YOLOv3：Darknet代码解析（六）简化的程序与卷积拆分

水深无声 2022-05-16 05:23 169阅读 0赞

**背景：**之前代码过多无用代码，我们只需要神经网络的前馈运算的代码。卷积核需要不用gemm的方式而用更简单的卷积来运算。

**目的：**读懂简化版的yolo2\_light代码，并将其中卷积改为9个并行的基本单元。

代码地址： [https://github.com/AlexeyAB/yolo2\_light][https_github.com_AlexeyAB_yolo2_light]

[YOLOv3：Darknet代码解析（一）安装Darknet][YOLOv3_Darknet_Darknet]

[YOLOv3：Darknet代码解析（二）代码初步][YOLOv3_Darknet]

[YOLOv3：Darknet代码解析（三）卷积操作][YOLOv3_Darknet 1]

[YOLOv3：Darknet代码解析（四）结构更改与训练][YOLOv3_Darknet 2]

[YOLOv3：Darknet代码解析（五）权重与特征存储][YOLOv3_Darknet 3]

[YOLOv3：Darknet代码解析（六）简化的程序与卷积拆分][YOLOv3_Darknet 4]

**目录**

1.函数的功能与位置

2.检验

2.1 程序输出的检验

2.2 卷积的检验

3.卷积运算

3.1 zynqNet中卷积的运算

3.2 原始的卷积语句

3.3 改为定值卷积

3.4  3\*3的9并行

--------------------

~/datasets/xxr/yolo2_light/bin$ ./darknet detector test obj.data obj.cfg obj_6000.weights 17.jpg
    layer     filters    size              input                output
        0 conv     16  3 x 3 / 1   416 x 416 x   3   ->   416 x 416 x  16
        1 max          2 x 2 / 2   416 x 416 x  16   ->   208 x 208 x  16
        2 conv     32  3 x 3 / 1   208 x 208 x  16   ->   208 x 208 x  32
        3 max          2 x 2 / 2   208 x 208 x  32   ->   104 x 104 x  32
        4 conv     64  3 x 3 / 1   104 x 104 x  32   ->   104 x 104 x  64
        5 max          2 x 2 / 2   104 x 104 x  64   ->    52 x  52 x  64
        6 conv    128  3 x 3 / 1    52 x  52 x  64   ->    52 x  52 x 128
        7 max          2 x 2 / 2    52 x  52 x 128   ->    26 x  26 x 128
        8 conv    256  3 x 3 / 1    26 x  26 x 128   ->    26 x  26 x 256
        9 max          2 x 2 / 2    26 x  26 x 256   ->    13 x  13 x 256
       10 conv    512  3 x 3 / 1    13 x  13 x 256   ->    13 x  13 x 512
       11 max          2 x 2 / 1    13 x  13 x 512   ->    13 x  13 x 512
       12 conv   1024  3 x 3 / 1    13 x  13 x 512   ->    13 x  13 x1024
       13 conv   1024  3 x 3 / 1    13 x  13 x1024   ->    13 x  13 x1024
       14 conv     30  1 x 1 / 1    13 x  13 x1024   ->    13 x  13 x  30
       15 detection
    Loading weights from obj_6000.weights...Done!
     Fuse Convolutional layer                l->size = 3
     Skip layer: 3
     Fuse Convolutional layer                l->size = 3
     Skip layer: 3
     Fuse Convolutional layer                l->size = 3
     Skip layer: 3
     Fuse Convolutional layer                l->size = 3
     Skip layer: 3
     Fuse Convolutional layer                l->size = 3
     Skip layer: 3
     Fuse Convolutional layer                l->size = 3
     Skip layer: 3
     Fuse Convolutional layer                l->size = 3
     Fuse Convolutional layer                l->size = 3
     Fuse Convolutional layer                l->size = 1
     Skip layer: 21
    
