[comp.specification] Linear Algebra and Specifications

jwb@cepmax.ncsu.EDU (John W. Baugh Jr.) (07/01/90)

I'd like to find references to any work that's been done
(particularly in the formal specification community) on
specifying matrix operators, including tools, notations,
etc.

Also, it seems that the algebra of matrix elements has to
be considered to do anything interesting with these
specifications--are there any definitions of the "nice"
properties that floating point representations are
supposed to obey?

Or perhaps all of this is just too messy--maybe the
chasm between numerical analysis and linear algebra
is too great.  Any comments/suggestions welcome.

John Baugh
jwb@cepmax.ncsu.edu

steve@hubcap.clemson.edu ("Steve" Stevenson) (07/03/90)

jwb@cepmax.ncsu.EDU (John W. Baugh Jr.) writes:

>Or perhaps all of this is just too messy--maybe the
>chasm between numerical analysis and linear algebra
>is too great.  Any comments/suggestions welcome

As a numerical analyst with lots of interests and experience in numerical
linear algebra, I think you're missing much of the point. In any traditional
sense, linear algebra is a major component of numerical. If you're
restricting numerical to ``floating point'' then  I suggest that you survey
the literature a bit. Kahaner, who got the Turing Award This time, is just
one of several schools of thought. For example, in Europe, there is
a large following of Kuelish, et al, who center their work around making
inner products work right---the rest follows from that.
The interval people --- out at the Oregon Grad Center --- are also quite
active.

There is no chasm between numerical analysis and linear algebra --- they're
intimately intertwined.

-- 
===============================================================================
Steve (really "D. E.") Stevenson           steve@hubcap.clemson.edu
Department of Computer Science,            (803)656-5880.mabell
Clemson University, Clemson, SC 29634-1906

jwb@cepmax.ncsu.EDU (John W. Baugh Jr.) (07/03/90)

I write about specifying matrix operators.

In article <9550@hubcap.clemson.edu>, steve@hubcap.clemson.edu ("Steve"
Stevenson) writes:
> As a numerical analyst with lots of interests and experience in numerical
> linear algebra, I think you're missing much of the point.
  [stuff deleted]
> There is no chasm between numerical analysis and linear algebra --- they're
> intimately intertwined.

Of course, I know that numerical analysis and linear algebra are
"intimately intertwined."  If you re-read my post you'll see that
I'm talking about _specifying_matrix_operators_.   My question
regards the level at which such operators are specified.  For
example, if I write a program that happens to make use of matrices,
I could take advantage of the "nice" algebraic properties of
real numbers, and hence the matrices defined over them, to reason
about my program.  Of course, matrices of finite-precision numbers
don't share these "nice" properties, which might encourage one to
specify even more details, namely a floating point representation
for matrix elements.  The trouble is that pretty soon I'm at an
"implementation" level, and I might just as well be writing
Fortran code (since I'm specifying all these details anyway).
The dramatic difference between these two levels of specification
is the "chasm" I'm referring to.  So, my question is: has any work
been done in the area of specifying matrix operators?

John Baugh
jwb@cepmax.ncsu.edu