[R] Rare behaviour for nlme::reStruct example and question about ?lmeObject

[Martin Maechler]

>>>>> Andrew Simmons 
>>>>>     on Tue, 15 Nov 2022 18:01:55 -0500 writes:

   > This seems to be a bug. I tried creating this function in the global
   > environment:

   > str.pdMat <- function (object, ...)
   > {
   >     if (nlme::isInitialized(object)) {
   >         NextMethod()
   >     }
   >     else {
   >         cat(" Uninitialized positive definite matrix structure of class ",
   >             class(object)[1], ".\n", sep = "")
   >     }
   > }

Thank you, Iago, for the question and Andrew for your proposal.

Yes, I agree that something like the above -- which is derived from the
print.pdMat method --  should be added to nlme and will do this
myself.

   > and the code you sent works:
   > 
   > > library(nlme)
   > > rs1 <- reStruct(list(Dog = ~day, Side = ~1), data = Pixel)
   > > rs1
   > Uninitialized random effects structure
   > > str(rs1)
   > List of 2
   >  $ Side: Uninitialized positive definite matrix structure of class pdLogChol.
   >  $ Dog : Uninitialized positive definite matrix structure of class pdLogChol.
   >  - attr(*, "settings")= int [1:5] 0 1 0 4 4
   >  - attr(*, "class")= chr "reStruct"

In addition, Iago, asked

   > > >     In addition to that I would like to ask if shouldn't be `terms`
   > > >     documented in `?lmeObject`.

I probably have misunderstood the question completely (?)

I've now searched through ?lmeObject 
which was written under the assumption that the reader has
already read (parts of) the  ?lme  help page.

Now "terms" only appears in  ?lmeObject in this paragraph

   fixDF: a list with components ‘X’ and ‘terms’ specifying the
          denominator degrees of freedom for, respectively, t-tests for
          the individual fixed effects and F-tests for the
          fixed-effects terms in the models.

and I don't think that there needs to be more explanation.

(??)

Martin