Dear list,

I'm trying to construct a zero-inflated negative binomial model but I get
greeted by an error. I haven't had the chance to try my dataset on different
OSs or different R version, but I did mange to try that for the "cod
parasite" data from Zuur et al book (Mixed effect models...) and I get a
similar error (models with different formulas may or may not go through,
depending on R  version and the system). This is the error I get for the cod
data.

1> nb1a <- zeroinfl(Intensity ~ Area*Year | Area*Year + Length,
dist="negbin", link="logit", data=ParasiteCod2)
Error in solve.default(as.matrix(fit$hessian)) :
  system is computationally singular: reciprocal condition number =
1.5208e-17

I get the same error on my data:

frm <- formula(st_zir ~ obs_b+sonce+mraz+nmv | obs_b+sonce+mraz+nmv)
nb <- zeroinfl(frm, dist="negbin", link="logit", data=zir2)
Error in solve.default(as.matrix(fit$hessian)) :
  system is computationally singular: reciprocal condition number =
3.87086e-25

Has anyone any idea how to solve this? It has been suggested that it's
something in my data, but I don't know what to think if the cod parasite
data shows different success/failures on different versions for the same
model.

Cheers,
Roman


-- 
In God we trust, all others bring data.

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