pdConstruct.pdInd: Construct pdInd object
In gmonette/nlmeYextra: Functions to add functionality to nlme

This function is a constructor for a pdInd object.

1 2	pdConstruct.pdInd(object, value = numeric(0), form = formula(object), nam = Names(object), data = sys.parent(), ...)

`object`	an object inheriting from the class `pdInd`, representing a positive definite matrix with zero covariances except in the first row and column.
`value`	and option initialization value, which can be any of the following ...
`form`	an optional one-sided linear formula specifying the row/column names for the matrix represented by `object`.
`nam`	and optional vector of character strings specifying the row/column names for the matrix represented by `object`.
`data`	and optional data frame i which to evaluate the variables names in `value` and `form`. ...