void
nmod_poly_mat_det(nmod_poly_t det, const nmod_poly_mat_t A)
{
slong n = A->r;
if (n == 0)
{
nmod_poly_one(det);
}
else if (n == 1)
{
nmod_poly_set(det, nmod_poly_mat_entry(A, 0, 0));
}
else if (n == 2)
{
nmod_poly_t tmp;
nmod_poly_init(tmp, nmod_poly_mat_modulus(A));
nmod_poly_mul(det, nmod_poly_mat_entry(A, 0, 0),
nmod_poly_mat_entry(A, 1, 1));
nmod_poly_mul(tmp, nmod_poly_mat_entry(A, 0, 1),
nmod_poly_mat_entry(A, 1, 0));
nmod_poly_sub(det, det, tmp);
nmod_poly_clear(tmp);
}
else if (n < 15) /* should be entry sensitive too */
{
nmod_poly_mat_det_fflu(det, A);
}
else
{
nmod_poly_mat_det_interpolate(det, A);
}
}
void nmod_poly_factor_set(nmod_poly_factor_t res, const nmod_poly_factor_t fac)
{
if (res != fac)
{
if (fac->num == 0)
{
nmod_poly_factor_clear(res);
nmod_poly_factor_init(res);
}
else
{
slong i;
nmod_poly_factor_fit_length(res, fac->num);
for (i = 0; i < fac->num; i++)
{
nmod_poly_set(res->p + i, fac->p + i);
(res->p + i)->mod = (fac->p + i)->mod;
res->exp[i] = fac->exp[i];
}
for ( ; i < res->num; i++)
{
nmod_poly_zero(res->p + i);
res->exp[i] = 0;
}
res->num = fac->num;
}
}
}
void nmod_poly_divrem_newton(nmod_poly_t Q, nmod_poly_t R,
const nmod_poly_t A, const nmod_poly_t B)
{
const long lenA = A->length, lenB = B->length;
mp_ptr q, r;
if (lenB == 0)
{
printf("Exception: division by zero in nmod_poly_divrem_newton\n");
abort();
}
if (lenA < lenB)
{
nmod_poly_set(R, A);
nmod_poly_zero(Q);
return;
}
if (Q == A || Q == B)
{
q = _nmod_vec_init(lenA - lenB + 1);
}
else
{
nmod_poly_fit_length(Q, lenA - lenB + 1);
q = Q->coeffs;
}
if (R == A || R == B)
{
r = _nmod_vec_init(lenB - 1);
}
else
{
nmod_poly_fit_length(R, lenB - 1);
r = R->coeffs;
}
_nmod_poly_divrem_newton(q, r, A->coeffs, lenA,
B->coeffs, lenB, B->mod);
if (Q == A || Q == B)
{
_nmod_vec_clear(Q->coeffs);
Q->coeffs = q;
Q->alloc = lenA - lenB + 1;
}
if (R == A || R == B)
{
_nmod_vec_clear(R->coeffs);
R->coeffs = r;
R->alloc = lenB - 1;
}
Q->length = lenA - lenB + 1;
R->length = lenB - 1;
_nmod_poly_normalise(R);
}
void
nmod_poly_taylor_shift_convolution(nmod_poly_t g, const nmod_poly_t f,
mp_limb_t c)
{
if (f != g)
nmod_poly_set(g, f);
_nmod_poly_taylor_shift_convolution(g->coeffs, c, g->length, g->mod);
}
void
nmod_poly_mat_set(nmod_poly_mat_t B, const nmod_poly_mat_t A)
{
if (A != B)
{
long i, j;
for (i = 0; i < A->r; i++)
for (j = 0; j < A->c; j++)
nmod_poly_set(nmod_poly_mat_entry(B, i, j),
nmod_poly_mat_entry(A, i, j));
}
}
void
nmod_poly_pow(nmod_poly_t res, const nmod_poly_t poly, ulong e)
{
const slong len = poly->length;
slong rlen;
if ((len < 2) | (e < UWORD(3)))
{
