Hi everyone,

SAGE 2.8.5 finally adds a method for LLL lattice reduction to the 
Matrix_integer_dense class. For now it only wraps NTL but we actually have 
two more implementations available in SAGE which are to be wrapped 
conveniently soon. However, as ticket 

http://trac.sagemath.org/sage_trac/ticket/723

points out, they are all blown away by MAGMA.

sage: a = random_matrix(ZZ,200)
sage: time b=a.lll() # NTL, delta = 3/4
CPU times: user 10.63 s, sys: 0.03 s, total: 10.66 s
Wall time: 10.67

sage: m = magma(a)
sage: time b = m.LLL() # MAGMA, delta = 3/4
CPU times: user 0.00 s, sys: 0.00 s, total: 0.00 s
Wall time: 1.72

sage: p = pari(a)
sage: time b = p.qflll(1) # Pari
CPU times: user 10.47 s, sys: 0.03 s, total: 10.51 s
Wall time: 10.61

sage: g = gap(a)
sage: time b = g.LLLReducedBasis() # GAP
killed after two minutes

The relevant MAGMA documentation is at

http://www.msri.org/about/computing/docs/magma/html/text833.htm

The relevant PARI documentation is at

http://pari.math.u-bordeaux.fr/dochtml/html.stable/Vectors,_matrices,_linear_algebra_and_sets.html#qflll

The relevant NTL documentation is at:

http://www.shoup.net/ntl/doc/LLL.txt

Also, Google came up with

http://www.math.uu.nl/people/vdkallen/lllimplementations.html

which could be relevant or not, I don't know.

The point of this mail is to ask you -- dear LLL wizards -- (a) why Magma is 
so much faster and (b) what we can do about it.

Thoughts?
Martin

-- 
name: Martin Albrecht
_pgp: http://pgp.mit.edu:11371/pks/lookup?op=get&search=0x8EF0DC99
_www: http://www.informatik.uni-bremen.de/~malb
_jab: [EMAIL PROTECTED]


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