Function InvokeWithThreadId

internal/ceres/parallel_invoke.h:46–54

// InvokeWithThreadId handles passing thread_id to the function
template <typename F, typename... Args>
void InvokeWithThreadId(int thread_id, F&& function, Args&&... args) {
  constexpr bool kPassThreadId = std::is_invocable_v<F, int, Args...>;

  if constexpr (kPassThreadId) {
    function(thread_id, std::forward<Args>(args)...);
  } else {
    function(std::forward<Args>(args)...);
  }
}

// InvokeOnSegment either runs a loop over segment indices or passes it to the
// function