hypellfrob.h

/* ============================================================================

   hypellfrob.h:  header for hypellfrob.cpp
   
   This file is part of hypellfrob (version 2.1.1).

   Copyright (C) 2007, 2008, David Harvey

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License along
   with this program; if not, write to the Free Software Foundation, Inc.,
   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

============================================================================ */


#include <NTL/ZZ.h>
#include <NTL/ZZX.h>
#include <NTL/mat_ZZ.h>


namespace hypellfrob {


/*
Computes frobenius matrix for given p, to precision p^N, for the
hyperelliptic curve y^2 = Q(x), on the standard basis of cohomology.

PRECONDITIONS:
   p must be a prime > (2g+1)(2N-1).
   N >= 1.
   Degree of Q should be 2g+1 for some g >= 1.
   Q must be monic. The reduction of Q mod p must have no multiple roots.
   
RETURN VALUE:
   1 on success, in which case "output" holds the resulting 2g * 2g matrix.
   0 if any of the above conditions are not satisfied. (EXCEPTION: matrix()
       will not check that p is prime. That's up to you.)

*/
int matrix(NTL::mat_ZZ& output, const NTL::ZZ& p, int N, const NTL::ZZX& Q,
           int force_ntl = 0);


};

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