1 files changed, 64 insertions, 0 deletions
diff --git a/test/math/discreteLogarithm.cpp b/test/math/discreteLogarithm.cpp
new file mode 100644
index 0000000..0f9eecf
--- /dev/null
+++ b/test/math/discreteLogarithm.cpp
@@ -0,0 +1,64 @@
+#include "../util.h"
+#include <math/modPowIterativ.cpp>
+#include <math/legendre.cpp>
+
+ll overwrite = 0;
+ll getMemory(ll /**/) {return overwrite - 1;} //dlog code adds one...
+#define sqrtl getMemory
+#include <math/discreteLogarithm.cpp>
+#undef sqrtl
+
+template<typename F>
+void stress_test(F&& f) {
+	ll work = 0;
+	for (ll tries = 0; tries < 3'000; tries++) {
+		ll p = Random::prime<ll>(1'000);
+		overwrite = f(p);
+		ll a = Random::integer<ll>(1, p);
+		vector<bool> naive(p);
+		for (ll i = 0, j = 1; i < p; i++, j = (j * a) % p) {
+			naive[j] = true;
+		}
+		for (ll b = 0; b < p; b++) {
+			ll got = dlog(a, b, p);
+			if (got < -1 || got >= p) cerr << "error: out of range" << FAIL;
+			if ((got >= 0) != naive[b]) {
+				cerr << a << " " << b << " " << p << endl;
+				cerr << got << endl;
+				cerr << "error" << FAIL;
+			}
+			if (got >= 0 && powMod(a, got, p) != b) {
+				cerr << a << "^" << got << " = " << powMod(a, got, p) << " != " << b << " % " << p << endl;
+				cerr << "error: wrong" << FAIL;
+			}
+			work++;
+		}
+	}
+	cerr << "stress tested: " << work << endl;
+}
+
+constexpr int N = 25;
+constexpr ll mod = 1'394'633'899;
+void performance_test() {
+	timer t;
+	hash_t hash = 0;
+	overwrite = sqrt(mod);
+	for (int operations = 0; operations < N; operations++) {
+		ll a = Random::integer<ll>(1, mod);
+		ll b = Random::integer<ll>(0, mod);
+		t.start();
+		hash += dlog(a, b, mod);
+		t.stop();
+	}
+	if (t.time > 500) cerr << "too slow: " << t.time << FAIL;
+	cerr << "tested performance: " << t.time << "ms (hash: " << hash << ")" << endl;
+}
+
+
+int main() {
+	stress_test([](ll p){return sqrtl(p);});
+	stress_test([](ll p){return min<ll>(10, p - 1);});
+	stress_test([](ll p){return min<ll>(p - 1, sqrtl(p) + 100);});
+	performance_test();
+}
+