예제 #1
0
void
acb_modular_theta_const_sum(acb_t theta2, acb_t theta3, acb_t theta4,
    const acb_t q, slong prec)
{
    mag_t qmag, err;
    double log2q_approx;
    int is_real, is_real_or_imag;
    slong N;

    mag_init(qmag);
    mag_init(err);

    acb_get_mag(qmag, q);
    log2q_approx = mag_get_d_log2_approx(qmag);

    is_real = arb_is_zero(acb_imagref(q));
    is_real_or_imag = is_real || arb_is_zero(acb_realref(q));

    if (log2q_approx >= 0.0)
    {
        N = 1;
        mag_inf(err);
    }
    else
    {
        N = 0;

        while (0.05 * N * N < prec)
        {
            if (log2q_approx * ((N+2)*(N+2)/4) < -prec - 2)
                break;
            N++;
        }
        N = (N+2)*(N+2)/4;

        mag_geom_series(err, qmag, N);
        mag_mul_2exp_si(err, err, 1); /* each term is taken twice */

        if (mag_is_inf(err))
            N = 1;
    }

    if (N < 1800)
        acb_modular_theta_const_sum_basecase(theta2, theta3, theta4, q, N, prec);
    else
        acb_modular_theta_const_sum_rs(theta2, theta3, theta4, q, N, prec);

    if (is_real_or_imag)
        arb_add_error_mag(acb_realref(theta2), err);
    else
        acb_add_error_mag(theta2, err);

    if (is_real)
    {
        arb_add_error_mag(acb_realref(theta3), err);
        arb_add_error_mag(acb_realref(theta4), err);
    }
    else
    {
        acb_add_error_mag(theta3, err);
        acb_add_error_mag(theta4, err);
    }

    mag_clear(qmag);
    mag_clear(err);
}
예제 #2
0
void
_arb_bell_sum_taylor(arb_t res, const fmpz_t n,
        const fmpz_t a, const fmpz_t b, const fmpz_t mmag, long tol)
{
    fmpz_t m, r, R, tmp;
    mag_t B, C, D, bound;
    arb_t t, u;
    long wp, k, N;

    if (_fmpz_sub_small(b, a) < 5)
    {
        arb_bell_sum_bsplit(res, n, a, b, mmag, tol);
        return;
    }

    fmpz_init(m);
    fmpz_init(r);
    fmpz_init(R);
    fmpz_init(tmp);

    /* r = max(m - a, b - m) */
    /* m = a + (b - a) / 2 */
    fmpz_sub(r, b, a);
    fmpz_cdiv_q_2exp(r, r, 1);
    fmpz_add(m, a, r);

    fmpz_mul_2exp(R, r, RADIUS_BITS);

    mag_init(B);
    mag_init(C);
    mag_init(D);
    mag_init(bound);

    arb_init(t);
    arb_init(u);

    if (fmpz_cmp(R, m) >= 0)
    {
        mag_inf(C);
        mag_inf(D);
    }
    else
    {
        /* C = exp(R * |F'(m)| + (1/2) R^2 * (n/(m-R)^2 + 1/(m-R))) */
        /* C = exp(R * (|F'(m)| + (1/2) R * (n/(m-R) + 1)/(m-R))) */
        /* D = (1/2) R * (n/(m-R) + 1)/(m-R) */
        fmpz_sub(tmp, m, R);
        mag_set_fmpz(D, n);
        mag_div_fmpz(D, D, tmp);
        mag_one(C);
        mag_add(D, D, C);
        mag_div_fmpz(D, D, tmp);
        mag_mul_fmpz(D, D, R);
        mag_mul_2exp_si(D, D, -1);

        /* C = |F'(m)| */
        wp = 20 + 1.05 * fmpz_bits(n);
        arb_set_fmpz(t, n);
        arb_div_fmpz(t, t, m, wp);
        fmpz_add_ui(tmp, m, 1);
        arb_set_fmpz(u, tmp);
        arb_digamma(u, u, wp);
        arb_sub(t, t, u, wp);
        arb_get_mag(C, t);

        /* C = exp(R * (C + D)) */
        mag_add(C, C, D);
        mag_mul_fmpz(C, C, R);
        mag_exp(C, C);
    }

    if (mag_cmp_2exp_si(C, tol / 4 + 2) > 0)
    {
        _arb_bell_sum_taylor(res, n, a, m, mmag, tol);
        _arb_bell_sum_taylor(t, n, m, b, mmag, tol);
        arb_add(res, res, t, 2 * tol);
    }
    else
    {
        arb_ptr mx, ser1, ser2, ser3;

