Error in MEEM(object, conLin, control$niterEM) : Singularity in backsolve at level 0, block 1 in LME model

Thank you for your explanation. I really appreciate it.
However, there is no change using nlme (Error in MEEM(object, conLin,
control$niterEM) : Singularity in backsolve at level 0, block 1 in LME
model) and lmer (fixed-effect model matrix is rank deficient so dropping 6
columns / coefficients). My problem is not resolved.
There is a problem with repetition only when I use lmer model.

Arivoara Rabarijaona

Le mer. 7 juil. 2021 ? 16:26, Ben Bolker <bbolker at gmail.com> a ?crit :

   You have constructed a model with multicollinear predictors (another
way to put this is that your model matrix is rank-deficient).  R's
formula interface usually takes care of discarding redundant columns,
but when interactions are spelled out explicitly with it can't always
manage. You might do better expressing the fixed effects component of
the model as

(provenance + treatment + status)^2
'
As is often stated in this forum, you may have trouble fitting a random
effect with only four levels (repetition).

   Ben Bolker

On 7/7/21 4:01 AM, Arivoara Rabarijaona wrote:

Thank you,
provenance:treatment is normal, nothing is unexpected
I think the problem is with provenance:status, but I don't know how to
resolve it.
Using lmer, I get the message: fixed-effect model matrix is rank

deficient

so dropping 18 columns / coefficients

Ari

Le mer. 7 juil. 2021 ? 09:52, romunov <romunov at gmail.com> a ?crit :

Have you tried plotting this? My guess is that you will find something
unexpected in the provenance:treatment level combination.

Cheers,
Roman

On Wed, Jul 7, 2021 at 9:03 AM Arivoara Rabarijaona <

arivoara at gmail.com>

wrote:

Hi,
I hope someone can help me. I'm using nlme to fit models.

My dataframe (1785 obs) :
$ id: Factor w/595 levels
$ treatment: Factor w/3 levels
$ provenance: Factor w/16 levels
$ repetition: Factor w/4 levels
$ bloc: Factor w/66 levels # nested to repetition
$ response: num ... (1777 obs and 8 NA) # 3 repeated measures by id
$ status: Factor w/3 levels, "dominant","codominant","suppressed" #

there

are 6 provenances without suppressed trees

I want to run a modele like this :

modele <- lme(response  ~ provenance + treatment +

provenance:treatment +

status + status:treatment + statuts:provenance,
                    random = ~ 1|repetition/bloc,
                    correlation = corAR1(form = ~

1|repetition/bloc/id),

                    data, method= "ML", na.action =na.omit)

I get the message :
Error in MEEM(object, conLin, control$niterEM) :   Singularity in
backsolve
at level 0, block 1 in LME model

If I run the modele without the interaction statuts:provenance, it

works.

Can anyone tell me how to resolve this error ?

Thanks,
Arivoara Rabarijaona

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In God we trust, all others bring data.

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