void
acb_hypgeom_m_asymp(acb_t res, const acb_t a, const acb_t b, const acb_t z, int regularized, slong prec)
{
acb_t t, u, v, c;
acb_init(t);
acb_init(u);
acb_init(v);
acb_init(c);
acb_sub(c, b, a, prec);
acb_neg(v, z);
acb_hypgeom_u_asymp(t, a, b, z, -1, prec);
acb_hypgeom_u_asymp(u, c, b, v, -1, prec);
/* gamma(b-a) */
acb_rgamma(v, c, prec);
acb_mul(t, t, v, prec);
/* z^(a-b) */
acb_neg(c, c);
acb_pow(v, z, c, prec);
acb_mul(u, u, v, prec);
/* gamma(a) */
acb_rgamma(v, a, prec);
acb_mul(u, u, v, prec);
/* exp(z) */
acb_exp(v, z, prec);
acb_mul(u, u, v, prec);
/* (-z)^(-a) */
acb_neg(c, a);
acb_neg(v, z);
acb_pow(v, v, c, prec);
acb_mul(t, t, v, prec);
acb_add(t, t, u, prec);
if (!regularized)
{
acb_gamma(v, b, prec);
acb_mul(t, t, v, prec);
}
if (acb_is_real(a) && acb_is_real(b) && acb_is_real(z))
{
arb_zero(acb_imagref(t));
}
acb_swap(res, t);
acb_clear(t);
acb_clear(u);
acb_clear(v);
acb_clear(c);
}
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);
}
}
/* todo: move this to the acb module? */
static void
acb_beta(acb_t res, const acb_t a, const acb_t b, slong prec)
{
acb_t t, u;
acb_init(t);
acb_init(u);
acb_gamma(t, a, prec);
acb_gamma(u, b, prec);
acb_add(res, a, b, prec);
acb_rgamma(res, res, prec);
acb_mul(res, res, t, prec);
acb_mul(res, res, u, prec);
acb_clear(t);
acb_clear(u);
}
/* f(z) = gamma(z) */
int
f_gamma(acb_ptr res, const acb_t z, void * param, slong order, slong prec)
{
if (order > 1)
flint_abort(); /* Would be needed for Taylor method. */
acb_gamma(res, z, prec);
return 0;
}
void acb_hypgeom_beta_lower(acb_t res,
const acb_t a, const acb_t b, const acb_t z, int regularized, slong prec)
{
acb_t t, u;
if (acb_is_zero(z) && arb_is_positive(acb_realref(a)))
{
acb_zero(res);
return;
}
if (acb_is_one(z) && arb_is_positive(acb_realref(b)))
{
if (regularized)
acb_one(res);
else
acb_beta(res, a, b, prec);
return;
}
acb_init(t);
acb_init(u);
acb_sub_ui(t, b, 1, prec);
acb_neg(t, t);
acb_add_ui(u, a, 1, prec);
if (regularized)
{
acb_hypgeom_2f1(t, a, t, u, z, 1, prec);
acb_add(u, a, b, prec);
acb_gamma(u, u, prec);
acb_mul(t, t, u, prec);
acb_rgamma(u, b, prec);
acb_mul(t, t, u, prec);
}
else
{
acb_hypgeom_2f1(t, a, t, u, z, 0, prec);
acb_div(t, t, a, prec);
}
acb_pow(u, z, a, prec);
acb_mul(t, t, u, prec);
acb_set(res, t);
acb_clear(t);
acb_clear(u);
}
void
acb_rising_ui(acb_t y, const acb_t x, ulong n, long prec)
{
if (n < FLINT_MAX(prec, 100))
{
acb_rising_ui_rec(y, x, n, prec);
}
else
{
acb_t t;
acb_init(t);
acb_add_ui(t, x, n, prec);
acb_gamma(t, t, prec);
acb_rgamma(y, x, prec);
acb_mul(y, y, t, prec);
acb_clear(t);
}
}
void
acb_rising(acb_t y, const acb_t x, const acb_t n, long prec)
{
if (acb_is_int(n) && arf_sgn(arb_midref(acb_realref(n))) >= 0 &&
arf_cmpabs_ui(arb_midref(acb_realref(n)), FLINT_MAX(prec, 100)) < 0)
{
acb_rising_ui_rec(y, x,
arf_get_si(arb_midref(acb_realref(n)), ARF_RND_DOWN), prec);
}
else
{
acb_t t;
acb_init(t);
acb_add(t, x, n, prec);
acb_gamma(t, t, prec);
acb_rgamma(y, x, prec);
acb_mul(y, y, t, prec);
acb_clear(t);
}
}
void
_acb_hypgeom_legendre_q_single(acb_t res, const acb_t n, const acb_t m,
const acb_t z, slong prec)
{
acb_t a, b, c, z2, t, u;
acb_init(a);
acb_init(b);
acb_init(c);
acb_init(z2);
acb_init(t);
acb_init(u);
/* invalid in (-1,0) */
if (!_acb_hypgeom_legendre_q_single_valid(z))
{
acb_indeterminate(res);
return;
}
acb_pow_si(z2, z, -2, prec); /* z2 = 1/z^2 */
/* t = 2F1r((m+n+1)/2, (m+n)/2+1, n+3/2, 1/z^2) */
acb_add(b, m, n, prec);
acb_add_ui(a, b, 1, prec);
acb_mul_2exp_si(a, a, -1);
acb_mul_2exp_si(b, b, -1);
acb_add_ui(b, b, 1, prec);
acb_set_ui(c, 3);
acb_mul_2exp_si(c, c, -1);
acb_add(c, c, n, prec);
acb_hypgeom_2f1(t, a, b, c, z2, 1, prec);
/* prefactor sqrt(pi) 2^-n (z+1)^(m/2) (z-1)^(m/2) exp(i pi m) */
/* (1/2) gamma(m+n+1) z^(-m-n-1) */
if (!acb_is_zero(m))
{
acb_add_ui(z2, z, 1, prec);
acb_mul_2exp_si(c, m, -1);
acb_pow(z2, z2, c, prec);
acb_mul(t, t, z2, prec);
acb_sub_ui(z2, z, 1, prec);
acb_mul_2exp_si(c, m, -1);
acb_pow(z2, z2, c, prec);
acb_mul(t, t, z2, prec);
acb_exp_pi_i(z2, m, prec);
acb_mul(t, t, z2, prec);
}
acb_set_ui(z2, 2);
acb_neg(c, n);
acb_pow(z2, z2, c, prec);
acb_mul(t, t, z2, prec);
acb_add(c, m, n, prec);
acb_add_ui(c, c, 1, prec);
acb_gamma(z2, c, prec);
acb_mul(t, t, z2, prec);
acb_neg(c, c);
acb_pow(z2, z, c, prec);
acb_mul(t, t, z2, prec);
acb_mul_2exp_si(t, t, -1);
arb_const_sqrt_pi(acb_realref(u), prec);
acb_mul_arb(t, t, acb_realref(u), prec);
acb_set(res, t);
acb_clear(a);
acb_clear(b);
acb_clear(c);
acb_clear(z2);
acb_clear(t);
acb_clear(u);
}
void
acb_dirichlet_l(acb_t res, const acb_t s,
const dirichlet_group_t G, const dirichlet_char_t chi, slong prec)
{
if (!acb_is_finite(s))
{
acb_indeterminate(res);
}
else if (G == NULL || G->q == 1)
{
acb_dirichlet_zeta(res, s, prec);
}
else if (dirichlet_char_is_primitive(G, chi) &&