        /* D = T(m) */
        wp = 20 + 1.05 * fmpz_bits(n);
        arb_set_fmpz(t, m);
        arb_pow_fmpz(t, t, n, wp);
        fmpz_add_ui(tmp, m, 1);
        arb_gamma_fmpz(u, tmp, wp);
        arb_div(t, t, u, wp);
        arb_get_mag(D, t);

        /* error bound: (b-a) * C * D * B^N / (1 - B), B = r/R */
        /*              ((b-a) * C * D * 2) * 2^(-N*RADIUS_BITS) */

        /* ((b-a) * C * D * 2) */
        mag_mul(bound, C, D);
        mag_mul_2exp_si(bound, bound, 1);
        fmpz_sub(tmp, b, a);
        mag_mul_fmpz(bound, bound, tmp);

        /* N = (tol + log2((b-a)*C*D*2) - mmag) / RADIUS_BITS */
        if (mmag == NULL)
        {
            /* estimate D ~= 2^mmag */
            fmpz_add_ui(tmp, MAG_EXPREF(C), tol);
            fmpz_cdiv_q_ui(tmp, tmp, RADIUS_BITS);
        }
        else
        {
            fmpz_sub(tmp, MAG_EXPREF(bound), mmag);
            fmpz_add_ui(tmp, tmp, tol);
            fmpz_cdiv_q_ui(tmp, tmp, RADIUS_BITS);
        }

        if (fmpz_cmp_ui(tmp, 5 * tol / 4) > 0)
            N = 5 * tol / 4;
        else if (fmpz_cmp_ui(tmp, 2) < 0)
            N = 2;
        else
            N = fmpz_get_ui(tmp);

        /* multiply by 2^(-N*RADIUS_BITS) */
        mag_mul_2exp_si(bound, bound, -N * RADIUS_BITS);

        mx = _arb_vec_init(2);
        ser1 = _arb_vec_init(N);
        ser2 = _arb_vec_init(N);
        ser3 = _arb_vec_init(N);

        /* estimate (this should work for moderate n and tol) */
        wp = 1.1 * tol + 1.05 * fmpz_bits(n) + 5;

        /* increase precision until convergence */
        while (1)
        {
            /* (m+x)^n / gamma(m+1+x) */
            arb_set_fmpz(mx, m);
            arb_one(mx + 1);
            _arb_poly_log_series(ser1, mx, 2, N, wp);
            for (k = 0; k < N; k++)
                arb_mul_fmpz(ser1 + k, ser1 + k, n, wp);
            arb_add_ui(mx, mx, 1, wp);
            _arb_poly_lgamma_series(ser2, mx, 2, N, wp);
            _arb_vec_sub(ser1, ser1, ser2, N, wp);
            _arb_poly_exp_series(ser3, ser1, N, N, wp);

            /* t = a - m, u = b - m */
            arb_set_fmpz(t, a);
            arb_sub_fmpz(t, t, m, wp);
            arb_set_fmpz(u, b);
            arb_sub_fmpz(u, u, m, wp);
            arb_power_sum_vec(ser1, t, u, N, wp);

            arb_zero(res);
            for (k = 0; k < N; k++)
                arb_addmul(res, ser3 + k, ser1 + k, wp);

            if (mmag != NULL)
            {
                if (_fmpz_sub_small(MAG_EXPREF(arb_radref(res)), mmag) <= -tol)
                    break;
            }
            else
            {
                if (arb_rel_accuracy_bits(res) >= tol)
                    break;
            }

            wp = 2 * wp;
        }

        /* add the series truncation bound */
        arb_add_error_mag(res, bound);

        _arb_vec_clear(mx, 2);
        _arb_vec_clear(ser1, N);
        _arb_vec_clear(ser2, N);
        _arb_vec_clear(ser3, N);
    }

    mag_clear(B);
    mag_clear(C);
    mag_clear(D);
    mag_clear(bound);
    arb_clear(t);
    arb_clear(u);

    fmpz_clear(m);
    fmpz_clear(r);
    fmpz_clear(R);
    fmpz_clear(tmp);
}
예제 #3
0
파일: u_asymp.c 프로젝트: argriffing/arb
void acb_hypgeom_u_asymp(acb_t res, const acb_t a, const acb_t b,
    const acb_t z, slong n, slong prec)
{
    acb_struct aa[3];
    acb_t s, t, w, winv;
    int R, p, q, is_real, is_terminating;
    slong n_terminating;

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

    acb_init(aa);
    acb_init(aa + 1);
    acb_init(aa + 2);
    acb_init(s);
    acb_init(t);
    acb_init(w);
    acb_init(winv);

    is_terminating = 0;
    n_terminating = WORD_MAX;

