Transition rate matrix


In probability theory, a transition rate matrix is an array of numbers describing the instantaneous rate at which a continuous time Markov chain transitions between states.
In a transition rate matrix Q element qij denotes the rate departing from i and arriving in state j. Diagonal elements qii are defined such that
and therefore the rows of the matrix sum to zero.

Definition

A Q matrix satisfies the following conditions
This definition can be interpreted as the Laplacian of a directed, weighted graph whose vertices correspond to the Markov chain's states.

Example

An M/M/1 queue, a model which counts the number of jobs in a queueing system with arrivals at rate λ and services at rate μ, has transition rate matrix