long CRT(vec_ZZ& gg, ZZ& a, const vec_zz_p& G) { long n = gg.length(); if (G.length() != n) Error("CRT: vector length mismatch"); long p = zz_p::modulus(); ZZ new_a; mul(new_a, a, p); long a_inv; a_inv = rem(a, p); a_inv = InvMod(a_inv, p); long p1; p1 = p >> 1; ZZ a1; RightShift(a1, a, 1); long p_odd = (p & 1); long modified = 0; long h; ZZ g; long i; for (i = 0; i < n; i++) { if (!CRTInRange(gg[i], a)) { modified = 1; rem(g, gg[i], a); if (g > a1) sub(g, g, a); } else g = gg[i]; h = rem(g, p); h = SubMod(rep(G[i]), h, p); h = MulMod(h, a_inv, p); if (h > p1) h = h - p; if (h != 0) { modified = 1; if (!p_odd && g > 0 && (h == p1)) MulSubFrom(g, a, h); else MulAddTo(g, a, h); } gg[i] = g; } a = new_a; return modified; }
long CRT(mat_ZZ& gg, ZZ& a, const mat_zz_p& G) { long n = gg.NumRows(); long m = gg.NumCols(); if (G.NumRows() != n || G.NumCols() != m) Error("CRT: dimension mismatch"); long p = zz_p::modulus(); ZZ new_a; mul(new_a, a, p); long a_inv; a_inv = rem(a, p); a_inv = InvMod(a_inv, p); long p1; p1 = p >> 1; ZZ a1; RightShift(a1, a, 1); long p_odd = (p & 1); long modified = 0; long h; ZZ g; long i, j; for (i = 0; i < n; i++) { for (j = 0; j < m; j++) { if (!CRTInRange(gg[i][j], a)) { modified = 1; rem(g, gg[i][j], a); if (g > a1) sub(g, g, a); } else g = gg[i][j]; h = rem(g, p); h = SubMod(rep(G[i][j]), h, p); h = MulMod(h, a_inv, p); if (h > p1) h = h - p; if (h != 0) { modified = 1; if (!p_odd && g > 0 && (h == p1)) MulSubFrom(g, a, h); else MulAddTo(g, a, h); } gg[i][j] = g; } } a = new_a; return modified; }