void fmpz_poly_q_canonicalise(fmpz_poly_q_t rop)
{
fmpz_poly_t gcd;
if (fmpz_poly_is_zero(rop->den))
{
flint_printf("Exception (fmpz_poly_q_canonicalise). Denominator is zero.\n");
abort();
}
if (fmpz_poly_is_one(rop->den))
return;
fmpz_poly_init(gcd);
fmpz_poly_gcd(gcd, rop->num, rop->den);
if (!fmpz_poly_is_unit(gcd))
{
fmpz_poly_div(rop->num, rop->num, gcd);
fmpz_poly_div(rop->den, rop->den, gcd);
}
fmpz_poly_clear(gcd);
if (fmpz_sgn(fmpz_poly_lead(rop->den)) < 0)
{
fmpz_poly_neg(rop->num, rop->num);
fmpz_poly_neg(rop->den, rop->den);
}
}
void dgsl_rot_mp_clear(dgsl_rot_mp_t *self) {
if (!self)
return;
fmpz_poly_clear(self->c_z);
fmpq_poly_clear(self->c);
if (!fmpz_poly_is_zero(self->B))
fmpz_poly_clear(self->B);
if (!fmpq_poly_is_zero(self->B_inv))
fmpq_poly_clear(self->B_inv);
if(self->call == dgsl_rot_mp_call_identity) {
if(self->D) {
dgs_disc_gauss_mp_clear(self->D[0]);
free(self->D);
}
}
if(self->call == dgsl_rot_mp_call_gpv_inlattice) {
}
if(self->call == dgsl_rot_mp_call_inlattice) {
mpfr_clear(self->r_f);
fmpq_poly_clear(self->sigma_sqrt);
}
mpfr_clear(self->sigma);
free(self);
}
void
fmpz_poly_randtest_not_zero(fmpz_poly_t f, flint_rand_t state,
long len, mp_bitcnt_t bits)
{
if ((bits == 0) || (len == 0))
{
printf("Exception: 0 passed to fmpz_poly_randtest_not_zero\n");
abort();
}
fmpz_poly_randtest(f, state, len, bits);
if (fmpz_poly_is_zero(f))
fmpz_poly_set_ui(f, 1);
}
long
fmpz_poly_mat_find_pivot_any(const fmpz_poly_mat_t mat,
long start_row, long end_row, long c)
{
long r;
for (r = start_row; r < end_row; r++)
{
if (!fmpz_poly_is_zero(fmpz_poly_mat_entry(mat, r, c)))
return r;
}
return -1;
}
static
long fmpz_poly_mat_ord_p(const fmpz_poly_mat_t A, const fmpz_t p)
{
long i, j, v, w = LONG_MAX;
for (i = 0; i < A->r; i++)
for (j = 0; j < A->c; j++)
{
const fmpz_poly_struct *poly = fmpz_poly_mat_entry(A, i, j);
if (!fmpz_poly_is_zero(poly))
{
v = _fmpz_vec_ord_p(poly->coeffs, poly->length, p);
w = FLINT_MIN(v, w);
if (w == 0)
return 0;
}
}
return w;
}
static
void fmpz_poly_evaluate_qadic(qadic_t rop,
const fmpz_poly_t op1, const qadic_t op2, const qadic_ctx_t ctx)
{
const long N = qadic_prec(rop);
const long d = qadic_ctx_degree(ctx);
if (N <= 0 || op2->val != 0 || rop == op2)
{
printf("Exception (fmpz_poly_evaluate_qadic):\n");
printf("Currently assumes that N > 0 and op2->val == 0, \n");
printf("and does not support aliasing.\n");
abort();
}
if (fmpz_poly_is_zero(op1))
{
qadic_zero(rop);
}
else if (qadic_is_zero(op2))
{