(arf_cmp_d(arb_midref(acb_realref(s)), -0.5) < 0 ||
(G->q != 1 && dirichlet_parity_char(G, chi) == 0 &&
arf_cmpabs_d(arb_midref(acb_imagref(s)), 0.125) < 0 &&
arf_cmp_d(arb_midref(acb_realref(s)), 0.125) < 0)))
{
/* use functional equation */
acb_t t, u, v;
int parity;
ulong q;
parity = dirichlet_parity_char(G, chi);
q = G->q;
acb_init(t);
acb_init(u);
acb_init(v);
/* gamma((1-s+p)/2) / gamma((s+p)/2) */
acb_add_ui(t, s, parity, prec);
acb_mul_2exp_si(t, t, -1);
acb_rgamma(t, t, prec);
if (!acb_is_zero(t)) /* assumes q != 1 when s = 0 */
{
acb_neg(u, s);
acb_add_ui(u, u, 1 + parity, prec);
acb_mul_2exp_si(u, u, -1);
acb_gamma(u, u, prec);
acb_mul(t, t, u, prec);
/* epsilon */
acb_dirichlet_root_number(u, G, chi, prec);
acb_mul(t, t, u, prec);
/* (pi/q)^(s-1/2) */
acb_const_pi(u, prec);
acb_div_ui(u, u, q, prec);
acb_set_d(v, -0.5);
acb_add(v, v, s, prec);
acb_pow(u, u, v, prec);
acb_mul(t, t, u, prec);
acb_sub_ui(u, s, 1, prec);
acb_neg(u, u);
acb_conj(u, u);
acb_dirichlet_l_general(u, u, G, chi, prec);
acb_conj(u, u);
acb_mul(t, t, u, prec);
if (dirichlet_char_is_real(G, chi) && acb_is_real(s))
arb_zero(acb_imagref(t));
}
acb_set(res, t);
acb_clear(t);
acb_clear(u);
acb_clear(v);
}
else
{
acb_dirichlet_l_general(res, s, G, chi, prec);
}
}
void
acb_hypgeom_legendre_q(acb_t res, const acb_t n, const acb_t m,
const acb_t z, int type, slong prec)
{
if (type == 0)
{
/* http://functions.wolfram.com/07.11.26.0033.01 */
/* todo: simplify the gamma quotients and the sqrt pi factor... */
acb_t a, b, c, z2, mn, nm, t, u;
acb_init(a);
acb_init(b);
acb_init(c);
acb_init(z2);
acb_init(mn);
acb_init(nm);
acb_init(t);
acb_init(u);
acb_add(mn, m, n, prec); /* mn = m + n */
acb_sub(nm, n, m, prec); /* nm = n - m */
acb_mul(z2, z, z, prec); /* z2 = z^2 */
/* t = 2F1((1-m-n)/2, (n-m)/2+1, 3/2, z^2) */
acb_sub_ui(a, mn, 1, prec);
acb_neg(a, a);
acb_mul_2exp_si(a, a, -1);
acb_mul_2exp_si(b, nm, -1);
acb_add_ui(b, b, 1, prec);
acb_set_ui(c, 3);
acb_mul_2exp_si(c, c, -1);
acb_hypgeom_2f1(t, a, b, c, z2, 0, prec);
/* u = 2F1(-(m+n)/2, (n-m+1)/2, 1/2, z^2) */
acb_neg(a, mn);
acb_mul_2exp_si(a, a, -1);
acb_add_ui(b, nm, 1, prec);
acb_mul_2exp_si(b, b, -1);
acb_one(c);
acb_mul_2exp_si(c, c, -1);
acb_hypgeom_2f1(u, a, b, c, z2, 0, prec);
/* a = cospi((m+n)/2) gamma((m+n)/2+1) rgamma((n-m+1)/2) z */
/* b = sinpi((m+n)/2) gamma((m+n+1)/2) rgamma((n-m)/2+1) / 2 */
acb_mul_2exp_si(a, mn, -1);
acb_sin_cos_pi(b, a, a, prec);
acb_mul_2exp_si(c, mn, -1);
acb_add_ui(c, c, 1, prec);
acb_gamma(c, c, prec);
acb_mul(a, a, c, prec);
acb_add_ui(c, nm, 1, prec);
acb_mul_2exp_si(c, c, -1);
acb_rgamma(c, c, prec);
acb_mul(a, a, c, prec);
acb_mul(a, a, z, prec);
acb_add_ui(c, mn, 1, prec);
acb_mul_2exp_si(c, c, -1);
acb_gamma(c, c, prec);
acb_mul(b, b, c, prec);
acb_mul_2exp_si(c, nm, -1);
acb_add_ui(c, c, 1, prec);
acb_rgamma(c, c, prec);
acb_mul(b, b, c, prec);
acb_mul_2exp_si(b, b, -1);
/* at - bu */
acb_mul(t, t, a, prec);
acb_mul(u, u, b, prec);
acb_sub(t, t, u, prec);
/* prefactor sqrt(pi) 2^m (1-z^2)^(-m/2) */
if (!acb_is_zero(m))
{
acb_sub_ui(u, z2, 1, prec);
acb_neg(u, u);
acb_neg(c, m);
acb_mul_2exp_si(c, c, -1);
acb_pow(u, u, c, prec);
acb_set_ui(c, 2);
acb_pow(c, c, m, prec);
acb_mul(u, u, c, prec);
acb_mul(t, t, u, prec);
}
arb_const_sqrt_pi(acb_realref(u), prec);
acb_mul_arb(t, t, acb_realref(u), prec);
acb_set(res, t);
acb_clear(a);
acb_clear(b);
acb_clear(c);
acb_clear(z2);
acb_clear(mn);
acb_clear(nm);
acb_clear(t);
acb_clear(u);
}
else if (type == 1)
{
if ((arf_cmpabs_2exp_si(arb_midref(acb_realref(z)), -2) < 0 &&
arf_cmpabs_2exp_si(arb_midref(acb_imagref(z)), -2) < 0) ||
!_acb_hypgeom_legendre_q_single_valid(z))
{
_acb_hypgeom_legendre_q_double(res, n, m, z, prec);
}
else
{
_acb_hypgeom_legendre_q_single(res, n, m, z, prec);
}
}
else
{
flint_printf("unsupported 'type' %d for legendre q\n", type);
abort();
}
}
int main()
{
long iter;
flint_rand_t state;
printf("legendre_q....");
fflush(stdout);
flint_randinit(state);
for (iter = 0; iter < 1000; iter++)
{
acb_t n, m, z, res1, res2;
long prec1, prec2, ebits;
acb_init(n);
acb_init(m);
acb_init(z);
acb_init(res1);
acb_init(res2);
prec1 = 2 + n_randint(state, 300);
prec2 = 2 + n_randint(state, 300);
ebits = 1 + n_randint(state, 10);
if (n_randint(state, 2))
{
acb_set_si(m, n_randint(state, 20) - 10);
acb_set_si(n, n_randint(state, 20) - 10);
}
else
{
acb_randtest_param(n, state, 1 + n_randint(state, 400), ebits);
acb_randtest_param(m, state, 1 + n_randint(state, 400), ebits);
}
acb_randtest_param(z, state, 1 + n_randint(state, 400), ebits);
_acb_hypgeom_legendre_q_single(res1, n, m, z, prec1);
_acb_hypgeom_legendre_q_double(res2, n, m, z, prec2);
if (!acb_overlaps(res1, res2))
{
printf("FAIL: consistency 1\n\n");
printf("iter = %ld, prec1 = %ld, prec2 = %ld\n\n", iter, prec1, prec2);
printf("m = "); acb_printd(m, 30); printf("\n\n");
printf("n = "); acb_printd(n, 30); printf("\n\n");
