Test for autocorrelation of residuals

Extracts residuals from a load.model (where residuals may be for the calibration data or for a new set of observations). Applies car::durbinWatsonTest to test for autocorrelation of those residuals.

Usage

residDurbinWatson(
  load.model,
  flux.or.conc = c("flux", "conc"),
  abs.or.rel.resids = c("absolute", "relative"),
  use.log = FALSE,
  newdata = NULL,
  plot.acf = TRUE,
  timestep.tol = .Machine$double.eps^0.5,
  irregular.timesteps.ok = NA
)

Arguments

load.model

a loadModel descendant

flux.or.conc

character. The format in which residuals should be calculated

abs.or.rel.resids

character. Should residuals be computed as the difference or the ratio of the observed and predicted values?

use.log

logical. use log residuals?

newdata

The data from which to compute residuals; if NULL, the original fitting data for load.model will be used.

plot.acf

logical. Should the autocorrelation function be plotted?

timestep.tol

the acceptable tolerance for considering timesteps regular.

irregular.timesteps.ok

logical. If FALSE, this function requires that the timesteps between observations are identical to one another, and a plot is generated and an error is thrown if this requirement is not met. If TRUE, the check is not performed. If NA (the default), the check is performed but the function proceeds with a warning and no plot if the timesteps are found to be irregular. Tests of autocorrelation are weak to wrong when timesteps are irregular, but timesteps are often at least a bit irregular in the real world.

Value

A Durbin-Watson test statistic applied to residuals.

See also

car::durbinWatsonTest

Other diagnostics: estimateRho(), getCorrectionFraction()