Gordon Sande
worldnet.att.net> wrote:
> On 2008-09-09 16:16:39 -0300, Ron Ford said:
>
>> On Tue, 09 Sep 2008 12:58:19 GMT, Gordon Sande posted:
>
>>> Sight unseen I would be willing to take a small bet that MatLab is likely
>>> have packaged the pair for ready use with access to the intermediate forms
>>> taking more trouble if even possible.
>>
>> Matlab being an educational tool and Hessenberg form being beyond the
>> content for a semester of linear algebra, I would put up two dollars of
>> risk capital to contend to the contrary.
>
> A full two semester course would have had Hessemberg forms as the nonsymmetric
> analogue of tridiagonal forms. Both of which are preliminaries to finding
> eigenvalues and eigenvectors.
>
> The guy who did Matlab was a professor of Computer Science speicalizing in
> Numerical Analysis a long time ago so it is a sucker bet that all of NetLib
> will be there. Look up Cleve Moler with google.
While you are looking such things up, look up Eispack and note its
authors. To save the 30 seconds of work that would take, I'll give the
hint that one of them is Cleve Moler, making it even more of a sucker
bet the Cleve would have used his own software in Matlab.
I used to have a copy of the source code for the original Matlab (the
arguably "public domain" one written in Fortran). I rather recall it as
being pretty much a wrapper around the Eispack and Linpack stuff. Hmm,
let's spend another 30 seconds in research...The Wikipedia reinforces my
recollection. From the history section of its Matlab article
"MATLAB was invented in the late 1970s by Cleve Moler, then chairman
of the computer science department at the University of New Mexico.[3]
He designed it to give his students access to LINPACK and EISPACK
without having to learn Fortran."
Following the reference 3 citation link on that page to Cleve's article
on the origins of Matlab (hosted at the Mathworks site), we find that
Cleve says
"In the late 1970s, following Wirth's methodology, I used Fortran and
portions of LINPACK and EISPACK to develop the first version of MATLAB."
Hessenberg forms were certainly in my undergrad education in linear
algebra. One uses them for all kinds of things, See, for example, the
algebraic Riccatti equation (important in control theory).
And where would Ron have gotten the strange idea that Matlab was solely,
or even primarily an educational product? Wow is that far from the mark
- very far - pretty much in the complete wrong direction. Matab is a
darned expensive product aimed at professional use. The NASA site where
I used to work paid over $100,00 per year for Matlab licenses. That's
not exactly student prices. Perhaps Ron has only seen the educational
version. One might take a hint from the fact that there is a separate
educational version. That fairly obviously exists so that Mathworks can
draw students into using the product, which they clearly would not do at
the regular prices, and later those same students will push their
employers to buy the product at the professional prices.
--
Richard Maine | Good judgement comes from experience;
email: last name at domain . net | experience comes from bad judgement.
domain: summertriangle | -- Mark Twain
