Get weights for regression

Get weights for WRTDS for a single observation using a tri-cubic weighting function

getwts(dat_in, ...)

# S3 method for default
getwts(
  dat_in,
  ref_in,
  wt_vars = c("day_num", "dec_time", "flo"),
  wins = list(0.5, 10, NULL),
  all = FALSE,
  slice = TRUE,
  ngrzero = FALSE,
  wins_only = FALSE,
  min_obs = 100,
  ...
)

Arguments

dat_in

input tidal object

...

arguments passed to or from other methods

ref_in

row of tidal object as reference for weights

wt_vars

chr string of three elements indicating names of columns in tidal object that are used for reference row weights

wins

list of half-window widths for time, year, and flow

all

logical to return individual weights rather than the product of all three, default FALSE

slice

logical indicating if data are subset by observations within the maximum window width for faster calculations

ngrzero

logical indicating if count of observations with weights greater than zero is returned

wins_only

logical if the half-window widths should be returned as a list

min_obs

numeric vector for window widening if the number of observations with non-zero weights is less than the specified value, use min_obs = NULL to suppress this behavior

Value

A vector of weights with length equal to the number of observations (rows) in the tidal object. Vectors for all three weighting variables are returned if all = TRUE.

Details

The default half-window widths for day_num, year, and flow are half a day (12 hours), 10 years, and half the range of salinity/flow in the input data. The half-window widths are expanded by 10% until at least 100 observations have weights greater than zero. This behavior can be suppressed by setting min_obs = NULL.

Examples

##
data(tidobj)

# get weights for first row
first <- tidobj[1, ]
wts <- getwts(tidobj, first)

plot(wts, type = 'l')


if (FALSE) {

# get count of observations with grzero weights
sapply(1:nrow(tidobj), function(row) getwts(tidobj, tidobj[row, ], 
 ngrzero = TRUE))
}