padic_poly_set_fmpz(rop, op1->coeffs + 0, &ctx->pctx);
}
else
{
fmpz_t pN;
fmpz_init(pN);
fmpz_pow_ui(pN, (&ctx->pctx)->p, N);
padic_poly_fit_length(rop, d);
_fmpz_mod_poly_compose_smod(rop->coeffs,
op1->coeffs, op1->length, op2->coeffs, op2->length,
ctx->a, ctx->j, ctx->len, pN);
_padic_poly_set_length(rop, d);
qadic_reduce(rop, ctx);
fmpz_clear(pN);
}
}
int
main(void)
{
int i, result;
flint_rand_t state;
printf("revert_series....");
fflush(stdout);
flint_randinit(state);
/* Check aliasing */
for (i = 0; i < 50; i++)
{
fmpz_poly_t f, g;
long n;
fmpz_poly_init(f);
fmpz_poly_init(g);
fmpz_poly_randtest(g, state, n_randint(state, 50),
1+n_randint(state,100));
fmpz_poly_set_coeff_ui(g, 0, 0);
fmpz_poly_set_coeff_ui(g, 1, 1);
if (n_randlimb(state) % 2)
fmpz_poly_neg(g, g); /* get -x term */
n = n_randint(state, 50);
fmpz_poly_revert_series(f, g, n);
fmpz_poly_revert_series(g, g, n);
result = (fmpz_poly_equal(f, g));
if (!result)
{
printf("FAIL (aliasing):\n");
fmpz_poly_print(f), printf("\n\n");
fmpz_poly_print(g), printf("\n\n");
abort();
}
fmpz_poly_clear(f);
fmpz_poly_clear(g);
}
/* Check f(f^(-1)) = id */
for (i = 0; i < 50; i++)
{
fmpz_poly_t f, g, h;
long n;
fmpz_poly_init(f);
fmpz_poly_init(g);
fmpz_poly_init(h);
fmpz_poly_randtest(g, state, n_randint(state, 50), 10);
fmpz_poly_set_coeff_ui(g, 0, 0);
fmpz_poly_set_coeff_ui(g, 1, 1);
if (n_randlimb(state) % 2)
fmpz_poly_neg(g, g); /* get -x term */
n = n_randint(state, 50);
fmpz_poly_revert_series(f, g, n);
fmpz_poly_compose_series(h, g, f, n);
result = ((n <= 1 && fmpz_poly_is_zero(h)) ||
(h->length == 2 && fmpz_is_zero(h->coeffs + 0) &&
fmpz_is_one(h->coeffs + 1)));
if (!result)
{
printf("FAIL (comparison):\n");
fmpz_poly_print(f), printf("\n\n");
fmpz_poly_print(g), printf("\n\n");
fmpz_poly_print(h), printf("\n\n");
abort();
}
fmpz_poly_clear(f);
fmpz_poly_clear(g);
fmpz_poly_clear(h);
}
flint_randclear(state);
_fmpz_cleanup();
printf("PASS\n");
return 0;
}
int
main(void)
{
int i, result;
FLINT_TEST_INIT(state);
flint_printf("revert_series_lagrange_fast....");
fflush(stdout);
/* Check aliasing */
for (i = 0; i < 10 * flint_test_multiplier(); i++)
{
fmpz_poly_t f, g;
slong n;
fmpz_poly_init(f);
fmpz_poly_init(g);
fmpz_poly_randtest(g, state, n_randint(state, 50),
1+n_randint(state,100));
fmpz_poly_set_coeff_ui(g, 0, 0);
fmpz_poly_set_coeff_ui(g, 1, 1);
if (n_randlimb(state) % 2)
fmpz_poly_neg(g, g); /* get -x term */
n = n_randint(state, 50);
fmpz_poly_revert_series_lagrange_fast(f, g, n);
fmpz_poly_revert_series_lagrange_fast(g, g, n);
