Explanation of why precision drops to 0?

[anvenkat09]

Hi MathGaron,

Thanks for your wonderful implementation of MAP. I was just wondering if you could explain the reasoning as to why for some classes the precision just drops to 0 after decreasing for a little bit. In your Readme for Class 0, the precision drops to 0 at a recall level of 0.9. Could you please explain this to me?

Thanks a lot!