void
fmprb_mul_main_naive(fmprb_t z, const fmprb_t x, const fmprb_t y, slong prec)
{
if (fmpr_is_pos_inf(fmprb_radref(x)) || fmpr_is_pos_inf(fmprb_radref(y)))
{
fmpr_mul(fmprb_midref(z), fmprb_midref(x), fmprb_midref(y), prec, FMPR_RND_DOWN);
fmpr_pos_inf(fmprb_radref(z));
}
else
{
fmpr_t t, u;
slong r;
fmpr_init(t);
fmpr_init(u);
/* (x+a)*(y+b) = x*y + x*b + y*a + a*b*/
fmpr_mul(t, fmprb_midref(x), fmprb_radref(y), FMPRB_RAD_PREC, FMPR_RND_UP);
fmpr_abs(t, t);
fmpr_mul(u, fmprb_midref(y), fmprb_radref(x), FMPRB_RAD_PREC, FMPR_RND_UP);
fmpr_abs(u, u);
fmpr_add(t, t, u, FMPRB_RAD_PREC, FMPR_RND_UP);
fmpr_addmul(t, fmprb_radref(x), fmprb_radref(y), FMPRB_RAD_PREC, FMPR_RND_UP);
r = fmpr_mul(fmprb_midref(z), fmprb_midref(x), fmprb_midref(y), prec, FMPR_RND_DOWN);
fmpr_add_error_result(fmprb_radref(z), t,
fmprb_midref(z), r, FMPRB_RAD_PREC, FMPR_RND_UP);
fmpr_clear(t);
fmpr_clear(u);
}
}
void
fmprb_sqrt(fmprb_t z, const fmprb_t x, slong prec)
{
slong r;
if (fmprb_contains_negative(x))
{
fmpr_nan(fmprb_midref(z));
fmpr_pos_inf(fmprb_radref(z));
return;
}
if (fmprb_is_exact(x))
{
r = fmpr_sqrt(fmprb_midref(z), fmprb_midref(x), prec, FMPR_RND_DOWN);
fmpr_set_error_result(fmprb_radref(z), fmprb_midref(z), r);
}
else
{
fmpr_t err;
fmpr_init(err);
fmpr_sub(err, fmprb_midref(x), fmprb_radref(x), FMPRB_RAD_PREC, FMPR_RND_DOWN);
fmpr_rsqrt(err, err, FMPRB_RAD_PREC, FMPR_RND_UP);
fmpr_mul(err, fmprb_radref(x), err, FMPRB_RAD_PREC, FMPR_RND_UP);
fmpr_mul_2exp_si(err, err, -1);
r = fmpr_sqrt(fmprb_midref(z), fmprb_midref(x), prec, FMPR_RND_DOWN);
fmpr_add_error_result(fmprb_radref(z), err, fmprb_midref(z), r,
FMPRB_RAD_PREC, FMPR_RND_UP);
fmpr_clear(err);
}
fmprb_adjust(z);
}
void
gamma_taylor_bound_remainder(fmpr_t err, const fmpr_t z, long n)
{
fmpr_t t, u;
gamma_taylor_bound_extend_cache(n + 1);
fmpr_init(t);
fmpr_init(u);
/* denominator: 1 - r(n+1) * z, rounded down */
fmpr_mul(t, gamma_taylor_bound_ratio_cache + n + 1,
z, FMPRB_RAD_PREC, FMPR_RND_UP);
fmpr_one(u);
fmpr_sub(u, u, t, FMPRB_RAD_PREC, FMPR_RND_DOWN);
if (fmpr_sgn(u) <= 0)
{
fmpr_pos_inf(err);
}
else
{
fmpr_pow_sloppy_ui(t, z, n, FMPRB_RAD_PREC, FMPR_RND_UP);
fmpr_mul_2exp_si(t, t, gamma_taylor_bound_mag_cache[n + 1]);
fmpr_div(err, t, u, FMPRB_RAD_PREC, FMPR_RND_UP);
}
fmpr_clear(t);
fmpr_clear(u);
}
void
fmprb_mul_fmpr_naive(fmprb_t z, const fmprb_t x, const fmpr_t y, slong prec)
{
/* (x+a) * y = x*y + y*a */
if (fmpr_is_pos_inf(fmprb_radref(x)))
{
fmpr_mul(fmprb_midref(z), fmprb_midref(x), y, prec, FMPR_RND_DOWN);
fmpr_pos_inf(fmprb_radref(z));
}
else if (fmpr_is_zero(fmprb_radref(x)))
{
slong r;
r = fmpr_mul(fmprb_midref(z), fmprb_midref(x), y, prec, FMPR_RND_DOWN);
fmpr_set_error_result(fmprb_radref(z), fmprb_midref(z), r);
}
else
{
slong r;
fmpr_mul(fmprb_radref(z), fmprb_radref(x), y, FMPRB_RAD_PREC, FMPR_RND_UP);
fmpr_abs(fmprb_radref(z), fmprb_radref(z));
r = fmpr_mul(fmprb_midref(z), fmprb_midref(x), y, prec, FMPR_RND_DOWN);
