mp_limb_t n_primitive_root_prime_prefactor(mp_limb_t p, n_factor_t * factors)
{
slong i;
int found;
mp_limb_t result, a, pm1;
double pinv;
if (p == 2)
{
return 1;
}
pm1 = p - 1;
pinv = n_precompute_inverse(p);
for (a = 2; a < p; a++)
{
found = 1;
for (i = 0; i < factors->num; i++)
{
result = n_powmod_precomp(a, pm1 / factors->p[i], p, pinv);
if (result == 1)
{
found = 0;
break;
}
}
if (found)
{
return a;
}
}
flint_printf("Exception (n_primitive_root_prime_prefactor). root not found.\n");
abort();
}
int main(void)
{
int i, result;
flint_rand_t state;
printf("powmod_precomp....");
fflush(stdout);
flint_randinit(state);
for (i = 0; i < 100000; i++)
{
mp_limb_t a, d, r1, r2, bits;
mpz_t a_m, d_m, r2_m;
mp_limb_signed_t exp;
double dpre;
mpz_init(a_m);
mpz_init(d_m);
mpz_init(r2_m);
bits = n_randint(state, FLINT_D_BITS) + 1;
d = n_randbits(state, bits);
do
{
a = n_randint(state, d);
} while (n_gcd(d, a) != 1UL);
exp = n_randtest(state);
dpre = n_precompute_inverse(d);
r1 = n_powmod_precomp(a, exp, d, dpre);
mpz_set_ui(a_m, a);
mpz_set_ui(d_m, d);
if (exp < 0L)
{
mpz_powm_ui(r2_m, a_m, -exp, d_m);
mpz_invert(r2_m, r2_m, d_m);
} else
mpz_powm_ui(r2_m, a_m, exp, d_m);
r2 = mpz_get_ui(r2_m);
result = (r1 == r2);
if (!result)
{
printf("FAIL:\n");
printf("a = %lu, exp = %ld, d = %lu\n", a, exp, d);
printf("r1 = %lu, r2 = %lu\n", r1, r2);
abort();
}
mpz_clear(a_m);
mpz_clear(d_m);
mpz_clear(r2_m);
}
flint_randclear(state);
printf("PASS\n");
return 0;
}
