a question about optim.R and optim.c in R
Hi,
On Mon, Jul 7, 2014 at 4:34 PM, Zhiyuan Dong <zhiyuan.dong at gmail.com> wrote:
Hi, I am learning R by reading R source code.
That's very brave of you. You might also try reading some of the documentation and contributed documentation, like: http://adv-r.had.co.nz/C-interface.html and http://cran.r-project.org/doc/manuals/r-devel/R-exts.html Sarah Here is one question I have
about the optim function in R. The context : In the optim.R, after all the prep steps, the main function call call is made via : .External2(C_optim, par, fn1, gr1, method, con, lower, upper). So, it seems to me, to follow what is going on from here, that I should read the optim function in \src\library\stats\src\optim.c where it has this signature : SEXP optim(SEXP call, SEXP op, SEXP args, SEXP rho) I am not sure I follow here : In the .External2 call, we have 7 parameters : par, fn1, gr1, method, con, lower, upper; This does not seem to match the signature of SEXP optim(SEXP call, SEXP op, SEXP args, SEXP rho) However, it seems (from the source code) that the 7 parameters are somehow embedded in the 'args' parameter. I am not sure what is going on...Am I missing something? Thanks much!!! Best, Zhiyuan
Sarah Goslee http://www.functionaldiversity.org