fmpr_add_error_result(fmprb_radref(z), fmprb_radref(z),
fmprb_midref(z), r, FMPRB_RAD_PREC, FMPR_RND_UP);
}
}
slong
fmpr_rsqrt(fmpr_t y, const fmpr_t x, slong prec, fmpr_rnd_t rnd)
{
slong r;
if (fmpr_is_special(x))
{
if (fmpr_is_zero(x))
fmpr_pos_inf(y);
else if (fmpr_is_pos_inf(x))
fmpr_zero(y);
else
fmpr_nan(y);
return FMPR_RESULT_EXACT;
}
if (fmpr_sgn(x) < 0)
{
fmpr_nan(y);
return FMPR_RESULT_EXACT;
}
/* special case: 4^n */
if (fmpz_is_one(fmpr_manref(x)) && fmpz_is_even(fmpr_expref(x)))
{
r = fmpr_set_round(y, x, prec, rnd);
fmpz_tdiv_q_2exp(fmpr_expref(y), fmpr_expref(y), 1);
fmpz_neg(fmpr_expref(y), fmpr_expref(y));
return r;
}
{
fmpr_t t;
fmpz_t e;
fmpr_init(t);
fmpz_init(e);
fmpz_neg(e, fmpr_expref(x));
if (fmpz_is_odd(e))
fmpz_add_ui(e, e, 1);
fmpr_mul_2exp_fmpz(t, x, e);
CALL_MPFR_FUNC(r, mpfr_rec_sqrt, y, t, prec, rnd);
fmpz_tdiv_q_2exp(e, e, 1);
fmpr_mul_2exp_fmpz(y, y, e);
fmpr_clear(t);
fmpz_clear(e);
return r;
}
}
slong
fmpr_mul_fmpz(fmpr_t z, const fmpr_t x, const fmpz_t y, slong prec, fmpr_rnd_t rnd)
{
fmpz xv, yv;
fmpz yexp;
if (fmpr_is_special(x) || fmpz_is_zero(y))
{
if (fmpr_is_zero(x))
{
fmpr_zero(z);
}
else if (fmpz_is_zero(y) && fmpr_is_finite(x))
{
fmpr_zero(z);
}
else if (fmpr_is_inf(x) && !fmpz_is_zero(y))
{
if (fmpr_sgn(x) == fmpz_sgn(y))
fmpr_pos_inf(z);
else
fmpr_neg_inf(z);
}
else
{
fmpr_nan(z);
}
return FMPR_RESULT_EXACT;
}
xv = *fmpr_manref(x);
yv = *y;
if (!COEFF_IS_MPZ(xv) && !COEFF_IS_MPZ(yv))
{
mp_limb_t ytmp;
unsigned int bc;
ytmp = FLINT_ABS(yv);
count_trailing_zeros(bc, ytmp);
ytmp >>= bc;
yexp = bc;
return _fmpr_mul_1x1(z, FLINT_ABS(xv), fmpr_expref(x),
ytmp, &yexp, (xv ^ yv) < 0, prec, rnd);
}
static void
_fmpr_div_special(fmpr_t z, const fmpr_t x, const fmpr_t y)
{
if ((fmpr_is_zero(x) && !fmpr_is_zero(y) && !fmpr_is_nan(y)) ||
(fmpr_is_inf(y) && !fmpr_is_special(x)))
{
fmpr_zero(z);
}
else if (fmpr_is_zero(y) || (fmpr_is_special(x) && fmpr_is_special(y)) ||
fmpr_is_nan(x) || fmpr_is_nan(y))
{
fmpr_nan(z);
}
else if (fmpr_sgn(x) == fmpr_sgn(y))
fmpr_pos_inf(z);
else
fmpr_neg_inf(z);
}
void
arf_get_fmpr(fmpr_t y, const arf_t x)
{
if (arf_is_special(x))
{
if (arf_is_zero(x))
fmpr_zero(y);
else if (arf_is_pos_inf(x))
fmpr_pos_inf(y);
else if (arf_is_neg_inf(x))
fmpr_neg_inf(y);
else
fmpr_nan(y);
}
else
{
arf_get_fmpz_2exp(fmpr_manref(y), fmpr_expref(y), x);
}
}
void
fmpr_randtest_special(fmpr_t x, flint_rand_t state, slong bits, slong mag_bits)
{
switch (n_randint(state, 32))
{
case 0:
fmpr_zero(x);
break;
case 1:
fmpr_pos_inf(x);
break;
case 2:
fmpr_neg_inf(x);
break;
case 3:
fmpr_nan(x);
break;
default:
fmpr_randtest_not_zero(x, state, bits, mag_bits);
}
}
void
zeta_series_em_vec_bound(fmprb_ptr bound, const fmpcb_t s, const fmpcb_t a, ulong N, ulong M, long len, long wp)
{
fmprb_t K, C, AN, S2M;
fmprb_ptr F, R;
long k;
fmprb_srcptr alpha = fmpcb_realref(a);
fmprb_srcptr beta = fmpcb_imagref(a);
fmprb_srcptr sigma = fmpcb_realref(s);