printf("z = "); acb_printd(z, 30); printf("\n\n");
printf("res1 = "); acb_printd(res1, 30); printf("\n\n");
printf("res2 = "); acb_printd(res2, 30); printf("\n\n");
abort();
}
acb_clear(n);
acb_clear(m);
acb_clear(z);
acb_clear(res1);
acb_clear(res2);
}
for (iter = 0; iter < 2000; iter++)
{
acb_t n, m, z, res1, res2, t, u;
long prec1, prec2, ebits;
int type;
acb_init(n);
acb_init(m);
acb_init(z);
acb_init(res1);
acb_init(res2);
acb_init(t);
acb_init(u);
prec1 = 2 + n_randint(state, 300);
prec2 = 2 + n_randint(state, 300);
ebits = 1 + n_randint(state, 10);
if (n_randint(state, 2))
{
acb_set_si(m, n_randint(state, 20) - 10);
acb_set_si(n, n_randint(state, 20) - 10);
}
else
{
acb_randtest_param(n, state, 1 + n_randint(state, 400), ebits);
acb_randtest_param(m, state, 1 + n_randint(state, 400), ebits);
}
acb_randtest_param(z, state, 1 + n_randint(state, 400), ebits);
type = n_randint(state, 2);
acb_hypgeom_legendre_q(res1, n, m, z, type, prec1);
acb_neg(t, m);
acb_hypgeom_legendre_p(res2, n, t, z, type, prec2);
acb_add(u, m, n, prec2);
acb_add_ui(u, u, 1, prec2);
acb_gamma(u, u, prec2);
acb_mul(res2, res2, u, prec2);
acb_sub(u, n, m, prec2);
acb_add_ui(u, u, 1, prec2);
acb_rgamma(u, u, prec2);
acb_mul(res2, res2, u, prec2);
acb_hypgeom_legendre_p(t, n, m, z, type, prec2);
if (type == 0)
{
acb_cos_pi(u, m, prec2);
acb_mul(t, t, u, prec2);
}
acb_sub(res2, t, res2, prec2);
if (type == 1)
{
acb_exp_pi_i(t, m, prec2);
acb_mul(res2, res2, t, prec2);
}
acb_sin_pi(t, m, prec2);
if (acb_contains_zero(t))
acb_indeterminate(res2);
else
acb_div(res2, res2, t, prec2);
acb_const_pi(t, prec2);
acb_mul(res2, res2, t, prec2);
acb_mul_2exp_si(res2, res2, -1);
if (!acb_overlaps(res1, res2))
{
printf("FAIL: consistency 2\n\n");
printf("iter = %ld, prec1 = %ld, prec2 = %ld\n\n", iter, prec1, prec2);
printf("type = %d\n\n", type);
printf("m = "); acb_printd(m, 30); printf("\n\n");
printf("n = "); acb_printd(n, 30); printf("\n\n");
printf("z = "); acb_printd(z, 30); printf("\n\n");
printf("res1 = "); acb_printd(res1, 30); printf("\n\n");
printf("res2 = "); acb_printd(res2, 30); printf("\n\n");
abort();
}
acb_clear(n);
acb_clear(m);
acb_clear(z);
acb_clear(res1);
acb_clear(res2);
acb_clear(t);
acb_clear(u);
}
flint_randclear(state);
flint_cleanup();
printf("PASS\n");
return EXIT_SUCCESS;
}
int main()
{
slong iter;
flint_rand_t state;
flint_printf("gamma....");
fflush(stdout);
flint_randinit(state);
for (iter = 0; iter < 3000; iter++)
{
acb_t a, b, c;
slong prec1, prec2;
prec1 = 2 + n_randint(state, 1000);
prec2 = prec1 + 30;
acb_init(a);
acb_init(b);
acb_init(c);
arb_randtest_precise(acb_realref(a), state, 1 + n_randint(state, 1000), 3);
arb_randtest_precise(acb_imagref(a), state, 1 + n_randint(state, 1000), 3);
acb_gamma(b, a, prec1);
acb_gamma(c, a, prec2);
if (!acb_overlaps(b, c))
{
flint_printf("FAIL: overlap\n\n");
flint_printf("a = "); acb_print(a); flint_printf("\n\n");
flint_printf("b = "); acb_print(b); flint_printf("\n\n");
flint_printf("c = "); acb_print(c); flint_printf("\n\n");
abort();
}
/* check gamma(z+1) = z gamma(z) */
acb_mul(b, b, a, prec1);
acb_add_ui(c, a, 1, prec1);
acb_gamma(c, c, prec1);
if (!acb_overlaps(b, c))
{
flint_printf("FAIL: functional equation\n\n");
flint_printf("a = "); acb_print(a); flint_printf("\n\n");
flint_printf("b = "); acb_print(b); flint_printf("\n\n");
flint_printf("c = "); acb_print(c); flint_printf("\n\n");
abort();
}
acb_clear(a);
acb_clear(b);
acb_clear(c);
}
flint_randclear(state);
flint_cleanup();
flint_printf("PASS\n");
return EXIT_SUCCESS;
}
int main()
{
slong iter;
flint_rand_t state;
flint_printf("u_asymp....");
fflush(stdout);
flint_randinit(state);
for (iter = 0; iter < 10000 * arb_test_multiplier(); iter++)
{
acb_t a, b, a2, b2, z, U1, U2, t, u, M1, M2, am;
acb_struct bm[2];
ulong n1, n2;
slong prec0, prec1, prec2;
acb_init(a);
acb_init(b);
acb_init(a2);
acb_init(b2);
acb_init(z);
acb_init(U1);
acb_init(U2);
acb_init(t);
acb_init(u);
acb_init(M1);
acb_init(M2);
acb_init(am);
acb_init(bm);
acb_init(bm + 1);
if (n_randint(state, 4) == 0)
{
n1 = n_randint(state, 200);
n2 = n_randint(state, 200);
prec0 = 2 + n_randint(state, 1000);
prec1 = 2 + n_randint(state, 1000);
prec2 = 2 + n_randint(state, 1000);
}
else
{
n1 = n_randint(state, 40);
n2 = n_randint(state, 40);
prec0 = 2 + n_randint(state, 300);
prec1 = 2 + n_randint(state, 300);
prec2 = 2 + n_randint(state, 300);
}
acb_randtest_param(a, state, prec0, 1 + n_randint(state, 20));
if (n_randint(state, 4) == 0)
acb_add_ui(b, a, n_randint(state, 10), prec0);
else
acb_randtest_param(b, state, prec0, 1 + n_randint(state, 20));
acb_randtest(z, state, prec0, 1 + n_randint(state, 20));
/* Test Kummer's transformation */
acb_sub(a2, a, b, prec0);
acb_add_ui(a2, a2, 1, prec0);
acb_sub_ui(b2, b, 2, prec0);
acb_neg(b2, b2);
acb_hypgeom_u_asymp(U1, a, b, z, n1, prec1);
