getwts function

Get weights for regression

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

getwts(dat_in, ...)

## Default S3 method:
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

Returns

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')

## Not run:

# get count of observations with grzero weights
sapply(1:nrow(tidobj), function(row) getwts(tidobj, tidobj[row, ], 
 ngrzero = TRUE))
## End(Not run)