factors.cpp

Driver for showing how to use the core functionalities of the Number Theory module by itself as well as with the openGPMP ThreadPool. This features functions related to integer factorization.

 
#include <chrono>
#include <cmath>
#include <iostream>
#include <openGPMP/core/threads.hpp>
#include <openGPMP/nt/factorization.hpp>
#include <vector>
 
int main() {
    gpmp::Factorization factorization;
 
    // find prime factor of 123456789
    int64_t n = 9223372036854775803;
    int64_t factor = factorization.pollard_rho(n);
 
    // print the result
    std::cout << "The smallest prime factor of " << n << " is " << factor
              << std::endl;
 
    /******* EXAMPLE USING openGPMP's THREADPOOL *******/
    //
    // specify the numbers to factorize
    // pollard_rho accepts 64 bit integers
    // std::vector<int64_t> nums_to_factorize = {
    //    9223372036854775803, 9223372036854775807, 9223372036854775303,
    //    4567890123456789LL,  5678901234567890LL,  6789012345678901LL,
    //    7890123456789012LL,  8901234567890123LL};
    std::vector<uint64_t> nums_to_factorize = {
        9223372036854775803,   9223372036854775807,   9223372036854775303,
        4567890123456789LL,    5678901234567890LL,    6789012345678901LL,
        7890123456789012LL,    8901234567890123LL,    9999999967LL,
        12345678901234567LL,   987654321987654321LL,  2147483647LL,
        9223372036854775783LL, 1311768467463790320LL, 7237005577332262210LL,
        3037000499LL,          2305843009213693951LL, 2305843009213693967LL,
        2305843009213693971LL, 2305843009213693973LL, 2305843009213693977LL,
        2305843009213693989LL};
 
    // std::vector<std::future<int64_t>> results =
    //    factorization.pollard_rho_thread(nums_to_factorize);
 
    //    for (auto &res : results) {
    //        std::cout << res.get() << std::endl;
    //    }
 
    std::vector<std::future<uint64_t>> results;
    gpmp::core::ThreadPool *pool = new gpmp::core::ThreadPool(2);
    gpmp::Factorization factors;
    for (const auto &num : nums_to_factorize) {
        results.emplace_back(gpmp::core::ThreadDispatch().dispatch(
            *pool,
            &gpmp::Factorization::pollard_rho,
            &factors,
            num));
    }
 
    for (auto &res : results) {
        std::cout << res.get() << std::endl;
    }
 
    delete pool;
 
    return 0;
}