I have two functions which appear to differ only in their environments. They look like:
> d1 > function (x, mean = 0, sd = 1, log = FALSE) > (((x - mean)/sd)^2 - 1) * if (log) 1 else dnorm(x, mean, sd)/sd > <environment: namespace:stats> and > d2 > function (x, mean = 0, sd = 1, log = FALSE) > (((x - mean)/sd)^2 - 1) * if (log) 1 else dnorm(x, mean, sd)/sd Typing "environment(d1)" gives > <environment: namespace:stats> and typing "environment(d2)" gives > <environment: R_GlobalEnv> The d2() function however gives an incorrect result: > d1(1,0,3,TRUE) > [1] -0.2962963 > d2(1,0,3,TRUE) > [1] -0.8888889 In d2() the result of the if() statement does not get divided by the final "sd" whereas in d1() it does (which is the desired/correct result). Of course the code is ridiculously kludgy (it was produced by "symbolic differentiation"). That's not the point. I'm just curious (idly?) as to *why* the association of the namespace:stats environment with d1() causes it to "do the right thing". Can anyone give me any insight? Ta. cheers, Rolf Turner -- Honorary Research Fellow Department of Statistics University of Auckland Phone: +64-9-373-7599 ext. 88276 ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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.