if (len == 0)
nmod_poly_zero(res);
else if (len == 1)
{
nmod_poly_fit_length(res, 1);
res->coeffs[0] = n_powmod2_ui_preinv(poly->coeffs[0], e,
poly->mod.n, poly->mod.ninv);
res->length = 1;
_nmod_poly_normalise(res);
}
else if (e == UWORD(0))
{
nmod_poly_set_coeff_ui(res, 0, UWORD(1));
res->length = 1;
_nmod_poly_normalise(res);
}
else if (e == UWORD(1))
nmod_poly_set(res, poly);
else /* e == UWORD(2) */
nmod_poly_mul(res, poly, poly);
return;
}
rlen = (slong) e * (len - 1) + 1;
if (res != poly)
{
nmod_poly_fit_length(res, rlen);
_nmod_poly_pow(res->coeffs, poly->coeffs, len, e, poly->mod);
}
else
{
nmod_poly_t t;
nmod_poly_init2(t, poly->mod.n, rlen);
_nmod_poly_pow(t->coeffs, poly->coeffs, len, e, poly->mod);
nmod_poly_swap(res, t);
nmod_poly_clear(t);
}
res->length = rlen;
_nmod_poly_normalise(res);
}
void
nmod_poly_rem_basecase(nmod_poly_t R, const nmod_poly_t A, const nmod_poly_t B)
{
const long lenA = A->length, lenB = B->length;
mp_ptr r, W;
nmod_poly_t t;
if (lenB == 0)
{
printf("Exception: division by zero in nmod_poly_rem_basecase\n");
abort();
}
if (lenA < lenB)
{
nmod_poly_set(R, A);
return;
}
if (R == A || R == B)
{
nmod_poly_init2_preinv(t, B->mod.n, B->mod.ninv, lenB - 1);
r = t->coeffs;
}
else
{
nmod_poly_fit_length(R, lenB - 1);
r = R->coeffs;
}
W = _nmod_vec_init(NMOD_DIVREM_BC_ITCH(lenA, lenB, A->mod));
_nmod_poly_rem_basecase(r, W, A->coeffs, lenA,
B->coeffs, lenB, B->mod);
if (R == A || R == B)
{
nmod_poly_swap(R, t);
nmod_poly_clear(t);
}
R->length = lenB - 1;
_nmod_vec_clear(W);
_nmod_poly_normalise(R);
}
long
nmod_poly_mat_nullspace(nmod_poly_mat_t res, const nmod_poly_mat_t mat)
{
long i, j, k, m, n, rank, nullity;
long * pivots;
long * nonpivots;
nmod_poly_mat_t tmp;
nmod_poly_t den;
m = mat->r;
n = mat->c;
nmod_poly_init(den, nmod_poly_mat_modulus(mat));
nmod_poly_mat_init_set(tmp, mat);
rank = nmod_poly_mat_rref(tmp, den, NULL, tmp);
nullity = n - rank;
nmod_poly_mat_zero(res);
if (rank == 0)
{
for (i = 0; i < nullity; i++)
nmod_poly_one(res->rows[i] + i);
}
else if (nullity)
{
pivots = flint_malloc(rank * sizeof(long));
nonpivots = flint_malloc(nullity * sizeof(long));
for (i = j = k = 0; i < rank; i++)
{
while (nmod_poly_is_zero(tmp->rows[i] + j))
{
nonpivots[k] = j;
k++;
j++;
}
pivots[i] = j;
j++;
}
while (k < nullity)
{
nonpivots[k] = j;
k++;
j++;
}
nmod_poly_set(den, tmp->rows[0] + pivots[0]);
for (i = 0; i < nullity; i++)
{
for (j = 0; j < rank; j++)
nmod_poly_set(res->rows[pivots[j]] + i,
tmp->rows[j] + nonpivots[i]);
nmod_poly_neg(res->rows[nonpivots[i]] + i, den);
}
flint_free(pivots);
flint_free(nonpivots);
}
