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_polygamma(acb_t res, const acb_t s, const acb_t z, long prec)
{
if (acb_is_zero(s))
{
acb_digamma(res, z, prec);
}
else if (acb_is_int(s) && arb_is_positive(acb_realref(s)))
{
acb_t t, u;
acb_init(t);
acb_init(u);
acb_add_ui(t, s, 1, prec);
acb_gamma(u, t, prec);
acb_hurwitz_zeta(t, t, z, prec);
if (arf_is_int_2exp_si(arb_midref(acb_realref(s)), 1))
acb_neg(t, t);
acb_mul(res, t, u, prec);
acb_clear(t);
acb_clear(u);
}
else
{
acb_t t, u;
acb_struct v[2];
acb_init(t);
acb_init(u);
acb_init(v);
acb_init(v + 1);
/* u = psi(-s) + gamma */
acb_neg(t, s);
acb_digamma(u, t, prec);
arb_const_euler(acb_realref(v), prec);
arb_add(acb_realref(u), acb_realref(u), acb_realref(v), prec);
acb_add_ui(t, s, 1, prec);
_acb_poly_zeta_cpx_series(v, t, z, 0, 2, prec);
acb_addmul(v + 1, v, u, prec);
acb_neg(t, s);
acb_rgamma(u, t, prec);
acb_mul(res, v + 1, u, prec);
acb_clear(v);
acb_clear(v + 1);
acb_clear(t);
acb_clear(u);
}
}
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);
}
int main()
{
slong iter;
flint_rand_t state;
flint_printf("is_int_2exp_si....");
fflush(stdout);
flint_randinit(state);
for (iter = 0; iter < 10000 * arb_test_multiplier(); iter++)
{
arf_t x, y;
fmpz_t t;
slong e;
int res1, res2;
arf_init(x);
arf_init(y);
fmpz_init(t);
arf_randtest_special(x, state, 2000, 100);
e = n_randtest(state);
arf_mul_2exp_si(y, x, e);
res1 = arf_is_int(x);
res2 = arf_is_int_2exp_si(y, e);
if (res1 != res2)
{
flint_printf("FAIL! (1)\n");
flint_printf("x = "); arf_print(x); flint_printf("\n\n");
flint_printf("y = "); arf_print(y); flint_printf("\n\n");
flint_printf("res1 = %d, res2 = %d\n\n", res1, res2);
abort();
}
if (res1)
{
if (n_randint(state, 2))
arf_floor(y, x);
else
arf_ceil(y, x);
if (!arf_equal(x, y) || !arf_is_finite(x))
{
flint_printf("FAIL! (2)\n");
flint_printf("x = "); arf_print(x); flint_printf("\n\n");
flint_printf("y = "); arf_print(y); flint_printf("\n\n");
flint_printf("res1 = %d\n\n", res1);
abort();
}
}
if (arf_is_finite(x) && !arf_is_zero(x))
{
arf_bot(t, x);
fmpz_neg(t, t);
arf_mul_2exp_fmpz(x, x, t);
res1 = arf_is_int(x);
arf_mul_2exp_si(y, x, -1);
res2 = arf_is_int(y);
if (!arf_is_int(x) || arf_is_int(y))
{
flint_printf("FAIL! (3)\n");
flint_printf("x = "); arf_print(x); flint_printf("\n\n");
flint_printf("y = "); arf_print(y); flint_printf("\n\n");
flint_printf("res1 = %d, res2 = %d\n\n", res1, res2);
abort();
}
}
arf_clear(x);
arf_clear(y);
fmpz_clear(t);
}
flint_randclear(state);
flint_cleanup();
flint_printf("PASS\n");
return EXIT_SUCCESS;
}
