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///
/// @file phi_tiny.cpp
/// @brief Test the partial sieve function phi_tiny(x, a)
/// which counts the numbers <= x that are not divisible
/// by any of the first a primes with a <= 8.
///
/// Copyright (C) 2021 Kim Walisch, <kim.walisch@gmail.com>
///
/// This file is distributed under the BSD License. See the COPYING
/// file in the top level directory.
///
#include <PhiTiny.hpp>
#include <generate_primes.hpp>
#include <stdint.h>
#include <iostream>
#include <cstdlib>
#include <vector>
#include <random>
using std::size_t;
using namespace primecount;
void check(bool OK)
{
std::cout << " " << (OK ? "OK" : "ERROR") << "\n";
if (!OK)
std::exit(1);
}
// Count the number of unsieved elements
int count(std::vector<char>& sieve)
{
int cnt = 0;
for (size_t i = 1; i < sieve.size(); i++)
cnt += sieve[i];
return cnt;
}
int main()
{
std::random_device rd;
std::mt19937 gen(rd());
std::uniform_int_distribution<int> dist(10000000, 20000000);
int64_t max_a = PhiTiny::max_a();
int64_t size = dist(gen);
int64_t x = size - 1;
auto primes = generate_n_primes<int32_t>(max_a);
std::vector<char> sieve(size, 1);
for (int a = 1; a <= max_a; a++)
{
// remove primes[a] and its multiples
for (int j = primes[a]; j <= x; j += primes[a])
sieve[j] = 0;
std::cout << "phi_tiny(" << x << ", " << a << ") = " << phi_tiny(x, a);
check(phi_tiny(x, a) == count(sieve));
}
std::cout << std::endl;
std::cout << "All tests passed successfully!" << std::endl;
return 0;
}
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