void
hypgeom_precompute(hypgeom_t hyp)
{
if (fmpz_poly_is_one(hyp->A) && fmpz_poly_is_one(hyp->B))
{
_hypgeom_precompute(hyp, hyp->P, hyp->Q);
}
else
{
fmpz_poly_t P2, Q2;
fmpz_poly_init(P2);
fmpz_poly_init(Q2);
hypgeom_standardize(P2, Q2, hyp->A, hyp->B, hyp->P, hyp->Q);
_hypgeom_precompute(hyp, P2, Q2);
{
fmpz_t t;
fmpz_init(t);
fmpz_poly_evaluate_si(t, hyp->A, 0);
mag_mul_fmpz(hyp->MK, hyp->MK, t);
fmpz_poly_evaluate_si(t, hyp->B, 0);
mag_div_fmpz(hyp->MK, hyp->MK, t);
fmpz_clear(t);
}
fmpz_poly_clear(P2);
fmpz_poly_clear(Q2);
}
}
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);
}
}
/**
* \ingroup StringConversions
*
* Returns the string representation of the rational function \c op.
*/
char * fmpz_poly_q_get_str(const fmpz_poly_q_t op)
{
int i, j;
char * str;
char * numstr;
char * denstr;
if (fmpz_poly_is_one(op->den))
{
numstr = fmpz_poly_get_str(op->num);
i = strlen(numstr) - 1;
if (numstr[i] == ' ')
{
numstr[i] = '\0';
}
return numstr;
}
numstr = fmpz_poly_get_str(op->num);
denstr = fmpz_poly_get_str(op->den);
i = strlen(numstr) - 1;
if (numstr[i] == ' ')
numstr[i] = '\0';
i = strlen(denstr) - 1;
if (denstr[i] == ' ')
denstr[i] = '\0';
str = flint_malloc(strlen(numstr) + strlen(denstr) + 2);
if (str == NULL)
{
printf("ERROR (fmpz_poly_q_get_str). Memory allocation failed.\n");
abort();
}
for (i = 0; i < strlen(numstr); i++)
str[i] = numstr[i];
str[i++] = '/';
for (j = 0; j < strlen(denstr); j++)
str[i++] = denstr[j];
str[i] = '\0';
flint_free(numstr);
flint_free(denstr);
return str;
}
dgsl_rot_mp_t *dgsl_rot_mp_init(const long n, const fmpz_poly_t B, mpfr_t sigma, fmpq_poly_t c, const dgsl_alg_t algorithm, const oz_flag_t flags) {
assert(mpfr_cmp_ui(sigma, 0) > 0);
dgsl_rot_mp_t *self = (dgsl_rot_mp_t*)calloc(1, sizeof(dgsl_rot_mp_t));
if(!self) dgs_die("out of memory");
dgsl_alg_t alg = algorithm;
self->n = n;
self->prec = mpfr_get_prec(sigma);
fmpz_poly_init(self->B);
fmpz_poly_set(self->B, B);
if(fmpz_poly_length(self->B) > n)
dgs_die("polynomial is longer than length n");
else
fmpz_poly_realloc(self->B, n);
fmpz_poly_init(self->c_z);
fmpq_poly_init(self->c);
mpfr_init2(self->sigma, self->prec);
mpfr_set(self->sigma, sigma, MPFR_RNDN);
if (alg == DGSL_DETECT) {
if (fmpz_poly_is_one(self->B) && (c && fmpq_poly_is_zero(c))) {
alg = DGSL_IDENTITY;
} else if (c && fmpq_poly_is_zero(c))
alg = DGSL_INLATTICE;
else
alg = DGSL_COSET; //TODO: we could test for lattice membership here
}
size_t tau = 3;
if (2*ceil(sqrt(log2((double)n))) > tau)
tau = 2*ceil(sqrt(log2((double)n)));
switch(alg) {
case DGSL_IDENTITY: {
self->D = (dgs_disc_gauss_mp_t**)calloc(1, sizeof(dgs_disc_gauss_mp_t*));
mpfr_t c_;
mpfr_init2(c_, self->prec);
mpfr_set_d(c_, 0.0, MPFR_RNDN);
self->D[0] = dgs_disc_gauss_mp_init(self->sigma, c_, tau, DGS_DISC_GAUSS_DEFAULT);
self->call = dgsl_rot_mp_call_identity;
mpfr_clear(c_);
break;
}
case DGSL_GPV_INLATTICE: {
self->D = (dgs_disc_gauss_mp_t**)calloc(n, sizeof(dgs_disc_gauss_mp_t*));
if (c && !fmpq_poly_is_zero(c)) {
fmpq_t c_i;
fmpq_init(c_i);
for(int i=0; i<n; i++) {
