Hi all,
Sorry for the omission in the first post.
I have difficulties in specifying a weight vector inside lm which is called
inside a function.
++++Also stepAIC will not behave as expected.
I have had the hope that this problem would go away by switching to R from
S+, as a variable generated inside a function should be visible to lm
inside it, but the evaluation of formulae seems to get in the way.
regrbest(Una,"vr3c1",ind,"W")
with names(Una) containing the elements of ind:
.... "vr91" "vr92" .. and additionally....
"W"
regrbest <- function(x,y,ind,wt=NULL)
form <- as.formula(paste(y,paste(ind, collapse = "+"), sep =
"~"),
env=parent.frame()) # is env WRONG here???
# form = vr3c1 ~ vr91 + vr92 with the actual call
nna <- apply(x[,c(ind,wt)],1,function(x) all(!is.na(x)))
xx <- x[nna,]
wtt <- !is.null(wt) && any(wt!=1)
if (wtt) { # is TRUE here
w <- xx[,wt]
lm1 <- lm(form,data=xx,weights=w)
else {
lm1 <- lm(form,data=xx,na.action=na.omit)
stw <- stepAIC(lm1,direction="forward",trace=2, k=2)
Error in eval(expr, envir, enclos) : Object "w" not found
The weights w are not found ????
Calling with
regrbest(Una,"vr3c1",ind)
will generate lm1 but will stall at stepAIC:
Error in terms.formula(formula, data = data) :
Object "xx" not found> traceback()
9: terms.formula(formula, data = data)
8: terms(formula, data = data)
7: lm(formula = vr3c1 ~ vr91 + vr92 + vr18c1 + vr18c2 + vr191 +
vr192 + vr193 + vr211 + vr212 + vr221 + vr222 + vr223 + vr231 +
vr232 + F26REG.J + F27SEX + F28ALTER + F31PERS + vr361 +
vr362 + F37A + Urban + F6WISSEN + F7B1 + F7B2 + F7B3 + F7B4 +
F7B5 + F29CH + F30SCHUL + F33HUND + F35GART, data = xx, na.action
na.omit)
6: eval(expr, envir, enclos)
5: eval(call, parent.frame())
4: update.default(fit, paste("~ .", change))
3: update(fit, paste("~ .", change))
2: stepAIC(lm1, direction = "forward", trace = 2, k = 2)
1: regrbest(Una, "vr3c1", ind.9P6)
Is there a general rule on how to treat this kind of problems?
I very often build linear models inside functions and temporary variables
seem to be a problem for models.
Thanks for your consideration.
-christian
Dr.sc.math.Christian W. Hoffmann
Mathematics and Statistical Computing
Landscape Modeling and Web Applications
Swiss Federal Research Institute WSL
Zuercherstrasse 111
CH-8903 Birmensdorf, Switzerland
phone: ++41-1-739 22 77 fax: ++41-1-739 22 15
e-mail: christian.hoffmann_at_wsl.ch__prevent_spamming
www: http://www.wsl.ch/staff/christian.hoffmann/
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On Mon, 16 Jul 2001, Christian Hoffmann wrote:> Hi all, > > Sorry for the omission in the first post. > > I have difficulties in specifying a weight vector inside lm which is called > inside a function. > > ++++Also stepAIC will not behave as expected. > > I have had the hope that this problem would go away by switching to R from > S+, as a variable generated inside a function should be visible to lm > inside it, but the evaluation of formulae seems to get in the way. > > regrbest(Una,"vr3c1",ind,"W") > with names(Una) containing the elements of ind: > .... "vr91" "vr92" .. and additionally.... "W" > > regrbest <- function(x,y,ind,wt=NULL) > form <- as.formula(paste(y,paste(ind, collapse = "+"), sep = "~"), > env=parent.frame()) # is env WRONG here??? > # form = vr3c1 ~ vr91 + vr92 with the actual call > nna <- apply(x[,c(ind,wt)],1,function(x) all(!is.na(x))) > xx <- x[nna,] > wtt <- !is.null(wt) && any(wt!=1) > if (wtt) { # is TRUE here > w <- xx[,wt] > lm1 <- lm(form,data=xx,weights=w) > else { > lm1 <- lm(form,data=xx,na.action=na.omit) > stw <- stepAIC(lm1,direction="forward",trace=2, k=2) > > Error in eval(expr, envir, enclos) : Object "w" not found > The weights w are not found ????Right, as they are not in the scope of re-fitting the model. Why are you not using lm1 <- lm(form,data=xx,weights=wt) anyway?