     running yolov2_forward_netwrok_cpu
     layer num: 0    CONVOLUTIONAL
    FilterNum:16,Input Channels:3,Input Height:416,input width:416,FilterSize:3
    layer num: 1     MAXPOOL
    layer num: 2     CONVOLUTIONAL
    FilterNum:32,Input Channels:16,Input Height:208,input width:208,FilterSize:3
    layer num: 3     MAXPOOL
    layer num: 4     CONVOLUTIONAL
    FilterNum:64,Input Channels:32,Input Height:104,input width:104,FilterSize:3
    layer num: 5     MAXPOOL
    layer num: 6     CONVOLUTIONAL
    FilterNum:128,Input Channels:64,Input Height:52,input width:52,FilterSize:3
    layer num: 7     MAXPOOL
    layer num: 8     CONVOLUTIONAL
    FilterNum:256,Input Channels:128,Input Height:26,input width:26,FilterSize:3
    layer num: 9     MAXPOOL
    layer num: 10    CONVOLUTIONAL
    FilterNum:512,Input Channels:256,Input Height:13,input width:13,FilterSize:3
    layer num: 11    MAXPOOL
    layer num: 12    CONVOLUTIONAL
    FilterNum:1024,Input Channels:512,Input Height:13,input width:13,FilterSize:3
    layer num: 13    CONVOLUTIONAL
    FilterNum:1024,Input Channels:1024,Input Height:13,input width:13,FilterSize:3
    layer num: 14    CONVOLUTIONAL
    FilterNum:30,Input Channels:1024,Input Height:13,input width:13,FilterSize:1
    layer num: 15    REGION
    Check done!
    17.jpg: Predicted in 1.542322 seconds.
    classes= 1  : 80%       (left_x:  124   top_y:   82   width:   45   height:   53)
    classes= 1  : 70%       (left_x:  187   top_y:   17   width:   28   height:   40)
    classes= 1  : 83%       (left_x:  195   top_y:  157   width:   50   height:   64)
    Not compiled with OpenCV, saving to predictions.png instead

# 1.函数的功能与位置 #

只有前馈之后，网络的代码简短了不少。

**主函数：**mian.c中，main函数中，运用network\_predict\_cpu这个函数来获得图片的输出。

**前馈计算：**yolov2\_forward\_network.c中，定义了network\_predict\_cpu函数yolov2\_forward\_network\_cpu函数作用就是一层一层的前馈计算。

**卷积运算：**forward\_convolutional\_layer\_cpu 也在这个函数中

# 2.检验 #

## 2.1 程序输出的检验 ##

~/datasets/xxr/yolo2_light/bin$ ./darknet detector test obj.data obj.cfg obj_6000.weights 17.jpg

![70][]

predictions.png

## 2.2 卷积的检验 ##

将每次卷积结果输入check.txt文件，

// yolov2_forward_network.c
    void yolov2_forward_network_cpu(network net, network_state state)
    {
    	FILE* check=fopen("check.txt","w");
    	
    	printf("\n running yolov2_forward_netwrok_cpu\n ");
        state.workspace = net.workspace;
        int i;
        for (i = 0; i < net.n; ++i) {
    		printf("layer num: %d \t",i);
            state.index = i;
            layer l = net.layers[i];
    
            if (l.type == CONVOLUTIONAL) {
    			printf(" CONVOLUTIONAL \n");
                forward_convolutional_layer_cpu(l, state);
    			fwrite(l.output,l.outputs,sizeof(float),check);
            }
            else if (l.type == MAXPOOL) {
    			printf(" MAXPOOL \n");
                forward_maxpool_layer_cpu(l, state);
            }
    
            state.input = l.output;
        }
    	fclose(check);
    }

写入文件后，程序更改为这样，把每层卷积的l.output进行进行检验。

void yolov2_forward_network_cpu(network net, network_state state)
    {
    	FILE* check=fopen("check.txt","r");
    	
    	printf("\n running yolov2_forward_netwrok_cpu\n ");
        state.workspace = net.workspace;
        int i;
        for (i = 0; i < net.n; ++i) {
    		printf("layer num: %d \t",i);
            state.index = i;
            layer l = net.layers[i];
    
            if (l.type == CONVOLUTIONAL) {
    			printf(" CONVOLUTIONAL \n");
                forward_convolutional_layer_cpu(l, state);
    			
    			float *buffer=(float*)malloc(l.outputs*sizeof(float));
    			fread(buffer,l.outputs,sizeof(float),check);
    			for(int i=0;i<l.outputs;i++){
    				if(buffer[i]!=l.output[i]){
    					printf("Check error!\n");
    					break;
    				}
    			}
            }
            else if (l.type == MAXPOOL) {
    			printf(" MAXPOOL \n");
                forward_maxpool_layer_cpu(l, state);
            }
    
            state.input = l.output;
        }
    	fclose(check);
    	printf("Check done!\n");
    }

