void parfor(std::size_t idx_start,
std::size_t idx_end,
Lambda &&loopBody,
TaskScheduler &scheduler,
std::size_t blockSize = 32)
{
static_assert(std::is_same<void, typename std::result_of<Lambda(std::size_t)>::type>::value,
"Loop body must return void");
auto loopLen = (idx_end - idx_start);
//Execute short loops in serial
if(loopLen < 10*blockSize) {
for(std::size_t i=idx_start; i<idx_end; ++i) {
loopBody(i);
}
return;
}
auto full_blocks = loopLen / blockSize;
auto cleanup_start = full_blocks * blockSize + idx_start;
auto Nblocks = full_blocks + ((cleanup_start < idx_end) ? 1 : 0);
std::vector<std::future<void>> futs;
futs.reserve(Nblocks);
for (std::size_t iblock = 0; iblock < Nblocks; ++iblock) {
std::size_t i_start = idx_start + iblock * blockSize;
std::size_t i_end = i_start + blockSize;
i_end = (i_end < idx_end) ? i_end : idx_end;
auto [task, fut] = scheduler.createTask([&loopBody, i_start, i_end]() {
for (auto i = i_start; i < i_end; ++i) {
loopBody(i);
}
});
scheduler.enqueue(task);
futs.push_back(std::move(fut));
}
wait_all(futs);
//return futs;
}