result = (fmpz_poly_equal(f, g));
if (!result)
{
flint_printf("FAIL (aliasing):\n");
fmpz_poly_print(f), flint_printf("\n\n");
fmpz_poly_print(g), flint_printf("\n\n");
abort();
}
fmpz_poly_clear(f);
fmpz_poly_clear(g);
}
/* Check f(f^(-1)) = id */
for (i = 0; i < 10 * flint_test_multiplier(); i++)
{
fmpz_poly_t f, g, h;
slong n;
fmpz_poly_init(f);
fmpz_poly_init(g);
fmpz_poly_init(h);
fmpz_poly_randtest(g, state, n_randint(state, 50), 1+n_randint(state,100));
fmpz_poly_set_coeff_ui(g, 0, 0);
fmpz_poly_set_coeff_ui(g, 1, 1);
if (n_randlimb(state) % 2)
fmpz_poly_neg(g, g); /* get -x term */
n = n_randint(state, 50);
fmpz_poly_revert_series_lagrange_fast(f, g, n);
fmpz_poly_compose_series(h, g, f, n);
result = ((n <= 1 && fmpz_poly_is_zero(h)) ||
(h->length == 2 && fmpz_is_zero(h->coeffs + 0) &&
fmpz_is_one(h->coeffs + 1)));
if (!result)
{
flint_printf("FAIL (comparison):\n");
fmpz_poly_print(f), flint_printf("\n\n");
fmpz_poly_print(g), flint_printf("\n\n");
fmpz_poly_print(h), flint_printf("\n\n");
abort();
}
fmpz_poly_clear(f);
fmpz_poly_clear(g);
fmpz_poly_clear(h);
}
FLINT_TEST_CLEANUP(state);
flint_printf("PASS\n");
return 0;
}
int
fmpz_poly_mat_inv(fmpz_poly_mat_t Ainv, fmpz_poly_t den,
const fmpz_poly_mat_t A)
{
long n = fmpz_poly_mat_nrows(A);
if (n == 0)
{
fmpz_poly_one(den);
return 1;
}
else if (n == 1)
{
fmpz_poly_set(den, E(A, 0, 0));
fmpz_poly_one(E(Ainv, 0, 0));
return !fmpz_poly_is_zero(den);
}
else if (n == 2)
{
fmpz_poly_mat_det(den, A);
if (fmpz_poly_is_zero(den))
{
return 0;
}
else if (Ainv == A)
{
fmpz_poly_swap(E(A, 0, 0), E(A, 1, 1));
fmpz_poly_neg(E(A, 0, 1), E(A, 0, 1));
fmpz_poly_neg(E(A, 1, 0), E(A, 1, 0));
return 1;
}
else
{
fmpz_poly_set(E(Ainv, 0, 0), E(A, 1, 1));
fmpz_poly_set(E(Ainv, 1, 1), E(A, 0, 0));
fmpz_poly_neg(E(Ainv, 0, 1), E(A, 0, 1));
fmpz_poly_neg(E(Ainv, 1, 0), E(A, 1, 0));
return 1;
}
}
else
{
fmpz_poly_mat_t LU, I;
long * perm;
int result;
perm = _perm_init(n);
fmpz_poly_mat_init_set(LU, A);
result = (fmpz_poly_mat_fflu(LU, den, perm, LU, 1) == n);
if (result)
{
fmpz_poly_mat_init(I, n, n);
fmpz_poly_mat_one(I);
fmpz_poly_mat_solve_fflu_precomp(Ainv, perm, LU, I);
fmpz_poly_mat_clear(I);
}
else
fmpz_poly_zero(den);
if (_perm_parity(perm, n))
{
fmpz_poly_mat_neg(Ainv, Ainv);
fmpz_poly_neg(den, den);
}
_perm_clear(perm);
fmpz_poly_mat_clear(LU);
return result;
}
}
bool
poly_inverse_poly_p(fmpz_poly_t Fp,
const fmpz_poly_t a,
const ntru_params *params)
{
bool retval = false;
int k = 0,
j = 0;
fmpz *b_last;