nmod_poly_clear(den);
nmod_poly_mat_clear(tmp);
return nullity;
}
void
nmod_poly_divrem_basecase(nmod_poly_t Q, nmod_poly_t R, const nmod_poly_t A,
const nmod_poly_t B)
{
const slong lenA = A->length, lenB = B->length;
mp_ptr Q_coeffs, R_coeffs, W;
nmod_poly_t t1, t2;
TMP_INIT;
if (lenB == 0)
{
flint_printf("Exception (nmod_poly_divrem). Division by zero.\n");
abort();
}
if (lenA < lenB)
{
nmod_poly_set(R, A);
nmod_poly_zero(Q);
return;
}
if (Q == A || Q == B)
{
nmod_poly_init2_preinv(t1, B->mod.n, B->mod.ninv, lenA - lenB + 1);
Q_coeffs = t1->coeffs;
}
else
{
nmod_poly_fit_length(Q, lenA - lenB + 1);
Q_coeffs = Q->coeffs;
}
if (R == A || R == B)
{
nmod_poly_init2_preinv(t2, B->mod.n, B->mod.ninv, lenB - 1);
R_coeffs = t2->coeffs;
}
else
{
nmod_poly_fit_length(R, lenB - 1);
R_coeffs = R->coeffs;
}
TMP_START;
W = TMP_ALLOC(NMOD_DIVREM_BC_ITCH(lenA, lenB, A->mod)*sizeof(mp_limb_t));
_nmod_poly_divrem_basecase(Q_coeffs, R_coeffs, W, A->coeffs, lenA,
B->coeffs, lenB, B->mod);
if (Q == A || Q == B)
{
nmod_poly_swap(Q, t1);
nmod_poly_clear(t1);
}
if (R == A || R == B)
{
nmod_poly_swap(R, t2);
nmod_poly_clear(t2);
}
Q->length = lenA - lenB + 1;
R->length = lenB - 1;
TMP_END;
_nmod_poly_normalise(R);
}
int
main(void)
{
int i, result;
flint_rand_t state;
flint_randinit(state);
printf("shift_left_right....");
fflush(stdout);
/* Check a << shift >> shift == a */
for (i = 0; i < 10000; i++)
{
nmod_poly_t a, b;
mp_limb_t n = n_randtest_not_zero(state);
long shift = n_randint(state, 100);
nmod_poly_init(a, n);
nmod_poly_init(b, n);
nmod_poly_randtest(a, state, n_randint(state, 100));
nmod_poly_shift_left(b, a, shift);
nmod_poly_shift_right(b, b, shift);
result = (nmod_poly_equal(a, b));
if (!result)
{
printf("FAIL:\n");
printf("shift = %ld, a->length = %ld, n = %lu\n",
shift, a->length, a->mod.n);
nmod_poly_print(a), printf("\n\n");
nmod_poly_print(b), printf("\n\n");
abort();
}
nmod_poly_clear(a);
nmod_poly_clear(b);
}
/* Check a << shift >> shift == a aliasing the other way */
for (i = 0; i < 10000; i++)
{
nmod_poly_t a, b, c;
mp_limb_t n = n_randtest_not_zero(state);
long shift = n_randint(state, 100);
nmod_poly_init(a, n);
nmod_poly_init(b, n);
nmod_poly_init(c, n);
nmod_poly_randtest(c, state, n_randint(state, 100));
nmod_poly_set(a, c);
nmod_poly_shift_left(c, c, shift);
nmod_poly_shift_right(b, c, shift);
result = (nmod_poly_equal(a, b));
if (!result)
{
printf("FAIL:\n");
printf("shift = %ld, c->length = %ld, n = %lu\n",
shift, c->length, a->mod.n);
nmod_poly_print(a), printf("\n\n");
nmod_poly_print(b), printf("\n\n");
abort();
}
nmod_poly_clear(a);
nmod_poly_clear(b);
