[R] dimnames and solve

[ripley@stats.ox.ac.uk]

A feature.  What you really are doing is solve(V, diag(3)), and you get 
the colnames of the RHS.  See the help page!

On Mon, 20 Jan 2003, Giovanni Marchetti wrote:

> If I have a covariance matrix V 
> for example 
> > V = var(trees)
> > V
>            Girth   Height    Volume
> Girth   9.847914 10.38333  49.88812
> Height 10.383333 40.60000  62.66000
> Volume 49.888118 62.66000 270.20280
> 
> I woul like that the inverse (i.e. the concentration matrix) 
> had the same dimnames. But  I get instead 
>  > solve(V)
>               [,1]        [,2]        [,3]
> Girth   1.71516635  0.07801175 -0.33476574
> Height  0.07801175  0.04190776 -0.02412188
> Volume -0.33476574 -0.02412188  0.07110330
> 
> I would like to know if this is a feature or a mistake.
> 
> Thank you to all. 
> 
>    -- Giovanni
> < Giovanni M. Marchetti >
> Dipartimento di Statistica, Univ. di Firenze   Phone:  +39 055 4237 204
> viale Morgagni, 59                             Fax:    +39 055 4223 560
> I 50134 Firenze, Italy                         email:  gmm at ds.unifi.it
> 
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> 

-- 
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 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595