fmpz_poly_t a_tmp,
b,
c,
f,
g;
/* general initialization of temp variables */
fmpz_poly_init(b);
fmpz_poly_set_coeff_ui(b, 0, 1);
fmpz_poly_init(c);
fmpz_poly_init(f);
fmpz_poly_set(f, a);
/* set g(x) = x^N − 1 */
fmpz_poly_init(g);
fmpz_poly_set_coeff_si(g, 0, -1);
fmpz_poly_set_coeff_si(g, params->N, 1);
/* avoid side effects */
fmpz_poly_init(a_tmp);
fmpz_poly_set(a_tmp, a);
fmpz_poly_zero(Fp);
while (1) {
while (fmpz_poly_get_coeff_ptr(f, 0) &&
fmpz_is_zero(fmpz_poly_get_coeff_ptr(f, 0))) {
for (uint32_t i = 1; i <= params->N; i++) {
fmpz *f_coeff = fmpz_poly_get_coeff_ptr(f, i);
fmpz *c_coeff = fmpz_poly_get_coeff_ptr(c, params->N - i);
/* f(x) = f(x) / x */
fmpz_poly_set_coeff_fmpz_n(f, i - 1,
f_coeff);
/* c(x) = c(x) * x */
fmpz_poly_set_coeff_fmpz_n(c, params->N + 1 - i,
c_coeff);
}
fmpz_poly_set_coeff_si(f, params->N, 0);
fmpz_poly_set_coeff_si(c, 0, 0);
k++;
if (fmpz_poly_degree(f) == -1)
goto cleanup;
}
if (fmpz_poly_is_zero(g) == 1)
goto cleanup;
if (fmpz_poly_degree(f) == 0)
break;
if (fmpz_poly_degree(f) < fmpz_poly_degree(g)) {
/* exchange f and g and exchange b and c */
fmpz_poly_swap(f, g);
fmpz_poly_swap(b, c);
}
{
fmpz_poly_t c_tmp,
g_tmp;
fmpz_t u,
mp_tmp;
fmpz_init(u);
fmpz_zero(u);
fmpz_init_set(mp_tmp, fmpz_poly_get_coeff_ptr(f, 0));
fmpz_poly_init(g_tmp);
fmpz_poly_set(g_tmp, g);
fmpz_poly_init(c_tmp);
fmpz_poly_set(c_tmp, c);
/* u = f[0] * g[0]^(-1) mod p */
/* = (f[0] mod p) * (g[0] inverse mod p) mod p */
fmpz_invmod_ui(u,
fmpz_poly_get_coeff_ptr(g, 0),
params->p);
fmpz_mod_ui(mp_tmp, mp_tmp, params->p);
fmpz_mul(u, mp_tmp, u);
fmpz_mod_ui(u, u, params->p);
/* f = f - u * g mod p */
fmpz_poly_scalar_mul_fmpz(g_tmp, g_tmp, u);
fmpz_poly_sub(f, f, g_tmp);
fmpz_poly_mod_unsigned(f, params->p);
/* b = b - u * c mod p */
fmpz_poly_scalar_mul_fmpz(c_tmp, c_tmp, u);
fmpz_poly_sub(b, b, c_tmp);
fmpz_poly_mod_unsigned(b, params->p);
fmpz_clear(u);
fmpz_poly_clear(g_tmp);
fmpz_poly_clear(c_tmp);
}
}
k = k % params->N;
b_last = fmpz_poly_get_coeff_ptr(b, params->N);
if (fmpz_cmp_si_n(b_last, 0))
goto cleanup;
/* Fp(x) = x^(N-k) * b(x) */
for (int i = params->N - 1; i >= 0; i--) {
fmpz *b_i;
/* b(X) = f[0]^(-1) * b(X) (mod p) */
{
fmpz_t mp_tmp;
fmpz_init(mp_tmp);
fmpz_invmod_ui(mp_tmp,
fmpz_poly_get_coeff_ptr(f, 0),
params->p);
if (fmpz_poly_get_coeff_ptr(b, i)) {
fmpz_mul(fmpz_poly_get_coeff_ptr(b, i),
fmpz_poly_get_coeff_ptr(b, i),
mp_tmp);
fmpz_mod_ui(fmpz_poly_get_coeff_ptr(b, i),
fmpz_poly_get_coeff_ptr(b, i),
params->p);
}
}
j = i - k;
