Hi list,
i see this question is quiet a regular feature,
but searching the past instances i could not
find an answer to my specific problem.
Simply, trying to optimize this model gives
a singular gradient problem -- tough optim()
seems to be able to solve it would like to
do these things in nls().
Treated<-Puromycin[Puromycin$state=="treated",]
weighted.MM<-function(resp,conc,K){
pred<-K[1]+(1-exp(K[2]))*conc
(resp-pred)
}
Pur.wt<-nls(~weighted.MM(rate,conc,K),data=Treated,start=list(K=c(0,0.1)))
Please advise,
Best,
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