get number of threads of current sys
| 70 | |
| 71 | // get number of threads of current sys |
| 72 | inline size_t total_threads() { |
| 73 | const auto threads = std::thread::hardware_concurrency(); |
| 74 | return threads == 0 ? 1 : threads; |
| 75 | } |
| 76 | |
| 77 | template <typename T, typename TP> |
| 78 | float distance_ratio( |