[R] Computing the rank of a matrix.

[Ravi Varadhan]

Hi,

qr(A)$rank will work, but just be wary of the tolerance parameter (default
is 1.e-07), since the rank computation could be sensitive to the tolerance
chosen.  

Ravi.

----------------------------------------------------------------------------
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Ravi Varadhan, Ph.D.

Assistant Professor, The Center on Aging and Health

Division of Geriatric Medicine and Gerontology 

Johns Hopkins University

Ph: (410) 502-2619

Fax: (410) 614-9625

Email: rvaradhan at jhmi.edu

Webpage:  http://www.jhsph.edu/agingandhealth/People/Faculty/Varadhan.html

 

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-----Original Message-----
From: r-help-bounces at stat.math.ethz.ch
[mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of apjaworski at mmm.com
Sent: Friday, April 06, 2007 11:07 AM
To: José Luis Aznarte M.
Cc: r-help at stat.math.ethz.ch; r-help-bounces at stat.math.ethz.ch
Subject: Re: [R] Computing the rank of a matrix.

How about

      qr(A)$rank

or perhaps

      qr(A, LAPACK=TRUE)$rank

Cheers,

Andy

__________________________________
Andy Jaworski
518-1-01
Process Laboratory
3M Corporate Research Laboratory
-----
E-mail: apjaworski at mmm.com
Tel:  (651) 733-6092
Fax:  (651) 736-3122


                                                                           
             "José Luis                                                    
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                                       [R] Computing the rank of a matrix. 
                                                                           
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    Hi! Maybe this is a silly question, but I need the column rank
(http://en.wikipedia.org/wiki/Rank_matrix) of a matrix and R function
'rank()' only gives me the ordering of the elements of my matrix.
    How can I compute the column rank of a matrix? Is there not an R
equivalent to Matlab's 'rank()'?
    I've been browsing for a time now and I can't find anything, so any
help will be greatly appreciated. Best regards!


--                                                      --
Jose Luis Aznarte M.       http://decsai.ugr.es/~jlaznarte
Department of Computer Science and Artificial Intelligence
Universidad de Granada           Tel. +34 - 958 - 24 04 67
GRANADA (Spain)                  Fax: +34 - 958 - 24 00 79

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