fmpq_poly_get_coeff_fmpq(c_i, c, i);
fmpz_poly_set_coeff_fmpz(self->c_z, i, fmpq_numref(c_i));
}
fmpq_clear(c_i);
}
mpfr_mat_t G;
mpfr_mat_init(G, n, n, self->prec);
mpfr_mat_set_fmpz_poly(G, B);
mpfr_mat_gso(G, MPFR_RNDN);
mpfr_t sigma_;
mpfr_init2(sigma_, self->prec);
mpfr_t norm;
mpfr_init2(norm, self->prec);
mpfr_t c_;
mpfr_init2(c_, self->prec);
mpfr_set_d(c_, 0.0, MPFR_RNDN);
for(long i=0; i<n; i++) {
_mpfr_vec_2norm(norm, G->rows[i], n, MPFR_RNDN);
assert(mpfr_cmp_d(norm, 0.0) > 0);
mpfr_div(sigma_, self->sigma, norm, MPFR_RNDN);
assert(mpfr_cmp_d(sigma_, 0.0) > 0);
self->D[i] = dgs_disc_gauss_mp_init(sigma_, c_, tau, DGS_DISC_GAUSS_DEFAULT);
}
mpfr_clear(sigma_);
mpfr_clear(norm);
mpfr_clear(c_);
mpfr_mat_clear(G);
self->call = dgsl_rot_mp_call_gpv_inlattice;
break;
}
case DGSL_INLATTICE: {
fmpq_poly_init(self->sigma_sqrt);
long r= 2*ceil(sqrt(log(n)));
fmpq_poly_t Bq; fmpq_poly_init(Bq);
fmpq_poly_set_fmpz_poly(Bq, self->B);
fmpq_poly_oz_invert_approx(self->B_inv, Bq, n, self->prec, flags);
fmpq_poly_clear(Bq);
_dgsl_rot_mp_sqrt_sigma_2(self->sigma_sqrt, self->B, sigma, r, n, self->prec, flags);
mpfr_init2(self->r_f, self->prec);
mpfr_set_ui(self->r_f, r, MPFR_RNDN);
self->call = dgsl_rot_mp_call_inlattice;
break;
}
case DGSL_COSET:
dgs_die("not implemented");
default:
dgs_die("not implemented");
}
return self;
}
void fmpz_poly_q_mul(fmpz_poly_q_t rop,
const fmpz_poly_q_t op1, const fmpz_poly_q_t op2)
{
if (fmpz_poly_q_is_zero(op1) || fmpz_poly_q_is_zero(op2))
{
fmpz_poly_q_zero(rop);
return;
}
if (op1 == op2)
{
fmpz_poly_pow(rop->num, op1->num, 2);
fmpz_poly_pow(rop->den, op1->den, 2);
return;
}
if (rop == op1 || rop == op2)
{
fmpz_poly_q_t t;
fmpz_poly_q_init(t);
fmpz_poly_q_mul(t, op1, op2);
fmpz_poly_q_swap(rop, t);
fmpz_poly_q_clear(t);
return;
}
/*
From here on, we may assume that rop, op1 and op2 refer to distinct
objects in memory, and that op1 and op2 are non-zero
*/
/* Polynomials? */
if (fmpz_poly_length(op1->den) == 1 && fmpz_poly_length(op2->den) == 1)
{
const slong len1 = fmpz_poly_length(op1->num);
const slong len2 = fmpz_poly_length(op2->num);
fmpz_poly_fit_length(rop->num, len1 + len2 - 1);
if (len1 >= len2)
{
_fmpq_poly_mul(rop->num->coeffs, rop->den->coeffs,
op1->num->coeffs, op1->den->coeffs, len1,
op2->num->coeffs, op2->den->coeffs, len2);
}
else
{
_fmpq_poly_mul(rop->num->coeffs, rop->den->coeffs,
op2->num->coeffs, op2->den->coeffs, len2,
op1->num->coeffs, op1->den->coeffs, len1);
}
_fmpz_poly_set_length(rop->num, len1 + len2 - 1);
_fmpz_poly_set_length(rop->den, 1);
return;
}
fmpz_poly_gcd(rop->num, op1->num, op2->den);
if (fmpz_poly_is_one(rop->num))
{
fmpz_poly_gcd(rop->den, op2->num, op1->den);
if (fmpz_poly_is_one(rop->den))
{
fmpz_poly_mul(rop->num, op1->num, op2->num);
fmpz_poly_mul(rop->den, op1->den, op2->den);
}
else
{
fmpz_poly_div(rop->num, op2->num, rop->den);
fmpz_poly_mul(rop->num, op1->num, rop->num);
fmpz_poly_div(rop->den, op1->den, rop->den);
fmpz_poly_mul(rop->den, rop->den, op2->den);
}
}
else
{
fmpz_poly_gcd(rop->den, op2->num, op1->den);
