mp_limb_t _nmod_poly_evaluate_nmod(mp_srcptr poly, slong len, mp_limb_t c, nmod_t mod) { slong m; mp_limb_t val; if (len == 0) return 0; if (len == 1 || c == 0) return poly[0]; m = len - 1; val = poly[m]; m--; for ( ; m >= 0; m--) { val = n_mulmod2_preinv(val, c, mod.n, mod.ninv); val = n_addmod(val, poly[m], mod.n); } return val; }
// X_i^p = X_i void nmod_multi_poly_mod_fermat(mp_ptr f_bar, const mp_ptr f, slong p, slong d, slong m, const slong* P) { if(p < d) { slong i, cpt, *pos, coord_p; _nmod_vec_zero(f_bar,n_pow(p,m)); pos = (slong*)calloc(sizeof(slong),m); coord_p; cpt = 0; while(pos[m-1] != d) { coord_p = Coord_mod(P,p,pos,m); f_bar[coord_p] = n_addmod(f_bar[coord_p],f[cpt],p); pos[0]++; cpt++; i = 0; while( (pos[i] == d) && (i != (m-1)) ) { pos[i] = 0; // Le i est incrémenté avant pos++ pos[++i]++; } } free(pos); } }
void _fq_nmod_trace(fmpz_t rop2, const mp_limb_t *op, slong len, const fq_nmod_ctx_t ctx) { const slong d = fq_nmod_ctx_degree(ctx); ulong i, l; mp_limb_t *t, rop; t = _nmod_vec_init(d); _nmod_vec_zero(t, d); t[0] = n_mod2_preinv(d, ctx->mod.n, ctx->mod.ninv); for (i = 1; i < d; i++) { for (l = ctx->len - 2; l >= 0 && ctx->j[l] >= d - (i - 1); l--) { t[i] = n_addmod(t[i], n_mulmod2_preinv(t[ctx->j[l] + i - d], ctx->a[l], ctx->mod.n, ctx->mod.ninv), ctx->mod.n); } if (l >= 0 && ctx->j[l] == d - i) { t[i] = n_addmod(t[i], n_mulmod2_preinv(ctx->a[l], i, ctx->mod.n, ctx->mod.ninv), ctx->mod.n); } t[i] = n_negmod(t[i], ctx->mod.n); } rop = WORD(0); for (i = 0; i < d; i++) { rop = n_addmod(rop, n_mulmod2_preinv(op[i], t[i], ctx->mod.n, ctx->mod.ninv), ctx->mod.n); } _nmod_vec_clear(t); fmpz_set_ui(rop2, rop); }
mp_limb_t _fmpz_poly_evaluate_mod(const fmpz * poly, slong len, mp_limb_t a, mp_limb_t n, mp_limb_t ninv) { mp_limb_t c, res = 0; while (len--) { c = fmpz_fdiv_ui(poly + len, n); res = n_addmod(n_mulmod2_preinv(res, a, n, ninv), c, n); } return res; }
void elem_add(elem_ptr res, elem_srcptr op1, elem_srcptr op2, const ring_t ring) { switch (ring->type) { case TYPE_FMPZ: fmpz_add(res, op1, op2); break; case TYPE_LIMB: *((mp_ptr) res) = *((mp_srcptr) op1) + *((mp_srcptr) op2); break; case TYPE_POLY: elem_poly_add(res, op1, op2, ring); break; case TYPE_MOD: { switch (RING_PARENT(ring)->type) { case TYPE_LIMB: *((mp_ptr) res) = n_addmod(*((mp_srcptr) op1), *((mp_srcptr) op2), ring->nmod.n); break; case TYPE_FMPZ: fmpz_add(res, op1, op2); if (fmpz_cmpabs(res, RING_MODULUS(ring)) >= 0) fmpz_sub(res, res, RING_MODULUS(ring)); break; default: NOT_IMPLEMENTED("add (mod)", ring); } } break; case TYPE_FRAC: elem_frac_add(res, op1, op2, ring); break; case TYPE_COMPLEX: elem_add(REALPART(res, ring), REALPART(op1, ring), REALPART(op2, ring), ring->parent); elem_add(IMAGPART(res, ring), IMAGPART(op1, ring), IMAGPART(op2, ring), ring->parent); break; default: NOT_IMPLEMENTED("add", ring); } }
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 _nmod_poly_compose_divconquer(mp_ptr res, mp_srcptr poly1, long len1, mp_srcptr poly2, long len2, nmod_t mod) { long i, j, k, n; long * hlen, alloc, powlen; mp_ptr v, * h, pow, temp; if (len1 == 1) { res[0] = poly1[0]; return; } if (len2 == 1) { res[0] = _nmod_poly_evaluate_nmod(poly1, len1, poly2[0], mod); return; } if (len1 == 2) { _nmod_poly_compose_horner(res, poly1, len1, poly2, len2, mod); return; } /* Initialisation */ hlen = (long *) flint_malloc(((len1 + 1) / 2) * sizeof(long)); for (k = 1; (2 << k) < len1; k++) ; hlen[0] = hlen[1] = ((1 << k) - 1) * (len2 - 1) + 1; for (i = k - 1; i > 0; i--) { long hi = (len1 + (1 << i) - 1) / (1 << i); for (n = (hi + 1) / 2; n < hi; n++) hlen[n] = ((1 << i) - 1) * (len2 - 1) + 1; } powlen = (1 << k) * (len2 - 1) + 1; alloc = 0; for (i = 0; i < (len1 + 1) / 2; i++) alloc += hlen[i]; v = _nmod_vec_init(alloc + 2 * powlen); h = (mp_ptr *) flint_malloc(((len1 + 1) / 2) * sizeof(mp_ptr)); h[0] = v; for (i = 0; i < (len1 - 1) / 2; i++) { h[i + 1] = h[i] + hlen[i]; hlen[i] = 0; } hlen[(len1 - 1) / 2] = 0; pow = v + alloc; temp = pow + powlen; /* Let's start the actual work */ for (i = 0, j = 0; i < len1 / 2; i++, j += 2) { if (poly1[j + 1] != 0L) { _nmod_vec_scalar_mul_nmod(h[i], poly2, len2, poly1[j + 1], mod); h[i][0] = n_addmod(h[i][0], poly1[j], mod.n); hlen[i] = len2; } else if (poly1[j] != 0L) { h[i][0] = poly1[j]; hlen[i] = 1; } } if ((len1 & 1L)) { if (poly1[j] != 0L) { h[i][0] = poly1[j]; hlen[i] = 1; } } _nmod_poly_mul(pow, poly2, len2, poly2, len2, mod); powlen = 2 * len2 - 1; for (n = (len1 + 1) / 2; n > 2; n = (n + 1) / 2) { if (hlen[1] > 0) { long templen = powlen + hlen[1] - 1; _nmod_poly_mul(temp, pow, powlen, h[1], hlen[1], mod); _nmod_poly_add(h[0], temp, templen, h[0], hlen[0], mod); hlen[0] = FLINT_MAX(hlen[0], templen); } for (i = 1; i < n / 2; i++) { if (hlen[2*i + 1] > 0) { _nmod_poly_mul(h[i], pow, powlen, h[2*i + 1], hlen[2*i + 1], mod); hlen[i] = hlen[2*i + 1] + powlen - 1; } else hlen[i] = 0; _nmod_poly_add(h[i], h[i], hlen[i], h[2*i], hlen[2*i], mod); hlen[i] = FLINT_MAX(hlen[i], hlen[2*i]); } if ((n & 1L)) { mpn_copyi(h[i], h[2*i], hlen[2*i]); hlen[i] = hlen[2*i]; } _nmod_poly_mul(temp, pow, powlen, pow, powlen, mod); powlen += powlen - 1; { mp_ptr t = pow; pow = temp; temp = t; } } _nmod_poly_mul(res, pow, powlen, h[1], hlen[1], mod); _nmod_vec_add(res, res, h[0], hlen[0], mod); _nmod_vec_clear(v); flint_free(h); flint_free(hlen); }
void embeddings_isomorphism_2(nmod_poly_t G, mp_srcptr F, const embeddings_t FP, const embeddings_t FQ, const embeddings_t FR){ nmod_t mod = G->mod; long m = nmod_poly_degree(FP->P); long n = nmod_poly_degree(FQ->P); long np = n + m - 1; long p = ceil(sqrt(np)); long q = ceil((1.0*np)/p); long i, j, k; nmod_poly_t iT, iTm, T, X, tmp; nmod_poly_struct *TT; nmod_poly_init(iTm, mod.n); nmod_poly_init(iT, mod.n); nmod_poly_init(T, mod.n); nmod_poly_init(X, mod.n); nmod_poly_init(tmp, mod.n); nmod_poly_mat_t MT, MH, MV; nmod_poly_mat_init(MT, q, n, mod.n); nmod_poly_mat_init(MH, p, q, mod.n); nmod_poly_mat_init(MV, p, n, mod.n); TT = flint_malloc(sizeof(nmod_poly_struct) * (q+1)); for (i = 0; i < q+1; i++) nmod_poly_init(TT+i, mod.n); nmod_poly_set_coeff_ui(X, 1, 1); embeddings_embed(T, X, FQ, FP, FR); nmod_poly_invmod(iT, T, FR->P); nmod_poly_powmod_ui_binexp(iTm, iT, m-1, FR->P); nmod_poly_zero(TT); nmod_poly_set_coeff_ui(TT, 0, 1); for (i = 1; i < q+1; i++) nmod_poly_mulmod(TT+i, TT+(i-1), T, FR->P); for (i = 0; i < q; i++) for (j = 0; j < n; j++){ long jm = j*m; for (k = 0; k < m; k++) nmod_poly_set_coeff_ui(nmod_poly_mat_entry(MT, i, j), k, nmod_poly_get_coeff_ui(TT+i, k+jm)); } for (i = 0; i < p; i++) for (j = 0; j < q; j++){ long idx = i*q+j; long lo = FLINT_MAX(0,m-1-idx); long hi = FLINT_MIN(m,n+m-1-idx); for (k = lo; k < hi; k++) nmod_poly_set_coeff_ui(nmod_poly_mat_entry(MH, i, j), k, F[k*n+k+idx-m+1]); } nmod_poly_mat_mul(MV, MH, MT); nmod_poly_zero(G); for (i = p-1; i >= 0; i--){ nmod_poly_zero(tmp); for (j = 0; j < n; j++){ long len = nmod_poly_mat_entry(MV, i, j)->length; mp_ptr coefs = nmod_poly_mat_entry(MV, i, j)->coeffs; long jm = j*m; for (k = 0; k < len; k++) nmod_poly_set_coeff_ui(tmp, k+jm, n_addmod(nmod_poly_get_coeff_ui(tmp, k+jm), coefs[k], mod.n)); } nmod_poly_rem(tmp, tmp, FR->P); nmod_poly_mulmod(G, G, TT+q, FR->P); nmod_poly_add(G, G, tmp); } nmod_poly_mulmod(G, G, iTm, FR->P); nmod_poly_clear(tmp); nmod_poly_mat_clear(MT); nmod_poly_mat_clear(MH); nmod_poly_mat_clear(MV); for (i = 0; i < q+1; i++) nmod_poly_clear(TT+i); flint_free(TT); nmod_poly_clear(iTm); nmod_poly_clear(iT); nmod_poly_clear(T); nmod_poly_clear(X); }