Beispiel #1
0
int main()
{
    slong iter;
    flint_rand_t state;

    flint_printf("2f1....");
    fflush(stdout);

    flint_randinit(state);

    for (iter = 0; iter < 3000; iter++)
    {
        acb_t a, b, c, z, w1, w2, t;
        slong prec1, prec2;
        int reg1, reg2, ebits;
        int alg1, alg2;

        acb_init(a);
        acb_init(b);
        acb_init(c);
        acb_init(z);
        acb_init(w1);
        acb_init(w2);
        acb_init(t);

        prec1 = 2 + n_randint(state, 300);
        prec2 = 2 + n_randint(state, 300);

        if (n_randint(state, 20) == 0)
            ebits = 30;
        else
            ebits = 5;

        switch (n_randint(state, 3))
        {
            case 0:
                acb_set_si(a, n_randint(state, 500));
                acb_set_si(b, n_randint(state, 500));
                acb_set_si(c, n_randint(state, 10));
                break;
            case 1:
                acb_set_si(a, n_randint(state, 200) - 100);
                acb_set_si(b, n_randint(state, 200) - 100);
                acb_set_si(c, n_randint(state, 200) - 100);
                break;
            default:
                acb_randtest_param(a, state, 1 + n_randint(state, 400), 1 + n_randint(state, ebits));
                acb_randtest_param(b, state, 1 + n_randint(state, 400), 1 + n_randint(state, ebits));
                acb_randtest_param(c, state, 1 + n_randint(state, 400), 1 + n_randint(state, ebits));
        }

        acb_randtest_param(z, state, 1 + n_randint(state, 400), 1 + n_randint(state, ebits));
        acb_randtest(w1, state, 1 + n_randint(state, 400), 1 + n_randint(state, ebits));
        acb_randtest(w2, state, 1 + n_randint(state, 400), 1 + n_randint(state, ebits));

        reg1 = n_randint(state, 2);
        reg2 = n_randint(state, 2);

        alg1 = n_randint(state, 10);
        alg2 = n_randint(state, 10);

        switch (alg1)
        {
            case 0:
                acb_hypgeom_2f1_direct(w1, a, b, c, z, reg1, prec1);
                break;
            case 1:
            case 2:
            case 3:
            case 4:
            case 5:
                acb_hypgeom_2f1_transform(w1, a, b, c, z, reg1, alg1, prec1);
                break;
            case 6:
                acb_hypgeom_2f1_corner(w1, a, b, c, z, reg1, prec1);
                break;
            default:
                acb_hypgeom_2f1(w1, a, b, c, z, reg1, prec1);
        }

        switch (alg2)
        {
            case 0:
                acb_hypgeom_2f1_direct(w2, a, b, c, z, reg2, prec2);
                break;
            case 1:
            case 2:
            case 3:
            case 4:
            case 5:
                acb_hypgeom_2f1_transform(w2, a, b, c, z, reg2, alg2, prec2);
                break;
            case 6:
                acb_hypgeom_2f1_corner(w2, a, b, c, z, reg2, prec2);
                break;
            default:
                acb_hypgeom_2f1(w2, a, b, c, z, reg2, prec2);
        }

        if (reg1 != reg2)
        {
            acb_rgamma(t, c, prec2);

            if (reg1)
                acb_mul(w2, w2, t, prec2);
            else
                acb_mul(w1, w1, t, prec2);
        }

        if (!acb_overlaps(w1, w2))
        {
            flint_printf("FAIL: consistency\n\n");
            flint_printf("iter = %wd, prec1 = %wd, prec2 = %wd\n\n", iter, prec1, prec2);
            flint_printf("alg1 = %d, alg2 = %d\n\n", alg1, alg2);
            flint_printf("reg1 = %d, reg2 = %d\n\n", reg1, reg2);
            flint_printf("a = "); acb_printd(a, 30); flint_printf("\n\n");
            flint_printf("b = "); acb_printd(b, 30); flint_printf("\n\n");
            flint_printf("c = "); acb_printd(c, 30); flint_printf("\n\n");
            flint_printf("z = "); acb_printd(z, 30); flint_printf("\n\n");
            flint_printf("w1 = "); acb_printd(w1, 30); flint_printf("\n\n");
            flint_printf("w2 = "); acb_printd(w2, 30); flint_printf("\n\n");
            abort();
        }

        acb_clear(a);
        acb_clear(b);
        acb_clear(c);
        acb_clear(z);
        acb_clear(w1);
        acb_clear(w2);
        acb_clear(t);
    }

    flint_randclear(state);
    flint_cleanup();
    flint_printf("PASS\n");
    return EXIT_SUCCESS;
}
Beispiel #2
0
void
acb_hypgeom_2f1(acb_t res, const acb_t a, const acb_t b,
        const acb_t c, const acb_t z, int flags, slong prec)
{
    int algorithm, regularized;

