From 2c6d4ba1d5cffd26c5c9527175d565a81226e18d Mon Sep 17 00:00:00 2001
From: Joseph Redmon <pjreddie@gmail.com>
Date: Wed, 19 Feb 2014 21:41:44 +0000
Subject: [PATCH] Single image feature extraction for VOC

---
 src/convolutional_layer.c |  283 +++++++++++++++++++++++++++++++++++---------------------
 1 files changed, 177 insertions(+), 106 deletions(-)

diff --git a/src/convolutional_layer.c b/src/convolutional_layer.c
index 45b55b8..8d8efc1 100644
--- a/src/convolutional_layer.c
+++ b/src/convolutional_layer.c
@@ -1,110 +1,177 @@
 #include "convolutional_layer.h"
 #include "utils.h"
+#include "mini_blas.h"
 #include <stdio.h>
 
+int convolutional_out_height(convolutional_layer layer)
+{
+    return (layer.h-layer.size)/layer.stride + 1;
+}
+
+int convolutional_out_width(convolutional_layer layer)
+{
+    return (layer.w-layer.size)/layer.stride + 1;
+}
+
 image get_convolutional_image(convolutional_layer layer)
 {
     int h,w,c;
-    if(layer.edge){
-        h = (layer.h-1)/layer.stride + 1;
-        w = (layer.w-1)/layer.stride + 1;
-    }else{
-        h = (layer.h - layer.size)/layer.stride+1;
-        w = (layer.h - layer.size)/layer.stride+1;
-    }
+    h = convolutional_out_height(layer);
+    w = convolutional_out_width(layer);
     c = layer.n;
-    return double_to_image(h,w,c,layer.output);
+    return float_to_image(h,w,c,layer.output);
 }
 
 image get_convolutional_delta(convolutional_layer layer)
 {
     int h,w,c;
-    if(layer.edge){
-        h = (layer.h-1)/layer.stride + 1;
-        w = (layer.w-1)/layer.stride + 1;
-    }else{
-        h = (layer.h - layer.size)/layer.stride+1;
-        w = (layer.h - layer.size)/layer.stride+1;
-    }
+    h = convolutional_out_height(layer);
+    w = convolutional_out_width(layer);
     c = layer.n;
-    return double_to_image(h,w,c,layer.delta);
+    return float_to_image(h,w,c,layer.delta);
 }
 
 convolutional_layer *make_convolutional_layer(int h, int w, int c, int n, int size, int stride, ACTIVATION activation)
 {
     int i;
-    int out_h,out_w;
+    size = 2*(size/2)+1; //HA! And you thought you'd use an even sized filter...
     convolutional_layer *layer = calloc(1, sizeof(convolutional_layer));
     layer->h = h;
     layer->w = w;
     layer->c = c;
     layer->n = n;
-    layer->edge = 1;
     layer->stride = stride;
-    layer->kernels = calloc(n, sizeof(image));
-    layer->kernel_updates = calloc(n, sizeof(image));
-    layer->kernel_momentum = calloc(n, sizeof(image));
-    layer->biases = calloc(n, sizeof(double));
-    layer->bias_updates = calloc(n, sizeof(double));
-    layer->bias_momentum = calloc(n, sizeof(double));
-    double scale = 2./(size*size);
+    layer->size = size;
+
+    layer->filters = calloc(c*n*size*size, sizeof(float));
+    layer->filter_updates = calloc(c*n*size*size, sizeof(float));
+    layer->filter_momentum = calloc(c*n*size*size, sizeof(float));
+
+    layer->biases = calloc(n, sizeof(float));
+    layer->bias_updates = calloc(n, sizeof(float));
+    layer->bias_momentum = calloc(n, sizeof(float));
+    float scale = 1./(size*size*c);
+    for(i = 0; i < c*n*size*size; ++i) layer->filters[i] = scale*(rand_uniform());
     for(i = 0; i < n; ++i){
         //layer->biases[i] = rand_normal()*scale + scale;
         layer->biases[i] = 0;
-        layer->kernels[i] = make_random_kernel(size, c, scale);
-        layer->kernel_updates[i] = make_random_kernel(size, c, 0);
-        layer->kernel_momentum[i] = make_random_kernel(size, c, 0);
     }
-    layer->size = 2*(size/2)+1;
-    if(layer->edge){
-        out_h = (layer->h-1)/layer->stride + 1;
-        out_w = (layer->w-1)/layer->stride + 1;
-    }else{
-        out_h = (layer->h - layer->size)/layer->stride+1;
-        out_w = (layer->h - layer->size)/layer->stride+1;
-    }
-    fprintf(stderr, "Convolutional Layer: %d x %d x %d image, %d filters -> %d x %d x %d image\n", h,w,c,n, out_h, out_w, n);
-    layer->output = calloc(out_h * out_w * n, sizeof(double));
-    layer->delta  = calloc(out_h * out_w * n, sizeof(double));
-    layer->upsampled = make_image(h,w,n);
+    int out_h = (h-size)/stride + 1;
+    int out_w = (w-size)/stride + 1;
+
+    layer->col_image = calloc(out_h*out_w*size*size*c, sizeof(float));
+    layer->output = calloc(out_h * out_w * n, sizeof(float));
+    layer->delta  = calloc(out_h * out_w * n, sizeof(float));
     layer->activation = activation;
 