acb_hypgeom_u_asymp(U2, a2, b2, z, n2, prec2);
if (!acb_overlaps(U1, U2))
{
flint_printf("FAIL (Kummer transformation)\n");
flint_printf("iter = %wd\n", iter);
flint_printf("a = "); acb_printd(a, 50); flint_printf("\n");
flint_printf("b = "); acb_printd(b, 50); flint_printf("\n");
flint_printf("z = "); acb_printd(z, 50); flint_printf("\n");
flint_printf("n1 = %wd, n2 = %wd, prec1 = %wd, prec2 = %wd\n", n1, n2, prec1, prec2);
flint_printf("U1 = "); acb_printd(U1, 100); flint_printf("\n");
flint_printf("U2 = "); acb_printd(U2, 100); flint_printf("\n");
abort();
}
/* Check contiguous relation
(b-a-1)U(a,b-1,z) + z U(a,b+1,z) + (1-b-z) U(a,b,z) = 0 */
acb_one(t);
acb_sub(t, t, b, prec0);
acb_sub(t, t, z, prec0);
acb_mul(u, U1, t, prec1);
acb_add_ui(b2, b, 1, prec0);
acb_hypgeom_u_asymp(U2, a, b2, z, n2, prec2);
acb_addmul(u, U2, z, prec1);
acb_sub_ui(b2, b, 1, prec0);
acb_hypgeom_u_asymp(U2, a, b2, z, n2, prec2);
acb_sub(t, b, a, prec0);
acb_sub_ui(t, t, 1, prec0);
acb_mul(t, t, U2, prec0);
acb_add(t, t, u, prec0);
if (!acb_contains_zero(t))
{
flint_printf("FAIL (contiguous relation)\n");
flint_printf("iter = %wd\n", iter);
flint_printf("a = "); acb_printd(a, 50); flint_printf("\n");
flint_printf("b = "); acb_printd(b, 50); flint_printf("\n");
flint_printf("z = "); acb_printd(z, 50); flint_printf("\n");
flint_printf("n1 = %wd, n2 = %wd, prec1 = %wd, prec2 = %wd\n", n1, n2, prec1, prec2);
flint_printf("U1 = "); acb_printd(U1, 100); flint_printf("\n");
flint_printf("t = "); acb_printd(t, 100); flint_printf("\n");
abort();
}
/* Test U(a,b,z) = gamma(1-b)/gamma(a-b+1) M(a,b,z)
+ gamma(b-1)/gamma(a) z^(1-b) M(a-b+1,2-b,z) */
acb_set(am, a);
acb_set(bm, b);
acb_one(bm + 1);
acb_hypgeom_pfq_direct(M1, am, 1, bm, 2, z, n2, prec2);
acb_sub(am, a, b, prec2);
acb_add_ui(am, am, 1, prec2);
acb_sub_ui(bm, b, 2, prec2);
acb_neg(bm, bm);
acb_one(bm + 1);
acb_hypgeom_pfq_direct(M2, am, 1, bm, 2, z, n2, prec2);
acb_sub(am, a, b, prec2);
acb_add_ui(am, am, 1, prec2);
acb_rgamma(am, am, prec2);
acb_mul(M1, M1, am, prec2);
acb_sub_ui(am, b, 1, prec2);
acb_neg(am, am);
acb_gamma(am, am, prec2);
acb_mul(M1, M1, am, prec2);
acb_rgamma(am, a, prec2);
acb_mul(M2, M2, am, prec2);
acb_sub_ui(am, b, 1, prec2);
acb_gamma(am, am, prec2);
acb_mul(M2, M2, am, prec2);
acb_sub_ui(am, b, 1, prec2);
acb_neg(am, am);
acb_pow(am, z, am, prec2);
acb_mul(M2, M2, am, prec2);
acb_add(U2, M1, M2, prec2);
acb_pow(am, z, a, prec2);
acb_mul(U2, U2, am, prec2);
if (!acb_overlaps(U1, U2))
{
flint_printf("FAIL (U in terms of M)\n");
flint_printf("iter = %wd\n", iter);
flint_printf("a = "); acb_printd(a, 50); flint_printf("\n");
flint_printf("b = "); acb_printd(b, 50); flint_printf("\n");
flint_printf("z = "); acb_printd(z, 50); flint_printf("\n");
flint_printf("n1 = %wd, n2 = %wd, prec1 = %wd, prec2 = %wd\n", n1, n2, prec1, prec2);
flint_printf("U1 = "); acb_printd(U1, 100); flint_printf("\n");
flint_printf("U2 = "); acb_printd(U2, 100); flint_printf("\n");
abort();
}
/* Test special value: b = a+1 */
acb_add_ui(b, a, 1, prec0);
acb_hypgeom_u_asymp(U1, a, b, z, n1, prec1);
acb_one(U2);
if (!acb_overlaps(U1, U2))
{
flint_printf("FAIL (special value)\n");
flint_printf("iter = %wd\n", iter);
flint_printf("a = "); acb_printd(a, 50); flint_printf("\n");
flint_printf("b = "); acb_printd(b, 50); flint_printf("\n");
flint_printf("z = "); acb_printd(z, 50); flint_printf("\n");
flint_printf("n1 = %wd, n2 = %wd, prec1 = %wd, prec2 = %wd\n", n1, n2, prec1, prec2);
flint_printf("U1 = "); acb_printd(U1, 100); flint_printf("\n");
flint_printf("U2 = "); acb_printd(U2, 100); flint_printf("\n");
abort();
}
acb_clear(a);
acb_clear(b);
acb_clear(a2);
acb_clear(b2);
acb_clear(z);
acb_clear(U1);
acb_clear(U2);
acb_clear(t);
acb_clear(u);
acb_clear(M1);
acb_clear(M2);
acb_clear(am);
acb_clear(bm);
acb_clear(bm + 1);
}
flint_randclear(state);
flint_cleanup();
flint_printf("PASS\n");
return EXIT_SUCCESS;
}
int main()
{
slong iter;
flint_rand_t state;
flint_printf("gamma_upper_series....");
fflush(stdout);
flint_randinit(state);
for (iter = 0; iter < 1000 * arb_test_multiplier(); iter++)
{
slong m, n1, n2, bits1, bits2, bits3;
acb_poly_t S, A, B, C;
acb_t s, t, c;
int regularized;
regularized = n_randint(state, 3);
bits1 = 2 + n_randint(state, 200);
bits2 = 2 + n_randint(state, 200);
bits3 = 2 + n_randint(state, 200);
m = 1 + n_randint(state, 10);
n1 = 1 + n_randint(state, 10);
n2 = 1 + n_randint(state, 10);
acb_poly_init(S);
acb_poly_init(A);
acb_poly_init(B);
acb_poly_init(C);
acb_init(s);
acb_init(t);
acb_init(c);
acb_poly_randtest(S, state, m, bits1, 3);
acb_poly_randtest(A, state, m, bits1, 3);
acb_poly_randtest(B, state, m, bits1, 3);
acb_randtest(s, state, bits1, 3);
acb_hypgeom_gamma_upper_series(A, s, S, regularized, n1, bits2);
acb_hypgeom_gamma_upper_series(B, s, S, regularized, n2, bits3);
acb_poly_set(C, A);
