Entropy production rate of a Markov chain
= Entropy production rate of a Markov chain
For edge current $J_{ij}=w_{ij}P_i-w_{ji}P_j$, the total entropy production rate is
$$
\dot S_{\rm tot}=\frac12\sum_{i,j}J_{ij}
\log\frac{w_{ij}P_i}{w_{ji}P_j}\geq0.
$$
It vanishes precisely when every occupied edge satisfies detailed balance.