On 9/1/05, Bill Shipley <[EMAIL PROTECTED]> wrote: > Hello. Following pages 342-347 of Pinheiro & Bates, I am trying to > write a self-starting nonlinear function (a non-rectagular hyperbola) to > be used in nonlinear least squares regression (and eventually for a > mixed model). When I use the getInitial function for my self-starting > function I get the following error message:
> > getInitial(photo~NRhyperbola(Irr,theta,Am,alpha,Rd),dat) > > Error in tapply(y, x, mean, na.rm = TRUE) : > > arguments must have same length > > Since I do not explicitly call tapply in my function that makes > NRhyperbola a self-starting function (called NRhyperbolaInit, see > below), I assume that the error is coming from within the mCall function > but I can't figure out where or how. My guess is that it is occuring in the call to sortedXyData but I won't be able to tell for sure without test data. One of the things that sortedXyData does is to average the y values for replicated x values. It seems that in the call the lengths of the x and y arguments are different. > > > > Would someone who has successfully done this be willing to look at my > code and see where the problem arises? > > > > > NRhyperbolaInit > > function(mCall,LHS,data) > > { > > xy<-sortedXyData(mCall[["x"]],LHS,data) > > if(nrow(xy)<3){ > > stop("Too few unique irradiance values") > > } > > theta<-0.75 > > Rd<-min(xy[,"y"]) > > Am<-max(xy[,"y"]) + abs(Rd) > > if(sum(xy[,"x"]<50)>3)alpha<-coef(lm(y~x,data=xy,subset=x<50))[2] > > if(sum(xy[,"x"]<50)<=3)alpha<-0.07 > > value<-c(theta,Am,alpha,Rd) > > names(value)<-mCall[c("theta","Am","alpha","Rd")] > > value > > } > > > > Bill Shipley > > [EMAIL PROTECTED] > > <http://callisto.si.usherb.ca:8080/bshipley/> > http://callisto.si.usherb.ca:8080/bshipley/ > > > > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help@stat.math.ethz.ch mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html > ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html