C Y wrote:
> If Maxima can run on two totally different systems and get the same
> mathematical result, it is a reassurance that there are no subtle
> problems with one of the lisps.
Common Lisp does not require bit-for-bit identicality. E.g. some
implementation can use the same arithmetic width for single and double,
another can use different widths for short, single, double, long.
Nevertheless this kind of testing is occasionally useful as we have seen...
"I get this wrong answer on system XXX" --> "That's odd, I get the
right answer on system YYY, therefore the bug is not in Maxima source but
in system YYY".
Same thing goes for operating
> systems - at some level the lisp depends on the OS behavior being
> correct. In fact, this is also my argument for why both Axiom and
> Maxima are necessary - they provide a totally independant check on
> each other's correctness. They could both be wrong, of course, but
> every little bit helps.
Not only could they be wrong, but there is a whole class of bugs in
which nearly every CAS gets the same wrong answer. In fact, some of us take
particular pride in finding them.
>
> Really, it would be nice if this type of software could be developed
> using proof systems, but before that makes sense we would probably
> need something like Coyotos to mature, since without a provably
> correct OS I don't see how you could prove your application
> behavior. (To full rigor anyway.)
You can read MKM (Mathematica Knowledge Management) conference proceedings
if you want to see what the current state of the art is. Don't expect
much.
>
>
>>Incidentally, I count 633 messages in the 2004 mailing
>>list archive (of 2176 in all) which mention at least one
>>of gcl, cmucl, clisp, or sbcl. I count 197 messages
>>which mention at least two Lisp versions.
>>
>>(I did the counting with the nset functions. w00t!)
>
>
> I understand the frustration. I do agree that it would be nice if
> the time spent on these issues were to go into mathematical/feature
> work.
One question though, is whether the people doing the SBCL etc hacking
are at all interested or able to improve the math stuff, or are
they treating Maxima as just a big benchmark?
But I think the best way to ensure Maxima is here for the
> long haul is to make it as portable as possible.
Aren't we taking out the conditionalizations that
make it run on PDP-10, Multics, Franz Lisp/VAX? I generally do
that so I can read the relevant code. But I haven't fed stuff into CVS.
Look where we
> would be if Berkeley had decided not to mess with porting it off
> the original PDPs!
An interesting hypothesis.
> Maxima has outlived many lisps and many
> platforms, and hopefully it will continue to do so in the future.
> (I guess I get a little infected by Tim Daly's 30 year horizon
> discussions.)
>
> CY
>
>
>
> __________________________________
> Do you Yahoo!?
> Yahoo! Small Business - Try our new resources site!
> http://smallbusiness.yahoo.com/resources/
>
> _______________________________________________
> Maxima mailing list
> Maxima@www.math.utexas.edu
> http://www.math.utexas.edu/mailman/listinfo/maxima