/*
    Copyright (C) 2013 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 "acb.h"

TEST_FUNCTION_START(acb_expm1, state)
{
    slong iter;

    for (iter = 0; iter < 2000 * 0.1 * flint_test_multiplier(); iter++)
    {
        acb_t x, a, b;
        slong prec1, prec2;

        prec1 = 2 + n_randint(state, 400);
        prec2 = 2 + n_randint(state, 400);

        acb_init(x);
        acb_init(a);
        acb_init(b);

        acb_randtest_special(x, state, 1 + n_randint(state, 1000), 2 + n_randint(state, 100));
        acb_randtest_special(a, state, 1 + n_randint(state, 1000), 2 + n_randint(state, 100));
        acb_randtest_special(b, state, 1 + n_randint(state, 1000), 2 + n_randint(state, 100));

        acb_expm1(a, x, prec1);
        acb_set(b, x);  /* also test aliasing */
        acb_expm1(b, b, prec2);

        /* check consistency */
        if (!acb_overlaps(a, b))
        {
            flint_printf("FAIL: overlap\n\n");
            flint_printf("x = "); acb_printd(x, 15); flint_printf("\n\n");
            flint_printf("a = "); acb_printd(a, 15); flint_printf("\n\n");
            flint_printf("b = "); acb_printd(b, 15); flint_printf("\n\n");
            flint_abort();
        }

        /* check expm1(x) = exp(x)-1 */
        acb_exp(b, x, prec2);
        acb_sub_ui(b, b, 1, prec2);

        if (!acb_overlaps(a, b))
        {
            flint_printf("FAIL: expm1 vs exp\n\n");
            flint_printf("x = "); acb_printd(x, 15); flint_printf("\n\n");
            flint_printf("a = "); acb_printd(a, 15); flint_printf("\n\n");
            flint_printf("b = "); acb_printd(b, 15); flint_printf("\n\n");
            flint_abort();
        }

        acb_clear(x);
        acb_clear(a);
        acb_clear(b);
    }

    TEST_FUNCTION_END(state);
}
