applyWindows: applyWindows

In REddyProc: Data processing and plotting utilities of (half-)hourly eddy-covariance measurements

Description

apply a function to several windows of a data.frame

Usage

applyWindows(ds, FUN, prevRes = list(), winSizeInDays = winSizeRefInDays, 
    winSizeRefInDays = 4L, strideInDays = floor(winSizeRefInDays/2L), 
    isVerbose = TRUE, nRecInDay = 48L, ...)

Arguments

ds	dataframe to iterate
FUN	function to apply to subsets of the data.frame taking a subset of the data.frame as first argument the second: a one-row data.frame with window information (iWindow, dayStart, dayEnd, iRecStart, iRecEnd, iCentralRec) the third a list that can transport values from previous fits, i.e. the third item of its return value with first item a list (objects that cannot be rowbound) second item a single row data.frame (summary that can be row-bound) third item a list that is will be provided to the call of this function on the next window as the second argument
prevRes	initial values for the list that is carried between windows
winSizeInDays	Window size in days
winSizeRefInDays	Window size in days for reference window (e.g. day-Window for night time)
strideInDays	step in days for shifting the window, for alligning usually a factor of winSizeRef
isVerbose	set to FALSE to suppress messages
nRecInDay	number of records within one day (for half-hourly data its 48)
...	further arguments to FUN

Details

Assumes equidistant rows with nRecInDay records forming one day and reporting full days i.e. all of the nRecInDay records are in the first day.

In order to have a common reference winSizeRefInDays is given so that results by a different window size correspond to each window of shifting a window of winSizeRefInDays Each window is anchord so that the center equals the center of the reference window. This becomes important when selecting records at the edges of the series.

Value

a list with components that correspond to the three result components of FUN

resOptList	a list with restults of length nrow(ds)
summary	a data.frame with nrow(ds) rows, also including window information (iWindow, dayStart, dayEnd, iRecStart, iRecEnd, iCentralRec)
prevRes	last result of the values carried over between windows

Author(s)

(Department for Biogeochemical Integration at MPI-BGC, Jena, Germany)

REddyProc documentation built on May 2, 2019, 5:19 p.m.