/// /// @file P2_xa.cpp /// @brief Test the 2nd partial sieve function P2(x, a) /// that counts the numbers <= x that have exactly /// 2 prime factors each exceeding the a-th prime. /// /// Copyright (C) 2017 Kim Walisch, /// /// This file is distributed under the BSD License. See the COPYING /// file in the top level directory. /// #include #include #include #include #include #include #include #include using std::size_t; using namespace primecount; void check(bool OK) { std::cout << " " << (OK ? "OK" : "ERROR") << "\n"; if (!OK) std::exit(1); } int main() { std::random_device rd; std::mt19937 gen(rd()); std::uniform_int_distribution dist(50000, 70000); int threads = 1; int64_t x = dist(gen); auto primes = generate_primes(x); for (int a = 1; primes[a] <= isqrt(x); a++) { int64_t p2 = 0; for (size_t b = a + 1; b < primes.size(); b++) for (size_t c = b; c < primes.size(); c++) if (primes[b] * primes[c] <= x) p2++; std::cout << "P2(" << x << ", " << a << ") = " << p2; check(p2 == P2(x, primes[a], threads)); } std::cout << std::endl; std::cout << "All tests passed successfully!" << std::endl; return 0; }