1 ///
2 /// @file generate_pi.cpp
3 /// @brief Test the generate_pi(n) function
4 /// @link https://en.wikipedia.org/wiki/Prime-counting_function
5 ///
6 /// Copyright (C) 2017 Kim Walisch, <kim.walisch@gmail.com>
7 ///
8 /// This file is distributed under the BSD License. See the COPYING
9 /// file in the top level directory.
10 ///
11
12 #include <generate.hpp>
13 #include <primesieve.hpp>
14
15 #include <stdint.h>
16 #include <iostream>
17 #include <cstdlib>
18 #include <vector>
19 #include <random>
20
21 using std::size_t;
22 using namespace primecount;
23
24 std::vector<int> pix =
25 {
26 0, 0, 1, 2, 2, 3, 3, 4, 4, 4,
27 4, 5, 5, 6, 6, 6, 6, 7, 7, 8,
28 8, 8, 8, 9, 9, 9, 9, 9, 9, 10,
29 10, 11, 11, 11, 11, 11, 11, 12, 12, 12,
30 12, 13, 13, 14, 14, 14, 14, 15, 15, 15,
31 15, 15, 15, 16, 16, 16, 16, 16, 16, 17,
32 17, 18, 18, 18, 18, 18, 18, 19, 19, 19,
33 19, 20, 20, 21, 21, 21, 21, 21, 21
34 };
35
check(bool OK)36 void check(bool OK)
37 {
38 std::cout << " " << (OK ? "OK" : "ERROR") << "\n";
39 if (!OK)
40 std::exit(1);
41 }
42
main()43 int main()
44 {
45 std::random_device rd;
46 std::mt19937 gen(rd());
47 std::uniform_int_distribution<int> dist(1000000, 2000000);
48 auto pi = generate_pi(dist(gen));
49
50 for (size_t i = 0; i < pix.size(); i++)
51 {
52 std::cout << "pi(" << i << ") = " << pi[i];
53 check(pi[i] == pix[i]);
54 }
55
56 primesieve::iterator it;
57 uint64_t prime = it.next_prime();
58 int count = 1;
59
60 while (prime < pi.size())
61 {
62 std::cout << "pi(" << prime << ") = " << pi[prime];
63 check(pi[prime] == count);
64 prime = it.next_prime();
65 count++;
66 }
67
68 for (int i = 0; i < 10000; i++)
69 {
70 int n = dist(gen) % pi.size();
71 std::cout << "pi(" << n << ") = " << pi[n];
72 check(pi[n] == (int) primesieve::count_primes(0, n));
73 }
74
75 std::cout << std::endl;
76 std::cout << "All tests passed successfully!" << std::endl;
77
78 return 0;
79 }
80