Recurrence plot

In descriptive statistics and chaos theory, a recurrence plot (RP) is a plot showing, for each moment ${\displaystyle j}$ in time, the times at which the state of a dynamical system returns to the previous state at ${\displaystyle i}$, i.e., when the phase space trajectory visits roughly the same area in the phase space as at time ${\displaystyle j}$. In other words, it is a plot of

${\displaystyle {\vec {x}}(i)\approx {\vec {x}}(j),}$

showing ${\displaystyle i}$ on a horizontal axis and ${\displaystyle j}$ on a vertical axis, where ${\displaystyle {\vec {x}}}$ is the state of the system (or its phase space trajectory).