fmprb_srcptr tau = fmpcb_imagref(s);
fmprb_init(AN);
fmprb_init(S2M);
/* require alpha + N > 1, sigma + 2M > 1 */
fmprb_add_ui(AN, alpha, N - 1, wp);
fmprb_add_ui(S2M, sigma, 2*M - 1, wp);
if (!fmprb_is_positive(AN) || !fmprb_is_positive(S2M) || N < 1 || M < 1)
{
fmprb_clear(AN);
fmprb_clear(S2M);
for (k = 0; k < len; k++)
{
fmpr_pos_inf(fmprb_midref(bound + k));
fmpr_zero(fmprb_radref(bound + k));
}
return;
}
/* alpha + N, sigma + 2M */
fmprb_add_ui(AN, AN, 1, wp);
fmprb_add_ui(S2M, S2M, 1, wp);
R = _fmprb_vec_init(len);
F = _fmprb_vec_init(len);
fmprb_init(K);
fmprb_init(C);
/* bound for power integral */
bound_C(C, AN, beta, wp);
bound_K(K, AN, beta, tau, wp);
bound_I(R, AN, S2M, C, len, wp);
for (k = 0; k < len; k++)
{
fmprb_mul(R + k, R + k, K, wp);
fmprb_div_ui(K, K, k + 1, wp);
}
/* bound for rising factorial */
bound_rfac(F, s, 2*M, len, wp);
/* product (TODO: only need upper bound; write a function for this) */
_fmprb_poly_mullow(bound, F, len, R, len, len, wp);
/* bound for bernoulli polynomials, 4 / (2pi)^(2M) */
fmprb_const_pi(C, wp);
fmprb_mul_2exp_si(C, C, 1);
fmprb_pow_ui(C, C, 2 * M, wp);
fmprb_ui_div(C, 4, C, wp);
_fmprb_vec_scalar_mul(bound, bound, len, C, wp);
fmprb_clear(K);
fmprb_clear(C);
fmprb_clear(AN);
fmprb_clear(S2M);
_fmprb_vec_clear(R, len);
_fmprb_vec_clear(F, len);
}
static void
_fmprb_gamma(fmprb_t y, const fmprb_t x, long prec, int inverse)
{
int reflect;
long r, n, wp;
fmprb_t t, u, v;
if (fmprb_is_exact(x))
{
const fmpr_struct * mid = fmprb_midref(x);
if (fmpr_is_special(mid))
{
if (!inverse && fmpr_is_pos_inf(mid))
{
fmprb_set(y, x);
}
else if (fmpr_is_nan(mid) || fmpr_is_neg_inf(mid) || !inverse)
{
fmpr_nan(fmprb_midref(y));
fmpr_pos_inf(fmprb_radref(y));
}
else
{
fmprb_zero(y);
}
return;
}
else
{
const fmpz exp = *fmpr_expref(mid);
const fmpz man = *fmpr_manref(mid);
/* fast gamma(n), gamma(n/2) or gamma(n/4) */
if (!COEFF_IS_MPZ(exp) && (exp >= -2) &&
((double) fmpz_bits(&man) + exp < prec))
{
fmpq_t a;
fmpq_init(a);
fmpr_get_fmpq(a, mid);
fmprb_gamma_fmpq(y, a, prec + 2 * inverse);
if (inverse)
fmprb_ui_div(y, 1, y, prec);
fmpq_clear(a);
return;
}
}
}
wp = prec + FLINT_BIT_COUNT(prec);
gamma_stirling_choose_param_fmprb(&reflect, &r, &n, x, 1, 0, wp);
fmprb_init(t);
fmprb_init(u);
fmprb_init(v);
if (reflect)
{
/* gamma(x) = (rf(1-x, r) * pi) / (gamma(1-x+r) sin(pi x)) */
fmprb_sub_ui(t, x, 1, wp);
fmprb_neg(t, t);
gamma_rising_fmprb_ui_bsplit(u, t, r, wp);
fmprb_const_pi(v, wp);
fmprb_mul(u, u, v, wp);
fmprb_add_ui(t, t, r, wp);
gamma_stirling_eval_fmprb(v, t, n, 0, wp);
fmprb_exp(v, v, wp);
fmprb_sin_pi(t, x, wp);
fmprb_mul(v, v, t, wp);
}
else
{
/* gamma(x) = gamma(x+r) / rf(x,r) */
fmprb_add_ui(t, x, r, wp);
gamma_stirling_eval_fmprb(u, t, n, 0, wp);
fmprb_exp(u, u, prec);
gamma_rising_fmprb_ui_bsplit(v, x, r, wp);
}
if (inverse)
fmprb_div(y, v, u, prec);
else
fmprb_div(y, u, v, prec);
fmprb_clear(t);
fmprb_clear(u);
fmprb_clear(v);
}
