Re: [R] Error with function lda in package MASS (dimnames not equal?)

From: Prof Brian Ripley <>
Date: Sat 11 Jun 2005 - 00:10:30 EST

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:
> 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:
>, 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)
>> dimnames(classes)
> 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?
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Brian D. Ripley,        
Professor of Applied Statistics,
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

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Received on Sat Jun 11 00:15:07 2005

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