Dear All,

I have some questions regarding using the genpoisson{VGAM} .

genpoisson(llambda="elogit", ltheta="loge",
           elambda=if(llambda=="elogit") list(min=-1,max=1) else list(),
           etheta=list(), ilambda=NULL, itheta=NULL,
           use.approx=TRUE, method.init=1, zero=1)

and I am understanding the part  zero An integer vector, containing the
value 1 or 2. If so, *λ* or *theta* respectively are modeled as an
intercept only. If set to NULL then both linear/additive predictors are
modelled as functions of the explanatory variables.


For a simple generalized model like mu=exp(a+bx)=theta/(1-phi) which option
to select 0/1/NULL. I am not getting the parameterization used here. PLease
help!

Thanks!

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