ok, so the docstring reaveals (1) that the pari version is "by far the
fastest" as I suspected, but also that for n>50000 that we use a gp
interface rather than the pari library " since the C-library interface
to PARI
        is limited in memory for individual operations" -- whatever that means!

That might explain David's timing observations.

I tihnk the pari implementation is actually quite simple (and there is
a huge amount about Berouilli nos in Henri Cohen's latest book too)
which suggests that doing a cython implementation would not be hard.

Maybe this is time for a repeat performance of the partitions
competition with M**ca!

John

2008/5/2 John Cremona <[EMAIL PROTECTED]>:
> I might take a look at this, as there are some ways fo computing B nos
>  which are very much faster tha others, and not everyone knows them.
>  Pari has something respectable, certainly.
>
>  John
>
>  2008/5/2 mhampton <[EMAIL PROTECTED]>:
>
>
> >
>  >  It takes about 30 seconds on my machine to get the 10^5 Bernoulli
>  >  number.  The mathematica blog says it took a "development" version of
>  >  mathematica 6 days to do the 10^7 calc.  So it would probably take
>  >  some work, but we are not that badly off as is.
>  >
>  >  -M. Hampton
>  >
>  >  On May 2, 12:34 pm, Fredrik  Johansson <[EMAIL PROTECTED]>
>  >  wrote:
>  >
>  > > Oleksandr Pavlyk reports on the Wolfram Blog that he has computed the
>  >  > 10 millionth Bernoulli number using 
> Mathematica:http://blog.wolfram.com/2008/04/29/today-we-broke-the-bernoulli-recor...
>  >
>  >
>  > >
>  >  > How does sage's Bernoulli number implementation compare? I'd like to
>  >  > see bernoulli(10^7) in sage beating Mathematica's time. And then
>  >  > computing the 20 millionth Bernoulli number...
>  >  >
>  >  > Fredrik
>  >  >  >
>  >
>

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