title: Loss and mAP chart in YOLOv4
body: <p>I'm still new to &quot;You Only Look Once&quot; object detection algorithm (YOLOv4 to be exact). I have some questions regarding the mAP and loss chart.</p>
  <p>I tried to follow the instructions from <a href="https://github.com/AlexeyAB/darknet#how-to-train-to-detect-your-custom-objects" rel="noreferrer">AlexeyAB Darknet</a>, and train my custom object detector using Google Colabs. After the training, it shows the loss and mAP chart as shown below.</p>
  <p>Loss and mAP chart:</p>
  <p><a href="https://i.stack.imgur.com/ftGtE.png" rel="noreferrer"><img src="https://i.stack.imgur.com/ftGtE.png" alt="image" /></a></p>
  <p>My questions are:</p>
  <ol>
  <li>Is there any chart other than this?</li>
  <li>Is this loss for training or validation?</li>
  <li>Why is there a sudden drop near iteration 1200?</li>
  <li>Is the output of the training only that chart and the weight files?</li>
  </ol>