I fully understand that this is a volunteer project, I'm a Debian user (not a developer... yet).
I have read the posting guide, but I forgot the protocol. First offence, won't happen again. Thanks. On 6/11/05, Prof Brian Ripley <[EMAIL PROTECTED]> wrote: > The code will be changed to give a more informative error message in a > future release. However, do remember that this is volunteer code, and it > is not reasonable to expect volunteers to anticipate that a user will > apply it in extremely unlikely circumstances. > > If you have a suggestion about code in a contributed package, please send > it to the package maintainer (as the posting guide asks). > > On Sat, 11 Jun 2005, Joshua Gilbert wrote: > > > This is true, they are equal. I hadn't noticed that. Thank you. > > > > Now, if lda fails on this given input (equal means), shouldn't we > > catch it and give a slightly better error message? I've spent a good > > while going through the debugging process with lda.default. From that > > perspective it appears that there is a simple change to remove the > > problem. I am not saying that it is correct in any shape or form, but > > there is a point where a single transpose would silence the error. > > > > So, from a usability standpoint, could we add a check for equal means > > between classes and throw an error for that specific condition? Yes, > > the user should not do that. But users may become more interested in > > making the code run than checking on whether it's doing anything sane. > > > > If this isn't the place to do so, tell me. But, I'd like to petition > > to alter the code of lda.default. > > > > On 6/10/05, Prof Brian Ripley <[EMAIL PROTECTED]> wrote: > >> lda.default <- MASS:::lda.default and proceed. > >> > >> Look at the group means of your data: they are identical to machine > >> accuracy. > >> > >> The question has to be `why are you trying to use lda to separate > >> two groups with identical means'? Lda is not protected against that > >> and it is rather unlikely unless you failed to inspect your data in any > >> way. > >> > >> On Fri, 10 Jun 2005, Joshua Gilbert wrote: > >> > >>> This question appears to have been asked previously, but not answered. > >>> the last response I can find to this previous thread is here: > >>> http://tolstoy.newcastle.edu.au/R/help/04/07/0126.html. The asnwer was > >>> to provide debugging info, not an answer. > >>> > >>> So the problem is that I'm trying to use lda on my dataset. You can > >>> download my data here: > >>> http://northstar-www.dartmouth.edu/~jgilbert/nolda, I used R's save > >>> function to save objects data and classes (yes, I realize that I name > >>> stomped the data function in package utils). To replicate my results, > >>> simply enter the following: > >>>> library(MASS) > >>>> load('nolda') > >>>> lda(data,classes) > >>> Error in lda.default(x, grouping, ...) : length of 'dimnames' [2] not > >>> equal to array extent > >>> > >>> Now, I don't know what that means. > >>>> dimnames(data) > >>> NULL > >>>> dimnames(classes) > >>> NULL > >>> > >>> As for debugging, I don't know how. I cannot debug lda.default as I > >>> get the following: > >>>> debug(lda.default) > >>> Error: Object "lda.default" not found > >>> > >>> I think that that's pretty much it. Can anyone help me? > >>> > >>> ______________________________________________ > >>> [email protected] mailing list > >>> https://stat.ethz.ch/mailman/listinfo/r-help > >>> PLEASE do read the posting guide! > >>> http://www.R-project.org/posting-guide.html > >>> > >> > >> -- > >> Brian D. Ripley, [EMAIL PROTECTED] > >> 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 272866 (PA) > >> Oxford OX1 3TG, UK Fax: +44 1865 272595 > >> > > > > > > -- > Brian D. Ripley, [EMAIL PROTECTED] > 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 272866 (PA) > Oxford OX1 3TG, UK Fax: +44 1865 272595 > ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
