Oh Sorry I did not want to mean mAP as a Criterion (differentiable Layer). I just wanted to find an exact implementation of that as metric.
On the other hand, I want to say that we can find an exact implementation of mAP specifically for each dataset. Since I benefited from MSCOCO Detection Dataset, the author of MSCOCO present a good module in python to measure this metric.
By the way thanks for your response!