Re: [Maxima-discuss] float(exp(10000)) works, but float(exp(10000/3)) doesn't

[David S. <d.s...@go...>]

Oh, and for CCL, I get even different results:

(%i1) float(exp(10000));
(%o1) 8.806818225658306b4342

(%i2) float(exp(10000/3));
Maxima encountered a Lisp error:
 FLOATING-POINT-OVERFLOW detected
performing EXP on (3333.3333333333335)
Automatically continuing.
To enable the Lisp debugger set *debugger-hook* to nil.

(%i3) float(exp(10000.0));
float: floating point overflow converting 8.806818225662922b4342
 -- an error. To debug this try: debugmode(true);

2016-01-26 10:44 GMT+01:00 David Scherfgen <d.s...@go...>:
> Hello,
>
> I'm getting very weird and inconsistent behavior when doing
> float(exp(10000)) vs. float(exp(10000/3)) and float(exp(10000.0)).
>
> The first one works - the result is promoted to bigfloat.
> The second one gives me floating point infinity, even though the exp
> argument is actually smaller!
> The third one gives an error.
>
> I guess this is not intended, right?
>
> Maxima branch_5_37_base_407_g2af0c38 http://maxima.sourceforge.net
> using Lisp GNU Common Lisp (GCL) GCL 2.6.12
> Distributed under the GNU Public License. See the file COPYING.
> Dedicated to the memory of William Schelter.
> The function bug_report() provides bug reporting information.
>
> (%i1) float(exp(10000));
> (%o1)                       8.806818225658306b4342
>
> (%i2) float(exp(10000/3));
> (%o2)                               i.nfE+0
>
> (%i3) float(exp(10000.0));
> float: floating point overflow converting 8.806818225662922b4342
>  -- an error. To debug this try: debugmode(true);
>
> Best regards,
> David Scherfgen