remove #if

core/src/index/knowhere/knowhere/index/vector_index/IndexNSG.cpp

@@ -116,23 +116,29 @@ NSG::Train(const DatasetPtr& dataset, const Config& config) {
     }
 
     // TODO(linxj): dev IndexFactory, support more IndexType
+    bool use_gpu = false;
 #ifdef MILVUS_GPU_VERSION
+    use_gpu = true;
     auto temp_resource = FaissGpuResourceMgr::GetInstance().GetRes(build_cfg->gpu_id);
-#if temp_resource == nullptr
-    auto preprocess_index = std::make_shared<IVF>();
-#else
-    auto preprocess_index = std::make_shared<GPUIVF>(build_cfg->gpu_id);
+    if (temp_resource == nullptr)
+        use_gpu = false;
 #endif
-
-#else
-    auto preprocess_index = std::make_shared<IVF>();
-#endif
-    auto model = preprocess_index->Train(dataset, config);
-    preprocess_index->set_index_model(model);
-    preprocess_index->AddWithoutIds(dataset, config);
-
     Graph knng;
-    preprocess_index->GenGraph(build_cfg->knng, knng, dataset, config);
+    if (use_gpu) {
+        auto preprocess_index = std::make_shared<GPUIVF>(build_cfg->gpu_id);
+        auto model = preprocess_index->Train(dataset, config);
+        preprocess_index->set_index_model(model);
+        preprocess_index->AddWithoutIds(dataset, config);
+
+        preprocess_index->GenGraph(build_cfg->knng, knng, dataset, config);
+    } else {
+        auto preprocess_index = std::make_shared<IVF>();
+        auto model = preprocess_index->Train(dataset, config);
+        preprocess_index->set_index_model(model);
+        preprocess_index->AddWithoutIds(dataset, config);
+
+        preprocess_index->GenGraph(build_cfg->knng, knng, dataset, config);
+    }
 
     algo::BuildParams b_params;
     b_params.candidate_pool_size = build_cfg->candidate_pool_size;