[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Reproducible Research Hackathon: Friday, July 3rd

From: Ludovic Courtès
Subject: Re: Reproducible Research Hackathon: Friday, July 3rd
Date: Tue, 14 Jul 2020 15:18:12 +0200
User-agent: Gnus/5.13 (Gnus v5.13) Emacs/26.3 (gnu/linux)

Hi Konrad,

Konrad Hinsen <> skribis:

> Indeed. The details are here:

Oooh, thank you!  It looks like an “interesting” bug, one of those that
can help make the case for precise software environment control.  :-) (Bonface M. K.) skribis:

> That's strange. To get the right results, you'd have to do a `2L ** 64`.
> When I tried `2 ** 63` I got `-9223372036854775808`. There's also an
> overflow error. Here's a snippet of what fails from
> Python-2.4.6/Lib/test:
> ```
>     # If this fails, probably using a strict IEEE-754 conforming libm, and x
>     # is +Inf afterwards.  But Python wants overflows detected by default.
>     try:
>         x = math.exp(1000000000)
>     except OverflowError:
>         pass
>     else:
>         raise TestFailed("overflowing exp() didn't trigger OverflowError")
> ```
> Maybe there's an overflow somewhere and we'd have to tweak libm? I'm
> speculating though. I'd have to investigate this later.

Uh, weird!  We could check whether building Python with ‘-fwrapv’ helps.
See also <>.


reply via email to

[Prev in Thread] Current Thread [Next in Thread]