if (j < 0)
j = j + params->N;
b_i = fmpz_poly_get_coeff_ptr(b, i);
fmpz_poly_set_coeff_fmpz_n(Fp, j, b_i);
}
/* check if the f * Fp = 1 (mod p) condition holds true */
fmpz_poly_set(a_tmp, a);
poly_starmultiply(a_tmp, a_tmp, Fp, params, params->p);
if (fmpz_poly_is_one(a_tmp))
retval = true;
else
fmpz_poly_zero(Fp);
cleanup:
fmpz_poly_clear(a_tmp);
fmpz_poly_clear(b);
fmpz_poly_clear(c);
fmpz_poly_clear(f);
fmpz_poly_clear(g);
return retval;
}
bool
poly_inverse_poly_q(fmpz_poly_t Fq,
const fmpz_poly_t a,
const ntru_params *params)
{
bool retval = false;
int k = 0,
j = 0;
fmpz *b_last;
fmpz_poly_t a_tmp,
b,
c,
f,
g;
/* general initialization of temp variables */
fmpz_poly_init(b);
fmpz_poly_set_coeff_ui(b, 0, 1);
fmpz_poly_init(c);
fmpz_poly_init(f);
fmpz_poly_set(f, a);
/* set g(x) = x^N − 1 */
fmpz_poly_init(g);
fmpz_poly_set_coeff_si(g, 0, -1);
fmpz_poly_set_coeff_si(g, params->N, 1);
/* avoid side effects */
fmpz_poly_init(a_tmp);
fmpz_poly_set(a_tmp, a);
fmpz_poly_zero(Fq);
while (1) {
while (fmpz_poly_get_coeff_ptr(f, 0) &&
fmpz_is_zero(fmpz_poly_get_coeff_ptr(f, 0))) {
for (uint32_t i = 1; i <= params->N; i++) {
fmpz *f_coeff = fmpz_poly_get_coeff_ptr(f, i);
fmpz *c_coeff = fmpz_poly_get_coeff_ptr(c, params->N - i);
/* f(x) = f(x) / x */
fmpz_poly_set_coeff_fmpz_n(f, i - 1,
f_coeff);
/* c(x) = c(x) * x */
fmpz_poly_set_coeff_fmpz_n(c, params->N + 1 - i,
c_coeff);
}
fmpz_poly_set_coeff_si(f, params->N, 0);
fmpz_poly_set_coeff_si(c, 0, 0);
k++;
if (fmpz_poly_degree(f) == -1)
goto cleanup;
}
if (fmpz_poly_is_zero(g) == 1)
goto cleanup;
if (fmpz_poly_degree(f) == 0)
break;
if (fmpz_poly_degree(f) < fmpz_poly_degree(g)) {
fmpz_poly_swap(f, g);
fmpz_poly_swap(b, c);
}
fmpz_poly_add(f, g, f);
fmpz_poly_mod_unsigned(f, 2);
fmpz_poly_add(b, c, b);
fmpz_poly_mod_unsigned(b, 2);
}
k = k % params->N;
b_last = fmpz_poly_get_coeff_ptr(b, params->N);
if (fmpz_cmp_si_n(b_last, 0))
goto cleanup;
/* Fq(x) = x^(N-k) * b(x) */
for (int i = params->N - 1; i >= 0; i--) {
fmpz *b_i;
j = i - k;
if (j < 0)
j = j + params->N;
b_i = fmpz_poly_get_coeff_ptr(b, i);
fmpz_poly_set_coeff_fmpz_n(Fq, j, b_i);
}
poly_mod2_to_modq(Fq, a_tmp, params);
/* check if the f * Fq = 1 (mod p) condition holds true */
fmpz_poly_set(a_tmp, a);
poly_starmultiply(a_tmp, a_tmp, Fq, params, params->q);
if (fmpz_poly_is_one(a_tmp))
retval = true;
else
fmpz_poly_zero(Fq);
cleanup:
fmpz_poly_clear(a_tmp);
fmpz_poly_clear(b);
fmpz_poly_clear(c);
fmpz_poly_clear(f);
fmpz_poly_clear(g);
return retval;
}
