[R-sig-ME] help: error in fn(x, ...): Downdated VtV is not positive definite

[Ben Bolker]

 what is frace?

  This is a relatively rare error message.  It usually indicates a
strongly unbalanced/unstable model for some reason. Have you tried
rescaling parameters?  Do simpler versions of the model work?
On Thu, Jul 19, 2018 at 3:15 PM Ahreum Maeng <amaengwork using gmail.com> wrote:
>
> Hello,
>
> I got a following error message while running a MLM using lme4 package.
>
> Error in fn(x, ...) : Downdated VtV is not positive definite
>
>
> my model was as following:
>
> out <- lmer(situ ~ cult*change + (change || id) + (0 + frace | type), data
> = tidy.total, REML=FALSE)
>
> where
> situ:  numeric
> change: numeric
> cult: factor (coded in 1 and -1)
>
>
> How could I fix this issue?
>
> Thanks a lot,
> Ahreum
>
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>
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