pqc/external/flint-2.4.3/fq_zech/ctx_init.c

188 lines
5.0 KiB
C
Raw Normal View History

2014-05-18 22:03:37 +00:00
/*=============================================================================
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) 2013 Mike Hansen
******************************************************************************/
#include <stdio.h>
#include <string.h>
#include "flint.h"
#include "fq_zech.h"
void
fq_zech_ctx_init(fq_zech_ctx_t ctx, const fmpz_t p, slong d, const char *var)
{
fq_nmod_ctx_struct * fq_nmod_ctx;
fq_nmod_ctx = flint_malloc(sizeof(fq_nmod_ctx_struct));
fq_nmod_ctx_init(fq_nmod_ctx, p, d, var);
fq_zech_ctx_init_fq_nmod_ctx(ctx, fq_nmod_ctx);
ctx->owns_fq_nmod_ctx = 1;
}
void
fq_zech_ctx_init_conway(fq_zech_ctx_t ctx, const fmpz_t p, slong d,
const char *var)
{
fq_nmod_ctx_struct * fq_nmod_ctx;
fq_nmod_ctx = flint_malloc(sizeof(fq_nmod_ctx_struct));
fq_nmod_ctx_init_conway(fq_nmod_ctx, p, d, var);
fq_zech_ctx_init_fq_nmod_ctx(ctx, fq_nmod_ctx);
ctx->owns_fq_nmod_ctx = 1;
}
int
_fq_zech_ctx_init_conway(fq_zech_ctx_t ctx, const fmpz_t p, slong d,
const char *var)
{
int result;
fq_nmod_ctx_struct * fq_nmod_ctx;
fq_nmod_ctx = flint_malloc(sizeof(fq_nmod_ctx_struct));
result = _fq_nmod_ctx_init_conway(fq_nmod_ctx, p, d, var);
if (!result)
{
flint_free(fq_nmod_ctx);
return result;
}
fq_zech_ctx_init_fq_nmod_ctx(ctx, fq_nmod_ctx);
ctx->owns_fq_nmod_ctx = 1;
return result;
}
void
fq_zech_ctx_init_modulus(fq_zech_ctx_t ctx,
const nmod_poly_t modulus,
const char *var)
{
fq_nmod_ctx_struct * fq_nmod_ctx;
fq_nmod_ctx = flint_malloc(sizeof(fq_nmod_ctx_struct));
fq_nmod_ctx_init_modulus(fq_nmod_ctx, modulus, var);
fq_zech_ctx_init_fq_nmod_ctx(ctx, fq_nmod_ctx);
ctx->owns_fq_nmod_ctx = 1;
}
void
fq_zech_ctx_init_fq_nmod_ctx(fq_zech_ctx_t ctx,
fq_nmod_ctx_t fq_nmod_ctx)
{
ulong i, n;
fq_nmod_t r, gen;
slong up, q;
fmpz_t result, order;
mp_limb_t j, nz, result_ui;
mp_limb_t *n_reverse_table;
ctx->fq_nmod_ctx = fq_nmod_ctx;
ctx->owns_fq_nmod_ctx = 0;
fmpz_init(order);
fq_nmod_ctx_order(order, fq_nmod_ctx);
if (fmpz_bits(order) > FLINT_BITS)
{
flint_printf("Exception (fq_zech_ctx_init_nmod_ctx). Requires q < 2^FLINT_BITS\n");
abort();
}
q = fmpz_get_ui(order);
up = fmpz_get_ui(fq_nmod_ctx_prime(fq_nmod_ctx));
ctx->p = up;
ctx->ppre = n_precompute_inverse(ctx->p);
ctx->qm1 = q - 1;
if (up == 2)
{
ctx->qm1o2 = 0;
}
else
{
ctx->qm1o2 = ctx->qm1 / 2;
}
ctx->qm1opm1 = ctx->qm1 / (up - 1);
ctx->prime_root = n_primitive_root_prime(ctx->p);
ctx->zech_log_table = (mp_limb_t *) flint_malloc(q * sizeof(mp_limb_t));
ctx->prime_field_table = (mp_limb_t *) flint_malloc(up * sizeof(mp_limb_t));
n_reverse_table = (mp_limb_t *) flint_malloc(q * sizeof(mp_limb_t));
ctx->eval_table = (mp_limb_t *) flint_malloc(q * sizeof(mp_limb_t));
ctx->zech_log_table[ctx->qm1] = 0;
ctx->prime_field_table[0] = ctx->qm1;
n_reverse_table[0] = ctx->qm1;
ctx->eval_table[ctx->qm1] = 0;
fq_nmod_init(r, ctx->fq_nmod_ctx);
fq_nmod_init(gen, ctx->fq_nmod_ctx);
fq_nmod_one(r, ctx->fq_nmod_ctx);
fq_nmod_gen(gen, ctx->fq_nmod_ctx);
fmpz_init(result);
for (i = 0; i < ctx->qm1; i++)
{
nmod_poly_evaluate_fmpz(result, r, fq_nmod_ctx_prime(fq_nmod_ctx));
result_ui = fmpz_get_ui(result);
n_reverse_table[result_ui] = i;
ctx->eval_table[i] = result_ui;
if (r->length == 1)
{
ctx->prime_field_table[result_ui] = i;
}
fq_nmod_mul(r, r, gen, fq_nmod_ctx);
}
i = 1;
for (i = 0; i < q; i++)
{
j = n_reverse_table[i];
n = i;
if (n % up == up - 1)
{
nz = n - up + 1;
}
else
{
nz = n + 1;
}
ctx->zech_log_table[j] = n_reverse_table[nz];
}
fq_nmod_clear(r, fq_nmod_ctx);
fq_nmod_clear(gen, fq_nmod_ctx);
flint_free(n_reverse_table);
fmpz_clear(result);
fmpz_clear(order);
}