# Significant digits in calculations.

As a chemist, I have always wanted my programs to recognize and manage
significant digits.
At this time, I have code that records significant digits on input, manages them
correctly on add/subtract/multiply/divide, and correctly formats output.
FORTRAN style input, e.g. 1.234567E+021 is accepted. On output, the exponent
is changed to a SI suffix, e.g. (E-003, m), (E-006, u), (E-009, n), (E+006, M).
These
are recognized on input as well.
A matrix algebra package is provided on top of these libraries. It is quite
interesting
to perform matrix calculations, especially eigenvector calculations, using
significant
digits.
The library and matrix multiply source is available, and is described briefly in
an upcoming article in Computers and Mathematics with Applications.
I have been using this code now for over a year with minimal changes. I would
now like some volunteers to "exercise" this code. System requirements
are
1) A SPARC station.
2) A Mac II (68020 or higher)
or 3) A vax running Ultrix and an X terminal.
ftp access is recommended. Some setup is required.
--Aubrey McIntosh