unity_zpq_pow.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) 2015 Vladimir Glazachev
   
******************************************************************************/

#include "aprcl.h"

void unity_zpq_pow(unity_zpq f, const unity_zpq g, const fmpz_t pow)
{
    ulong j;
    unity_zpq value;
    fmpz_t power, rem;

    unity_zpq_init(value, f->q, f->p, f->n);
    fmpz_init_set(power, pow);
    fmpz_init(rem);

    unity_zpq_coeff_set_ui(f, 0, 0, 1);

    unity_zpq_copy(value, g);

    while (fmpz_is_zero(power) == 0)
    {
        unity_zpq temp_pow;
        fmpz_fdiv_r_2exp(rem, power, 1);
        if (fmpz_is_zero(rem) == 0)
        {
            unity_zpq temp;
            unity_zpq_init(temp, f->q, f->p, f->n);

            unity_zpq_mul(temp, f, value);
            unity_zpq_swap(f, temp);

            unity_zpq_clear(temp);
        }

        unity_zpq_init(temp_pow, f->q, f->p, f->n);
        unity_zpq_mul(temp_pow, value, value);
        unity_zpq_swap(value, temp_pow);
        fmpz_fdiv_q_2exp(power, power, 1);

        unity_zpq_clear(temp_pow);
    }


    fmpz_clear(power);
    fmpz_clear(rem);
    unity_zpq_clear(value);
}

void unity_zpq_pow_ui(unity_zpq f, const unity_zpq g, ulong pow)
{
    fmpz_t p;
    fmpz_init_set_ui(p, pow);
    unity_zpq_pow(f, g, p);
    fmpz_clear(p);
}