    /* special case, for incomplete gamma
      [todo: also when they happen to be exact and with difference 1...] */
    if (a == b)
    {
        acb_set(aa, a);
        p = 1;
        q = 0;
    }
    else
    {
        acb_set(aa, a);
        acb_sub(aa + 1, a, b, prec);
        acb_add_ui(aa + 1, aa + 1, 1, prec);
        acb_one(aa + 2);
        p = 2;
        q = 1;
    }

    if (acb_is_nonpositive_int(aa))
    {
        is_terminating = 1;

        if (arf_cmpabs_ui(arb_midref(acb_realref(aa)), prec) < 0)
            n_terminating = 1 - arf_get_si(arb_midref(acb_realref(aa)), ARF_RND_DOWN);
    }

    if (p == 2 && acb_is_nonpositive_int(aa + 1))
    {
        is_terminating = 1;

        if (arf_cmpabs_ui(arb_midref(acb_realref(aa + 1)), n_terminating) < 0)
            n_terminating = 1 - arf_get_si(arb_midref(acb_realref(aa + 1)), ARF_RND_DOWN);
    }

    acb_neg(w, z);
    acb_inv(w, w, prec);
    acb_neg(winv, z);

    /* low degree polynomial -- no need to try to terminate sooner */
    if (is_terminating && n_terminating < 8)
    {
        acb_hypgeom_pfq_sum_invz(s, t, aa, p, aa + p, q, w, winv,
            n_terminating, prec);
        acb_set(res, s);
    }
    else
    {
        mag_t C1, Cn, alpha, nu, sigma, rho, zinv, tmp, err;

        mag_init(C1);
        mag_init(Cn);
        mag_init(alpha);
        mag_init(nu);
        mag_init(sigma);
        mag_init(rho);
        mag_init(zinv);
        mag_init(tmp);
        mag_init(err);

        acb_hypgeom_u_asymp_bound_factors(&R, alpha, nu,
            sigma, rho, zinv, a, b, z);

        is_real = acb_is_real(a) && acb_is_real(b) && acb_is_real(z) &&
            (is_terminating || arb_is_positive(acb_realref(z)));

        if (R == 0)
        {
            /* if R == 0, the error bound is infinite unless terminating */
            if (is_terminating && n_terminating < prec)
            {
                acb_hypgeom_pfq_sum_invz(s, t, aa, p, aa + p, q, w, winv,
                    n_terminating, prec);
                acb_set(res, s);
            }
            else
            {
                acb_indeterminate(res);
            }
        }
        else
        {
            /* C1 */
            acb_hypgeom_mag_Cn(C1, R, nu, sigma, 1);

            /* err = 2 * alpha * exp(...) */
            mag_mul(tmp, C1, rho);
            mag_mul(tmp, tmp, alpha);
            mag_mul(tmp, tmp, zinv);
            mag_mul_2exp_si(tmp, tmp, 1);
            mag_exp(err, tmp);
            mag_mul(err, err, alpha);
            mag_mul_2exp_si(err, err, 1);

            /* choose n automatically */
            if (n < 0)
            {
                slong moreprec;

                /* take err into account when finding truncation point */
                /* we should take Cn into account as well, but this depends
                   on n which is to be determined; it's easier to look
                   only at exp(...) which should be larger anyway */
                if (mag_cmp_2exp_si(err, 10 * prec) > 0)
                    moreprec = 10 * prec;
                else if (mag_cmp_2exp_si(err, 0) < 0)
                    moreprec = 0;
                else
                    moreprec = MAG_EXP(err);

                n = acb_hypgeom_pfq_choose_n_max(aa, p, aa + p, q, w,
                    prec + moreprec, FLINT_MIN(WORD_MAX / 2, 50 + 10.0 * prec));
            }

            acb_hypgeom_pfq_sum_invz(s, t, aa, p, aa + p, q, w, winv, n, prec);

            /* add error bound, if not terminating */
            if (!(is_terminating && n == n_terminating))
            {
                acb_hypgeom_mag_Cn(Cn, R, nu, sigma, n);
                mag_mul(err, err, Cn);

                /* nth term * factor */
                acb_get_mag(tmp, t);
                mag_mul(err, err, tmp);

                if (is_real)
                    arb_add_error_mag(acb_realref(s), err);
                else
                    acb_add_error_mag(s, err);
            }

            acb_set(res, s);
        }

        mag_clear(C1);
        mag_clear(Cn);
        mag_clear(alpha);
        mag_clear(nu);
        mag_clear(sigma);
        mag_clear(rho);
        mag_clear(zinv);
        mag_clear(tmp);
        mag_clear(err);
    }

    acb_clear(aa);
    acb_clear(aa + 1);
    acb_clear(aa + 2);
    acb_clear(s);
    acb_clear(t);
    acb_clear(w);
    acb_clear(winv);
}
예제 #4
0
int main()
{
    slong iter;
    flint_rand_t state;