+    fprintf(stderr, "Convolutional Layer: %d x %d x %d image, %d filters -> %d x %d x %d image\n", h,w,c,n, out_h, out_w, n);
+    srand(0);
+
     return layer;
 }
 
-void forward_convolutional_layer(const convolutional_layer layer, double *in)
-{
-    image input = double_to_image(layer.h, layer.w, layer.c, in);
-    image output = get_convolutional_image(layer);
-    int i,j;
-    for(i = 0; i < layer.n; ++i){
-        convolve(input, layer.kernels[i], layer.stride, i, output, layer.edge);
-    }
-    for(i = 0; i < output.c; ++i){
-        for(j = 0; j < output.h*output.w; ++j){
-            int index = i*output.h*output.w + j;
-            output.data[index] += layer.biases[i];
-            output.data[index] = activate(output.data[index], layer.activation);
-        }
-    }
-}
-
-void backward_convolutional_layer(convolutional_layer layer, double *input, double *delta)
+void forward_convolutional_layer(const convolutional_layer layer, float *in)
 {
     int i;
+    int m = layer.n;
+    int k = layer.size*layer.size*layer.c;
+    int n = ((layer.h-layer.size)/layer.stride + 1)*
+            ((layer.w-layer.size)/layer.stride + 1);
 
-    image in_delta = double_to_image(layer.h, layer.w, layer.c, delta);
-    image out_delta = get_convolutional_delta(layer);
-    zero_image(in_delta);
+    memset(layer.output, 0, m*n*sizeof(float));
 
-    for(i = 0; i < layer.n; ++i){
-        back_convolve(in_delta, layer.kernels[i], layer.stride, i, out_delta, layer.edge);
+    float *a = layer.filters;
+    float *b = layer.col_image;
+    float *c = layer.output;
+
+    im2col_cpu(in,  layer.c,  layer.h,  layer.w,  layer.size,  layer.stride, b);
+    gemm(0,0,m,n,k,1,a,k,b,n,1,c,n);
+
+    for(i = 0; i < m*n; ++i){
+        layer.output[i] = activate(layer.output[i], layer.activation);
+    }
+    //for(i = 0; i < m*n; ++i) if(i%(m*n/10+1)==0) printf("%f, ", layer.output[i]); printf("\n");
+
+}
+
+void gradient_delta_convolutional_layer(convolutional_layer layer)
+{
+    int i;
+    int size = convolutional_out_height(layer)
+                *convolutional_out_width(layer)
+                *layer.n;
+    for(i = 0; i < size; ++i){
+        layer.delta[i] *= gradient(layer.output[i], layer.activation);
     }
 }
 
