void
arb_pow(arb_t z, const arb_t x, const arb_t y, slong prec)
{
if (arb_is_zero(y))
{
arb_one(z);
return;
}
if (arb_is_zero(x))
{
if (arb_is_positive(y))
arb_zero(z);
else
arb_indeterminate(z);
return;
}
if (arb_is_exact(y) && !arf_is_special(arb_midref(x)))
{
const arf_struct * ymid = arb_midref(y);
/* small half-integer or integer */
if (arf_cmpabs_2exp_si(ymid, BINEXP_LIMIT) < 0 &&
arf_is_int_2exp_si(ymid, -1))
{
fmpz_t e;
fmpz_init(e);
if (arf_is_int(ymid))
{
arf_get_fmpz_fixed_si(e, ymid, 0);
arb_pow_fmpz_binexp(z, x, e, prec);
}
else
{
arf_get_fmpz_fixed_si(e, ymid, -1);
arb_sqrt(z, x, prec + fmpz_bits(e));
arb_pow_fmpz_binexp(z, z, e, prec);
}
fmpz_clear(e);
return;
}
else if (arf_is_int(ymid) && arf_sgn(arb_midref(x)) < 0)
{
/* use (-x)^n = (-1)^n * x^n to avoid NaNs
at least at high enough precision */
int odd = !arf_is_int_2exp_si(ymid, 1);
_arb_pow_exp(z, x, 1, y, prec);
if (odd)
arb_neg(z, z);
return;
}
}
_arb_pow_exp(z, x, 0, y, prec);
}
void
acb_pow_arb(acb_t z, const acb_t x, const arb_t y, long prec)
{
const arf_struct * ymid = arb_midref(y);
const mag_struct * yrad = arb_radref(y);
if (arb_is_zero(y))
{
acb_one(z);
return;
}
if (mag_is_zero(yrad))
{
/* small half-integer or integer */
if (arf_cmpabs_2exp_si(ymid, BINEXP_LIMIT) < 0 &&
arf_is_int_2exp_si(ymid, -1))
{
fmpz_t e;
fmpz_init(e);
if (arf_is_int(ymid))
{
arf_get_fmpz_fixed_si(e, ymid, 0);
acb_pow_fmpz_binexp(z, x, e, prec);
}
else
{
/* hack: give something finite here (should fix sqrt/rsqrt etc) */
if (arb_contains_zero(acb_imagref(x)) && arb_contains_nonpositive(acb_realref(x)))
{
_acb_pow_arb_exp(z, x, y, prec);
fmpz_clear(e);
return;
}
arf_get_fmpz_fixed_si(e, ymid, -1);
acb_sqrt(z, x, prec + fmpz_bits(e));
acb_pow_fmpz_binexp(z, z, e, prec);
}
fmpz_clear(e);
return;
}
}
_acb_pow_arb_exp(z, x, y, prec);
}
void
bernoulli_rev_init(bernoulli_rev_t iter, ulong nmax)
{
long j;
fmpz_t t;
arb_t x;
arf_t u;
int round1, round2;
long wp;
nmax -= (nmax % 2);
iter->n = nmax;
iter->alloc = 0;
if (nmax < BERNOULLI_REV_MIN)
return;
iter->prec = wp = bernoulli_global_prec(nmax);
iter->max_power = bernoulli_zeta_terms(nmax, iter->prec);
iter->alloc = iter->max_power + 1;
iter->powers = _fmpz_vec_init(iter->alloc);
fmpz_init(iter->pow_error);
arb_init(iter->prefactor);
arb_init(iter->two_pi_squared);
arb_init(x);
fmpz_init(t);
arf_init(u);
/* precompute powers */
for (j = 3; j <= iter->max_power; j += 2)
{
arb_ui_pow_ui(x, j, nmax, bernoulli_power_prec(j, nmax, wp));
arb_inv(x, x, bernoulli_power_prec(j, nmax, wp));
round1 = arf_get_fmpz_fixed_si(t, arb_midref(x), -wp);
fmpz_set(iter->powers + j, t);
/* error: the radius, plus two roundings */
arf_set_mag(u, arb_radref(x));
round2 = arf_get_fmpz_fixed_si(t, u, -wp);
fmpz_add_ui(t, t, (round1 != 0) + (round2 != 0));
if (fmpz_cmp(iter->pow_error, t) < 0)
fmpz_set(iter->pow_error, t);
}
/* precompute (2pi)^2 and 2*(n!)/(2pi)^n */
arb_fac_ui(iter->prefactor, nmax, wp);
arb_mul_2exp_si(iter->prefactor, iter->prefactor, 1);
arb_const_pi(x, wp);
arb_mul_2exp_si(x, x, 1);