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

    flint_randinit(state);

    for (iter = 0; iter < 10000 * arb_test_multiplier(); iter++)
    {
        arb_t a, b, c;
        arf_t m, r;

        arb_init(a);
        arb_init(b);
        arb_init(c);
        arf_init(m);
        arf_init(r);

        arb_randtest_special(a, state, 1 + n_randint(state, 2000), 10);
        arb_randtest_special(b, state, 1 + n_randint(state, 2000), 10);
        arb_randtest_special(c, state, 1 + n_randint(state, 2000), 10);
        arf_randtest_special(m, state, 1 + n_randint(state, 2000), 10);
        arf_randtest_special(r, state, 1 + n_randint(state, 2000), 10);

        /* c = a plus error bounds */
        arb_set(c, a);
        arf_set(arb_midref(b), m);
        arf_get_mag(arb_radref(b), r);
        arb_add_error(c, b);

        /* b = a + random point */
        arb_set(b, a);

        if (n_randint(state, 2))
            arf_add(arb_midref(b), arb_midref(b), m, ARF_PREC_EXACT, ARF_RND_DOWN);
        else
            arf_sub(arb_midref(b), arb_midref(b), m, ARF_PREC_EXACT, ARF_RND_DOWN);

        if (n_randint(state, 2))
            arf_add(arb_midref(b), arb_midref(b), r, ARF_PREC_EXACT, ARF_RND_DOWN);
        else
            arf_sub(arb_midref(b), arb_midref(b), r, ARF_PREC_EXACT, ARF_RND_DOWN);

        /* should this be done differently? */
        if (arf_is_nan(arb_midref(b)))
            arf_zero(arb_midref(b));

        if (!arb_contains(c, b))
        {
            flint_printf("FAIL (arb_add_error)\n\n");
            flint_printf("a = "); arb_printn(a, 50, 0); flint_printf("\n\n");
            flint_printf("b = "); arb_printn(b, 50, 0); flint_printf("\n\n");
            flint_printf("c = "); arb_printn(c, 50, 0); flint_printf("\n\n");
            abort();
        }

        arb_clear(a);
        arb_clear(b);
        arb_clear(c);
        arf_clear(m);
        arf_clear(r);
    }

    for (iter = 0; iter < 10000 * arb_test_multiplier(); iter++)
    {
        arb_t a, b, c;
        arf_t m;

        arb_init(a);
        arb_init(b);
        arb_init(c);
        arf_init(m);

        arb_randtest_special(a, state, 1 + n_randint(state, 2000), 10);
        arb_randtest_special(b, state, 1 + n_randint(state, 2000), 10);
        arb_randtest_special(c, state, 1 + n_randint(state, 2000), 10);
        arf_randtest_special(m, state, 1 + n_randint(state, 2000), 10);

        /* c = a plus error bounds */
        arb_set(c, a);
        arb_add_error_arf(c, m);

        /* b = a + random point */
        arb_set(b, a);

        if (n_randint(state, 2))
            arf_add(arb_midref(b), arb_midref(b), m, ARF_PREC_EXACT, ARF_RND_DOWN);
        else
            arf_sub(arb_midref(b), arb_midref(b), m, ARF_PREC_EXACT, ARF_RND_DOWN);

        /* should this be done differently? */
        if (arf_is_nan(arb_midref(b)))
            arf_zero(arb_midref(b));

        if (!arb_contains(c, b))
        {
            flint_printf("FAIL (arb_add_error_arf)\n\n");
            flint_printf("a = "); arb_printn(a, 50, 0); flint_printf("\n\n");
            flint_printf("b = "); arb_printn(b, 50, 0); flint_printf("\n\n");
            flint_printf("c = "); arb_printn(c, 50, 0); flint_printf("\n\n");
            abort();
        }

        arb_clear(a);
        arb_clear(b);
        arb_clear(c);
        arf_clear(m);
    }

    for (iter = 0; iter < 10000 * arb_test_multiplier(); iter++)
    {
        arb_t a, b, c;
        arf_t t;
        mag_t r;

        arb_init(a);
        arb_init(b);
        arb_init(c);
        mag_init(r);
        arf_init(t);

        arb_randtest_special(a, state, 1 + n_randint(state, 2000), 10);
        arb_randtest_special(b, state, 1 + n_randint(state, 2000), 10);
        mag_randtest(r, state, 10);

