int main()
{
slong iter;
flint_rand_t state;
flint_printf("2f1....");
fflush(stdout);
flint_randinit(state);
for (iter = 0; iter < 3000; iter++)
{
acb_t a, b, c, z, w1, w2, t;
slong prec1, prec2;
int reg1, reg2, ebits;
int alg1, alg2;
acb_init(a);
acb_init(b);
acb_init(c);
acb_init(z);
acb_init(w1);
acb_init(w2);
acb_init(t);
prec1 = 2 + n_randint(state, 300);
prec2 = 2 + n_randint(state, 300);
if (n_randint(state, 20) == 0)
ebits = 30;
else
ebits = 5;
switch (n_randint(state, 3))
{
case 0:
acb_set_si(a, n_randint(state, 500));
acb_set_si(b, n_randint(state, 500));
acb_set_si(c, n_randint(state, 10));
break;
case 1:
acb_set_si(a, n_randint(state, 200) - 100);
acb_set_si(b, n_randint(state, 200) - 100);
acb_set_si(c, n_randint(state, 200) - 100);
break;
default:
acb_randtest_param(a, state, 1 + n_randint(state, 400), 1 + n_randint(state, ebits));
acb_randtest_param(b, state, 1 + n_randint(state, 400), 1 + n_randint(state, ebits));
acb_randtest_param(c, state, 1 + n_randint(state, 400), 1 + n_randint(state, ebits));
}
acb_randtest_param(z, state, 1 + n_randint(state, 400), 1 + n_randint(state, ebits));
acb_randtest(w1, state, 1 + n_randint(state, 400), 1 + n_randint(state, ebits));
acb_randtest(w2, state, 1 + n_randint(state, 400), 1 + n_randint(state, ebits));
reg1 = n_randint(state, 2);
reg2 = n_randint(state, 2);
alg1 = n_randint(state, 10);
alg2 = n_randint(state, 10);
switch (alg1)
{
case 0:
acb_hypgeom_2f1_direct(w1, a, b, c, z, reg1, prec1);
break;
case 1:
case 2:
case 3:
case 4:
case 5:
acb_hypgeom_2f1_transform(w1, a, b, c, z, reg1, alg1, prec1);
break;
case 6:
acb_hypgeom_2f1_corner(w1, a, b, c, z, reg1, prec1);
break;
default:
acb_hypgeom_2f1(w1, a, b, c, z, reg1, prec1);
}
switch (alg2)
{
case 0:
acb_hypgeom_2f1_direct(w2, a, b, c, z, reg2, prec2);
break;
case 1:
case 2:
case 3:
case 4:
case 5:
acb_hypgeom_2f1_transform(w2, a, b, c, z, reg2, alg2, prec2);
break;
case 6:
acb_hypgeom_2f1_corner(w2, a, b, c, z, reg2, prec2);
break;
default:
acb_hypgeom_2f1(w2, a, b, c, z, reg2, prec2);
}
if (reg1 != reg2)
{
acb_rgamma(t, c, prec2);
if (reg1)
acb_mul(w2, w2, t, prec2);
else
acb_mul(w1, w1, t, prec2);
}
if (!acb_overlaps(w1, w2))
{
flint_printf("FAIL: consistency\n\n");
flint_printf("iter = %wd, prec1 = %wd, prec2 = %wd\n\n", iter, prec1, prec2);
flint_printf("alg1 = %d, alg2 = %d\n\n", alg1, alg2);
flint_printf("reg1 = %d, reg2 = %d\n\n", reg1, reg2);
flint_printf("a = "); acb_printd(a, 30); flint_printf("\n\n");
flint_printf("b = "); acb_printd(b, 30); flint_printf("\n\n");
flint_printf("c = "); acb_printd(c, 30); flint_printf("\n\n");
flint_printf("z = "); acb_printd(z, 30); flint_printf("\n\n");
flint_printf("w1 = "); acb_printd(w1, 30); flint_printf("\n\n");
flint_printf("w2 = "); acb_printd(w2, 30); flint_printf("\n\n");
abort();
}
acb_clear(a);
acb_clear(b);
acb_clear(c);
acb_clear(z);
acb_clear(w1);
acb_clear(w2);
acb_clear(t);
}
flint_randclear(state);
flint_cleanup();
flint_printf("PASS\n");
return EXIT_SUCCESS;
}
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(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);
}
}
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);
}
