126 lines
3.0 KiB
C
126 lines
3.0 KiB
C
/*=============================================================================
|
|
|
|
This file is part of FLINT.
|
|
|
|
FLINT 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.
|
|
|
|
FLINT 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 FLINT; if not, write to the Free Software
|
|
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
|
|
|
|
=============================================================================*/
|
|
/******************************************************************************
|
|
|
|
Copyright (C) 2012 Sebastian Pancratz
|
|
|
|
******************************************************************************/
|
|
|
|
#include <gmp.h>
|
|
#include "flint.h"
|
|
#include "fmpz.h"
|
|
#include "padic.h"
|
|
#include "ulong_extras.h"
|
|
|
|
void _padic_log_satoh(fmpz_t z, const fmpz_t y, slong v, const fmpz_t p, slong N)
|
|
{
|
|
if (N < 16)
|
|
{
|
|
_padic_log_rectangular(z, y, v, p, N);
|
|
}
|
|
else
|
|
{
|
|
const slong k = n_sqrt(N);
|
|
|
|
fmpz_t t, pk, pNk;
|
|
|
|
fmpz_init(t);
|
|
fmpz_init(pk);
|
|
fmpz_init(pNk);
|
|
fmpz_pow_ui(pk, p, k);
|
|
fmpz_pow_ui(pNk, p, N + k);
|
|
|
|
fmpz_sub_ui(t, y, 1);
|
|
fmpz_neg(t, t);
|
|
fmpz_powm(t, t, pk, pNk);
|
|
fmpz_sub_ui(t, t, 1);
|
|
fmpz_neg(t, t);
|
|
|
|
/* TODO: Improve suggested valuation */
|
|
_padic_log_rectangular(z, t, k + 1, p, N + k);
|
|
|
|
fmpz_divexact(z, z, pk);
|
|
|
|
fmpz_clear(t);
|
|
fmpz_clear(pk);
|
|
fmpz_clear(pNk);
|
|
}
|
|
}
|
|
|
|
int padic_log_satoh(padic_t rop, const padic_t op, const padic_ctx_t ctx)
|
|
{
|
|
const fmpz *p = ctx->p;
|
|
const slong N = padic_prec(rop);
|
|
|
|
if (padic_val(op) < 0)
|
|
{
|
|
return 0;
|
|
}
|
|
else
|
|
{
|
|
fmpz_t y;
|
|
int ans;
|
|
|
|
fmpz_init(y);
|
|
|
|
padic_get_fmpz(y, op, ctx);
|
|
fmpz_sub_ui(y, y, 1);
|
|
fmpz_neg(y, y);
|
|
|
|
if (fmpz_is_zero(y))
|
|
{
|
|
padic_zero(rop);
|
|
ans = 1;
|
|
}
|
|
else
|
|
{
|
|
fmpz_t t;
|
|
slong v;
|
|
|
|
fmpz_init(t);
|
|
v = fmpz_remove(t, y, ctx->p);
|
|
fmpz_clear(t);
|
|
|
|
if (v >= 2 || (!fmpz_equal_ui(p, 2) && v >= 1))
|
|
{
|
|
if (v >= N)
|
|
{
|
|
padic_zero(rop);
|
|
}
|
|
else
|
|
{
|
|
_padic_log_satoh(padic_unit(rop), y, v, p, N);
|
|
padic_val(rop) = 0;
|
|
padic_reduce(rop, ctx);
|
|
}
|
|
ans = 1;
|
|
}
|
|
else
|
|
{
|
|
ans = 0;
|
|
}
|
|
}
|
|
|
|
fmpz_clear(y);
|
|
return ans;
|
|
}
|
|
}
|
|
|