arb_mul(iter->two_pi_squared, x, x, wp);
arb_pow_ui(x, iter->two_pi_squared, nmax / 2, wp);
arb_div(iter->prefactor, iter->prefactor, x, wp);
fmpz_clear(t);
arb_clear(x);
arf_clear(u);
}
int main()
{
slong iter;
flint_rand_t state;
flint_printf("get_fmpz....");
fflush(stdout);
flint_randinit(state);
for (iter = 0; iter < 10000 * arb_test_multiplier(); iter++)
{
arf_t x, x2;
fmpz_t z, z2, e;
int ret1, ret2;
arf_init(x);
arf_init(x2);
fmpz_init(z);
fmpz_init(z2);
fmpz_init(e);
arf_randtest(x, state, 2 + n_randint(state, 1000), 10);
fmpz_randtest(z, state, 1 + n_randint(state, 1000));
fmpz_randtest(z2, state, 1 + n_randint(state, 1000));
fmpz_randtest(e, state, 1 + n_randint(state, 200));
arf_mul_2exp_fmpz(x2, x, e);
ret1 = arf_get_fmpz(z, x, ARF_RND_DOWN);
ret2 = arf_get_fmpz_fixed_fmpz(z2, x2, e);
if (!fmpz_equal(z, z2) || (ret1 != ret2))
{
flint_printf("FAIL (fixed_fmpz)\n\n");
flint_printf("x = "); arf_print(x); flint_printf("\n\n");
flint_printf("x2 = "); arf_print(x2); flint_printf("\n\n");
flint_printf("z = "); fmpz_print(z); flint_printf("\n\n");
flint_printf("z2 = "); fmpz_print(z2); flint_printf("\n\n");
flint_printf("ret1 = %d, ret2 = %d\n\n", ret1, ret2);
flint_abort();
}
arf_clear(x);
arf_clear(x2);
fmpz_clear(z);
fmpz_clear(z2);
fmpz_clear(e);
}
for (iter = 0; iter < 10000 * arb_test_multiplier(); iter++)
{
arf_t x, x2;
fmpz_t z, z2;
slong e;
int ret1, ret2;
arf_init(x);
arf_init(x2);
fmpz_init(z);
fmpz_init(z2);
arf_randtest(x, state, 2 + n_randint(state, 1000), 10);
fmpz_randtest(z, state, 1 + n_randint(state, 1000));
fmpz_randtest(z2, state, 1 + n_randint(state, 1000));
e = n_randtest(state);
arf_mul_2exp_si(x2, x, e);
ret1 = arf_get_fmpz(z, x, ARF_RND_DOWN);
ret2 = arf_get_fmpz_fixed_si(z2, x2, e);
if (!fmpz_equal(z, z2) || (ret1 != ret2))
{
flint_printf("FAIL (fixed_si)\n\n");
flint_printf("x = "); arf_print(x); flint_printf("\n\n");
flint_printf("x2 = "); arf_print(x2); flint_printf("\n\n");
flint_printf("z = "); fmpz_print(z); flint_printf("\n\n");
flint_printf("z2 = "); fmpz_print(z2); flint_printf("\n\n");
flint_printf("ret1 = %d, ret2 = %d\n\n", ret1, ret2);
flint_abort();
}
arf_clear(x);
arf_clear(x2);
fmpz_clear(z);
fmpz_clear(z2);
}
for (iter = 0; iter < 1000000 * arb_test_multiplier(); iter++)
{
slong bits;
arf_t x;
mpfr_t y;
fmpz_t z, z2;
mpz_t w;
int ret1, ret2;
bits = 2 + n_randint(state, 1000);
arf_init(x);
mpfr_init2(y, bits);
fmpz_init(z);
fmpz_init(z2);
mpz_init(w);
arf_randtest(x, state, bits, 10);
fmpz_randtest(z, state, 1 + n_randint(state, 1000));
arf_get_mpfr(y, x, MPFR_RNDN);
switch (n_randint(state, 5))
{
case 0:
ret1 = arf_get_fmpz(z, x, ARF_RND_FLOOR);
ret2 = mpfr_get_z(w, y, MPFR_RNDD);
break;
case 1:
ret1 = arf_get_fmpz(z, x, ARF_RND_CEIL);
ret2 = mpfr_get_z(w, y, MPFR_RNDU);
break;
case 2:
ret1 = arf_get_fmpz(z, x, ARF_RND_DOWN);
ret2 = mpfr_get_z(w, y, MPFR_RNDZ);
break;
case 3:
ret1 = arf_get_fmpz(z, x, ARF_RND_UP);
ret2 = mpfr_get_z(w, y, MPFR_RNDA);
break;
default:
ret1 = arf_get_fmpz(z, x, ARF_RND_NEAR);
ret2 = mpfr_get_z(w, y, MPFR_RNDN);
break;
}
