Message-ID: <1233935820.3122.68.camel@desktop.localhost>
Date: 2009-02-06T15:57:00Z
From: Gavin Simpson
Subject: Matrix Multiplication
In-Reply-To: <689267.5402.qm@web59514.mail.ac4.yahoo.com>
On Fri, 2009-02-06 at 04:57 -0800, Maithili Shiva wrote:
> Hi R helpers,
>
>
>
> I have two matrices A and B of the order (4 * 5) and (5 * 3)
> respectively. How to multiply these two matrices to obtain resultant
> matrix of the order (4 * 3).
?`%*%`
E.g.:
> A <- matrix(runif(4*5), nrow = 4)
> B <- matrix(rnorm(5*3), nrow = 5)
> A %*% B
[,1] [,2] [,3]
[1,] 0.11087765 0.1172641 -1.965684
[2,] 0.08811864 0.6628032 -2.704704
[3,] -0.99875302 1.2822072 -1.388777
[4,] -1.01109686 1.5752980 -1.560827
>
> Thanks in advance
>
> With regards
>
> Maithili
HTH
G
--
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Dr. Gavin Simpson [t] +44 (0)20 7679 0522
ECRC, UCL Geography, [f] +44 (0)20 7679 0565
Pearson Building, [e] gavin.simpsonATNOSPAMucl.ac.uk
Gower Street, London [w] http://www.ucl.ac.uk/~ucfagls/
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