[Fwd: RE: Future of Jama]

[Ron Boisvert <boisvert@nist.gov>]

Sender: "Cleve Moler" <Cleve.Moler@mathworks.com>
Subject: RE: Future of Jama


Hello --

Thanks for your interest in Jama.  We wrote Jama in 1998, when there
appeared to be a possibility that Java might become a serious language
for scientific computing.  Since then, Java has proved to be an
important tool for certain kinds of computing, but large scale
scientific computing is not one of them.  Our efforts to extend Java to
handle complex arithmetic and efficient matrix manipulation have not
been successful.  As a result, we have no plans for further development
of Java.

The MathWorks portion of the Jama team, myself included, have been
devoting our efforts to the development of MATLAB, not Jama.

Personally, I would be interested in hearing more about your plans for
Jama in Gaia.  For example, a linear equation solver that uses the SVD
might be a good idea, but it would not involve the inverse of S and
would involve some attention to rank deficiency, nonuniqueness, and
regularization.

  -- Cleve Moler 

-----Original Message-----
From: jama@nist.gov [mailto:jama@nist.gov] On Behalf Of Dimitri Pourbaix
Sent: Thursday, April 05, 2007 2:49 PM
To: Multiple recipients of list
Subject: Future of Jama

Dear,

I am leader of about 60 scientists who are designing codes for the data
reduction pipeline of the future European Space Agency mission Gaia.
Jama was adopted as our minear algebra package.  So far, almost so good.

I would like to know what your current plans are regarding the further
development of Jama.  The last change of the web page dates back to
July 2005 so I wonder if we can expect any post 1.0.2 release.

For instance, I am using SVD for least square model fitting.  Your
package
provides the singular value decomposition but it lacks an efficient way
of
solve a system of equation by SVD.  Such a solution indeed relies up the
inverse of S.  As a diagonal matrix, its inverse is straightforward to
compute if one accesses its elements.  Using Jama methods only. one
should
call the inverse method ... which cannot take any advantage of the
special
structure of S.  So, maybe a method which returns the inverse of S (both
as
vector and as a matrix) would be useful.  Do not you think?

I sure can write such an extension myself but I am sure a lot of Jama
users would benefit from such similar additional methods.

With my best regards,
D. Pourbaix.
------------------------------------------------------------------------
----
Dimitri Pourbaix                         *
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Universite Libre de Bruxelles            *
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