AR(1) Correlation Structure

Re-exports nlme::corAR1 from the nlme package.

Usage

corAR1(value, form, fixed)

Arguments

value

numeric value for the correlation parameter.

form

a one-sided formula of the form ~ t, ~ 1 | g, or ~ t | g, specifying a time covariate t, a grouping factor g, or both. When no time covariate is specified, the row order of the data within each group is assumed to represent the chronological order of measurements.

fixed

unused

Details

In the original nlme::corAR1 function, a covariate t must be an integer class. In pwr4exp, t can also be a factor class, which is then converted to an integer internally for chronological order. The class of t in the model formula, if present, is not converted. For example, a time covariate can be fitted as a factor in the model formula, whereas it is converted to an integer in the correlation formula.

See also

corClasses See nlme::corAR1 for original documentation.