//input
    ~/datasets/xxr/yolo2_light/bin$ ./darknet detector test voc.data head-hw-v2.cfg obj_9000.weights dog.jpg
    
    //output
    ......
    FilterNum:1024,Input Channels:1024,Input Height:13,input width:13,FilterSize:3
    layer num: 14    CONVOLUTIONAL
    FilterNum:30,Input Channels:1024,Input Height:13,input width:13,FilterSize:1
    layer num: 15    REGION
    Check done!
    dog.jpg: Predicted in 1.412451 seconds.

有输出check done！表示验证正确。

# 3.卷积运算 #

## 3.1 zynqNet中卷积的运算 ##

oid ProcessingElement::macc2d(const data_t pixels[9], const data_t weights[9],
                                   data_t& result) {
    #pragma HLS inline
    
      data_t accumulator = 0.0f;
      data_t multresult[9];
    #pragma HLS ARRAY_PARTITION variable = multresult complete dim = 0
    
    L_MACC_multiply:
      for (int i = 0; i < 9; i++) {
    #pragma HLS UNROLL
        multresult[i] = pixels[i] * weights[i];
      }
    
    L_MACC_accumulate:
      for (int i = 0; i < 9; i++) {
    #pragma HLS UNROLL
        accumulator = accumulator + multresult[i];
      }
    
      LOG("PE: macc2D -> %.2f \n", accumulator);
    
      result = accumulator;
    }

运用ARRAY\_PARTATION指令可以9个一起并行运算。先乘再加。

## 3.2 原始的卷积语句 ##

yolov2\_forward\_network.c文件中，forward\_convolutional\_layer\_cpu 函数

// l.n - number of filters on this layer
        // l.c - channels of input-array
        // l.h - height of input-array
        // l.w - width of input-array
        // l.size - width and height of filters (the same size for all filters)
    
    	printf("FilterNum:%d,Input Channels:%d,Input Height:%d,input width:%d,FilterSize:%d\n",
    	l.n,l.c,l.h,l.w,l.size);
    
        // 1. Convolution !!!
    #ifndef GEMMCONV
        int fil;
        // filter index
    #pragma omp parallel for      // "omp parallel for" - automatic parallelization of loop by using OpenMP
        for (fil = 0; fil < l.n; ++fil) {
            int chan, y, x, f_y, f_x;
            // channel index
            for (chan = 0; chan < l.c; ++chan)
                // input - y
                for (y = 0; y < l.h; ++y)
                    // input - x
                    for (x = 0; x < l.w; ++x)
                    {
                        int const output_index = fil*l.w*l.h + y*l.w + x;
                        int const weights_pre_index = fil*l.c*l.size*l.size + chan*l.size*l.size;
                        int const input_pre_index = chan*l.w*l.h;
                        float sum = 0;
    
                        // filter - y
                        for (f_y = 0; f_y < l.size; ++f_y)
                        {
                            int input_y = y + f_y - l.pad;
                            // filter - x
                            for (f_x = 0; f_x < l.size; ++f_x)
                            {
                                int input_x = x + f_x - l.pad;
                                if (input_y < 0 || input_x < 0 || input_y >= l.h || input_x >= l.w) continue;
    
                                int input_index = input_pre_index + input_y*l.w + input_x;
                                int weights_index = weights_pre_index + f_y*l.size + f_x;
    
                                sum += state.input[input_index] * l.weights[weights_index];
                            }
                        }
                        // l.output[filters][width][height] +=
                        //        state.input[channels][width][height] *
                        //        l.weights[filters][channels][filter_width][filter_height];
                        l.output[output_index] += sum;
                    }
        }

