Path: news.mathworks.com!not-for-mail From: <HIDDEN> Newsgroups: comp.soft-sys.matlab Subject: Re: eigenvectors sign problem Date: Wed, 29 Jun 2011 02:47:09 +0000 (UTC) Organization: University of Miami Lines: 11 Message-ID: <iue3nd$os2$1@newscl01ah.mathworks.com> References: <iot0fc$ii4$1@fred.mathworks.com> Reply-To: <HIDDEN> NNTP-Posting-Host: www-02-blr.mathworks.com Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Trace: newscl01ah.mathworks.com 1309315629 25474 172.30.248.47 (29 Jun 2011 02:47:09 GMT) X-Complaints-To: news@mathworks.com NNTP-Posting-Date: Wed, 29 Jun 2011 02:47:09 +0000 (UTC) X-Newsreader: MATLAB Central Newsreader 19787 Xref: news.mathworks.com comp.soft-sys.matlab:734133 "roman" wrote in message <iot0fc$ii4$1@fred.mathworks.com>... > Hello, > I'm working on a stress field problem and i want to find the eigenvector of a real symmetric matrix. When using eig() i get signs switched randomly, that apparently is common problem using this function. I understand that even if the change is switched the physical meaning of the eigenvector is the same, but I'd need to get the right sign to plot some trajectories, and the function streamslice seems not to like very much when signs are switched. I read in other posts that you can solve this by multiplying a component of the eigenvector by a factor, but I actually did not understand how to put this in practice. > Any help would be appreciated, > Alberto Hi Alberto, Did you find a solution for your problem? Francisco