acb_poly_truncate(C, FLINT_MIN(n1, n2));
acb_poly_truncate(B, FLINT_MIN(n1, n2));
if (!acb_poly_overlaps(B, C))
{
flint_printf("FAIL (consistency)\n\n");
flint_printf("regularized = %d\n\n", regularized);
flint_printf("S = "); acb_poly_printd(S, 15); flint_printf("\n\n");
flint_printf("A = "); acb_poly_printd(A, 15); flint_printf("\n\n");
flint_printf("B = "); acb_poly_printd(B, 15); flint_printf("\n\n");
flint_printf("C = "); acb_poly_printd(C, 15); flint_printf("\n\n");
flint_abort();
}
/* f(h(x)) = -exp(-h(x)) h(x)^(s-1) */
acb_poly_neg(C, S);
acb_poly_exp_series(C, C, n1, bits2);
acb_sub_ui(t, s, 1, bits2);
acb_poly_pow_acb_series(B, S, t, n1, bits2);
acb_poly_mullow(C, C, B, n1, bits2);
acb_poly_neg(C, C);
if (regularized == 0)
{
/* integral(f(h(x)) h'(x))' = f(h(x)) h'(x) */
acb_poly_derivative(B, S, bits2);
acb_poly_mullow(C, C, B, n1, bits2);
acb_poly_truncate(C, n1 - 1);
}
else if (regularized == 1)
{
/* (integral(f(h(x)) h'(x)) / c)' = (f(h(x)) h'(x)) / c */
acb_poly_derivative(B, S, bits2);
acb_poly_mullow(C, C, B, n1, bits2);
acb_gamma(c, s, bits2);
acb_poly_scalar_div(C, C, c, bits2);
acb_poly_truncate(C, n1 - 1);
}
else if (regularized == 2)
{
/* (h(x)^-s integral(f(h(x)) h'(x)))' =
* h(x)^-(s+1) (h(x) f(h(x)) - s integral(f(h(x)) h'(x))) h'(x) */
acb_poly_t D;
acb_poly_init(D);
acb_poly_derivative(B, S, bits2);
acb_poly_mullow(D, C, B, n1, bits2);
acb_poly_integral(D, D, bits2);
acb_poly_scalar_mul(D, D, s, bits2);
acb_poly_mullow(C, C, S, n1, bits2);
acb_poly_sub(D, C, D, bits2);
acb_add_ui(t, s, 1, bits2);
acb_neg(t, t);
acb_poly_pow_acb_series(B, S, t, n1, bits2);
acb_poly_mullow(C, D, B, n1, bits2);
acb_poly_derivative(B, S, bits2);
acb_poly_mullow(C, C, B, n1, bits2);
acb_poly_truncate(C, n1 - 1);
acb_poly_clear(D);
}
acb_poly_derivative(B, A, bits2);
if (!acb_poly_overlaps(B, C))
{
flint_printf("FAIL (derivative)\n\n");
flint_printf("regularized = %d\n\n", regularized);
flint_printf("S = "); acb_poly_printd(S, 15); flint_printf("\n\n");
flint_printf("A = "); acb_poly_printd(A, 15); flint_printf("\n\n");
flint_printf("B = "); acb_poly_printd(B, 15); flint_printf("\n\n");
flint_printf("C = "); acb_poly_printd(C, 15); flint_printf("\n\n");
flint_abort();
}
acb_hypgeom_gamma_upper_series(S, s, S, regularized, n1, bits2);
if (!acb_poly_overlaps(A, S))
{
flint_printf("FAIL (aliasing)\n\n");
flint_printf("regularized = %d\n\n", regularized);
flint_printf("S = "); acb_poly_printd(S, 15); flint_printf("\n\n");
flint_printf("A = "); acb_poly_printd(A, 15); flint_printf("\n\n");
flint_abort();
}
acb_poly_clear(S);
acb_poly_clear(A);
acb_poly_clear(B);
acb_poly_clear(C);
acb_clear(s);
acb_clear(t);
acb_clear(c);
}
flint_randclear(state);
flint_cleanup();
flint_printf("PASS\n");
return EXIT_SUCCESS;
}
void
acb_hypgeom_2f1(acb_t res, const acb_t a, const acb_t b,
const acb_t c, const acb_t z, int flags, slong prec)
{
int algorithm, regularized;
regularized = flags & ACB_HYPGEOM_2F1_REGULARIZED;
if (!acb_is_finite(a) || !acb_is_finite(b) || !acb_is_finite(c) || !acb_is_finite(z))
{
acb_indeterminate(res);
return;
}
if (acb_is_zero(z))
{
if (regularized)
acb_rgamma(res, c, prec);
else
acb_one(res);
return;
}
if (regularized && acb_is_int(c) && arb_is_nonpositive(acb_realref(c)))
{
if ((acb_is_int(a) && arb_is_nonpositive(acb_realref(a)) &&
arf_cmp(arb_midref(acb_realref(a)), arb_midref(acb_realref(c))) >= 0) ||
(acb_is_int(b) && arb_is_nonpositive(acb_realref(b)) &&
arf_cmp(arb_midref(acb_realref(b)), arb_midref(acb_realref(c))) >= 0))
{
acb_zero(res);
return;
}
}
if (regularized && acb_eq(a, c))
{
_acb_hypgeom_2f1r_reduced(res, b, c, z, prec);
return;
}
if (regularized && acb_eq(b, c))
{
_acb_hypgeom_2f1r_reduced(res, a, c, z, prec);
return;
}
/* polynomial */
if (acb_is_int(a) && arf_sgn(arb_midref(acb_realref(a))) <= 0 &&
arf_cmpabs_ui(arb_midref(acb_realref(a)), prec) < 0)
{
acb_hypgeom_2f1_direct(res, a, b, c, z, regularized, prec);
return;
}
/* polynomial */
if (acb_is_int(b) && arf_sgn(arb_midref(acb_realref(b))) <= 0 &&
arf_cmpabs_ui(arb_midref(acb_realref(b)), prec) < 0)
{
acb_hypgeom_2f1_direct(res, a, b, c, z, regularized, prec);
return;
}
/* Try to reduce to a polynomial case using the Pfaff transformation */
/* TODO: look at flags for integer c-b, c-a here, even when c is nonexact */
if (acb_is_exact(c))
{
acb_t t;
acb_init(t);
acb_sub(t, c, b, prec);
if (acb_is_int(t) && arb_is_nonpositive(acb_realref(t)))
{
acb_hypgeom_2f1_transform(res, a, b, c, z, flags, 1, prec);
acb_clear(t);
return;
}
acb_sub(t, c, a, prec);
if (acb_is_int(t) && arb_is_nonpositive(acb_realref(t)))
{
int f1, f2;
/* When swapping a, b, also swap the flags. */
f1 = flags & ACB_HYPGEOM_2F1_AC;
f2 = flags & ACB_HYPGEOM_2F1_BC;
flags &= ~ACB_HYPGEOM_2F1_AC;
flags &= ~ACB_HYPGEOM_2F1_BC;
if (f1) flags |= ACB_HYPGEOM_2F1_BC;
if (f2) flags |= ACB_HYPGEOM_2F1_AC;
