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; }