nancy_shackelford <nancy.shackelford <at> gmail.com> writes: > Hello all, > > I need to imitate the 'q' function (qnorm, qweibull, etc) for Clark's 2Dt > distribution model. I'm not skilled enough in R to code it myself, so I > thought I could find the base code for one of the existing 'q' functions and > just modify it. However, I'm having trouble navigating through the R Source > Code on the CRAN website. I've searched some forum and help sites, but I > can't find anything specific on locating function codes. > > I also read somewhere that Clark's 2Dt is available in the R distribution > functions, but I haven't found anything that confirms that.
You can find the C source code for qt in http://svn.r-project.org/R/trunk/src/nmath/qt.c and the R code is in http://svn.r-project.org/R/trunk/src/library/stats/R/distn.R but I don't think this is really what you want. As pointed out in Clark et al 1999 (Ecology), the "Clark 2Dt" function is just a bivariate version of the univariate t-distribution. I think that if you stare at the equations in Clark et al 1999 and (e.g.) in ?dt you can probably adapt the existing pt/qt functions to get where you need, adjusting normalizing constants as appropriate ... PS: when asking questions about field-specific topics on the general R list, it's a good idea to give a little more background -- even references, in case someone is interested. Few people outside of community ecology have heard of "Clark's 2Dt" ... good luck, Ben Bolker ______________________________________________ R-help@r-project.org 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.