fmpz_set_mpz(z2, w);
if (!fmpz_equal(z, z2) || (ret1 != (ret2 != 0)))
{
flint_printf("FAIL\n\n");
flint_printf("x = "); arf_print(x); flint_printf("\n\n");
flint_printf("z = "); fmpz_print(z); flint_printf("\n\n");
flint_printf("z2 = "); fmpz_print(z2); flint_printf("\n\n");
flint_printf("ret1 = %d, ret2 = %d\n\n", ret1, ret2);
flint_abort();
}
arf_clear(x);
mpfr_clear(y);
fmpz_clear(z);
fmpz_clear(z2);
mpz_clear(w);
}
flint_randclear(state);
flint_cleanup();
flint_printf("PASS\n");
return EXIT_SUCCESS;
}
void
arb_exp_arf_bb(arb_t z, const arf_t x, slong prec, int minus_one)
{
slong k, iter, bits, r, mag, q, wp, N;
slong argred_bits, start_bits;
mp_bitcnt_t Qexp[1];
int inexact;
fmpz_t t, u, T, Q;
arb_t w;
if (arf_is_zero(x))
{
if (minus_one)
arb_zero(z);
else
arb_one(z);
return;
}
if (arf_is_special(x))
{
abort();
}
mag = arf_abs_bound_lt_2exp_si(x);
/* We assume that this function only gets called with something
reasonable as input (huge/tiny input will be handled by
the main exp wrapper). */
if (mag > 200 || mag < -2 * prec - 100)
{
flint_printf("arb_exp_arf_bb: unexpectedly large/small input\n");
abort();
}
if (prec < 100000000)
{
argred_bits = 16;
start_bits = 32;
}
else
{
argred_bits = 32;
start_bits = 64;
}
/* Argument reduction: exp(x) -> exp(x/2^q). This improves efficiency
of the first iteration in the bit-burst algorithm. */
q = FLINT_MAX(0, mag + argred_bits);
/* Determine working precision. */
wp = prec + 10 + 2 * q + 2 * FLINT_BIT_COUNT(prec);
if (minus_one && mag < 0)
wp += (-mag);
fmpz_init(t);
fmpz_init(u);
fmpz_init(Q);
fmpz_init(T);
arb_init(w);
/* Convert x/2^q to a fixed-point number. */
inexact = arf_get_fmpz_fixed_si(t, x, -wp + q);
/* Aliasing of z and x is safe now that only use t. */
/* Start with z = 1. */
arb_one(z);
/* Bit-burst loop. */
for (iter = 0, bits = start_bits; !fmpz_is_zero(t);
iter++, bits *= 2)
{
/* Extract bits. */
r = FLINT_MIN(bits, wp);
fmpz_tdiv_q_2exp(u, t, wp - r);
/* Binary splitting (+1 fixed-point ulp truncation error). */
mag = fmpz_bits(u) - r;
N = bs_num_terms(mag, wp);
_arb_exp_sum_bs_powtab(T, Q, Qexp, u, r, N);
/* T = T / Q (+1 fixed-point ulp error). */
if (*Qexp >= wp)
{
fmpz_tdiv_q_2exp(T, T, *Qexp - wp);
fmpz_tdiv_q(T, T, Q);
}
else
{
fmpz_mul_2exp(T, T, wp - *Qexp);
fmpz_tdiv_q(T, T, Q);
}
/* T = 1 + T */
fmpz_one(Q);
fmpz_mul_2exp(Q, Q, wp);
fmpz_add(T, T, Q);
/* Now T = exp(u) with at most 2 fixed-point ulp error. */
/* Set z = z * T. */
arf_set_fmpz(arb_midref(w), T);
arf_mul_2exp_si(arb_midref(w), arb_midref(w), -wp);
mag_set_ui_2exp_si(arb_radref(w), 2, -wp);
arb_mul(z, z, w, wp);
/* Remove used bits. */
fmpz_mul_2exp(u, u, wp - r);
fmpz_sub(t, t, u);
}
/* We have exp(x + eps) - exp(x) < 2*eps (by assumption that the argument
reduction is large enough). */
if (inexact)
arb_add_error_2exp_si(z, -wp + 1);
fmpz_clear(t);
fmpz_clear(u);
fmpz_clear(Q);
fmpz_clear(T);
arb_clear(w);
/* exp(x) = exp(x/2^q)^(2^q) */
for (k = 0; k < q; k++)
arb_mul(z, z, z, wp);
if (minus_one)
arb_sub_ui(z, z, 1, wp);
arb_set_round(z, z, prec);
}