nmod_poly_clear(c);
}
flint_randclear(state);
printf("PASS\n");
return 0;
}
void
nmod_poly_factor_squarefree(nmod_poly_factor_t res, const nmod_poly_t f)
{
nmod_poly_t f_d, g, g_1;
mp_limb_t p;
slong deg, i;
if (f->length <= 1)
{
res->num = 0;
return;
}
if (f->length == 2)
{
nmod_poly_factor_insert(res, f, 1);
return;
}
p = nmod_poly_modulus(f);
deg = nmod_poly_degree(f);
/* Step 1, look at f', if it is zero then we are done since f = h(x)^p
for some particular h(x), clearly f(x) = sum a_k x^kp, k <= deg(f) */
nmod_poly_init(g_1, p);
nmod_poly_init(f_d, p);
nmod_poly_init(g, p);
nmod_poly_derivative(f_d, f);
/* Case 1 */
if (nmod_poly_is_zero(f_d))
{
nmod_poly_factor_t new_res;
nmod_poly_t h;
nmod_poly_init(h, p);
for (i = 0; i <= deg / p; i++) /* this will be an integer since f'=0 */
{
nmod_poly_set_coeff_ui(h, i, nmod_poly_get_coeff_ui(f, i * p));
}
/* Now run square-free on h, and return it to the pth power */
nmod_poly_factor_init(new_res);
nmod_poly_factor_squarefree(new_res, h);
nmod_poly_factor_pow(new_res, p);
nmod_poly_factor_concat(res, new_res);
nmod_poly_clear(h);
nmod_poly_factor_clear(new_res);
}
else
{
nmod_poly_t h, z;
nmod_poly_gcd(g, f, f_d);
nmod_poly_div(g_1, f, g);
i = 1;
nmod_poly_init(h, p);
nmod_poly_init(z, p);
/* Case 2 */
while (!nmod_poly_is_one(g_1))
{
nmod_poly_gcd(h, g_1, g);
nmod_poly_div(z, g_1, h);
/* out <- out.z */
if (z->length > 1)
{
nmod_poly_factor_insert(res, z, 1);
nmod_poly_make_monic(res->p + (res->num - 1),
res->p + (res->num - 1));
if (res->num)
res->exp[res->num - 1] *= i;
}
i++;
nmod_poly_set(g_1, h);
nmod_poly_div(g, g, h);
}
nmod_poly_clear(h);
nmod_poly_clear(z);
nmod_poly_make_monic(g, g);
if (!nmod_poly_is_one(g))
{
/* so now we multiply res with square-free(g^1/p) ^ p */
nmod_poly_t g_p; /* g^(1/p) */
nmod_poly_factor_t new_res_2;
nmod_poly_init(g_p, p);
for (i = 0; i <= nmod_poly_degree(g) / p; i++)
nmod_poly_set_coeff_ui(g_p, i, nmod_poly_get_coeff_ui(g, i*p));
nmod_poly_factor_init(new_res_2);
/* square-free(g^(1/p)) */
nmod_poly_factor_squarefree(new_res_2, g_p);
nmod_poly_factor_pow(new_res_2, p);
nmod_poly_factor_concat(res, new_res_2);
nmod_poly_clear(g_p);
nmod_poly_factor_clear(new_res_2);
}
}
nmod_poly_clear(g_1);
nmod_poly_clear(f_d);
nmod_poly_clear(g);
}
void
nmod_poly_compose_mod_horner(nmod_poly_t res,
const nmod_poly_t poly1, const nmod_poly_t poly2,
const nmod_poly_t poly3)
{
long len1 = poly1->length;
long len2 = poly2->length;
long len3 = poly3->length;
long len = len3 - 1;
mp_ptr ptr2;
if (len3 == 0)
{
printf("exception: division by zero in nmod_poly_compose_mod_horner\n");
