Dear all,

I am using R, version 2.9.2, to fit a linear mixed model with lme4 package
with the next structure:

BASE1<-lmer(log(H09)~ log(DN)+ PmaS+PmaP + PmaSPmaP+ TmaS+TmaP + TmaSTmaP+
PavS+PavP + PavSPavP +  (1|P)+(1|S/B)+(1|SP), REML=T, data=data)

[I want to see how tree allometry vary across environment gradients:
precipitation, temperature and number of growing season]

In this previous step I only want to see how the different variables
 influence the relation between height:diameter in trees in the fixed part
of the model, just to decide or to justify why I choose some of the
variables against the others.
I´ve already done this before with other species but in this case I get
this error message:

Error en mer_finalize(ans) : Downdated X'X is not positive definite, 9

How can I solve this? is a problem related with my data?

Thank you very much in advance,

Natalia VIZCAÍNO PALOMAR

Ph.D Student

Centro de Investigación Forestal (CIFOR) - INIA

Ctra A Coruña km 7,5

28040 Madrid. Spain

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