R: Interevents (or interarrivals) from events dates
interevt
R Documentation
Interevents (or interarrivals) from events dates
Description
Compute intervent durations from events dates
Usage
interevt(date,
skip = NULL, noskip = NULL)
Arguments
date
A POSIXct vector containing the date(time) of the events.
skip
A data.frame containing two POSIXct columns start and
end describing the periods to skip over.
noskip
A data.frame like skip but where the periods define the NON
skipped part of the events.
Details
Interevents are the time differences between successive dates. When
the date argument contains occurrence times T[i]
for successive events of an homogeneous Poisson process, interevents
T[i] - T[i-1] are mutually independent with the
same exponential distribution.
When some time intervals are skipped independently from the event
point process, we may consider the interevents
T[i] - T[i-1] between two non-skipped events such
that the time interval (T[i-1], T[i]) does not
contains any skipped interval. These interevents still are mutually
independent with the same exponential distribution. When skip
or noskip is not NULL the computation therefore only
retains couples of two successive datetimes "falling" in the same
non-skipped period, which number can therefore be associated with the
interevent.
Value
A list mainly containing a interevt data.frame.
interevt
Data.frame. Each row describes a retained interevent through a
period integer giving the "noskip" period, a start and
endPOSIXct and a duration in days.
noskip
Only when skip or noskip args have been given. A
data.frame containing broadly the same information as the
noskip arg is it was given or the information deduced from
the skip arg if given.
axis
When needed, a list with some material to build an axis with uneven
ticks as in the gof.date with skip.action = "omit".
Note
Only one of the two arguments skip and noskip should be
given in the call. In each case, the rows of the returned data.frame
objects describe periods in chronological order. That is: start
at row 2 must be after the end value of row 1 and
so on.
Note that there are usually less interevents than dates since two
successive dates will be retained for an interevent only when they are
not separated by missing period. As a limit case, there can be no
interevents if the noskip periods contain only one date from
the date vector.
Author(s)
Yves Deville
See Also
gof.date for goodness-of-fit diagnostics for dates of
events expplot for diagnostics concerning the
exponential distribution.
Examples
## Use Brest data
ie <- interevt(date = Brest$OTdata$date, skip = Brest$OTmissing)
expplot(ie$interevt$duration, rate = 1 / mean(ie$interevt$duration),
main = "No threshold")
## keep only data over a threshold
ind1 <- Brest$OTdata$Surge >= 35
ie1 <- interevt(Brest$OTdata$date[ind1], skip = Brest$OTmissing)
expplot(ie1$interevt$duration, main = "Threshold = 35")
## increase threshold
ind2 <- Brest$OTdata$Surge >= 55
ie2 <- interevt(date = Brest$OTdata$date[ind2], skip = Brest$OTmissing)
expplot(ie2$interevt$duration, main = "Threshold = 55 cm")
Results
R version 3.3.1 (2016-06-21) -- "Bug in Your Hair"
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> library(Renext)
Loading required package: evd
> png(filename="/home/ddbj/snapshot/RGM3/R_CC/result/Renext/interevt.Rd_%03d_medium.png", width=480, height=480)
> ### Name: interevt
> ### Title: Interevents (or interarrivals) from events dates
> ### Aliases: interevt
>
> ### ** Examples
>
> ## Use Brest data
> ie <- interevt(date = Brest$OTdata$date, skip = Brest$OTmissing)
>
> expplot(ie$interevt$duration, rate = 1 / mean(ie$interevt$duration),
+ main = "No threshold")
>
> ## keep only data over a threshold
> ind1 <- Brest$OTdata$Surge >= 35
> ie1 <- interevt(Brest$OTdata$date[ind1], skip = Brest$OTmissing)
> expplot(ie1$interevt$duration, main = "Threshold = 35")
>
> ## increase threshold
> ind2 <- Brest$OTdata$Surge >= 55
> ie2 <- interevt(date = Brest$OTdata$date[ind2], skip = Brest$OTmissing)
> expplot(ie2$interevt$duration, main = "Threshold = 55 cm")
>
>
>
>
>
> dev.off()
null device
1
>