-void backward_convolutional_layer2(convolutional_layer layer, double *input, double *delta)
+void learn_bias_convolutional_layer(convolutional_layer layer)
 {
-    image in_delta = double_to_image(layer.h, layer.w, layer.c, delta);
+    int i,j;
+    int size = convolutional_out_height(layer)
+                *convolutional_out_width(layer);
+    for(i = 0; i < layer.n; ++i){
+        float sum = 0;
+        for(j = 0; j < size; ++j){
+            sum += layer.delta[j+i*size];
+        }
+        layer.bias_updates[i] += sum/size;
+    }
+}
+
+void learn_convolutional_layer(convolutional_layer layer)
+{
+    gradient_delta_convolutional_layer(layer);
+    learn_bias_convolutional_layer(layer);
+    int m = layer.n;
+    int n = layer.size*layer.size*layer.c;
+    int k = ((layer.h-layer.size)/layer.stride + 1)*
+            ((layer.w-layer.size)/layer.stride + 1);
+
+    float *a = layer.delta;
+    float *b = layer.col_image;
+    float *c = layer.filter_updates;
+
+    gemm(0,1,m,n,k,1,a,k,b,k,1,c,n);
+}
+
+void backward_convolutional_layer(convolutional_layer layer, float *delta)
+{
+    int m = layer.size*layer.size*layer.c;
+    int k = layer.n;
+    int n = ((layer.h-layer.size)/layer.stride + 1)*
+            ((layer.w-layer.size)/layer.stride + 1);
+
+    float *a = layer.filters;
+    float *b = layer.delta;
+    float *c = layer.col_image;
+
+
+    memset(c, 0, m*n*sizeof(float));
+    gemm(1,0,m,n,k,1,a,m,b,n,1,c,n);
+
+    memset(delta, 0, layer.h*layer.w*layer.c*sizeof(float));
+    col2im_cpu(c,  layer.c,  layer.h,  layer.w,  layer.size,  layer.stride, delta);
+}
+
+void update_convolutional_layer(convolutional_layer layer, float step, float momentum, float decay)
+{
+    int i;
+    int size = layer.size*layer.size*layer.c*layer.n;
+    for(i = 0; i < layer.n; ++i){
+        layer.biases[i] += step*layer.bias_updates[i];
+        layer.bias_updates[i] *= momentum;
+    }
+    for(i = 0; i < size; ++i){
+        layer.filters[i] += step*(layer.filter_updates[i] - decay*layer.filters[i]);
+        layer.filter_updates[i] *= momentum;
+    }
+}
+/*
+
+void backward_convolutional_layer2(convolutional_layer layer, float *input, float *delta)
+{
+    image in_delta = float_to_image(layer.h, layer.w, layer.c, delta);
     image out_delta = get_convolutional_delta(layer);
     int i,j;
     for(i = 0; i < layer.n; ++i){
@@ -124,51 +191,74 @@
     }
 }
 
-void gradient_delta_convolutional_layer(convolutional_layer layer)
-{
-    int i;
-    image out_delta = get_convolutional_delta(layer);
-    image out_image = get_convolutional_image(layer);
-    for(i = 0; i < out_image.h*out_image.w*out_image.c; ++i){
-        out_delta.data[i] *= gradient(out_image.data[i], layer.activation);
-    }
-}
 
-void learn_convolutional_layer(convolutional_layer layer, double *input)
+void learn_convolutional_layer(convolutional_layer layer, float *input)
 {
     int i;
-    image in_image = double_to_image(layer.h, layer.w, layer.c, input);
+    image in_image = float_to_image(layer.h, layer.w, layer.c, input);
     image out_delta = get_convolutional_delta(layer);
     gradient_delta_convolutional_layer(layer);
     for(i = 0; i < layer.n; ++i){
         kernel_update(in_image, layer.kernel_updates[i], layer.stride, i, out_delta, layer.edge);
         layer.bias_updates[i] += avg_image_layer(out_delta, i);
-        //printf("%30.20lf\n", layer.bias_updates[i]);
     }
 }
 