acb_hypgeom_2f1_transform(res, b, a, c, z, flags, 1, prec);
acb_clear(t);
return;
}
acb_clear(t);
}
/* special value at z = 1 */
if (acb_is_one(z))
{
acb_t t, u, v;
acb_init(t);
acb_init(u);
acb_init(v);
acb_sub(t, c, a, prec);
acb_sub(u, c, b, prec);
acb_sub(v, t, b, prec);
if (arb_is_positive(acb_realref(v)))
{
acb_rgamma(t, t, prec);
acb_rgamma(u, u, prec);
acb_mul(t, t, u, prec);
acb_gamma(v, v, prec);
acb_mul(t, t, v, prec);
if (!regularized)
{
acb_gamma(v, c, prec);
acb_mul(t, t, v, prec);
}
acb_set(res, t);
}
else
{
acb_indeterminate(res);
}
acb_clear(t);
acb_clear(u);
acb_clear(v);
return;
}
algorithm = acb_hypgeom_2f1_choose(z);
if (algorithm == 0)
{
acb_hypgeom_2f1_direct(res, a, b, c, z, regularized, prec);
}
else if (algorithm >= 1 && algorithm <= 5)
{
acb_hypgeom_2f1_transform(res, a, b, c, z, flags, algorithm, prec);
}
else
{
acb_hypgeom_2f1_corner(res, a, b, c, z, regularized, prec);
}
}
int main()
{
slong iter;
flint_rand_t state;
flint_printf("gamma_lower....");
fflush(stdout);
flint_randinit(state);
for (iter = 0; iter < 2000 * arb_test_multiplier(); iter++)
{
acb_t a0, a1, b, z, w0, w1, t, u, enz;
slong prec0, prec1;
int regularized;
acb_init(a0);
acb_init(a1);
acb_init(b);
acb_init(z);
acb_init(w0);
acb_init(w1);
acb_init(t);
acb_init(u);
acb_init(enz);
regularized = n_randint(state, 3);
prec0 = 2 + n_randint(state, 1000);
prec1 = 2 + n_randint(state, 1000);
acb_randtest_param(a0, state, 1 + n_randint(state, 1000), 1 + n_randint(state, 100));
acb_randtest(z, state, 1 + n_randint(state, 1000), 1 + n_randint(state, 100));
acb_randtest(w0, state, 1 + n_randint(state, 1000), 1 + n_randint(state, 100));
acb_randtest(w1, state, 1 + n_randint(state, 1000), 1 + n_randint(state, 100));
acb_add_ui(a1, a0, 1, prec0);
acb_hypgeom_gamma_lower(w0, a0, z, regularized, prec0);
acb_hypgeom_gamma_lower(w1, a1, z, regularized, prec1);
acb_neg(enz, z);
acb_exp(enz, enz, prec0);
/* recurrence relations */
if (regularized == 2)
{
/* gamma^{*}(a,z) - exp(-z)/Gamma(a+1) - z gamma^{*}(a+1,z) = 0 */
/* http://dlmf.nist.gov/8.8.E4 */
acb_set(t, w0);
acb_rgamma(u, a1, prec0);
acb_submul(t, enz, u, prec0);
acb_submul(t, z, w1, prec0);
}
else if (regularized == 1)
{
/* P(a,z) - exp(-z) z^a / Gamma(a+1) - P(a+1,z) = 0 */
/* http://dlmf.nist.gov/8.8.E5 */
acb_pow(u, z, a0, prec0);
acb_rgamma(b, a1, prec0);
acb_mul(u, u, b, prec0);
acb_sub(t, w0, w1, prec0);
acb_submul(t, enz, u, prec0);
}
else
{
/* a gamma(a,z) - exp(-z) z^a - gamma(a+1,z) = 0 */
/* http://dlmf.nist.gov/8.8.E1 */
acb_pow(u, z, a0, prec0);
acb_mul(t, a0, w0, prec0);
acb_submul(t, enz, u, prec0);
acb_sub(t, t, w1, prec0);
}
if (!acb_contains_zero(t))
{
flint_printf("FAIL: recurrence relation\n\n");
flint_printf("regularized = %d\n\n", regularized);
flint_printf("a0 = "); acb_printd(a0, 30); flint_printf("\n\n");
flint_printf("z = "); acb_printd(z, 30); flint_printf("\n\n");
flint_printf("w0 = "); acb_printd(w0, 30); flint_printf("\n\n");
flint_printf("w1 = "); acb_printd(w1, 30); flint_printf("\n\n");
flint_printf("t = "); acb_printd(t, 30); flint_printf("\n\n");
abort();
}
/* identities relating lower and upper incomplete gamma functions */
if (regularized == 0 || regularized == 1)
{
acb_t u0;
acb_init(u0);
acb_hypgeom_gamma_upper(u0, a0, z, regularized, prec0);
acb_zero(t);
if (regularized == 1)
{
/* P(s,z) + Q(s,z) - 1 = 0 */
/* http://dlmf.nist.gov/8.2.E5 */
acb_add(t, w0, u0, prec0);
acb_sub_ui(t, t, 1, prec0);
}
else
{
/* gamma(s,z) + Gamma(s,z) - Gamma(s) = 0 */
/* excludes non-positive integer values of s */
/* http://dlmf.nist.gov/8.2.E3 */
if (!acb_is_int(a0) || arb_is_positive(acb_realref(a0)))
{
acb_gamma(b, a0, prec0);
acb_add(t, w0, u0, prec0);
acb_sub(t, t, b, prec0);
}
}
if (!acb_contains_zero(t))
{
flint_printf("FAIL: lower plus upper\n\n");
flint_printf("regularized = %d\n\n", regularized);
flint_printf("a0 = "); acb_printd(a0, 30); flint_printf("\n\n");
flint_printf("z = "); acb_printd(z, 30); flint_printf("\n\n");
flint_printf("w0 = "); acb_printd(w0, 30); flint_printf("\n\n");
flint_printf("w1 = "); acb_printd(w1, 30); flint_printf("\n\n");
flint_printf("t = "); acb_printd(t, 30); flint_printf("\n\n");
abort();
}
acb_clear(u0);
}
acb_clear(a0);
acb_clear(a1);
acb_clear(b);
acb_clear(z);
acb_clear(w0);
acb_clear(w1);
acb_clear(t);
acb_clear(u);
acb_clear(enz);
}
flint_randclear(state);
flint_cleanup();
flint_printf("PASS\n");
return EXIT_SUCCESS;
}
void
acb_hypgeom_bessel_k_0f1(acb_t res, const acb_t nu, const acb_t z, slong prec)
{
if (acb_is_int(nu))
{
acb_poly_t nux, zx, rx;
acb_poly_init(nux);
acb_poly_init(zx);
acb_poly_init(rx);
acb_poly_set_coeff_acb(nux, 0, nu);
acb_poly_set_coeff_si(nux, 1, 1);
acb_poly_set_acb(zx, z);
acb_hypgeom_bessel_k_0f1_series(rx, nux, zx, 1, prec);
acb_poly_get_coeff_acb(res, rx, 0);
acb_poly_clear(nux);
acb_poly_clear(zx);
acb_poly_clear(rx);
}
else
{
