void
fmprb_sqrt(fmprb_t z, const fmprb_t x, slong prec)
{
slong r;
if (fmprb_contains_negative(x))
{
fmpr_nan(fmprb_midref(z));
fmpr_pos_inf(fmprb_radref(z));
return;
}
if (fmprb_is_exact(x))
{
r = fmpr_sqrt(fmprb_midref(z), fmprb_midref(x), prec, FMPR_RND_DOWN);
fmpr_set_error_result(fmprb_radref(z), fmprb_midref(z), r);
}
else
{
fmpr_t err;
fmpr_init(err);
fmpr_sub(err, fmprb_midref(x), fmprb_radref(x), FMPRB_RAD_PREC, FMPR_RND_DOWN);
fmpr_rsqrt(err, err, FMPRB_RAD_PREC, FMPR_RND_UP);
fmpr_mul(err, fmprb_radref(x), err, FMPRB_RAD_PREC, FMPR_RND_UP);
fmpr_mul_2exp_si(err, err, -1);
r = fmpr_sqrt(fmprb_midref(z), fmprb_midref(x), prec, FMPR_RND_DOWN);
fmpr_add_error_result(fmprb_radref(z), err, fmprb_midref(z), r,
FMPRB_RAD_PREC, FMPR_RND_UP);
fmpr_clear(err);
}
fmprb_adjust(z);
}
int main()
{
long iter;
flint_rand_t state;
printf("rsqrt....");
fflush(stdout);
flint_randinit(state);
for (iter = 0; iter < 100000; iter++)
{
long bits, res;
fmpr_t x, z, w;
mpfr_t X, Z;
bits = 2 + n_randint(state, 200);
fmpr_init(x);
fmpr_init(z);
fmpr_init(w);
mpfr_init2(X, 2 * (bits + 100));
mpfr_init2(Z, bits);
fmpr_randtest_special(x, state, bits + n_randint(state, 100), 10);
fmpr_randtest_special(z, state, bits + n_randint(state, 100), 10);
fmpr_get_mpfr(X, x, MPFR_RNDN);
switch (n_randint(state, 4))
{
case 0:
mpfr_rec_sqrt(Z, X, MPFR_RNDZ);
res = fmpr_rsqrt(z, x, bits, FMPR_RND_DOWN);
break;
case 1:
mpfr_rec_sqrt(Z, X, MPFR_RNDA);
res = fmpr_rsqrt(z, x, bits, FMPR_RND_UP);
break;
case 2:
mpfr_rec_sqrt(Z, X, MPFR_RNDD);
res = fmpr_rsqrt(z, x, bits, FMPR_RND_FLOOR);
break;
default:
mpfr_rec_sqrt(Z, X, MPFR_RNDU);
res = fmpr_rsqrt(z, x, bits, FMPR_RND_CEIL);
break;
}
fmpr_set_mpfr(w, Z);
if (!fmpr_equal(z, w) || !fmpr_check_ulp(z, res, bits))
{
printf("FAIL\n\n");
printf("bits = %ld\n", bits);
printf("x = "); fmpr_print(x); printf("\n\n");
printf("z = "); fmpr_print(z); printf("\n\n");
printf("w = "); fmpr_print(w); printf("\n\n");
abort();
}
fmpr_clear(x);
fmpr_clear(z);
fmpr_clear(w);
mpfr_clear(X);
mpfr_clear(Z);
}
flint_randclear(state);
flint_cleanup();
printf("PASS\n");
return EXIT_SUCCESS;
}
