Charles Greathouse on Thu, 08 Aug 2013 21:04:04 +0200

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Re: 4th "Atelier PARI/GP" (january 2014)

My number one request is a forfactored() function which uses a sieve to produce factored values efficiently. I plan to write code for this, actually -- even poorly-optimized code will beat 'factoring each individual integer' by miles.

Along those lines, support for arithmetic functions on factored numbers would be nice. One can always do
prod(i=1, #f~, (f[i,1]-1)*f[i,1]^(f[i,2]-1))
but it would be much nicer to write eulerphi(f).

Another improvement that would be nice: a combinatorial algorithm for primepi() so that for large inputs the code wouldn't need to count the primes individually. (The analytic methods are too slow to be practical at this point...)

It seems that the GP syntax would allow ^^ to be added for tetration (repeated exponentiation); if this is interesting I'd be happy to code the implementation for t_INTMODs (the only interesting case).

From the TODO, I vote for "implement Jebelean-Krandick diviiexact".

Charles Greathouse
Case Western Reserve University

On Fri, Jul 26, 2013 at 1:16 PM, Karim Belabas <> wrote:
[ Apologies for multiple postings  -- K.B. ]

====== WORKSHOP: 4th Atelier PARI/GP in Besancon ==(First announcement)======

Dear colleagues,

we would like to announce a week-long workshop on the computer algebra system
"PARI/GP", from 6th to 10th January 2014, at Besancon University (France).

  Bill Allombert      <>
  Karim Belabas       <>
  Christophe Delaunay <>

This workshop is organized to discuss the current and future development
of the PARI/GP system. Anyone interested in helping out is welcome !

The workshop will include

(1) Short Status reports on the current development projects.

(2) Tutorial sessions.

(3) Brainstorming sessions, to spell out and discuss ideas about the system
development: new features, new algorithms, improving old implementations,
bug fixes, extensions to GP syntax, documentation overhaul ...

(4) Coding sessions: inspired by (3), but bring also your own problems !

Please share your ideas for Discussion topics (3) or Coding sessions (4)
with the development mailing list <>.
Feel free to suggest subjects for the Tutorial sessions (2).

To register, please contact <>.
Please mention in your email if you need financial help to attend.

Website: (under construction)

The Atelier is part of the Trimester "Methodes Arithmetiques et Applications"

Karim Belabas, IMB (UMR 5251)  Tel: (+33) (0)5 40 00 26 17
Universite Bordeaux 1          Fax: (+33) (0)5 40 00 69 50
351, cours de la Liberation
Talence (France)  [PARI/GP]