R help - May 2002 - ignoring some constants

Hi all,
    I'm trying to use the lda function from the MASS library to perform a
discrimant analysis. The problem is that some of the
variables within the data set are constant with relative to grouping variables
and the function gives an error. So when I use the
function as:

    > lda(d[11:14], d$set)

where d is the data object, [11:21] is the range of the variables to be
analysed, d$set is the grouping variable. It give the
following error:

    Error in lda.default(structure(data.matrix(x), class = "matrix"),
...) :
        variable(s) 1 2 3 4 appear to be constant within groups

Is there anyway that I can get the function to just ignore this error since
there are some variables that are not constant within
the groups. As far as I am concerned, the results are not an error and are just
part of the data.

If anyone could help me with this it would greatly appreciated.

Many Thanks

Rishabh

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On Thu, 30 May 2002, Rishabh Gupta wrote:
> Hi all,
>     I'm trying to use the lda function from the MASS library to perform
a discrimant analysis. The problem is that some of the
> variables within the data set are constant with relative to grouping
variables and the function gives an error. So when I use the
> function as:
>
>     > lda(d[11:14], d$set)
>
> where d is the data object, [11:21] is the range of the variables to be
analysed, d$set is the grouping variable. It give the
> following error:
>
>     Error in lda.default(structure(data.matrix(x), class =
"matrix"), ...) :
>         variable(s) 1 2 3 4 appear to be constant within groups
>
> Is there anyway that I can get the function to just ignore this error since
there are some variables that are not constant within
> the groups. As far as I am concerned, the results are not an error and are
just part of the data.
Try ?lda to improve your understanding.

-- 
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

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