[petsc-users] PetscTableCreateHashSize

[Kong, Fande]

Thanks a lot Satish!

Like Jed said, it would be better if we could come up an algorithm for
automatically computing a hash size for a given n.  Otherwise, we  may need
to  add more entries to the lookup again in the future.

Fande,

On Mon, Jan 9, 2017 at 2:14 PM, Satish Balay <balay at mcs.anl.gov> wrote:

> On Mon, 9 Jan 2017, Jed Brown wrote:
>
> > Satish Balay <balay at mcs.anl.gov> writes:
> > > Sure - I'm using a crappy algorithm [look-up table] to get
> > > "prime_number_close_to(1.4*sz)" - as I don't know how to generate
> > > these numbers automatically.
> >
> > FWIW, it only needs to be coprime with PETSC_HASH_FACT.
>
> Not sure I understand - are you saying coprime requirement is easier
> satisfy than a single prime?
>
> I had switched this code to use double-hasing algorithm - and the
> requirement here is - the table size be a prime number. [so I'm
> attempting to estimate a prime number suitable for the table size]
>
> I pushed the following
> https://urldefense.proofpoint.com/v2/url?u=https-3A__
> bitbucket.org_petsc_petsc_commits_d742c75fd0d514f7fa1873d5b10984
> bc3f363031&d=DQIBAg&c=54IZrppPQZKX9mLzcGdPfFD1hxrcB_
> _aEkJFOKJFd00&r=DUUt3SRGI0_JgtNaS3udV68GRkgV4ts7XKfj2opmi
> CY&m=nkPXHuaxZeHPzOteY25j_Dptk5XyWiqwzaJbEwI5uWY&s=
> eOjfGCXP3g18VLYhXY5xrlOr7AFn7o3G_YrYVo8Rw8Y&e=
>
> Satish
>
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