Description Usage Arguments Details Value Author(s) References See Also Examples
Computes the wavelet phasor mean field from a matrix of spatiotemporal data. Also the
creator function for the wpmf
class. The wpmf
class inherits from the
tts
class, which inherits from the list
class.
1 2 3 4 5 6 7 8 9 10 |
dat |
A locations (rows) x time (columns) matrix |
times |
A vector of time step values, spacing 1 |
scale.min |
The smallest scale of fluctuation that will be examined. At least 2. |
scale.max.input |
The largest scale of fluctuation guaranteed to be examined |
sigma |
The ratio of each time scale examined relative to the next timescale. Should be greater than 1. |
f0 |
The ratio of the period of fluctuation to the width of the envelop |
sigmethod |
Method for significance testing the wmpf, one of |
nrand |
The number of randomizations to be used for significance testing |
For sigmethod
equal to quick
, the empirical wpmf is compared to a distribution of
magnitudes of sums of random phasors, using the same number of phasors as there are time series. The signif
output is a list with first element "quick
" and second element a vector of nrand
magnitudes of sums
of random phasors. For sigmethod
equal to fft
, the empirical wpmf is compared to wmpfs of
Fourier surrogate datasets. The signif
output is a list with first element "fft
", second element
equal to nrand
, and third element the fraction of surrogate-based wpmf magnitudes that the empirical wpmf
magnitude is greater than (times by timescales matrix). For sigmethod
equal to aaft
, aaft
surrogates are used instead. Output has similar format to the fft
case. Values other than quick
,
fft
, and aaft
for sigmethod
result in no significance testing.
wpmf
returns an object of class wpmf
. Slots are:
values |
A matrix of complex numbers containing the wavelet phasor mean field, of dimensions |
times |
The times associated with the data and the |
timescales |
The timescales associated with the |
signif |
A list with information from the significance testing. Format depends on |
dat |
The data matrix (locations by time) from which the |
wtopt |
The inputted wavelet transform options scale.min, scale.max.input, sigma, f0 in a list |
Thomas Anderson, anderstl@gmail.com, Jon Walter, jaw3es@virginia.edu; Lawrence Sheppard, lwsheppard@ku.edu; Daniel Reuman, reuman@ku.edu
Sheppard, L.W., et al. (2016) Changes in large-scale climate alter spatial synchrony of aphid pests. Nature Climate Change. DOI: 10.1038/nclimate2881
wpmf_methods
, wmf
, tts
, plotmag
,
browseVignettes("wsyn")
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