C test functions for lmer()
On Sun, Oct 3, 2010 at 10:03 AM, murat k. <skorsky12 at gmail.com> wrote:
Hi, the caller side must be C based for my needs; Thanks for the lme4a suggestion.
I also saw an nlme package, which was a precursor to lme4 I belive.. Its interface seems to use more of basic C types, so it is easier to understand. I might actually go with that option, instead of lme4 which is too tightly integrated into R at this point.
Well the code in the nlme package is more than 10 years old and we have learned a lot about the computational methods in the intervening years. If you just want to fit a simple model with a random intercept you would be much better off starting from the equations or the C++ classes instead of trying to decide what the internal C code in either nlme or lme4 is doing.
On Sun, Oct 3, 2010 at 5:05 PM, Douglas Bates <bates at stat.wisc.edu> wrote:
On Sun, Oct 3, 2010 at 2:05 AM, Koala <skorsky12 at gmail.com> wrote:
Hi everyone, I am trying to use lmer() using only C; Does anyone have test functions available that do not require R? My main routine needs to be C, but I am having a hard time understanding the data types going back and forth between R and lme4 C code. Any help would be appreciated,
Well, naturally enough, those structures are the internal representations of R objects - vectors, matrices, functions, etc. ?You would need to read the "Writing R Extensions" manual to understand their structure and even then you would need most of the R API to be able to manipulate them. ?If you really want to embark on this, and it is definitely not trivial, I would recommend looking at the code in the lme4a package instead, because it is based on C++ classes and the Rcpp package. ?I'm not sure that I see the point, though, as R is already open source. ?If you want to reimplement for another system you would probably be better off examining the structure of the calculations and reimplementing them instead of trying to adapt the lme4 code.