acb_t t, u, v, w;
acb_struct b[2];
acb_init(t);
acb_init(u);
acb_init(v);
acb_init(w);
acb_init(b + 0);
acb_init(b + 1);
/* u = 0F1(1+nu), v = 0F1(1-nu) */
acb_mul(t, z, z, prec);
acb_mul_2exp_si(t, t, -2);
acb_add_ui(b, nu, 1, prec);
acb_one(b + 1);
acb_hypgeom_pfq_direct(u, NULL, 0, b, 2, t, -1, prec);
acb_sub_ui(b, nu, 1, prec);
acb_neg(b, b);
acb_hypgeom_pfq_direct(v, NULL, 0, b, 2, t, -1, prec);
/* v = v * gamma(nu) / (z/2)^nu */
acb_mul_2exp_si(t, z, -1);
acb_pow(t, t, nu, prec);
acb_gamma(w, nu, prec);
acb_mul(v, v, w, prec);
acb_div(v, v, t, prec);
/* u = u * t * pi / (gamma(nu) * nu * sin(pi nu)) */
acb_mul(u, u, t, prec);
acb_const_pi(t, prec);
acb_mul(u, u, t, prec);
acb_sin_pi(t, nu, prec);
acb_mul(t, t, w, prec);
acb_mul(t, t, nu, prec);
acb_div(u, u, t, prec);
acb_sub(res, v, u, prec);
acb_mul_2exp_si(res, res, -1);
acb_clear(t);
acb_clear(u);
acb_clear(v);
acb_clear(w);
acb_clear(b + 0);
acb_clear(b + 1);
}
}
void
acb_hypgeom_2f1_transform_limit(acb_t res, const acb_t a, const acb_t b,
const acb_t c, const acb_t z, int regularized, int which, slong prec)
{
acb_poly_t aa, bb, cc, zz;
acb_t t;
if (acb_contains_zero(z) || !acb_is_finite(z))
{
acb_indeterminate(res);
return;
}
if (arb_contains_si(acb_realref(z), 1) && arb_contains_zero(acb_imagref(z)))
{
acb_indeterminate(res);
return;
}
if (!regularized)
{
acb_init(t);
acb_gamma(t, c, prec);
acb_hypgeom_2f1_transform_limit(res, a, b, c, z, 1, which, prec);
acb_mul(res, res, t, prec);
acb_clear(t);
return;
}
acb_poly_init(aa);
acb_poly_init(bb);
acb_poly_init(cc);
acb_poly_init(zz);
acb_init(t);
acb_poly_set_acb(aa, a);
acb_poly_set_acb(bb, b);
acb_poly_set_acb(cc, c);
acb_poly_set_acb(zz, z);
if (which == 2 || which == 3)
{
acb_sub(t, b, a, prec);
acb_poly_set_coeff_si(aa, 1, 1);
/* prefer b-a nonnegative (either is correct) to avoid
expensive operations in the hypergeometric series */
if (arb_is_nonnegative(acb_realref(t)))
_acb_hypgeom_2f1_transform_limit(res, aa, bb, cc, zz, which, prec);
else
_acb_hypgeom_2f1_transform_limit(res, bb, aa, cc, zz, which, prec);
}
else
{
acb_poly_set_coeff_si(aa, 1, 1);
_acb_hypgeom_2f1_transform_limit(res, aa, bb, cc, zz, which, prec);
}
acb_poly_clear(aa);
acb_poly_clear(bb);
acb_poly_clear(cc);
acb_poly_clear(zz);
acb_clear(t);
}
void
acb_hypgeom_2f1_transform(acb_t res, const acb_t a, const acb_t b,
const acb_t c, const acb_t z, int flags, int which, slong prec)
{
int regularized;
regularized = flags & ACB_HYPGEOM_2F1_REGULARIZED;
if (which == 1)
{
acb_t t, u, v;
acb_init(t);
acb_init(u);
acb_init(v);
acb_sub_ui(t, z, 1, prec); /* t = z-1 */
acb_div(u, z, t, prec); /* u = z/(z-1) */
acb_neg(t, t);
acb_neg(v, a);
acb_pow(t, t, v, prec); /* t = (1-z)^-a */
acb_sub(v, c, b, prec); /* v = c-b */
/* We cannot use regularized=1 directly, since if c is a nonnegative
integer, the transformation formula reads (lhs) * 0 = (rhs) * 0. */
acb_hypgeom_2f1_direct(u, a, v, c, u, 1, prec);
if (!regularized)
{
acb_gamma(v, c, prec);
acb_mul(u, u, v, prec);
}
acb_mul(res, u, t, prec);
acb_clear(t);
acb_clear(u);
acb_clear(v);
}
else
{
acb_t d;
int limit;
acb_init(d);
if (which == 2 || which == 3)
{
if (flags & ACB_HYPGEOM_2F1_AB)
{
limit = 1;
}
else
{
acb_sub(d, b, a, prec);
limit = acb_is_int(d);
}
}
else
{
if (flags & ACB_HYPGEOM_2F1_ABC)
{
limit = 1;
}
else
{
acb_sub(d, c, a, prec);
acb_sub(d, d, b, prec);
limit = acb_is_int(d);
}
}
if (limit)
acb_hypgeom_2f1_transform_limit(res, a, b, c, z, regularized, which, prec);
else
acb_hypgeom_2f1_transform_nolimit(res, a, b, c, z, regularized, which, prec);
acb_clear(d);
}
if (!acb_is_finite(res))
acb_indeterminate(res);
}
void
acb_hypgeom_2f1_transform_nolimit(acb_t res, const acb_t a, const acb_t b,
const acb_t c, const acb_t z, int regularized, int which, slong prec)
{
acb_t ba, ca, cb, cab, ac1, bc1, ab1, ba1, w, t, u, v, s;
if (acb_contains_zero(z) || !acb_is_finite(z))
{
acb_indeterminate(res);
return;
}
if (arb_contains_si(acb_realref(z), 1) && arb_contains_zero(acb_imagref(z)))
{
acb_indeterminate(res);
return;
}
if (!regularized)
{
acb_init(t);
acb_gamma(t, c, prec);
acb_hypgeom_2f1_transform_nolimit(res, a, b, c, z, 1, which, prec);
acb_mul(res, res, t, prec);
acb_clear(t);
return;
}
acb_init(ba);
acb_init(ca); acb_init(cb); acb_init(cab);
acb_init(ac1); acb_init(bc1);
acb_init(ab1); acb_init(ba1);
acb_init(w); acb_init(t);
acb_init(u); acb_init(v);
acb_init(s);
acb_add_si(s, z, -1, prec); /* s = 1 - z */
acb_neg(s, s);
acb_sub(ba, b, a, prec); /* ba = b - a */
acb_sub(ca, c, a, prec); /* ca = c - a */
acb_sub(cb, c, b, prec); /* cb = c - b */
acb_sub(cab, ca, b, prec); /* cab = c - a - b */
acb_add_si(ac1, ca, -1, prec); acb_neg(ac1, ac1); /* ac1 = a - c + 1 */
acb_add_si(bc1, cb, -1, prec); acb_neg(bc1, bc1); /* bc1 = b - c + 1 */
acb_add_si(ab1, ba, -1, prec); acb_neg(ab1, ab1); /* ab1 = a - b + 1 */