    regularized = flags & ACB_HYPGEOM_2F1_REGULARIZED;

    if (!acb_is_finite(a) || !acb_is_finite(b) || !acb_is_finite(c) || !acb_is_finite(z))
    {
        acb_indeterminate(res);
        return;
    }

    if (acb_is_zero(z))
    {
        if (regularized)
            acb_rgamma(res, c, prec);
        else
            acb_one(res);
        return;
    }

    if (regularized && acb_is_int(c) && arb_is_nonpositive(acb_realref(c)))
    {
        if ((acb_is_int(a) && arb_is_nonpositive(acb_realref(a)) &&
            arf_cmp(arb_midref(acb_realref(a)), arb_midref(acb_realref(c))) >= 0) ||
            (acb_is_int(b) && arb_is_nonpositive(acb_realref(b)) &&
            arf_cmp(arb_midref(acb_realref(b)), arb_midref(acb_realref(c))) >= 0))
        {
            acb_zero(res);
            return;
        }
    }

    if (regularized && acb_eq(a, c))
    {
        _acb_hypgeom_2f1r_reduced(res, b, c, z, prec);
        return;
    }

    if (regularized && acb_eq(b, c))
    {
        _acb_hypgeom_2f1r_reduced(res, a, c, z, prec);
        return;
    }

    /* polynomial */
    if (acb_is_int(a) && arf_sgn(arb_midref(acb_realref(a))) <= 0 &&
         arf_cmpabs_ui(arb_midref(acb_realref(a)), prec) < 0)
    {
        acb_hypgeom_2f1_direct(res, a, b, c, z, regularized, prec);
        return;
    }

    /* polynomial */
    if (acb_is_int(b) && arf_sgn(arb_midref(acb_realref(b))) <= 0 &&
         arf_cmpabs_ui(arb_midref(acb_realref(b)), prec) < 0)
    {
        acb_hypgeom_2f1_direct(res, a, b, c, z, regularized, prec);
        return;
    }

    /* Try to reduce to a polynomial case using the Pfaff transformation */
    /* TODO: look at flags for integer c-b, c-a here, even when c is nonexact */
    if (acb_is_exact(c))
    {
        acb_t t;
        acb_init(t);

        acb_sub(t, c, b, prec);

        if (acb_is_int(t) && arb_is_nonpositive(acb_realref(t)))
        {
            acb_hypgeom_2f1_transform(res, a, b, c, z, flags, 1, prec);
            acb_clear(t);
            return;
        }

        acb_sub(t, c, a, prec);

        if (acb_is_int(t) && arb_is_nonpositive(acb_realref(t)))
        {
            int f1, f2;

            /* When swapping a, b, also swap the flags. */
            f1 = flags & ACB_HYPGEOM_2F1_AC;
            f2 = flags & ACB_HYPGEOM_2F1_BC;

            flags &= ~ACB_HYPGEOM_2F1_AC;
            flags &= ~ACB_HYPGEOM_2F1_BC;

            if (f1) flags |= ACB_HYPGEOM_2F1_BC;
            if (f2) flags |= ACB_HYPGEOM_2F1_AC;

            acb_hypgeom_2f1_transform(res, b, a, c, z, flags, 1, prec);
            acb_clear(t);
            return;
        }

        acb_clear(t);
    }

    /* special value at z = 1 */
    if (acb_is_one(z))
    {
        acb_t t, u, v;

        acb_init(t);
        acb_init(u);
        acb_init(v);

        acb_sub(t, c, a, prec);
        acb_sub(u, c, b, prec);
        acb_sub(v, t, b, prec);

        if (arb_is_positive(acb_realref(v)))
        {
            acb_rgamma(t, t, prec);
            acb_rgamma(u, u, prec);
            acb_mul(t, t, u, prec);
            acb_gamma(v, v, prec);
            acb_mul(t, t, v, prec);

            if (!regularized)
            {
                acb_gamma(v, c, prec);
                acb_mul(t, t, v, prec);
            }

            acb_set(res, t);
        }
        else
        {
            acb_indeterminate(res);
        }

        acb_clear(t);
        acb_clear(u);
        acb_clear(v);

        return;
    }

    algorithm = acb_hypgeom_2f1_choose(z);

    if (algorithm == 0)
    {
        acb_hypgeom_2f1_direct(res, a, b, c, z, regularized, prec);
    }
    else if (algorithm >= 1 && algorithm <= 5)
    {
        acb_hypgeom_2f1_transform(res, a, b, c, z, flags, algorithm, prec);
    }
    else
    {
        acb_hypgeom_2f1_corner(res, a, b, c, z, regularized, prec);
    }
}