C++ (Cpp) acb_cos Examples

Example #1

File: chebyshev_t.c Project: isuruf/arb

void
acb_hypgeom_chebyshev_t(acb_t res, const acb_t n, const acb_t z, slong prec)
{
    acb_t t;

    if (acb_is_int(n) && 
        arf_cmpabs_2exp_si(arb_midref(acb_realref(n)), FLINT_BITS - 1) < 0)
    {
        slong k = arf_get_si(arb_midref(acb_realref(n)), ARF_RND_DOWN);
        acb_chebyshev_t_ui(res, FLINT_ABS(k), z, prec);
        return;
    }

    if (acb_is_zero(z))
    {
        acb_mul_2exp_si(res, n, -1);
        acb_cos_pi(res, res, prec);
        return;
    }

    if (acb_is_one(z))
    {
        acb_one(res);
        return;
    }

    acb_init(t);
    acb_set_si(t, -1);

    if (acb_equal(t, z))
    {
        acb_cos_pi(res, n, prec);
    }
    else
    {
        acb_sub_ui(t, z, 1, prec);

        if (arf_cmpabs_2exp_si(arb_midref(acb_realref(t)), -2 - prec / 10) < 0 &&
            arf_cmpabs_2exp_si(arb_midref(acb_imagref(t)), -2 - prec / 10) < 0)
        {
            acb_t a, c;

            acb_init(a);
            acb_init(c);

            acb_neg(a, n);
            acb_one(c);
            acb_mul_2exp_si(c, c, -1);
            acb_neg(t, t);
            acb_mul_2exp_si(t, t, -1);
            acb_hypgeom_2f1(res, a, n, c, t, 0, prec);

            acb_clear(a);
            acb_clear(c);
        }
        else if (arb_is_nonnegative(acb_realref(t)))
        {
            acb_acosh(t, z, prec);
            acb_mul(t, t, n, prec);
            acb_cosh(res, t, prec);
        }
        else
        {
            acb_acos(t, z, prec);
            acb_mul(t, t, n, prec);
            acb_cos(res, t, prec);
        }
    }

    acb_clear(t);
}

Example #2

File: t-integrate_taylor.c Project: argriffing/arb

int main()
{
    slong iter;
    flint_rand_t state;

    flint_printf("integrate_taylor....");
    fflush(stdout);

    flint_randinit(state);

    for (iter = 0; iter < 150 * arb_test_multiplier(); iter++)
    {
        acb_t ans, res, a, b;
        arf_t inr, outr;
        double t;
        slong goal, prec;

        acb_init(ans);
        acb_init(res);
        acb_init(a);
        acb_init(b);
        arf_init(inr);
        arf_init(outr);

        goal = 2 + n_randint(state, 300);
        prec = 2 + n_randint(state, 300);

        acb_randtest(a, state, 1 + n_randint(state, 200), 2);
        acb_randtest(b, state, 1 + n_randint(state, 200), 2);

        acb_cos(ans, a, prec);
        acb_cos(res, b, prec);
        acb_sub(ans, ans, res, prec);

        t = (1 + n_randint(state, 20)) / 10.0;
        arf_set_d(inr, t);
        arf_set_d(outr, t + (1 + n_randint(state, 20)) / 5.0);

        acb_calc_integrate_taylor(res, sin_x, NULL,
            a, b, inr, outr, goal, prec);

        if (!acb_overlaps(res, ans))
        {
            flint_printf("FAIL! (iter = %wd)\n", iter);
            flint_printf("prec = %wd, goal = %wd\n", prec, goal);
            flint_printf("inr = "); arf_printd(inr, 15); flint_printf("\n");
            flint_printf("outr = "); arf_printd(outr, 15); flint_printf("\n");
            flint_printf("a = "); acb_printd(a, 15); flint_printf("\n");
            flint_printf("b = "); acb_printd(b, 15); flint_printf("\n");
            flint_printf("res = "); acb_printd(res, 15); flint_printf("\n\n");
            flint_printf("ans = "); acb_printd(ans, 15); flint_printf("\n\n");
            abort();
        }

        acb_clear(ans);
        acb_clear(res);
        acb_clear(a);
        acb_clear(b);
        arf_clear(inr);
        arf_clear(outr);
    }

    flint_randclear(state);
    flint_cleanup();
    flint_printf("PASS\n");
    return EXIT_SUCCESS;
}