mesytec-mnode/external/taskflow-3.8.0/examples/parallel_sort.cpp
2025-01-04 01:25:05 +01:00

83 lines
2.1 KiB
C++

// This program demonstrates how to sort a vector of strings
// in parallel using tf::Taskflow::sort and compares it against
// the sequential sort std::sort.
#include <taskflow/taskflow.hpp>
#include <taskflow/algorithm/sort.hpp>
// generate a random string
std::string random_string(size_t len) {
std::string tmp_s;
static const char alphanum[] =
"0123456789"
"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
"abcdefghijklmnopqrstuvwxyz";
std::default_random_engine eng{std::random_device{}()};
std::uniform_int_distribution<int> dist(1, 100000);
tmp_s.reserve(len);
for (size_t i = 0; i < len; ++i) {
tmp_s += alphanum[dist(eng) % (sizeof(alphanum) - 1)];
}
return tmp_s;
}
// generate a vector of random strings
std::vector<std::string> random_strings() {
std::vector<std::string> strings(1000000);
std::cout << "generating random strings ...\n";
for(auto& str : strings) {
str = random_string(32);
}
return strings;
}
// Function: main
int main(int argc, char* argv[]) {
if(argc != 2) {
std::cerr << "usage: ./parallel_sort s|p" << std::endl;
std::exit(EXIT_FAILURE);
}
// sequential sort
if(argv[1][0] == 's') {
auto strings = random_strings();
std::cout << "std::sort ... ";
auto beg = std::chrono::steady_clock::now();
std::sort(strings.begin(), strings.end());
auto end = std::chrono::steady_clock::now();
std::cout << std::chrono::duration_cast<std::chrono::milliseconds>(end-beg).count()
<< " ms\n";
}
// parallel sort
else if(argv[1][0] == 'p') {
auto strings = random_strings();
std::cout << "Taskflow Parallel Sort ... ";
auto beg = std::chrono::steady_clock::now();
{
tf::Taskflow taskflow;
tf::Executor executor;
taskflow.sort(strings.begin(), strings.end());
executor.run(taskflow).wait();
}
auto end = std::chrono::steady_clock::now();
std::cout << std::chrono::duration_cast<std::chrono::milliseconds>(end-beg).count()
<< " ms\n";
}
else {
std::cerr << "uncognized method character '" << argv[1][0] << "'\n";
std::exit(EXIT_FAILURE);
}
return 0;
}