What is the lmer/nlme equivalent of the REPEATED subcommand in SPSS's MIXED procedure?

Dear Ben, dear Phillip,

comparing [1] with [2] I think the /REPEATED command specifies 
the error (co)variance structure of the model. Would you agree with that?
If so, AFAIK this is not possible with lmer and thus the answer on 
Stack Overflow [3] would be wrong.

[1] 
https://stats.idre.ucla.edu/r/examples/alda/r-applied-longitudinal-data-analysis-ch-7/
[2] 
https://stats.idre.ucla.edu/spss/examples/alda/chapter7/applied-longitudinal-data-analysis-modeling-change-and-event-occurrenceby-judith-d-singer-and-john-b-willett-chapter-7-examining-the-multilevel-model-s-erro/
[3] 
https://stackoverflow.com/questions/48518514/what-is-the-lmer-nlme-equivalent-of-the-repeated-subcommand-in-spsss-mixed-proc

Regards,
Maarten

On Tue, Mar 20, 2018 at 2:10 PM, Ben Pelzer <b.pelzer at maw.ru.nl 
<mailto:b.pelzer at maw.ru.nl>> wrote:

    Dear Maarten,

    Take a look at

    https://stats.idre.ucla.edu/r/examples/alda/r-applied-longitudinal-data-analysis-ch-7/
    <https://stats.idre.ucla.edu/r/examples/alda/r-applied-longitudinal-data-analysis-ch-7/>

    which shows you a number of covariance structures, among which is
    the unstructured matrix, for repeated measures in R with lme. It
    refers to chapter 7 of Singer and Willett where they discuss all
    these different structures and how to choose among them. Regards,

    Ben.

    On 20-3-2018 9:00, Maarten Jung wrote:

        Dear list,
        I came across a SPSS syntax like this

        MIXED value BY factor1
             /CRITERIA=CIN(95) MXITER(100) MXSTEP(10) SCORING(1)
        SINGULAR(0.000000000001)
             HCONVERGE(0, ABSOLUTE) LCONVERGE(0, ABSOLUTE)
        PCONVERGE(0.000001,
             ABSOLUTE)
             /FIXED=factor1 | SSTYPE(3)
             /METHOD=REML
             /REPEATED=factor1 | SUBJECT(participant) COVTYPE(UN).

        and struggle to find an equivalent lmer/nlme (or R in general)
        formulation
        for this kind of models.
        Does anybody know how to convert the REPEATED subcommand into
        R code?

        Please note that I asked the question on Stack Overflow about
        two month ago:
        https://stackoverflow.com/questions/48518514/what-is-the-lmer-nlme-equivalent-of-the-repeated-subcommand-in-spsss-mixed-proc
        <https://stackoverflow.com/questions/48518514/what-is-the-lmer-nlme-equivalent-of-the-repeated-subcommand-in-spsss-mixed-proc>

        Best regards,
        Maarten

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