[R] use of covariates with nlmeODE

From: Jesus Frias <Jesus.Frias_at_dit.ie>
Date: Wed 16 Mar 2005 - 22:02:35 EST

Dear R-helpers,

        I have some problem with a model I am trying to run with nlmeODE. I have a covariate that I want to include in the model and I can't find in the documentation how to include it in the model so that it can calculate it.


PME ~ time | Ident

abcnoniso <- list(DiffEq=list(

                    debdt = ~ -ksol*pH*eb ,
                    desdt = ~ ksolref*pH*eb-kdegref*pH*es,
                    dpHdt= ~ -k*(pH-pHinf)
                    c1 = ~ 0,
                    c2 = ~ es,
                    c3 = ~ 0),
abcnonisomodc <- nlmeODE(abcnoniso,trial)

The variable pHinf is a covariate that changes from experiment to experiment. The model does not take very well pHinf.



Jesús María Frías Celayeta
School of Food Sci. and Env. Health.
Faculty of Tourism and Food
Dublin Institute of Technology
Cathal Brugha St., Dublin 1. Ireland
t +353 1 4024459 f +353 1 4024495
w www.dit.ie/DIT/tourismfood/science/staff/frias.html
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Received on Wed Mar 16 22:51:42 2005

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