flint-sys 0.9.0

/*
    Copyright (C) 2014 Fredrik Johansson

    This file is part of FLINT.

    FLINT is free software: you can redistribute it and/or modify it under
    the terms of the GNU Lesser General Public License (LGPL) as published
    by the Free Software Foundation; either version 3 of the License, or
    (at your option) any later version.  See <https://www.gnu.org/licenses/>.
*/

#include "test_helpers.h"
#include "fmpq.h"
#include "arb.h"

static void
_fmpq_nint(fmpz_t res, const fmpq_t x)
{
    /* nint(x) = floor(x+0.5) - isint((2*x-1)/4) */
    fmpq_t t;
    fmpq_init(t);
    fmpq_set_si(t, 1, 2);
    fmpq_add(t, x, t);
    fmpz_fdiv_q(res, fmpq_numref(t), fmpq_denref(t));

    if (fmpz_is_one(fmpq_denref(t)) && fmpz_is_odd(fmpq_numref(t)))
        fmpz_sub_ui(res, res, 1);

    fmpq_clear(t);
}

TEST_FUNCTION_START(arb_nint, state)
{
    slong iter;

    for (iter = 0; iter < 100000 * 0.1 * flint_test_multiplier(); iter++)
    {
        arb_t a, b;
        fmpq_t x;
        fmpz_t y;
        slong prec;

        arb_init(a);
        arb_init(b);

        fmpq_init(x);
        fmpz_init(y);

        arb_randtest(a, state, 1 + n_randint(state, 200), 10);
        arb_randtest(b, state, 1 + n_randint(state, 200), 10);
        prec = 2 + n_randint(state, 200);

        arb_get_rand_fmpq(x, state, a, 1 + n_randint(state, 200));

        if (n_randint(state, 2))
        {
            arb_nint(b, a, prec);
        }
        else
        {
            arb_set(b, a);
            arb_nint(b, b, prec);
        }

        _fmpq_nint(y, x);

        if (!arb_contains_fmpz(b, y))
        {
            flint_printf("FAIL: containment\n\n");
            flint_printf("a = "); arb_print(a); flint_printf("\n\n");
            flint_printf("x = "); fmpq_print(x); flint_printf("\n\n");
            flint_printf("b = "); arb_print(b); flint_printf("\n\n");
            flint_printf("y = "); fmpz_print(y); flint_printf("\n\n");
            flint_abort();
        }

        arb_clear(a);
        arb_clear(b);

        fmpq_clear(x);
        fmpz_clear(y);
    }

    TEST_FUNCTION_END(state);
}