abort();
}
if (len1 == 0 || len3 == 1)
{
nmod_poly_zero(res);
return;
}
if (len1 == 1)
{
nmod_poly_set(res, poly1);
return;
}
if (res == poly3 || res == poly1)
{
nmod_poly_t tmp;
nmod_poly_init_preinv(tmp, res->mod.n, res->mod.ninv);
nmod_poly_compose_mod_horner(tmp, poly1, poly2, poly3);
nmod_poly_swap(tmp, res);
nmod_poly_clear(tmp);
return;
}
ptr2 = _nmod_vec_init(len);
if (len2 <= len)
{
mpn_copyi(ptr2, poly2->coeffs, len2);
mpn_zero(ptr2 + len2, len - len2);
}
else
{
_nmod_poly_rem(ptr2, poly2->coeffs, len2,
poly3->coeffs, len3, res->mod);
}
nmod_poly_fit_length(res, len);
_nmod_poly_compose_mod_horner(res->coeffs,
poly1->coeffs, len1, ptr2, poly3->coeffs, len3, res->mod);
res->length = len;
_nmod_poly_normalise(res);
_nmod_vec_clear(ptr2);
}
void pq_nmod_elt_set_mono(pq_nmod_elt_t x, const nmod_poly_t val) {
nmod_poly_set(x->mono, val);
nmod_poly_zero(x->dual);
}
void _pq_nmod_elt_set_dual(pq_nmod_elt_t x, const nmod_poly_t val) {
nmod_poly_zero(x->mono);
nmod_poly_set(x->dual, val);
}
void pq_nmod_elt_set(pq_nmod_elt_t x, const pq_nmod_elt_t y) {
nmod_poly_set(x->mono, y->mono);
nmod_poly_set(x->dual, y->dual);
}
slong
nmod_poly_mat_rref(nmod_poly_mat_t R, nmod_poly_t den, const nmod_poly_mat_t A)
{
slong i, j, k, m, n, rank;
slong *pivots, *nonpivots;
rank = nmod_poly_mat_fflu(R, den, NULL, A, 0);
m = nmod_poly_mat_nrows(R);
n = nmod_poly_mat_ncols(R);
/* clear bottom */
for (i = rank; i < m; i++)
for (j = 0; j < n; j++)
nmod_poly_zero(nmod_poly_mat_entry(R, i, j));
/* Convert row echelon form to reduced row echelon form */
if (rank > 1)
{
nmod_poly_t tmp, tmp2;
nmod_poly_init(tmp, nmod_poly_mat_modulus(R));
nmod_poly_init(tmp2, nmod_poly_mat_modulus(R));
pivots = flint_malloc(sizeof(slong) * n);
nonpivots = pivots + rank;
/* find pivot positions */
for (i = j = k = 0; i < rank; i++)
{
while (nmod_poly_is_zero(nmod_poly_mat_entry(R, i, j)))
{
nonpivots[k] = j;
k++;
j++;
}
pivots[i] = j;
j++;
}
while (k < n - rank)
{
nonpivots[k] = j;
k++;
j++;
}
for (k = 0; k < n - rank; k++)
{
for (i = rank - 2; i >= 0; i--)
{
nmod_poly_mul(tmp, den, nmod_poly_mat_entry(R, i, nonpivots[k]));
for (j = i + 1; j < rank; j++)
{
nmod_poly_mul(tmp2, nmod_poly_mat_entry(R, i, pivots[j]),
nmod_poly_mat_entry(R, j, nonpivots[k]));
nmod_poly_sub(tmp, tmp, tmp2);
}
nmod_poly_div(nmod_poly_mat_entry(R, i, nonpivots[k]),
tmp, nmod_poly_mat_entry(R, i, pivots[i]));
}
}
/* clear pivot columns */
for (i = 0; i < rank; i++)
{
for (j = 0; j < rank; j++)
{
if (i == j)
nmod_poly_set(nmod_poly_mat_entry(R, j, pivots[i]), den);
else
nmod_poly_zero(nmod_poly_mat_entry(R, j, pivots[i]));
