Hi [this after some considerable thought as to R-help vs R-devel]
I want to write a (S3) method for as.function(); toy example follows. Given a matrix "a", I need to evaluate trace(ax) as a function of (matrix) "x". Here's a trace function: tr <- function (a) { i <- seq_len(nrow(a)) return(sum(a[cbind(i, i)])) } How do I accomplish the following: a <- crossprod(matrix(rnorm(12),ncol=3)) class(a) <- "foo" f <- as.function(a) # need help to write as.function.foo() x <- diag(3) f(x) #should give tr(ax) a <- 4 f(x) # should still give tr(ax) even though "a" has been reassigned. [my real example is very much more complicated than this but I need this toy one too and I can't see how to modify as.function.polynomial() to do what I want] -- Robin Hankin Uncertainty Analyst and Neutral Theorist, National Oceanography Centre, Southampton European Way, Southampton SO14 3ZH, UK tel 023-8059-7743 ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel