Path: news.mathworks.com!not-for-mail
From: <HIDDEN>
Newsgroups: comp.soft-sys.matlab
Subject: Re: calculating the inverse efficiently (not for solving equations :-) )
Date: Tue, 1 Apr 2008 20:02:06 +0000 (UTC)
Organization: The MathWorks, Inc.
Lines: 20
Message-ID: <fsu4bu$l24$1@fred.mathworks.com>
References: <fsu1r6$ib3$1@fred.mathworks.com>
Reply-To: <HIDDEN>
NNTP-Posting-Host: webapp-03-blr.mathworks.com
Content-Type: text/plain; charset="ISO-8859-1"
Content-Transfer-Encoding: 8bit
X-Trace: fred.mathworks.com 1207080126 21572 172.30.248.38 (1 Apr 2008 20:02:06 GMT)
X-Complaints-To: news@mathworks.com
NNTP-Posting-Date: Tue, 1 Apr 2008 20:02:06 +0000 (UTC)
X-Newsreader: MATLAB Central Newsreader 1187260
Xref: news.mathworks.com comp.soft-sys.matlab:460389



"M E" <gitsnedbutzi@hotmail.com> wrote in message <fsu1r6$ib3
$1@fred.mathworks.com>...
> ........
> I also thought of using eigenvalues, but that wouldn't help
> much since you need the inverse of the matrix with the
> eigenvectors.
> ........
> Albert Buehrli
---------
  If B is symmetric, real, and non-singular, you CAN use eigenvectors to find its 
inverse.  Just take the reciprocals of its eigenvalues:

 [v,d] = eig(B);
 Binv = v*diag(1./diag(d))*v';

  However, I am not claiming this is necessarily the most efficient way to solve 
your problem.

Roger Stafford