acb_add_si(ba1, ba, 1, prec); /* ba1 = b - a + 1 */
/* t = left term, u = right term (DLMF 15.8.1 - 15.8.5) */
if (which == 2)
{
acb_inv(w, z, prec); /* w = 1/z */
acb_hypgeom_2f1_direct(t, a, ac1, ab1, w, 1, prec);
acb_hypgeom_2f1_direct(u, b, bc1, ba1, w, 1, prec);
}
else if (which == 3)
{
acb_inv(w, s, prec); /* w = 1/(1-z) */
acb_hypgeom_2f1_direct(t, a, cb, ab1, w, 1, prec);
acb_hypgeom_2f1_direct(u, b, ca, ba1, w, 1, prec);
}
else if (which == 4)
{
acb_set(w, s); /* w = 1-z */
acb_add(v, ac1, b, prec); /* v = a+b-c+1 */
acb_hypgeom_2f1_direct(t, a, b, v, w, 1, prec);
acb_add_si(v, cab, 1, prec); /* v = c-a-b+1 */
acb_hypgeom_2f1_direct(u, ca, cb, v, w, 1, prec);
}
else if (which == 5)
{
acb_inv(w, z, prec); /* w = 1-1/z */
acb_neg(w, w);
acb_add_si(w, w, 1, prec);
acb_add(v, ac1, b, prec); /* v = a+b-c+1 */
acb_hypgeom_2f1_direct(t, a, ac1, v, w, 1, prec);
acb_add_si(v, cab, 1, prec); /* v = c-a-b+1 */
acb_add_si(u, a, -1, prec); /* u = 1-a */
acb_neg(u, u);
acb_hypgeom_2f1_direct(u, ca, u, v, w, 1, prec);
}
else
{
flint_printf("invalid transformation!\n");
flint_abort();
}
/* gamma factors */
acb_rgamma(v, a, prec);
acb_mul(u, u, v, prec);
acb_rgamma(v, ca, prec);
acb_mul(t, t, v, prec);
acb_rgamma(v, b, prec);
if (which == 2 || which == 3)
acb_mul(t, t, v, prec);
else
acb_mul(u, u, v, prec);
acb_rgamma(v, cb, prec);
if (which == 2 || which == 3)
acb_mul(u, u, v, prec);
else
acb_mul(t, t, v, prec);
if (which == 2 || which == 3)
{
if (which == 2)
acb_neg(s, z); /* -z, otherwise 1-z since before */
acb_neg(v, a);
acb_pow(v, s, v, prec);
acb_mul(t, t, v, prec);
acb_neg(v, b);
acb_pow(v, s, v, prec);
acb_mul(u, u, v, prec);
}
else
{
acb_pow(v, s, cab, prec);
acb_mul(u, u, v, prec);
if (which == 5)
{
acb_neg(v, a);
acb_pow(v, z, v, prec);
acb_mul(t, t, v, prec);
acb_neg(v, ca);
acb_pow(v, z, v, prec);
acb_mul(u, u, v, prec);
}
}
acb_sub(t, t, u, prec);
if (which == 2 || which == 3)
acb_sin_pi(v, ba, prec);
else
acb_sin_pi(v, cab, prec);
acb_div(t, t, v, prec);
acb_const_pi(v, prec);
acb_mul(t, t, v, prec);
acb_set(res, t);
acb_clear(ba);
acb_clear(ca); acb_clear(cb); acb_clear(cab);
acb_clear(ac1); acb_clear(bc1);
acb_clear(ab1); acb_clear(ba1);
acb_clear(w); acb_clear(t);
acb_clear(u); acb_clear(v);
acb_clear(s);
}
/* todo: use euler product for complex s, and check efficiency
for large negative integers */
void
acb_dirichlet_zeta(acb_t res, const acb_t s, slong prec)
{
acb_t a;
double cutoff;
if (acb_is_int(s) &&
arf_cmpabs_2exp_si(arb_midref(acb_realref(s)), FLINT_BITS - 1) < 0)
{
acb_zeta_si(res, arf_get_si(arb_midref(acb_realref(s)), ARF_RND_DOWN), prec);
return;
}
cutoff = 24.0 * prec * sqrt(prec);
if (arf_cmpabs_d(arb_midref(acb_imagref(s)), cutoff) >= 0 &&
arf_cmpabs_d(arb_midref(acb_realref(s)), 10 + prec * 0.1) <= 0)
{
acb_dirichlet_zeta_rs(res, s, 0, prec);
return;
}
acb_init(a);
acb_one(a);
if (arf_sgn(arb_midref(acb_realref(s))) < 0)
{
acb_t t, u, v;
slong wp = prec + 6;
acb_init(t);
acb_init(u);
acb_init(v);
acb_sub_ui(t, s, 1, wp);
/* 2 * (2pi)^(s-1) */
arb_const_pi(acb_realref(u), wp);
acb_mul_2exp_si(u, u, 1);
acb_pow(u, u, t, wp);
acb_mul_2exp_si(u, u, 1);
/* sin(pi*s/2) */
acb_mul_2exp_si(v, s, -1);
acb_sin_pi(v, v, wp);
acb_mul(u, u, v, wp);
/* gamma(1-s) zeta(1-s) */
acb_neg(t, t);
acb_gamma(v, t, wp);
acb_mul(u, u, v, wp);
acb_hurwitz_zeta(v, t, a, wp);
acb_mul(res, u, v, prec);
acb_clear(t);
acb_clear(u);
acb_clear(v);
}
else
{
acb_hurwitz_zeta(res, s, a, prec);
}
acb_clear(a);
}
void
acb_hypgeom_u_1f1(acb_t res, const acb_t a, const acb_t b, const acb_t z, long prec)
{
if (acb_is_int(b))
{
acb_poly_t aa, bb, zz;
acb_poly_init(aa);
acb_poly_init(bb);
acb_poly_init(zz);
acb_poly_set_acb(aa, a);
acb_poly_set_coeff_acb(bb, 0, b);
acb_poly_set_coeff_si(bb, 1, 1);
acb_poly_set_acb(zz, z);
acb_hypgeom_u_1f1_series(zz, aa, bb, zz, 1, prec);
acb_poly_get_coeff_acb(res, zz, 0);
acb_poly_clear(aa);
acb_poly_clear(bb);
acb_poly_clear(zz);
}
else
{
acb_t t, u, v;
acb_struct aa[3];
acb_init(t);
acb_init(u);
acb_init(v);
acb_init(aa + 0);
acb_init(aa + 1);
acb_init(aa + 2);
acb_set(aa, a);
acb_set(aa + 1, b);
acb_one(aa + 2);
acb_hypgeom_pfq_direct(u, aa, 1, aa + 1, 2, z, -1, prec);
acb_sub(aa, a, b, prec);
acb_add_ui(aa, aa, 1, prec);
acb_sub_ui(aa + 1, b, 2, prec);
acb_neg(aa + 1, aa + 1);
acb_hypgeom_pfq_direct(v, aa, 1, aa + 1, 2, z, -1, prec);
acb_sub_ui(aa + 1, b, 1, prec);
/* rgamma(a-b+1) * gamma(1-b) * u */
acb_rgamma(t, aa, prec);
acb_mul(u, u, t, prec);
acb_neg(t, aa + 1);
acb_gamma(t, t, prec);
acb_mul(u, u, t, prec);
/* rgamma(a) * gamma(b-1) * z^(1-b) * v */
acb_rgamma(t, a, prec);
acb_mul(v, v, t, prec);
acb_gamma(t, aa + 1, prec);
acb_mul(v, v, t, prec);
acb_neg(t, aa + 1);
acb_pow(t, z, t, prec);
acb_mul(v, v, t, prec);
acb_add(res, u, v, prec);
acb_clear(t);
acb_clear(u);
acb_clear(v);
acb_clear(aa + 0);
acb_clear(aa + 1);
acb_clear(aa + 2);
}
}
