kjetilh@umsanet.edu.bo
2000-Oct-02 15:27 UTC
[Rd] documentation error for deriv; MASS scripts ch8; (PR#676)
Hola! There is a bug in the documentation file for deriv, which says that the third argument is unimplemented. It seems only to be implemented differently than in s-plus. I show whith the MASS R-script ch8 file as example:> expn1 <- deriv(y ~ b0 + b1 * 2^(-x/th), c("b0", "b1", "th"),+ function(b0, b1, th, x) {})> expn1function(b0, b1, th, x) {} which cannnot be used whith nls! But changing to:> expn1 <- deriv(y ~ b0 + b1 * 2^(-x/th), c("b0", "b1", "th"),+ c("b0", "b1", "th", "x") )> expn1function (b0, b1, th, x) { .expr3 <- 2^(-x/th) .value <- b0 + b1 * .expr3 .grad <- array(0, c(length(.value), 3), list(NULL, c("b0", "b1", "th"))) .grad[, "b0"] <- 1 .grad[, "b1"] <- .expr3 .grad[, "th"] <- b1 * (.expr3 * (log(2) * (x/th^2))) attr(.value, "gradient") <- .grad .value } gives the desired result. Kjetil Halvorsen -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-devel mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-devel-request@stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._