#14007: When computing determinant over GF(p), don't lift to ZZ
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       Reporter:  jdemeyer        |         Owner:  jason, was         
           Type:  enhancement     |        Status:  needs_work         
       Priority:  blocker         |     Milestone:  sage-5.7           
      Component:  linear algebra  |    Resolution:                     
       Keywords:                  |   Work issues:                     
Report Upstream:  N/A             |     Reviewers:  Charles Bouillaguet
        Authors:  Jeroen Demeyer  |     Merged in:                     
   Dependencies:                  |      Stopgaps:                     
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Comment (by jdemeyer):

 Replying to [comment:11 Bouillaguet]:
 > I also checked that the corresponding PARI routine ({{{Flm_det_sp_OK}}}
 in {{{src/basemath/linalg1.c}}}) does not require the characteristic of
 the ring to be prime. The same procedure in PARI deals with determinants
 in ZZ/6ZZ and ZZ/11ZZ.
 PARI does require that the characteristic is prime, or at least that it
 won't encounter non-invertible elements:
 {{{
 gp> matdet([2,1,0;2,3,0;0,0,1]*Mod(1,4))
   ***   at top-level: matdet([2,1,0;2,3,0;
   ***                 ^--------------------
   *** matdet: impossible inverse modulo: Mod(2, 4).
 }}}

 > Another longer-term objective would ben when the modulus is too large,
 to use the chinese reminder theorem to work only modulo small primes
 This is what newer versions of PARI do.

-- 
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/14007#comment:12>
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