R-alpha: complex arithematic

Paul Gilbert (la-jassine@aix.pacwan.net)
Wed, 12 Feb 1997 04:55:56 -0400

Date: Wed, 12 Feb 1997 04:55:56 -0400
To: Bill Simpson <wsimpson@uwinnipeg.ca>
From: Paul Gilbert <la-jassine@aix.pacwan.net>
Subject: R-alpha: complex arithematic

There are at least two areas in which complex numbers are useful for my
work. First, as in  linear systems theory and system identification, I am
often interested in the eigenvalues of non-symmetric matrices.  To solve
this does not require a full implementation  of complex numbers. It is
possible to just deal with the real and imaginary parts as two real numbers
and write special code for Mod, etc. 

The second is looking at the roots of polynomials. Again, this could largely
be solved by dealing with the real and imaginary parts as two real numbers,
but there are certainly times when it is convenient to do addition,
subtraction, multiplication and division of complex numbers.

For my work a partial implementation would solve most of my problems. But
the incompatiblity with S would make it a real problem to maintain my code,
so I would much prefer the full implementation.

Paul Gilbert

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