Dear R-helpers,
To start I would like to thank Prof. Harrell for package rms. It is
one of the most useful packages for R that I have encountered.
Turning to my problem, I encountered a surprising problem when working
with rms::ols. It seems that insulating terms in a formula by using
I() to insulate terms in a formula seems to occasionally create a bug.
See the example below:
library(rms)
x <- rnorm(100)
y <- rnorm(100)
dd <- data.frame(cbind(x,y))
ols(y ~ x + I(x^2), data=dd)
ols() function gives the error:
Error in if (!length(fname) || !any(fname == zname)) { :
?missing value where TRUE/FALSE needed
Has anyone else encountered something similar? Is this a bug or does
this behavior have a reason?
There are of course trivial workarounds: one can either use poly(x, 2)
or save x^2 as a new column to dd, but trying to debug this was a
pain.
With kind regards,
Otto Kassi
Try this
Lm(y~X + I(X^2)), data=dd) # this runs OLS regression and it worked for me
Hope it helps
Lexi
-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
On Behalf Of Otto K?ssi
Sent: Thursday, July 01, 2010 3:28 PM
To: r-help at r-project.org
Subject: [R] rms::ols & I(.) in formulas
Dear R-helpers,
To start I would like to thank Prof. Harrell for package rms. It is
one of the most useful packages for R that I have encountered.
Turning to my problem, I encountered a surprising problem when working
with rms::ols. It seems that insulating terms in a formula by using
I() to insulate terms in a formula seems to occasionally create a bug.
See the example below:
library(rms)
x <- rnorm(100)
y <- rnorm(100)
dd <- data.frame(cbind(x,y))
ols(y ~ x + I(x^2), data=dd)
ols() function gives the error:
Error in if (!length(fname) || !any(fname == zname)) { :
missing value where TRUE/FALSE needed
Has anyone else encountered something similar? Is this a bug or does
this behavior have a reason?
There are of course trivial workarounds: one can either use poly(x, 2)
or save x^2 as a new column to dd, but trying to debug this was a
pain.
With kind regards,
Otto Kassi
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Hi, Lexi! I am aware that lm() is the standard way to do ols regression in R. The reason why I opted for rms::ols() is that later on in my work I need some rms functions which are not available for lm(). In retrospect, I should have mentioned this already in my original post. Nonetheless, thanks for a good suggestion :-) Br, OK On Fri, Jul 2, 2010 at 1:35 PM, Setlhare Lekgatlhamang <SetlhareL at bob.bw> wrote:> Try this > Lm(y~X + I(X^2)), data=dd) # this runs OLS regression and it worked for me > > Hope it helps > > Lexi > > -----Original Message----- > From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On Behalf Of Otto K?ssi > Sent: Thursday, July 01, 2010 3:28 PM > To: r-help at r-project.org > Subject: [R] rms::ols & I(.) in formulas > > Dear R-helpers, > > To start I would like to thank Prof. Harrell for package rms. It is > one of the most useful packages for R that I have encountered. > > Turning to my problem, I encountered a surprising problem when working > with rms::ols. It seems that insulating terms in a formula by using > I() to insulate terms in a formula seems to occasionally create a bug. > See the example below: > library(rms) > x <- rnorm(100) > y <- rnorm(100) > dd <- data.frame(cbind(x,y)) > ols(y ~ x + I(x^2), data=dd) > > ols() function gives the error: > Error in if (!length(fname) || !any(fname == zname)) { : > ?missing value where TRUE/FALSE needed > > Has anyone else encountered something similar? Is this a bug or does > this behavior have a reason? > > There are of course trivial workarounds: one can either use poly(x, 2) > or save x^2 as a new column to dd, but trying to debug this was a > pain. > > With kind regards, > Otto Kassi > > ______________________________________________ > R-help at r-project.org mailing list > 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. > > > > DISCLAIMER: > Sample Disclaimer added in a VBScript. >