Services & Resources / Wolfram Forums / MathGroup Archive
-----

MathGroup Archive 2007

[Date Index] [Thread Index] [Author Index]

Search the Archive

Re: eigenvectors is taking lot of time

  • To: mathgroup at smc.vnet.net
  • Subject: [mg82615] Re: eigenvectors is taking lot of time
  • From: Scott Hemphill <hemphill at hemphills.net>
  • Date: Fri, 26 Oct 2007 05:21:53 -0400 (EDT)
  • References: <ffppmk$l0d$1@smc.vnet.net>
  • Reply-to: hemphill at alumni.caltech.edu

vickyisai at gmail.com writes:

> Hi all
> 
> I am trying to calculate eigenvectors of a 30 X 30 matrix. and
> mathematica is still just "running".
> Is the any way to get the eigenvectors quickly.
> 
> After 45 mins ,it was still running and displayed a message "limit of
> "some number here(4096) exceeded"
> 
> i wanted eigen values and vectors both ..so i tried eigensystem....but
> tat also took long, so i switched to individualfunctions of
> eigenvalues and eigenvectors.
> 
> I aborted it...shud i execute it again and wait for longer?
> I use Mathematica 5.2 and got a AMD Turion 2.2 Gz, does tat matter for
> a  30 x 30 matrix??

If the elements of your matrix are approximate numbers, then you will
quickly get results.  If the elements of your matrix are exact
numbers, then it may be too hard to get exact results, so turn your
matrix into approximate numbers.

  m = N[m];

You can ask for extra precision if you want:

  m = N[m,32];

If the elements of your matrix are symbolic then this is too hard a
problem.

Scott
-- 
Scott Hemphill	hemphill at alumni.caltech.edu
"This isn't flying.  This is falling, with style."  -- Buzz Lightyear


  • Prev by Date: Re: Re: (x|y) \[element] Integers in Reduce function
  • Next by Date: Graphics export to BMP and JPEG
  • Previous by thread: Re: eigenvectors is taking lot of time
  • Next by thread: Re: mathematica 6.0 for linux crashes when manipulating plots of