search for: storchi

...;goto" associated to a "label") or a pause like command to prevent R from reading the entire script?? I actually have this kind of code reapeat{ ... ... ... switch(menu(c("continue to select points","modelling"),next,break)) } ... ... Thanks a lot Guillaume STORCHI

How is it possible to "split" a data.frame in order to get classes with variable size. actually I'd like to get classes of data with classe size (cs) so that cs becomes bigger with an other increasing value. Guillaume Storchi

...I got 8 fitted values that I enventually embedded in my nls() function, like above, yet R talled me: "Error in nlsModel(formula, mf, start) : singular gradient matrix at initial parameter estimates" should I use optim() or optimize()? How could I perform it? Thanks for help Guillaume Storchi

AFAIK most model fitting techniques will only deal with additive errors, not multiplicative ones. You might want to try fitting: log(y-x) = a*x + e which is linear. Andy > From: Angelo Secchi > > Hi, > is there a way in R to fit a non linear model like > > y=x+exp(a*x)*eps > > where a is the parameter and eps is the error term? > Thanks > Angelo > >

Hello, I have a problem with nls() when I want to fit a model with more than two parameters to be fitted which are written as start=list(a1=,a2=,a3=,...). Everytime, it displays:'error... singular gradient' it's a real pain!!! Hope sb knows something about this Thanks GS

if a and eps are parameters to be fitted X<-nls(y~x+exp(a*x)*eps, data=,start=list(a=,eps=))