This function uses Taken's method of delays to construct a phase-space representation of vector "x". It then calculates the euclidean distance matrix "D", and thresholds this matrix by "epsilon" to obtain the recurrence matrix (R). In addition, the time delay "tau", embedding dimension "emb", and threshold "epsilon" are all estimated if not provided by the user or left blank (refer to documentation in the function for details).
The recurrence matrix has information regarding the temporal relationship of the high-dimensional phase-space "A"...if there are many repeated trajectories over time, then the recurrence matrix will have many diagonal lines. There are many more sophisticated measurements that can be taken from the recurrence matrix, and many fantastic papers/posts can be found online.
This function is self-contained, i.e. it is not dependent on other functions that need to be downloaded.