https://blog.csdn.net/m0_37799466/article/details/105756319
计算anchor的指令：
./darknet detector calc_anchors cfg/voc.data -num_of_clusters 9 -width 416 -height 416
训练时计算相应的mAP值
./darknet detector train cfg/coco.data yolov3.cfg yolov3.conv.137 -map
测试时计算相应的mAP值，并保存result.txt
./darknet detector map data/obj.data yolo-obj.cfg backup\yolo-obj_7000.weights -dont_show -ext_output < data/train.txt > result.txt