R-users
E-mail: r-help@r-project.org

> This iteration seems to be for "iteratively reweighted least squares" not
>for backfitting. And lm.wfit may solve multiple linear equation using
>QR decomposition; but I am not sure.

   Let me tell you something about my guess above.
The iteration below is from 1 to maxit.

  for (iter in 1:maxit) {
        ------
        fit <- eval(bf.call)
        ------
  }

The help of "gam.control()" says:
   maxit: maximum number of local scoring iterations
   bf.maxit: maximum number of backfitting iterations

Therefore the iteration above is local scoring iteration not
backfitting iteration.

   The first line of "lm.wfit()" is:
function (x, y, w, offset = NULL, method = "qr", tol = 1e-07,
 singular.ok = TRUE, ...)
There is no "bf.maxit" or its equivalent in these arguments. And it
contains 'method = "qr"'; it may mean that this routine solves
a multiple linear equation using QR decomposition.
-- 
*****    r.otasuke@gmail.com    *****
http://cse.naro.affrc.go.jp/takezawa/intro.html

	[[alternative HTML version deleted]]

