Displaying 2 results from an estimated 2 matches for "vonbertalanffy".
2012 Sep 04
3
Comparing Von Bertalanffy Growth Curves
I am trying to compare Vbert growth curves from several years of fish data. I am following the code provided by: http://www.ncfaculty.net/dogle/fishR/gnrlex/VonBertalanffy/VonBertalanffy.pdf. Specifically the section on VBGM Comparisons between groups.
?
This code is pretty cut and dry. I am able to run it perfectly with the "fake" data that is provided. But when I run it with my own data I get stuck with this line:
fitGen <- nls(vbGen,data=LMB,start=s...
2008 Feb 11
0
Memory allocation problem with large dataset
...but I am not sure how
to fix this problem. I am using R 2.6.1, and I have had similar problems in
S-plus.
My dataset is mass growth data from the same 8 animals over 10 years, and is
a data.frame with 23,598 rows and 5 columns, and using object.size(data)=
664448 bytes. My first model, using the VonBertalanffy growth function:
vanfemfunc<-function(age.years, A, lk, t0)
A*((1-exp(-exp(lk)*(age.years-t0)))^3)
vanfemfit1<-nlme(model=mass~vanfemfunc(age.years, A, lk, t0), data=vanfem,
fixed=A+lk+t0~1, start=c("A"=201.8, "lk"=-1.17, "t0"=-2.71))
This fits fine, and has a...