n_pair_t
fchain2_preinv(mp_limb_t m, mp_limb_t n, mp_limb_t ninv)
{
n_pair_t current = {0, 0}, old;
int length;
mp_limb_t power, xy;
old.x = 2UL;
old.y = n - 3UL;
length = FLINT_BIT_COUNT(m);
power = (1UL << (length - 1));
for (; length > 0; length--)
{
xy = n_mulmod2_preinv(old.x, old.y, n, ninv);
xy = n_addmod(xy, 3UL, n);
if (m & power)
{
current.y =
n_submod(n_mulmod2_preinv(old.y, old.y, n, ninv), 2UL, n);
current.x = xy;
}
else
{
current.x =
n_submod(n_mulmod2_preinv(old.x, old.x, n, ninv), 2UL, n);
current.y = xy;
}
power >>= 1;
old = current;
}
return current;
}
void
elem_sub(elem_ptr res, elem_srcptr op1, elem_srcptr op2, const ring_t ring)
{
switch (ring->type)
{
case TYPE_FMPZ:
fmpz_sub(res, op1, op2);
break;
case TYPE_LIMB:
*((mp_ptr) res) = *((mp_srcptr) op1) - *((mp_srcptr) op2);
break;
case TYPE_POLY:
elem_poly_sub(res, op1, op2, ring);
break;
case TYPE_MOD:
{
switch (RING_PARENT(ring)->type)
{
case TYPE_LIMB:
*((mp_ptr) res) = n_submod(*((mp_srcptr) op1), *((mp_srcptr) op2), ring->nmod.n);
break;
case TYPE_FMPZ:
fmpz_sub(res, op1, op2);
if (fmpz_sgn(res) < 0)
fmpz_add(res, res, RING_MODULUS(ring));
break;
default:
NOT_IMPLEMENTED("sub (mod)", ring);
}
}
break;
case TYPE_FRAC:
elem_frac_sub(res, op1, op2, ring);
break;
case TYPE_COMPLEX:
elem_sub(REALPART(res, ring), REALPART(op1, ring), REALPART(op2, ring), ring->parent);
elem_sub(IMAGPART(res, ring), IMAGPART(op1, ring), IMAGPART(op2, ring), ring->parent);
break;
default:
NOT_IMPLEMENTED("sub", ring);
}
}
int main(void)
{
int i, result;
flint_rand_t state;
printf("submod....");
fflush(stdout);
flint_randinit(state);
for (i = 0; i < 1000000; i++)
{
mp_limb_t a, b, d, r1, r2, s1;
d = n_randtest(state);
a = n_randint(state, d);
b = n_randint(state, d);
r1 = n_submod(a, b, d);
add_ssaaaa(s1, r2, 0UL, a, 0UL, d);
sub_ddmmss(s1, r2, s1, r2, 0UL, b);
if ((s1) || (r2 >= d)) r2 -= d;
result = (r1 == r2);
if (!result)
{
printf("FAIL:\n");
printf("a = %lu, b = %lu, d = %lu\n", a, b, d);
printf("r1 = %lu, r2 = %lu\n", r1, r2);
abort();
}
}
flint_randclear(state);
printf("PASS\n");
return 0;
}
void _nmod_poly_divrem_q1(mp_ptr Q, mp_ptr R,
mp_srcptr A, long lenA, mp_srcptr B, long lenB,
nmod_t mod)
{
const mp_limb_t invL = (B[lenB-1] == 1) ? 1 : n_invmod(B[lenB-1], mod.n);
if (lenB == 1)
{
_nmod_vec_scalar_mul_nmod(Q, A, lenA, invL, mod);
}
else
{
mp_limb_t t;
Q[1] = n_mulmod2_preinv(A[lenA-1], invL, mod.n, mod.ninv);
t = n_mulmod2_preinv(Q[1], B[lenB-2], mod.n, mod.ninv);
t = n_submod(A[lenA-2], t, mod.n);
Q[0] = n_mulmod2_preinv(t, invL, mod.n, mod.ninv);
if (FLINT_BITS + 2 <= 2 * mod.norm)
{
mpn_mul_1(R, B, lenB - 1, Q[0]);
if (lenB > 2)
mpn_addmul_1(R + 1, B, lenB - 2, Q[1]);
_nmod_vec_reduce(R, R, lenB - 1, mod);
}
else
{
_nmod_vec_scalar_mul_nmod(R, B, lenB - 1, Q[0], mod);
if (lenB > 2)
_nmod_vec_scalar_addmul_nmod(R + 1, B, lenB - 2, Q[1], mod);
}
_nmod_vec_sub(R, A, R, lenB - 1, mod);
}
}
