windowdrp {crqa}

Windowed Recurrence Profile

Description

A recurrence plot is computed in overlapping windows of a specified size for a number of delays smaller than the size of the window. In every window, the recurrence value for the different delays is calculated. A mean is then taken across the delays to obtain a recurrence value in that particular window.

Usage

windowdrp(ts1, ts2, windowstep, windowsize, lagwidth,
radius, delay, embed, rescale, normalize, mindiagline, minvertline,
tw, whiteline, recpt, side, method, metric, datatype)

Arguments

ts1

First time-series

ts2

Second time-series

windowstep

Interval by which the window is moved.

windowsize

The size of the window

lagwidth

The number of delays to be considered within the window

radius

For numeric time-series, the cutoff distance to accept or reject two-points as recurrent

delay

The delay unit by which the series are lagged.

embed

The number of embedding dimension for phase-reconstruction, i.e., the lag intervals.

rescale

Rescale the distance matrix; if rescale = 0 (do nothing); if rescale = 1 (mean distance of entire matrix); if rescale = 2 (maximum distance of entire matrix). if rescale = 3 (minimum distance of entire matrix). if rescale = 4 (euclidean distance of entire matrix).

normalize

Normalize the time-series; if normalize = 0 (do nothing); if normalize = 1 (Unit interval); if normalize = 2 (z-score).

mindiagline

A minimum diagonal length of recurrent points. Usually set to 2, as it takes a minimum of two points to define any line.

minvertline

A minimum vertical length of recurrent points.

tw

The Theiler window parameter

whiteline

A logical flag to calculate (TRUE) or not (FALSE) empty vertical lines.

recpt

A logical flag indicating whether measures of cross-recurrence are calculated directly from a recurrent plot (TRUE) or not (FALSE).

side

A string indicating whether recurrence measures should be calculated in the 'upper' triangle of the RP 'lower' triangle of the matrix, or 'both'. LOC is automatically excluded for 'upper' and 'lower'.

method

A string to indicate the type of recurrence analysis to peform. There are three options: rqa (autorecurrence); crqa(cross-recurrence); mdcrqa(multidimensional recurrence). Default value is crqa

metric

A string to indicate the type of distance metric used, default is euclidean but see help rdist() to list all other possible metrics.

datatype

a string (continuous or categorical) to indicate whether the nature of the data type

Value

It returns a list of arguments where:

profile

Time-course windowed recurrence profile

maxrec

Maximal recurrence observed along the time-course

maxlag

The point where maximal recurrence is observed

Author(s)

Moreno I. Coco ([e-mail]) and Rick Dale ([e-mail])

References

Boker, S. M., Rotondo, J. L., Xu, M., and King, K. (2002). Windowed cross-correlation and peak picking for the analysis of variability in the association between behavioral time series. Psychological Methods, 7(3), 338.

See Also

drpfromts

Examples

# use the available data
data(crqa) 

listener = eyemovement$listener
narrator = eyemovement$narrator

# NB, the parameters for windowsize and windowstep are large to allow
# faster running time, please set them carefully in your analysis. 

delay = 1; embed = 1; rescale = 1; radius = 0.001;
normalize = 0; mindiagline = 2; minvertline = 2;
tw = 0; whiteline = FALSE; recpt = FALSE; side = "both"
method = 'crqa'; metric = 'euclidean';  
datatype = "continuous"; windowsize =  100; 
lagwidth = 10; windowstep = 200

ans = windowdrp(narrator, listener, windowstep, windowsize, lagwidth, 
                radius, delay, embed, rescale, normalize, 
                mindiagline, minvertline, tw, 
                whiteline, recpt, side, method, metric, 
                datatype)


profile = ans$profile; maxrec = ans$maxrec; maxlag = ans$maxlag

plot(profile, type = 'l')