Re: exp is faster the second time round

[Bill Allombert <Bill.Allombert@math.u-bordeaux1.fr>]

On Mon, Oct 22, 2012 at 10:31:36PM +0200, Karim Belabas wrote:
> * Dirk Laurie [2012-10-22 22:19]:
> > With \p 1000000, it takes about a minute to compute exp
> > on my laptop.  Immediate afterwards, it takes about 30 seconds.
> > 
> > Obviously some constants are being memoized.  Which
> > constants are these?
> 
> log(2)     

and Pi if you are using PARI 2.5, because we need Pi to compute log(2) using the AGM.
(We use another algorithm (binary splitting) in PARI 2.6 so we do not compute Pi).

Cheers,
Bill.