fix numa cpu distribution

The numa node location would be calculated based on the total number
of worker threads.
So we should always use the actual number of threads instead of using a min() op.

ktransformers/ktransformers_ext/cpu_backend/backend.cpp

@@ -54,7 +54,12 @@ void Backend::do_work_stealing_job(int task_num,
     init_func_ = init_func;
     compute_func_ = compute_func;
     finalize_func_ = finalize_func;
+#ifdef USE_NUMA
+    // numa node location will be calculated based on the number of threads
+    thread_num_ = max_thread_num_;
+#else
     thread_num_ = std::min(max_thread_num_, task_num);
+#endif
     int base = task_num / thread_num_;
     int remain = task_num % thread_num_;
     thread_state_[0].end = base + (0 < remain);
@@ -146,4 +151,4 @@ void Backend::worker_thread(int thread_id) {
             return;
         }
     }
-}
+}
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