jpl <s-jlubben1 <at> math.unl.edu> writes: > > > Hi, > > I am trying to fit a curve to data. My command line is: > > model10=nls(offspring~((A*c^k)/gamma(k))* ((degdays-alpha)^(k-1))*exp(-c*(degdays-alpha)), > start=list(A=30,k=2,c=.018,alpha=131)) >
try trace=TRUE to see where the function is trying to go. I think you could also simplify this a bit: model10 = nls(offspring~A*dgamma(degdays-alpha,rate=c,shape=k),...) You can probably also use algorithm="plinear" and eliminate the explicit A parameter. I would also consider using algorithm="port" and setting lower and upper boundaries. good luck, Ben Bolker ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