## 3.3 改为定值卷积 ##

14层之外的卷积层大小为3\*3，14层为1\*1卷积核。定值为3\*3

if(state.index!=14){
    	for (f_y = 0; f_y < 3; ++f_y)
    	{
    		int input_y = y + f_y - l.pad;
    		// filter - x
    		for (f_x = 0; f_x < 3; ++f_x)
    		{
    			int input_x = x + f_x - l.pad;
    			if (input_y < 0 || input_x < 0 || input_y >= l.h || input_x >= l.w) continue;
    
    			int input_index = input_pre_index + input_y*l.w + input_x;
    			int weights_index = weights_pre_index + f_y*l.size + f_x;
    
    			sum += state.input[input_index] * l.weights[weights_index];
    		}
    	}
    	
    else{
    	// filter - y
    	f_y = 0;
    	int input_y = y + f_y - l.pad;
    		// filter - x
    	f_x = 0;
    	
    	int input_x = x + f_x - l.pad;
    	if (input_y < 0 || input_x < 0 || input_y >= l.h || input_x >= l.w) continue;
    
    	int input_index = input_pre_index + input_y*l.w + input_x;
    	int weights_index = weights_pre_index + f_y*l.size + f_x;
    
    	sum += state.input[input_index] * l.weights[weights_index];
    	
    }

## 3.4  3\*3的9并行 ##

改为9的并行，将3\*3的卷积作为基本的卷积单元。

float input_buffer[9],weight_buffer[9],product_buffer[9];
    for(f_y=0;f_y<3;++f_y){
    intinput_y=y+f_y-l.pad;
    // filter - x
    	for (f_x = 0; f_x < 3; ++f_x)
    	{
    		int input_x = x + f_x - l.pad;
    		if (input_y < 0 || input_x < 0 || input_y >= l.h || input_x >= l.w) continue;
    
    		int input_index = input_pre_index + input_y*l.w + input_x;
    		int weights_index = weights_pre_index + f_y*l.size + f_x;
    
    		int buffer_idx=3*f_y+f_x;
    		input_buffer[buffer_idx]=state.input[input_index];
    		weight_buffer[buffer_idx]=l.weights[weights_index];
    		//sum += state.input[input_index] * l.weights[weights_index];
    	}
    }
    
    for(i=0;i<9;i++){
    	product_buffer[i]=input_buffer[i]*weight_buffer[i];
    }
    for(i=0;i<9;i++){
    	sum+=product_buffer[i];
    }

至此，我们将卷积改为了最基本的9个并行的运算。并用3.1中的方法验证通过。

[YOLOv3：Darknet代码解析（一）安装Darknet][YOLOv3_Darknet_Darknet]

[YOLOv3：Darknet代码解析（二）代码初步][YOLOv3_Darknet]

[YOLOv3：Darknet代码解析（三）卷积操作][YOLOv3_Darknet 1]

[YOLOv3：Darknet代码解析（四）结构更改与训练][YOLOv3_Darknet 2]

[YOLOv3：Darknet代码解析（五）权重与特征存储][YOLOv3_Darknet 3]

[YOLOv3：Darknet代码解析（六）简化的程序与卷积拆分][YOLOv3_Darknet 4]

[https_github.com_AlexeyAB_yolo2_light]: https://github.com/AlexeyAB/yolo2_light
[YOLOv3_Darknet_Darknet]: https://blog.csdn.net/weixin_36474809/article/details/80881043
[YOLOv3_Darknet]: https://blog.csdn.net/weixin_36474809/article/details/80975845
[YOLOv3_Darknet 1]: https://blog.csdn.net/weixin_36474809/article/details/81296612
[YOLOv3_Darknet 2]: https://blog.csdn.net/weixin_36474809/article/details/81326286
[YOLOv3_Darknet 3]: https://blog.csdn.net/weixin_36474809/article/details/81331175
[YOLOv3_Darknet 4]: https://blog.csdn.net/weixin_36474809/article/details/81739771
[70]: /images/20220516/37bb885181574badae597dbd9b785a82.png