bfloat hangs computer



On Wed, Mar 18, 2009 at 2:47 PM, Edwin Woollett <woollett at charter.net> wrote:

> I suppose a workaround is to define my own exponential function with
> graceful underflow behavior, but isn't this something which should be
> part of the bfloat code??

It appears the problem is due to failing to detect the limits
of the bigfloats that can be handled by the machine
(so it hangs or falls over instead of printing a Maxima
error message). I guess that's a bug.

1b<foo> attempts to call (EXPT 10 <foo>) so when <foo>
is a large integer (positive or negative), it is trying to compute
a very large integer or 1/(very large integer). I'm guessing that
when Maxima appears to hang, it is actually running EXPT and
just taking a very long time.

At this point I think the stuff about the exp function or arithmetic
is beside the point. I think if you just enter 1b<foo> for various
values of <foo> sooner or later you'll find one that causes an error.

FWIW

Robert