-size-1)/2 + 1;
+ int upper = size/2 + 1;
+
+ int lh = (h-lower < 0) ? 0 : h-lower;
+ int uh = (h+upper > im.h) ? im.h : h+upper;
+
+ int lw = (w-lower < 0) ? 0 : w-lower;
+ int uw = (w+upper > im.w) ? im.w : w+upper;
+
+ //printf("%d\n", -3/2);
+ //printf("%d %d\n", lower, upper);
+ //printf("%d %d %d %d\n", lh, uh, lw, uw);
+
+ float max = -FLT_MAX;
+ for(i = lh; i < uh; ++i){
+ for(j = lw; j < uw; ++j){
+ float val = get_pixel(im, i, j, c);
+ if (val > max) max = val;
+ }
+ }
+ return max;
+}
+
void forward_maxpool_layer(const maxpool_layer layer, float *in)
{
int b;
@@ -52,19 +79,40 @@
image output = float_to_image(h,w,c,layer.output+b*h*w*c);
int i,j,k;
- for(i = 0; i < output.h*output.w*output.c; ++i) output.data[i] = -DBL_MAX;
for(k = 0; k < input.c; ++k){
- for(i = 0; i < input.h; ++i){
- for(j = 0; j < input.w; ++j){
- float val = get_pixel(input, i, j, k);
- float cur = get_pixel(output, i/layer.stride, j/layer.stride, k);
- if(val > cur) set_pixel(output, i/layer.stride, j/layer.stride, k, val);
+ for(i = 0; i < input.h; i += layer.stride){
+ for(j = 0; j < input.w; j += layer.stride){
+ float max = get_max_region(input, i, j, k, layer.size);
+ set_pixel(output, i/layer.stride, j/layer.stride, k, max);
}
}
}
}
}
+float set_max_region_delta(image im, image delta, int h, int w, int c, int size, float max, float error)
+{
+ int i,j;
+ int lower = (-size-1)/2 + 1;
+ int upper = size/2 + 1;
+
+ int lh = (h-lower < 0) ? 0 : h-lower;
+ int uh = (h+upper > im.h) ? im.h : h+upper;
+
+ int lw = (w-lower < 0) ? 0 : w-lower;
+ int uw = (w+upper > im.w) ? im.w : w+upper;
+
+ for(i = lh; i < uh; ++i){
+ for(j = lw; j < uw; ++j){
+ float val = get_pixel(im, i, j, c);
+ if (val == max){
+ add_pixel(delta, i, j, c, error);
+ }
+ }
+ }
+ return max;
+}
+
void backward_maxpool_layer(const maxpool_layer layer, float *in, float *delta)
{
int b;
@@ -76,18 +124,15 @@
int c = layer.c;
image output = float_to_image(h,w,c,layer.output+b*h*w*c);
image output_delta = float_to_image(h,w,c,layer.delta+b*h*w*c);
+ zero_image(input_delta);
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){
- float val = get_pixel(input, i, j, k);
- float cur = get_pixel(output, i/layer.stride, j/layer.stride, k);
- float 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);
+ for(i = 0; i < input.h; i += layer.stride){
+ for(j = 0; j < input.w; j += layer.stride){
+ float max = get_pixel(output, i/layer.stride, j/layer.stride, k);
+ float error = get_pixel(output_delta, i/layer.stride, j/layer.stride, k);
+ set_max_region_delta(input, input_delta, i, j, k, layer.size, max, error);
}
}
}
--
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