        /* c = a plus error bounds */
        arb_set(c, a);
        arb_add_error_mag(c, r);

        /* b = a + random point */
        arb_set(b, a);
        arf_set_mag(t, r);
        if (n_randint(state, 2))
            arf_add(arb_midref(b), arb_midref(b), t, ARF_PREC_EXACT, ARF_RND_DOWN);
        else
            arf_sub(arb_midref(b), arb_midref(b), t, ARF_PREC_EXACT, ARF_RND_DOWN);

        /* should this be done differently? */
        if (arf_is_nan(arb_midref(b)))
            arf_zero(arb_midref(b));

        if (!arb_contains(c, b))
        {
            flint_printf("FAIL (arb_add_error_mag)\n\n");
            flint_printf("a = "); arb_printn(a, 50, 0); flint_printf("\n\n");
            flint_printf("b = "); arb_printn(b, 50, 0); flint_printf("\n\n");
            flint_printf("c = "); arb_printn(c, 50, 0); flint_printf("\n\n");
            abort();
        }

        arb_clear(a);
        arb_clear(b);
        arb_clear(c);
        mag_clear(r);
        arf_clear(t);
    }

    for (iter = 0; iter < 10000 * arb_test_multiplier(); iter++)
    {
        arb_t a, b, c;
        arf_t t;
        slong e;

        arb_init(a);
        arb_init(b);
        arb_init(c);
        arf_init(t);

        arb_randtest_special(a, state, 1 + n_randint(state, 2000), 10);
        arb_randtest_special(b, state, 1 + n_randint(state, 2000), 10);
        e = n_randint(state, 10) - 10;

        /* c = a plus error bounds */
        arb_set(c, a);
        arb_add_error_2exp_si(c, e);

        /* b = a + random point */
        arb_set(b, a);
        arf_one(t);
        arf_mul_2exp_si(t, t, e);
        if (n_randint(state, 2))
            arf_add(arb_midref(b), arb_midref(b), t, ARF_PREC_EXACT, ARF_RND_DOWN);
        else
            arf_sub(arb_midref(b), arb_midref(b), t, ARF_PREC_EXACT, ARF_RND_DOWN);

        /* should this be done differently? */
        if (arf_is_nan(arb_midref(b)))
            arf_zero(arb_midref(b));

        if (!arb_contains(c, b))
        {
            flint_printf("FAIL (arb_add_error_2exp_si)\n\n");
            flint_printf("a = "); arb_printn(a, 50, 0); flint_printf("\n\n");
            flint_printf("b = "); arb_printn(b, 50, 0); flint_printf("\n\n");
            flint_printf("c = "); arb_printn(c, 50, 0); flint_printf("\n\n");
            abort();
        }

        arb_clear(a);
        arb_clear(b);
        arb_clear(c);
        arf_clear(t);
    }

    for (iter = 0; iter < 10000 * arb_test_multiplier(); iter++)
    {
        arb_t a, b, c;
        arf_t t;
        fmpz_t e;

        arb_init(a);
        arb_init(b);
        arb_init(c);
        arf_init(t);
        fmpz_init(e);

        arb_randtest_special(a, state, 1 + n_randint(state, 2000), 10);
        arb_randtest_special(b, state, 1 + n_randint(state, 2000), 10);
        fmpz_randtest(e, state, 10);

        /* c = a plus error bounds */
        arb_set(c, a);
        arb_add_error_2exp_fmpz(c, e);

        /* b = a + random point */
        arb_set(b, a);
        arf_one(t);
        arf_mul_2exp_fmpz(t, t, e);
        if (n_randint(state, 2))
            arf_add(arb_midref(b), arb_midref(b), t, ARF_PREC_EXACT, ARF_RND_DOWN);
        else
            arf_sub(arb_midref(b), arb_midref(b), t, ARF_PREC_EXACT, ARF_RND_DOWN);

        /* should this be done differently? */
        if (arf_is_nan(arb_midref(b)))
            arf_zero(arb_midref(b));

        if (!arb_contains(c, b))
        {
            flint_printf("FAIL (arb_add_error_2exp_fmpz)\n\n");
            flint_printf("a = "); arb_printn(a, 50, 0); flint_printf("\n\n");
            flint_printf("b = "); arb_printn(b, 50, 0); flint_printf("\n\n");
            flint_printf("c = "); arb_printn(c, 50, 0); flint_printf("\n\n");
            abort();
        }

        arb_clear(a);
        arb_clear(b);
        arb_clear(c);
        arf_clear(t);
        fmpz_clear(e);
    }

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