diff --git a/.gitignore b/.gitignore
index 3eb961bb58..e0cd6a4d50 100644
--- a/.gitignore
+++ b/.gitignore
@@ -9,5 +9,6 @@ cmake_build
 *.o
 *.lo
 *.tar.gz
+*.log
 
 cpp/third_party/thrift-0.12.0/
diff --git a/cpp/src/wrapper/IndexBuilder.cpp b/cpp/src/wrapper/IndexBuilder.cpp
index 1e28df1914..5d0180a3a6 100644
--- a/cpp/src/wrapper/IndexBuilder.cpp
+++ b/cpp/src/wrapper/IndexBuilder.cpp
@@ -21,9 +21,11 @@ IndexBuilder::IndexBuilder(const Operand_ptr &opd) {
     opd_ = opd;
 }
 
-Index_ptr IndexBuilder::build_all(const long &nb, const vector<float> &xb,
-                                  const vector<long> &ids,
-                                  const long &nt, const vector<float> &xt) {
+Index_ptr IndexBuilder::build_all(const long &nb,
+                                  const float* xb,
+                                  const long* ids,
+                                  const long &nt,
+                                  const float* xt) {
     std::shared_ptr<faiss::Index> index = nullptr;
     index.reset(faiss::index_factory(opd_->d, opd_->index_type.c_str()));
 
@@ -31,14 +33,20 @@ Index_ptr IndexBuilder::build_all(const long &nb, const vector<float> &xb,
         // currently only cpu resources are used.
         std::lock_guard<std::mutex> lk(cpu_resource);
         if (!index->is_trained) {
-            nt == 0 || xt.empty() ? index->train(nb, xb.data())
-                                  : index->train(nt, xt.data());
+            nt == 0 || xt == nullptr ? index->train(nb, xb)
+                                  : index->train(nt, xt);
         }
-        index->add(nb, xb.data());
-        index->add_with_ids(nb, xb.data(), ids.data()); // todo(linxj): support add_with_idmap
+        index->add_with_ids(nb, xb, ids); // todo(linxj): support add_with_idmap
     }
 
     return std::make_shared<Index>(index);
+
+}
+
+Index_ptr IndexBuilder::build_all(const long &nb, const vector<float> &xb,
+                                  const vector<long> &ids,
+                                  const long &nt, const vector<float> &xt) {
+    return build_all(nb, xb.data(), ids.data(), nt, xt.data());
 }
 
 // Be Factory pattern later
diff --git a/cpp/src/wrapper/IndexBuilder.h b/cpp/src/wrapper/IndexBuilder.h
index 97479b91e5..ed5f8a3956 100644
--- a/cpp/src/wrapper/IndexBuilder.h
+++ b/cpp/src/wrapper/IndexBuilder.h
@@ -19,6 +19,12 @@ class IndexBuilder {
 public:
     explicit IndexBuilder(const Operand_ptr &opd);
 
+    Index_ptr build_all(const long &nb,
+                        const float* xb,
+                        const long* ids,
+                        const long &nt = 0,
+                        const float* xt = nullptr);
+
     Index_ptr build_all(const long &nb,
                         const std::vector<float> &xb,
                         const std::vector<long> &ids,
@@ -47,5 +53,3 @@ extern IndexBuilderPtr GetIndexBuilder(const Operand_ptr &opd);
 }
 }
 }
-
-