Hi Peter,
> On Apr 5, 2019, at 7:22 AM, peter dalgaard <pda...@gmail.com> wrote: > > Can't you just check for NA coefficients? > >> y <- rnorm(10) ; x <- rep(0,10) >> coef(lm(y~x)) > (Intercept) x > -0.0962404 NA > > so > >> any(is.na(coef(lm(y~x)))) > [1] TRUE > > I have a vague recollection that at some point there might have been dragons > lurking in there (? - NA coefs silently removed), but I can't see a problem > with it presently. I think that the problem you recall related to vcov.lm() and not coef(). vcov.lm() silently removed NAs, which motivated the introduction of the complete argument, defaulting to TRUE. AFAIK, coef() always included NAs in the coefficient vector for a singular fit. Best, John ------------------------------------------------- John Fox, Professor Emeritus McMaster University Hamilton, Ontario, Canada Web: http::/socserv.mcmaster.ca/jfox > > -pd > >> On 5 Apr 2019, at 12:14 , Witold E Wolski <wewol...@gmail.com> wrote: >> >> lme4 has a function isSingular to check if the fitted model is Singular, >> >> Although lm has the parameter singular.ok = TRUE by defualt, I could >> not find a function to check if the fitted model is singular. >> >> What would be the correct way to implement such a function for and lm object? >> Check if df.residuals == 0 >> >> Thanks >> Witek >> >> >> >> >> >> -- >> Witold Eryk Wolski >> >> ______________________________________________ >> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see >> 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. > > -- > Peter Dalgaard, Professor, > Center for Statistics, Copenhagen Business School > Solbjerg Plads 3, 2000 Frederiksberg, Denmark > Phone: (+45)38153501 > Office: A 4.23 > Email: pd....@cbs.dk Priv: pda...@gmail.com > > ______________________________________________ > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > 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. ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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.