if (fmpz_poly_is_one(rop->den))
{
fmpz_poly_div(rop->den, op2->den, rop->num);
fmpz_poly_mul(rop->den, op1->den, rop->den);
fmpz_poly_div(rop->num, op1->num, rop->num);
fmpz_poly_mul(rop->num, rop->num, op2->num);
}
else
{
fmpz_poly_t t, u;
fmpz_poly_init(t);
fmpz_poly_init(u);
fmpz_poly_div(t, op1->num, rop->num);
fmpz_poly_div(u, op2->den, rop->num);
fmpz_poly_div(rop->num, op2->num, rop->den);
fmpz_poly_mul(rop->num, t, rop->num);
fmpz_poly_div(rop->den, op1->den, rop->den);
fmpz_poly_mul(rop->den, rop->den, u);
fmpz_poly_clear(t);
fmpz_poly_clear(u);
}
}
}
int
main(void)
{
flint_rand_t state;
long i;
printf("inv....");
fflush(stdout);
flint_randinit(state);
/* Test aliasing */
for (i = 0; i < 400; i++)
{
fmpz_poly_mat_t A, Ainv;
fmpz_poly_t den1, den2;
long n, bits, deg;
float density;
int ns1, ns2;
int result;
n = n_randint(state, 8);
deg = 1 + n_randint(state, 5);
bits = 1 + n_randint(state, 100);
density = n_randint(state, 100) * 0.01;
fmpz_poly_mat_init(A, n, n);
fmpz_poly_mat_init(Ainv, n, n);
fmpz_poly_init(den1);
fmpz_poly_init(den2);
fmpz_poly_mat_randtest_sparse(A, state, deg, bits, density);
ns1 = fmpz_poly_mat_inv(Ainv, den1, A);
ns2 = fmpz_poly_mat_inv(A, den2, A);
result = ns1 == ns2;
if (result && ns1 != 0)
{
result = fmpz_poly_equal(den1, den2) &&
fmpz_poly_mat_equal(A, Ainv);
}
if (!result)
{
printf("FAIL (aliasing)!\n");
fmpz_poly_mat_print(A, "x"); printf("\n");
fmpz_poly_mat_print(Ainv, "x"); printf("\n");
abort();
}
fmpz_poly_mat_clear(A);
fmpz_poly_mat_clear(Ainv);
fmpz_poly_clear(den1);
fmpz_poly_clear(den2);
}
/* Check A^(-1) = A = 1 */
for (i = 0; i < 1000; i++)
{
fmpz_poly_mat_t A, Ainv, B, Iden;
fmpz_poly_t den, det;
long n, bits, deg;
float density;
int nonsingular;
n = n_randint(state, 10);
deg = 1 + n_randint(state, 5);
bits = 1 + n_randint(state, 100);
density = n_randint(state, 100) * 0.01;
fmpz_poly_mat_init(A, n, n);
fmpz_poly_mat_init(Ainv, n, n);
fmpz_poly_mat_init(B, n, n);
fmpz_poly_mat_init(Iden, n, n);
fmpz_poly_init(den);
fmpz_poly_init(det);
fmpz_poly_mat_randtest_sparse(A, state, deg, bits, density);
nonsingular = fmpz_poly_mat_inv(Ainv, den, A);
fmpz_poly_mat_det_interpolate(det, A);
if (n == 0)
{
if (nonsingular == 0 || !fmpz_poly_is_one(den))
{
printf("FAIL: expected empty matrix to pass\n");
abort();
}
}
else
{
if (!fmpz_poly_equal(den, det))
{
fmpz_poly_neg(det, det);
printf("FAIL: den != det(A)\n");
abort();
}
fmpz_poly_mat_mul(B, Ainv, A);
fmpz_poly_mat_one(Iden);
fmpz_poly_mat_scalar_mul_fmpz_poly(Iden, Iden, den);
if (!fmpz_poly_mat_equal(B, Iden))
{
printf("FAIL:\n");
printf("A:\n");
fmpz_poly_mat_print(A, "x");
printf("Ainv:\n");
fmpz_poly_mat_print(Ainv, "x");
printf("B:\n");
fmpz_poly_mat_print(B, "x");
printf("den:\n");
fmpz_poly_print_pretty(den, "x");
abort();
}
}
fmpz_poly_clear(den);
fmpz_poly_clear(det);
fmpz_poly_mat_clear(A);
fmpz_poly_mat_clear(Ainv);
fmpz_poly_mat_clear(B);
fmpz_poly_mat_clear(Iden);
}
flint_randclear(state);
_fmpz_cleanup();
printf("PASS\n");
return 0;
}
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;
}
