A cleaning robot wanders between three rooms — Kitchen, Hall, Study — and its room at the next minute depends only on the room it is in now. The transition probabilities are:
| Currently in | Kitchen | Hall | Study |
|---|---|---|---|
| Kitchen | |||
| Hall | |||
| Study |
A logger records which room the robot is in once every minute, forever. After the chain has settled into its long-run behaviour, the room recorded on a given minute behaves like a draw from the chain's stationary distribution.
You want the average surprisal of a single logged reading, judged on its own and ignoring which room preceded it — the Shannon entropy of that stationary distribution.
Base-2 logarithms (you will not need all of them):
What is that entropy, in bits? Round your answer to 3 decimal places.
Once you get it right, the reasoning behind the answer shows up here.
Observe convergence to the stationary state as the transition matrix powers update the state probability vector over time.