Message-ID: <43620475.9060208@pdf.com>
Date: 2005-10-28T10:59:01Z
From: Sundar Dorai-Raj
Subject: inverse matrix
In-Reply-To: <20051028052047.6111.qmail@web30608.mail.mud.yahoo.com>
Sam R. Smith wrote:
> if solve(a,b) means to calculate an inverse matrix of
> a with b, and i wonder why solve(a)%%b will get
> different result?
>
It does? Or perhaps your "%%" is not just a typo. It should be "%*%".
> a <- matrix(rnorm(16), 4, 4)
> b <- matrix(rnorm(4), 4, 1)
> solve(a, b)
[,1]
[1,] -0.8005768
[2,] 0.5913755
[3,] -1.8256012
[4,] 0.8973716
> solve(a) %*% b
[,1]
[1,] -0.8005768
[2,] 0.5913755
[3,] -1.8256012
[4,] 0.8973716
HTH,
--sundar