nlme (version 3.1-164)

formula.pdBlocked: Extract pdBlocked Formula

Description

The formula attributes of the pdMat elements of x are extracted and returned as a list, in case asList=TRUE, or converted to a single one-sided formula when asList=FALSE. If the pdMat elements do not have a formula attribute, a NULL value is returned.

Usage

# S3 method for pdBlocked
formula(x, asList, ...)

Value

a list of one-sided formulas, or a single one-sided formula, or

NULL.

Arguments

x

an object inheriting from class "pdBlocked", representing a positive definite block diagonal matrix.

asList

an optional logical value. If TRUE, a list with the formulas for the individual block diagonal elements of x is returned; else, if FALSE, a one-sided formula combining all individual formulas is returned. Defaults to FALSE.

...

some methods for this generic require additional arguments. None are used in this method.

Author

José Pinheiro and Douglas Bates

See Also

pdBlocked, pdMat

Examples

pd1 <- pdBlocked(list(~ age, ~ Sex - 1))
formula(pd1)
formula(pd1, asList = TRUE)