-void update_convolutional_layer(convolutional_layer layer, double step, double momentum, double decay)
+void update_convolutional_layer(convolutional_layer layer, float step, float momentum, float decay)
 {
-    //step = .01;
     int i,j;
     for(i = 0; i < layer.n; ++i){
         layer.bias_momentum[i] = step*(layer.bias_updates[i]) 
                                 + momentum*layer.bias_momentum[i];
         layer.biases[i] += layer.bias_momentum[i];
-        //layer.biases[i] = constrain(layer.biases[i],1.);
         layer.bias_updates[i] = 0;
         int pixels = layer.kernels[i].h*layer.kernels[i].w*layer.kernels[i].c;
         for(j = 0; j < pixels; ++j){
             layer.kernel_momentum[i].data[j] = step*(layer.kernel_updates[i].data[j] - decay*layer.kernels[i].data[j]) 
                                                 + momentum*layer.kernel_momentum[i].data[j];
             layer.kernels[i].data[j] += layer.kernel_momentum[i].data[j];
-            //layer.kernels[i].data[j] = constrain(layer.kernels[i].data[j], 1.);
         }
         zero_image(layer.kernel_updates[i]);
     }
 }
+*/
 
-void visualize_convolutional_filters(convolutional_layer layer, char *window)
+void test_convolutional_layer()
+{
+    convolutional_layer l = *make_convolutional_layer(4,4,1,1,3,1,LINEAR);
+    float input[] =    {1,2,3,4,
+                        5,6,7,8,
+                        9,10,11,12,
+                        13,14,15,16};
+    float filter[] =   {.5, 0, .3,
+                        0  , 1,  0,
+                        .2 , 0,  1};
+    float delta[] =    {1, 2,
+                        3,  4};
+    float in_delta[] = {.5,1,.3,.6,
+                        5,6,7,8,
+                        9,10,11,12,
+                        13,14,15,16};
+    l.filters = filter;
+    forward_convolutional_layer(l, input);
+    l.delta = delta;
+    learn_convolutional_layer(l);
+    image filter_updates = float_to_image(3,3,1,l.filter_updates);
+    print_image(filter_updates);
+    printf("Delta:\n");
+    backward_convolutional_layer(l, in_delta);
+    pm(4,4,in_delta);
+}
+
+image get_convolutional_filter(convolutional_layer layer, int i)
+{
+    int h = layer.size;
+    int w = layer.size;
+    int c = layer.c;
+    return float_to_image(h,w,c,layer.filters+i*h*w*c);
+}
+
+void visualize_convolutional_layer(convolutional_layer layer, char *window)
 {
     int color = 1;
     int border = 1;
@@ -176,7 +266,7 @@
     int size = layer.size;
     h = size;
     w = (size + border) * layer.n - border;
-    c = layer.kernels[0].c;
+    c = layer.c;
     if(c != 3 || !color){
         h = (h+border)*c - border;
         c = 1;
@@ -186,19 +276,13 @@
     int i,j;
     for(i = 0; i < layer.n; ++i){
         int w_offset = i*(size+border);
-        image k = layer.kernels[i];
+        image k = get_convolutional_filter(layer, i);
+        //printf("%f ** ", layer.biases[i]);
+        //print_image(k);
         image copy = copy_image(k);
-        /*
-        printf("Kernel %d - Bias: %f, Channels:",i,layer.biases[i]);
-        for(j = 0; j < k.c; ++j){
-            double a = avg_image_layer(k, j);
-            printf("%f, ", a);
-        }
-        printf("\n");
-        */
         normalize_image(copy);
         for(j = 0; j < k.c; ++j){
-            set_pixel(copy,0,0,j,layer.biases[i]);
+            //set_pixel(copy,0,0,j,layer.biases[i]);
         }
         if(c == 3 && color){
             embed_image(copy, filters, 0, w_offset);
@@ -223,16 +307,3 @@
     free_image(filters);
 }
 
-void visualize_convolutional_layer(convolutional_layer layer)
-{
-    int i;
-    char buff[256];
-    //image vis = make_image(layer.n*layer.size, layer.size*layer.kernels[0].c, 3);
-    for(i = 0; i < layer.n; ++i){
-        image k = layer.kernels[i];
-        sprintf(buff, "Kernel %d", i);
-        if(k.c <= 3) show_image(k, buff);
-        else show_image_layers(k, buff);
-    }
-}
-

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