Differences between revisions 7 and 9 (spanning 2 versions)
 ⇤ ← Revision 7 as of 2007-01-21 04:26:11 → Size: 1077 Editor: wstein Comment: ← Revision 9 as of 2008-11-14 13:42:00 → ⇥ Size: 1087 Editor: localhost Comment: converted to 1.6 markup Deletions are marked like this. Additions are marked like this. Line 11: Line 11: '''Challenge''': On sage.math.washington.edu, compute all \$a_p\$ for p < 10^6 in less than 1 second wall time. '''Challenge''': On sage.math.washington.edu, make a list of all \$a_n\$ for \$n < 10^6\$ in less than 1 second wall time. Line 13: Line 13: See [:msri07/threadsafety: Thread Safety of the SAGE Libraries] for information about PARI thread safety. See [[msri07/threadsafety| Thread Safety of the SAGE Libraries]] for information about PARI thread safety.

# Problem: Implementation in SAGE parallel computation of elliptic curve a_p for all p up to some bound

In the abstract the problem of point counting modulo p, for lots of different p, is an "embarassingly parallelize -- just do each p separately. The challenge here is *not* coming up with an algorithm, but figuring out how to implement something very efficient in SAGE that uses the PARI C library. In other words, you should make this session below run nearly n times as fast, on a machine with n cores:

```sage: E = EllipticCurve('37a')
sage: time v=E.anlist(10^6, pari_ints=True)
CPU times: user 7.24 s, sys: 0.06 s, total: 7.30 s
Wall time: 12.16```

Challenge: On sage.math.washington.edu, make a list of all a_n for n < 10^6 in less than 1 second wall time.

```sage: magma.version()