1 files changed, 116 insertions, 0 deletions
diff --git a/test/math/matrixPower.cpp b/test/math/matrixPower.cpp
new file mode 100644
index 0000000..4dfb0a8
--- /dev/null
+++ b/test/math/matrixPower.cpp
@@ -0,0 +1,116 @@
+#include "../util.h"
+
+constexpr ll mod = 1'394'633'899;
+
+struct mat {
+	vector<vector<ll>> m;
+	mat(int dim = 0, int diag = 1) : m(dim, vector<ll>(dim)) {
+		for (int i = 0; i < dim; i++) m[i][i] = diag;
+	}
+	mat(const vector<ll> c) : m(sz(c), vector<ll>(sz(c))) {
+		m[0] = c;
+		for (ll i = 1; i < sz(c); i++) {
+			m[i][i-1] = 1;
+		}
+	}
+
+	mat operator*(const mat& o) const {
+		int dim = sz(m);
+		mat res(dim, 0);
+		for (int i = 0; i < dim; i++) {
+			for (int j = 0; j < dim; j++) {
+				for (int k = 0; k < dim; k++) {
+					res.m[i][j] += m[i][k] * o.m[k][j];
+					res.m[i][j] %= mod;
+				}
+			}
+		}
+		return res;
+	}
+
+	vector<ll> operator*(const vector<ll>& o) const {
+		int dim = sz(m);
+		vector<ll> res(dim);
+		for (int i = 0; i < dim; i++) {
+			for (int j = 0; j < dim; j++) {
+				res[i] += m[i][j] * o[j];
+				res[i] %= mod;
+			}
+		}
+		return res;
+	}
+};
+
+#include <math/matrixPower.cpp>
+
+struct RandomRecurence {
+	vector<ll> f, c, cache;
+	RandomRecurence(int n) : f(Random::integers<ll>(n, 0, mod)), c(Random::integers<ll>(n, 0, mod)), cache(f) {}
+
+	ll operator()(ll k){
+		while (sz(cache) <= k) {
+			ll cur = 0;
+			for (ll i = 0; i < sz(c); i++) {
+				cur += (c[i] * cache[sz(cache) - i - 1]) % mod;
+			}
+			cur %= mod;
+			cache.push_back(cur);
+		}
+		return cache[k];
+	}
+};
+
+void stress_test() {
+	int queries = 0;
+	for (int i = 0; i < 10'000; i++) {
+		int n = Random::integer<int>(1, 10);
+		RandomRecurence f(n);
+		precalc(mat(f.c));
+		auto tmp = f.f;
+		reverse(all(tmp));
+
+		for (int j = 0; j < 100; j++) {
+			ll k = Random::integer<ll>(0, 1000);
+
+			vector<ll> got = calc(k, tmp);
+			vector<ll> expected(sz(f.f));
+			for (ll l = 0; l < n; l++) expected[n - 1 - l] = f(k + l);
+
+			if (got != expected) cerr << "error" << FAIL;
+			queries++;
+		}
+	}
+	cerr << "tested random queries: " << queries << endl;
+}
+
+constexpr int N = 100;
+constexpr int M = 500;
+void performance_test() {
+	timer t;
+	RandomRecurence f(N);
+	auto tmp = f.f;
+	reverse(all(tmp));
+
+	t.start();
+	precalc(mat(f.c));
+	t.stop();
+	if (t.time > 500) cerr << "too slow precalc: " << t.time << FAIL;
+	cerr << "tested performance: " << t.time << "ms" << endl;
+
+	t.reset();
+	hash_t hash = 0;
+	for (int i = 0; i < M; i++) {
+		ll k = Random::integer<ll>(1e17,1e18);
+		t.start();
+		hash += calc(k, tmp).back();
+		t.stop();
+	}
+	if (t.time > 750) cerr << "too slow: " << t.time << FAIL;
+	cerr << "tested performance: " << t.time << "ms (hash: " << hash << ")" << endl;
+}
+
+int main() {
+	stress_test();
+	performance_test();
+}
+