If you add a print(p), you will find that after a few iterations
u is negative which leads to problems with the power. It sometimes help write
u=exp(p), and compute the log later. From a statistical point of view, I am not
always happy with that solution, but even Pinheiro/Bates use it in the nlm
hi,
i try to apply a nls regression but i always have this error message
"Error in numericDeriv(form[[3]], names(ind), env) :
Missing value or an Infinity produced when evaluating the model"
i don't understand why it doesn't work
this is the programm that i run:
f <- function (x,p) {
u <
