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;
}
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();
}
}
