/* vector of log(k,a)*loga % order in Z/modZ */ void dlog_vec_loop(ulong * v, ulong nv, ulong a, ulong va, nmod_t mod, ulong na, nmod_t order) { ulong x, vx; dlog_vec_fill(v, nv, DLOG_NOT_FOUND); x = 1; vx = 0; do { if (x < nv) v[x] = vx; x = nmod_mul(x, a, mod); vx = nmod_add(vx, va, order); } while (x != 1); for (x = mod.n + 1; x < nv; x++) v[x] = v[x - mod.n]; }
int main() { slong bits, nv, iter; flint_rand_t state; int f, nf = 4; vec_f func[4] = { dlog_vec_trivial, dlog_vec_loop, dlog_vec_eratos, dlog_vec_sieve }; char * n[4] = { "trivial", "loop", "eratos", "sieve" }; flint_printf("vec...."); fflush(stdout); flint_randinit(state); for (bits = 10; bits <= FLINT_MIN(35, FLINT_BITS); bits += 5) { for (nv = 10; nv <= 10000; nv *= 10) { ulong *v, *ref; int iref; iref = (bits == 10 && nv <= 1000) ? 0 : 2; ref = flint_malloc(nv * sizeof(ulong)); v = flint_malloc(nv * sizeof(ulong)); for (iter = 0; iter < 10; iter++) { int k; ulong p, a, va, na; nmod_t mod, order; p = n_randprime(state, bits, 0); a = n_primitive_root_prime(p); nmod_init(&mod, p); va = 1; na = p - 1; nmod_init(&order, na); dlog_vec_fill(ref, nv, 0); (func[iref])(ref, nv, a, va, mod, na, order); /* compare */ for (f = iref + 1; f < nf; f++) { dlog_vec_fill(v, nv, 0); (func[f])(v, nv, a, va, mod, na, order); if ((k = dlog_vec_diff(v, ref, nv))) { flint_printf("FAIL: log(%wu,%wu) mod %wu: %s->%w != %s->%w\n", k, a, p, n[iref], ref[k], n[f], v[k]); abort(); } } } flint_free(ref); flint_free(v); } } flint_randclear(state); flint_cleanup(); flint_printf("PASS\n"); return EXIT_SUCCESS; }