Robert Dodier wrote:
> On 3/17/09, Raymond Toy <toy.raymond at gmail.com> wrote:
>
>
>> I can reproduce this problem with current CVS using gcl 2.6.8 on
>> Solaris. It's a bit slow on g(8,40), but it gets some kind of
>> unrecoverable error (fault count too high) with g(9,40) and proceeds to
>> dump core.
>>
>> This doesn't happen with cmucl. I don't know why gcl would fail in this
>> way.
>>
>
> Looks like exp(-1/(1 - xx)) underflows in an ungraceful way ....
> g(7, 40) yields a term exp(- 9.999999999712443b6) =>
> 1.51737304873662b-4342945, which (I guess) causes trouble.
> With Clisp it triggers the error "ASH: too large shift amount 14426900".
> The error is in FPPLUS. Is that the bigfloat code is trying to
> normalize terms to a common basis or something? Just a guess.
>
>
Interesting. My version of clisp (2.47) goes ahead and computes the
result. And a different version of gcl (2.6.8 pre, whatever that
means), works just fine too.
Ray