> Calling with > regrbest(Una,"vr3c1",ind) > > will generate lm1 but will stall at stepAIC: > Error in terms.formula(formula, data = data) : > Object "xx" not found > > traceback() > 9: terms.formula(formula, data = data) > 8: terms(formula, data = data) > 7: lm(formula = vr3c1 ~ vr91 + vr92 + vr18c1 + vr18c2 + vr191 + > vr192 + vr193 + vr211 + vr212 + vr221 + vr222 + vr223 + vr231 + > vr232 + F26REG.J + F27SEX + F28ALTER + F31PERS + vr361 + > vr362 + F37A + Urban + F6WISSEN + F7B1 + F7B2 + F7B3 + F7B4 + > F7B5 + F29CH + F30SCHUL + F33HUND + F35GART, data = xx, na.action > na.omit) > 6: eval(expr, envir, enclos) > 5: eval(call, parent.frame()) > 4: update.default(fit, paste("~ .", change)) > 3: update(fit, paste("~ .", change)) > 2: stepAIC(lm1, direction = "forward", trace = 2, k = 2) > 1: regrbest(Una, "vr3c1", ind.9P6) > > Is there a general rule on how to treat this kind of problems? > I very often build linear models inside functions and temporary variables > seem to be a problem for models.Put them in the data frame (but they are already there if accessed sensibly), and in S-PLUS, put the data frame in frame 1. -- Brian D. Ripley, ripley at stats.ox.ac.uk Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272860 (secr) Oxford OX1 3TG, UK Fax: +44 1865 272595 -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help 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-help-request at stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._
On Mon, 16 Jul 2001, Prof Brian Ripley wrote:> On Mon, 16 Jul 2001, Christian Hoffmann wrote: > > > Hi all, > > > > Sorry for the omission in the first post. > > > > I have difficulties in specifying a weight vector inside lm which is called > > inside a function. > > > > ++++Also stepAIC will not behave as expected. > > > > I have had the hope that this problem would go away by switching to R from > > S+, as a variable generated inside a function should be visible to lm > > inside it, but the evaluation of formulae seems to get in the way. > > > > regrbest(Una,"vr3c1",ind,"W") > > with names(Una) containing the elements of ind: > > .... "vr91" "vr92" .. and additionally.... "W" > > > > regrbest <- function(x,y,ind,wt=NULL) > > form <- as.formula(paste(y,paste(ind, collapse = "+"), sep = "~"), > > env=parent.frame()) # is env WRONG here??? > > # form = vr3c1 ~ vr91 + vr92 with the actual call > > nna <- apply(x[,c(ind,wt)],1,function(x) all(!is.na(x))) > > xx <- x[nna,] > > wtt <- !is.null(wt) && any(wt!=1) > > if (wtt) { # is TRUE here > > w <- xx[,wt] > > lm1 <- lm(form,data=xx,weights=w) > > else { > > lm1 <- lm(form,data=xx,na.action=na.omit) > > stw <- stepAIC(lm1,direction="forward",trace=2, k=2) > > > > Error in eval(expr, envir, enclos) : Object "w" not found > > The weights w are not found ???? > > Right, as they are not in the scope of re-fitting the model. > Why are you not using > > lm1 <- lm(form,data=xx,weights=wt) > > anyway?Sorry, I see now. This was meant to be a function definition, but there are no braces, so I read what was actually in the message .... Use xx$wt <- xx[,wt] lm1 <- lm(form,data=xx,weights=wt) -- Brian D. Ripley, ripley at stats.ox.ac.uk Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272860 (secr) Oxford OX1 3TG, UK Fax: +44 1865 272595 -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help 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-help-request at stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._