From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me
X-Spam-Level: 
X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,FREEMAIL_FROM
	autolearn=ham autolearn_force=no version=3.4.4
X-Google-Thread: 103376,2b8382e0387f53c5
X-Google-NewGroupId: yes
X-Google-Attributes: gida07f3367d7,domainid0,public,usenet
X-Google-Language: ENGLISH,ASCII-7-bit
Path: 
 g2news1.google.com!postnews.google.com!ei5g2000vbb.googlegroups.com!not-for-mail
From: Ada novice <yogeshwarsing@gmx.com>
Newsgroups: comp.lang.ada
Subject: Re: Eigenvalues to find roots of polynomials
Date: Tue, 26 Jul 2011 00:31:18 -0700 (PDT)
Organization: http://groups.google.com
Message-ID: 
 <bc535247-cf66-4b9d-ac11-e9b87b522330@ei5g2000vbb.googlegroups.com>
References: 
 <3ec148c9-a033-40a1-bc32-1aa52867478a@e35g2000yqc.googlegroups.com>
 <m2livmxg7y.fsf@pushface.org>
NNTP-Posting-Host: 130.240.232.139
Mime-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1
X-Trace: posting.google.com 1311665479 31640 127.0.0.1 (26 Jul 2011 07:31:19
 GMT)
X-Complaints-To: groups-abuse@google.com
NNTP-Posting-Date: Tue, 26 Jul 2011 07:31:19 +0000 (UTC)
Complaints-To: groups-abuse@google.com
Injection-Info: ei5g2000vbb.googlegroups.com; posting-host=130.240.232.139;
 posting-account=Rr9I-QoAAACS-nOzpA-mGxtAlZ46Nb6I
User-Agent: G2/1.0
X-Google-Web-Client: true
X-Google-Header-Order: HUALESNKRC
X-HTTP-UserAgent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.2.18)
 Gecko/20110614 Firefox/3.6.18 (.NET CLR 3.5.30729),gzip(gfe)
Xref: g2news1.google.com comp.lang.ada:20355
Date: 2011-07-26T00:31:18-07:00
List-Id: <comp.lang.ada>

On Jul 25, 9:22 pm, Simon Wright <si...@pushface.org> wrote:
> marius63 <amado.al...@gmail.com> writes:
>
> [...]
>
> Seehttp://sourceforge.net/projects/gnat-math-extn/for work I did
> supporting asymmetric real and non-hermitian complex matrices.

Thanks Simon for making this possible. I have been away from Ada for a
few months. Last week I looked at your codes and tested them for a few
cases. The codes worked fine :) as expected. In structural dynamics,
one can have three matrices to deal with. These three matrices are
combined with each other to form then the matrix A and B that you have
in your codes and hence it is a generalized eigenproblem. But the
eigenvalues are obtained in conjugate pairs as we are dealing with
double-sized matrices. I am waiting for a book to arrive here and then
I will formulate and use your Ada codes. For such a problem, I have my
codes in Matlab to compare with.

A very useful theorem that I learned several years back is the
Gershgorin Theorem. It lets you know the bounds for your eigenvalues.
More information here:

http://en.wikipedia.org/wiki/Gershgorin_circle_theorem


Cheers
YC