f-divergence

In probability theory, an ${\displaystyle f}$-divergence is a certain type of function ${\displaystyle D_{f}(P\|Q)}$ that measures the difference between two probability distributions ${\displaystyle P}$ and ${\displaystyle Q}$. Many common divergences, such as KL-divergence, Hellinger distance, and total variation distance, are special cases of ${\displaystyle f}$-divergence.