Crashes with a DivideByZeroError when there are no detections

[drewm1980]

Badly trained algorithms might not return detections at all. Tide should return meaningful results in this case instead of crashing on line:

https://github.com/dbolya/tide/blob/49a5d2a4aeb56795e93a3ed7cc7e6d25757bb4c1/tidecv/ap.py#L150

With a quick search, I see several other places in the code that perform unchecked divisions. Tide should check for zero and either return meaningful results or meaningful error messages in all of them.

[BartvanMarrewijk]

Similar issue when the using the plot function with a AP50 of 100%

[nikheelpandey]

Hey, has anyone found a fix for it?

[meftehs]

Hey, Similar for me too, I tried to test yolov7 on coco dataset and then when i run tide.summarize(), an error of division by 0 appears !!!