ar {brms}  R Documentation 
Set up AR(p) correlation structures
Description
Set up an autoregressive (AR) term of order p in brms. The function does not evaluate its arguments – it exists purely to help set up a model with AR terms.
Usage
ar(time = NA, gr = NA, p = 1, cov = FALSE)
Arguments
time 
An optional time variable specifying the time ordering of the observations. By default, the existing order of the observations in the data is used. 
gr 
An optional grouping variable. If specified, the correlation structure is assumed to apply only to observations within the same grouping level. 
p 
A nonnegative integer specifying the autoregressive (AR)
order of the ARMA structure. Default is 
cov 
A flag indicating whether ARMA effects should be estimated by
means of residual covariance matrices. This is currently only possible for
stationary ARMA effects of order 1. If the model family does not have
natural residuals, latent residuals are added automatically. If

Value
An object of class 'arma_term'
, which is a list
of arguments to be interpreted by the formula
parsing functions of brms.
See Also
Examples
## Not run:
data("LakeHuron")
LakeHuron < as.data.frame(LakeHuron)
fit < brm(x ~ ar(p = 2), data = LakeHuron)
summary(fit)
## End(Not run)