Re: Very simple eigenvector/eigenvalue calculation

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#1218

From: Uwe Schmitt
Date: Wed, 07 Nov 2001 10:44

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In sci.math.num-analysis jonmach <jonmach@informix.com> wrote:
| Hi All,

| I've trawled the net and have found some very comprehensive libraries
| and source for calculating the eigenvalues/eigenvectors of an nxn
| matrix.  However, this is very much overkill for what I need.

| I have a single 2X2 matrix holding real values and simply need to
| calculate the 2 eigenvalues and corresponding eigenvectors.  Is there
| a very simple algorithm for this that already exists in
| C/Fortran/Java/C++?

| Many many thanks in advance for any assistance on this.


use the charateristic polynomial of your 2x2 matrix. this polynomial
has the degree two and can be solved analytically. you gain the
corresponding eigenvectors by appropriate linear equations.

hope that helps, yours, uwe.

-- 
Dr. Uwe Schmitt                                 Uwe.Schmitt@num.uni-sb.de
Universitaet des Saarlandes                     Angewandte Mathematik
Building 36.1 Room 4.17         PO-Box 151150   D-66041 Saarbruecken
Mobile:0177/6806587    Fax:+49(0)681/302-4435   Office:+49(0)681/302-2468

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From: Uwe Schmitt <uwe@rocksport.de>
Newsgroups: sci.math.num-analysis,sci.math,comp.lang.c,aus.mathematics,alt.math.undergrad
Subject: Re: Very simple eigenvector/eigenvalue calculation
Date: 7 Nov 2001 10:44:32 GMT
Organization: University of Saarland, Computing Center, Germany.
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