
Solaris versions now available
What is shasta?
Mount Shasta is a 4317meter somewhat active volcano in Northern California.
Its snowcapped multiplecrater summit, pictured above, is a wellknown
california landmark as well as a ski resort. This page describes however
shasta, an interactive interface to the
Sum^it
library that provides some efficient computations revolving around operators
and systems in
Q[n,E] or Q(n)[E] where E is the
shift operator that sends n to n+1. In fact, the main goal
of shasta is to provide access to selected functionalities of the
Sum^it library to other computer algebra systems, or to users who
do not own an Aldor compiler, or who feel more confortable with interactive
access to a library. The functionalities currently provided by shasta are
the ones that tend to be missing from several commercial computer algebra
systems, namely:

Basic arithmetic in Q[n,E], including adjoints and left and
right gcd's and lcm's.

Exterior powers.

Rational kernels, i.e. Ker(L) /\ Q(n)
and rational solutions of inhomogeneous equations of the form
L(y) = g.

Rational kernels of systems of the form Y(n+1) = A(n) Y(n).

Hypergeometric solutions, i.e. the solutions y of L y = 0
such that y(n+1)/y(n) is in Q(n).

Factorisation and decomposition of second and thirdorder operators.
If you do not need any of the above computations, then you probably will
not have much use for shasta. Otherwise, since shasta provides implementations
of several recent algorithms for those computations, it is worth giving
it a try.
What is the current version?
The current distributed version is 1.0.0, released September 4, 2002.
How do I get shasta?
You must download first the platformindependent part by clicking
here,
then download the executable for the operating system(s) and platform(s)
you need:
How do I install shasta?
Issue tar xvzf shasta.tar.gz
to install the platformindependent parts.
The executables can be installed anywhere.
More installation details are in the
README
file and in the
online documentation
Are there other Sum^it servers?
Yes, if you are interested in linear ordinary differential equations,
you can take a look at the
Bernina server, that provides similar functionalities for those equations.
Last update: 28 October 2002