}
}
flint_free(pivots);
nmod_poly_clear(tmp);
nmod_poly_clear(tmp2);
}
return rank;
}
int
nmod_poly_mat_inv(nmod_poly_mat_t Ainv, nmod_poly_t den,
const nmod_poly_mat_t A)
{
slong n = nmod_poly_mat_nrows(A);
if (n == 0)
{
nmod_poly_one(den);
return 1;
}
else if (n == 1)
{
nmod_poly_set(den, E(A, 0, 0));
nmod_poly_one(E(Ainv, 0, 0));
return !nmod_poly_is_zero(den);
}
else if (n == 2)
{
nmod_poly_mat_det(den, A);
if (nmod_poly_is_zero(den))
{
return 0;
}
else if (Ainv == A)
{
nmod_poly_swap(E(A, 0, 0), E(A, 1, 1));
nmod_poly_neg(E(A, 0, 1), E(A, 0, 1));
nmod_poly_neg(E(A, 1, 0), E(A, 1, 0));
return 1;
}
else
{
nmod_poly_set(E(Ainv, 0, 0), E(A, 1, 1));
nmod_poly_set(E(Ainv, 1, 1), E(A, 0, 0));
nmod_poly_neg(E(Ainv, 0, 1), E(A, 0, 1));
nmod_poly_neg(E(Ainv, 1, 0), E(A, 1, 0));
return 1;
}
}
else
{
nmod_poly_mat_t LU, I;
slong * perm;
int result;
perm = _perm_init(n);
nmod_poly_mat_init_set(LU, A);
result = (nmod_poly_mat_fflu(LU, den, perm, LU, 1) == n);
if (result)
{
nmod_poly_mat_init(I, n, n, nmod_poly_mat_modulus(A));
nmod_poly_mat_one(I);
nmod_poly_mat_solve_fflu_precomp(Ainv, perm, LU, I);
nmod_poly_mat_clear(I);
}
else
nmod_poly_zero(den);
if (_perm_parity(perm, n))
{
nmod_poly_mat_neg(Ainv, Ainv);
nmod_poly_neg(den, den);
}
_perm_clear(perm);
nmod_poly_mat_clear(LU);
return result;
}
}
void
nmod_poly_compose_mod_brent_kung(nmod_poly_t res,
const nmod_poly_t poly1, const nmod_poly_t poly2,
const nmod_poly_t poly3)
{
long len1 = poly1->length;
long len2 = poly2->length;
long len3 = poly3->length;
long len = len3 - 1;
mp_ptr ptr2;
if (len3 == 0)
{
printf("exception: division by zero in "
"nmod_poly_compose_mod_brent_kung\n");
abort();
}
if (len1 >= len3)
{
printf("exception: nmod_poly_compose_brent_kung: the degree of the"
" first polynomial must be smaller than that of the modulus\n");
abort();
}
if (len1 == 0 || len3 == 1)
{
nmod_poly_zero(res);
return;
}
if (len1 == 1)
{
nmod_poly_set(res, poly1);
return;
}
if (res == poly3 || res == poly1)
{
nmod_poly_t tmp;
nmod_poly_init_preinv(tmp, res->mod.n, res->mod.ninv);
nmod_poly_compose_mod_brent_kung(tmp, poly1, poly2, poly3);
nmod_poly_swap(tmp, res);
nmod_poly_clear(tmp);
return;
}
ptr2 = _nmod_vec_init(len);
if (len2 <= len)
{
mpn_copyi(ptr2, poly2->coeffs, len2);
mpn_zero(ptr2 + len2, len - len2);
}
else
{
_nmod_poly_rem(ptr2, poly2->coeffs, len2,
poly3->coeffs, len3, res->mod);
}
nmod_poly_fit_length(res, len);
_nmod_poly_compose_mod_brent_kung(res->coeffs,
poly1->coeffs, len1, ptr2, poly3->coeffs, len3, res->mod);
res->length = len;
_nmod_poly_normalise(res);
_nmod_vec_clear(ptr2);
}
